tag:blogger.com,1999:blog-2450638257114166522024-03-13T01:30:27.556-04:00Skippy and BuzzSkippy and Buzz are two characters that represent the typical 'Yin and Yang' combo that I have observed in manufacturing environments. Perhaps you have as well. Though 'Jacks of all Trades and Masters of None', Skippy and Buzz will at all times feel compelled to share their opinions on topics and be glad to remind you that the value of their opinions is always free - and worth twice the price.eagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comBlogger42125tag:blogger.com,1999:blog-245063825711416652.post-15478713702316444572011-04-27T18:08:00.014-04:002011-08-15T22:17:44.773-04:00Convincing Employees to Eliminate Tooling DamageSkippy – morning Buzz – questions continue to come in.
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<br />Here is an interesting one about a thorny problem potentially vexing all business owners who invest heavily in specialized tooling and have to deal with employees who have less concern about it –
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<br /><span style="font-style:italic;"><span style="font-weight:bold;">“We enjoyed your article regarding ACME threads on plastic tooling, noting that they were often incorporated into tooling ‘designed for the ages’. We are investing in plastic tooling regularly, but we are having constant difficulty with operator damage to tooling – nicks and scratches from drops and prying. Any thoughts about how to get our operators to have a greater appreciation for the money we have invested in these tools?”</span></span>
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<br />Buzz – Easy answer? <span style="font-style:italic;">“Wax on, Wax off”</span>
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<br />Skippy – yes Buzz, I think you’re right. Time to dust off a very old paradigm and share a “process” that drove appreciation for the real value of tooling into the hearts of all who were exposed to it.
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<br />Buzz – Back in the early eighties, the movie <span style="font-weight:bold;">“The Karate Kid”</span> came out and introduced us to Daniel <span style="font-style:italic;">(played by Ralph Macchio)</span>, a young student from the east coast displaced to California. He felt he needed to master Karate skills and eventually meets his accidental mentor, Mr. Miyagi <span style="font-style:italic;">(played by Noriyuki “Pat” Morita)</span>; master of same.
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<br />The first of Mr. Miyagi’s low in quantity, but high in quality training started with Daniel waxing a number of Mr. Miyagi's cars with the simple starting instruction of “Wax on, Wax off”. To see the eventual outcome, rent this old classic – it is well worth it.
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<br />Skippy – Yes, and from that borrowed premise and teaching style we developed and applied the following program for some time to teach an appreciation for the "value" of tooling to new operators.
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<br />When a new operator joined our ranks, he was given a tour of the factory on day one with all of his other start up training elements. Along the tour of the factory, he would be given a small disc of steel – generally a slice one inch or so in thickness, cut from a 3” rod of steel in the shop.
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<br />Buzz – Along with the small piece of steel, they were given these simple instructions –
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<br />“This is <span style="font-style:italic;"><span style="font-weight:bold;">your</span></span> tool; keep it and work with it. When you have polished the surface to where we can see our face in the reflection well enough to shave with, you will be promoted and paid more money.”
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<br />Skippy – We continued, “There are only <span style="font-weight:bold;">two rules </span>–
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<br /><span style="font-style:italic;">1) you must do all the work by hand – NO POWER TOOLS are allowed, and
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<br />2) you need to inquire about what is to be done from all the more senior operators in our ranks. </span>
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<br /><span style="font-weight:bold;">"Good luck, let us know when you feel your steel tooling is ready for evaluation”</span>
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<br />Buzz – Exactly. Typically several days or a week or two would go by as the operator was getting his feet wet joining the operation, but soon, the lure of promised promotion and more money would begin to intrude on his or her thoughts and eventually they would reach out to the other operators for guidance.
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<br />Skippy – The simple instruction would be to start with 60 grit sand paper on a flat granite block in the shop – holding the small disc flat on the sand paper – PUSH it away from you a couple inches, then TURN it 90 degrees and PULL it back, then TURN it 90 degrees and repeat; over and over.
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<br />Buzz – After a month or two of intermittent activity – a few minutes here and a few minutes there, it would eventually occur to the trainee that nothing much new was happening. Of course, they would have been exposed to a great many more additional training opportunities along the way on the shop floor regarding our operations, but eventually they would need some help on the next step of their steel tooling journey.
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<br />Skippy – Another operator would clue them into the fact that there were smaller grits of sand paper available – 100, 200 and so on and so, the operator in due course would step through each of these.
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<br />Buzz – Until once again they would hit that plateau . . .
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<br />Skippy – “Simple enough” would be the help from the other operators “– now you switch over to “wet/dry” sand paper; the addition of liquid to the sanding carries away the materials removed allowing you to get a finer and finer surface.”
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<br />On and on they would climb – 200 grit, 400 grit, 600, 800, 1200, 1600 and so on; a few minutes a day here, a few there. Maybe a day or two would go by without any investment. Time passed.
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<br />Buzz – Often, months have passed, perhaps nearing a year or more and they can see first a blob, and then a blob with a nose in the reflection, but the mirror surface being asked for remains elusive.
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<br />Skippy – The operator’s help mates offer up more special advice - crocus cloth, jeweler’s paper and rouge, rubbing compound, metal polishes etc and as the results get better and better, the operator is thinking, we are so close . . .
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<br />Buzz – Remember the surprise on the operators face when he was told that for the final step, go down to the drug store and get that special low friction toothpaste and some paper towels to lay on the granite block and work with that?
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<br />. . . and the further surprise when a few days later –
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<br /><span style="font-style:italic;"><span style="font-weight:bold;">BINGO!</span> a mirror worthy of a close shave magically comes into focus.</span>
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<br />Skippy – Yes, and now after all that time, and with the prize so close they would come with their piece of steel tooling in hand and announce “all finished”.
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<br />To which they would hear the soft question <span style="font-style:italic;">“<span style="font-weight:bold;">Both sides?</span>”</span>
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<br />Buzz – Quick on the uptake and few seconds of thought later would come the
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<br />“ . . . er um, not <span style="font-style:italic;">yet</span>” reply and a furious amount of work would be then completed in just a few weeks while the second side was brought up to that magical mirrored luster.
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<br />Skippy – And finally the day for the “check in” – the operator presents the steel tooling with two perfect, mirrored faces for a final inspection.
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<br />Carefully we would accept the tooling and
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<br />to the operators <span style="font-weight:bold;">horror</span> as he watched, we would take a rather nasty looking metal implement out and <span style="font-style:italic;">gouge a deep scratch on one exquisite mirrored face</span> and announce, “Oh no, we can’t complete the measurement check with the tool in this condition – could you please polish out this scratch and get it back to us as soon as you can?”
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<br />Buzz – Wow – that always was a tough moment for those operators. This was where the wheat got separated from the chaff for sure. For three days they would walk around with a look between broken and ‘I’m going a put a hurtin’ on that SOB’, hoping for someone to commiserate with them for the dirty rotten thing that the maniac in the office did to their tool.
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<br />To their utter dismay, from all they encountered the same non-verbal reply. They would each simply shrug as if to say, well, it is what is . . .
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<br />Skippy – Yes, and fortunately, we lived through it and most of the operators stayed on.
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<br />It would take a couple days of course, but eventually, they would start the process of carefully sanding down their own hard won, brightly mirrored face to absolute dullness again as they worked with the scarred surface to remove the scratch; grumbling explicative’s quietly under their breath, but with HUGE resolve.
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<br />Buzz – As I recall, they would work tirelessly – any available minute to turn this around and generally within a week, they would be once again ready for the check in process. As before, we would innocuously ask them to surrender the tool to us for evaluation. Without fail, something similar to “Hold on just a minute now, we need to TALK before I am going to let you handle this piece of tooling again . . .” would come boiling out.
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<br />Skippy – “What do you mean” we would ask innocently? And the operator would in so many words remind us of the “horrible, wasteful and unforgivable damage” we did to his steel tooling the last time we were permitted to handle it and we would have to come to an ‘understanding’ prior to us getting our hands on it.
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<br />“You have to promise” they would say (or was it SWEAR?), “that you will handle this tooling with ultimate care and respect, as though it were your own AND you must further promise to return it to me in the SAME OR BETTER condition to me when you are through with it.”
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<br />Buzz – Breakthrough moment!
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<br />“Yes of course” we would agree, and as good as our word, observe and measure the piece of tooling, being sure to congratulate the candidate for not removing too much metal in the process. We would give him the promotion and the money.
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<br />We would do all that of course with the same solemn admonition repeated back “and we will continue to expect that you treat each and every piece of our tooling with the same care, love and respect”.
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<br />Skippy – And they always <span style="font-weight:bold;"><span style="font-style:italic;">did </span></span>
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<br />– the moral of the story?
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<br /><span style="font-style:italic;"><span style="font-weight:bold;">Hard work and a disciplined approach towards measurable important results create lasting value for those who pay the freight.</span></span>
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<br />Just our two cents
<br />Skippy and Buzzeagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.com0tag:blogger.com,1999:blog-245063825711416652.post-43224076429855865542011-04-18T07:05:00.002-04:002011-04-18T07:19:35.749-04:00Producing new plastic productsSkippy: Morning Buzz, another tax day comes and goes -<br /><br />Buzz: Yes, and questions continue to come by - seems like the economy continues to cause the "tinkerers" to continue working on the next newest items - for instance this week commented into another development project question -<br /><br /><span style="font-weight:bold;"><span style="font-style:italic;">"How does one go about having a new product made from plastic?" </span></span><br /><br />Skippy: - we've commented on this before, but here is an updated version with some additional thoughts regarding the needed items prior to sales and marketing -<br /><br />Buzz: Of course, first things first, <br /><br />I) protect any new intellectual property ideas with at least a low cost provisional patent which should be filed BEFORE selling anything. You aren’t out much if a subsequent patent search turns up issues with other IP rights at that point. <br /><br />Skippy: right, and<br /><br />II) Be sure to get confidentiality agreements in place with all (intended) vendors and any of their interested stakeholders. If you do have something new and exciting, you need to keep it for yourself. <br /><br />That said, any serious manufacturing professional will tell you that there are a few general thoughts to consider (assuming you have the DESIGN issues take care of) in a new product launch: <br /><br />a) Samples (in plastic) can be made from stereo lithography (photo or printer style)etc - generally, for around $1500 or so you can have sample parts (or parts of samples for assembly) made to dimension (which are either the actual parts or can be used for further mold generation etc) for critical assembly fits, including undercuts, blind holes etc.. <br /><br />Most parts don't have really need to have more than 3-4 CRITICAL dimensions for assembly. Try to keep these in mind in terms of what you NEED (see b) below) and work with a vendor interested in reducing your costs in terms of manufacturing. A major item to think about during the contract review process would be what OTHER mating parts and their critical dimensions does your system need to match up with? It may be that one of the parts is not yet fully developed in how it relates to them . . . <br /><br />b) understand what you NEED in terms of product dimensions, packaging, pricing and production capability in terms of WHERE it is produced and WHAT you can give and take on to reduce costs <br /><br />Buzz: ok, we've covered some of the pre-thoughts - what about the actual sampling process?<br /><br />Skippy: well<br /><br />c) insist that any near-final sample parts be produced from the actual production tooling at PRODUCTION rates from PRODUCTION material (particularly any that require testing) - nothing creates more availability to market headaches than to submit your sample assemblies for further certifications or other consideration only to find out that the sample parts were made from a general purpose or utility grade of material that does not include your special needs and<br /><br />d) work with a house that has their own in-house tooling capability or is willing to involve you with any outside houses during the design and tooling phases – you may need to know who and what is going on in the thinking process on your products <br /><br />Buzz: it also seems important to visit new vendors as well during the qualification process; sales brochures and websites are of value, but while there, notice how any intended manufacturing/assembly vendors keep unused tooling on the shelf - cleaned and measured, shiny and production ready or rusty, and unkempt against the day someone might reorder? Do they have scalable capability to handle upsurges in your business rather than building inventories of slow moving items against seasonality – expensive to tie up money in inventory. A number of houses will quote inexpensive tooling, but be wary of the how these tools work over time past the sample stage. <br /><br />Skippy: right, and<br /><br />e) be at least a little paranoid; Trust, but Verify. For every one of the good outfits out there, there are some who won't measure up beyond the sample parts. Look for a house that has some sort of quality policy (with or without the ISO moniker), with sample retains on less than perfect quality parts used year to year to maintain quality outputs, and written records of past production runs including retained information back to incoming raw materials and supplier raw materials certifications if possible etc. <br /><br />Buzz: remember as well that "If it hasn't been written, it hasn't been said" and<br /><br />f) get it in writing; material specs, quality and production records - ask to attend and help fill out a 'Contract Review' - answering the couple dozen critical questions that a good manufacturer/assembler needs answers to to 'help them help you' is a critical set of meetings. Some sales people can actually act in this 'Product Management' role; and unfortunately many can't. <br /><br />g) ask for and be prepared to get enough samples to have engineering testing done on the resulting samples - and do it <br /><br />A well run new product development process has additional nuances of course, but these should give you a good grounding. <br /><br />Just our two cents<br />Skippy and Buzzeagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.com1tag:blogger.com,1999:blog-245063825711416652.post-27799073790379597892011-03-30T21:16:00.014-04:002011-04-02T21:53:49.224-04:00Service Counters in AmericaSkippy - hey Buzz - nearing Tax time, what's news?<br /><br />Buzz - hey Skippy - well, with prices up on everything (due more to the ongoing doubling of the money supply more than anything else) a quick plastics related "only in America story" as a bit of comic relief -<br /><br />Seems that I have <span style="font-weight:bold;">a project involving coloring some special white tinted plastic additive to add to virgin resin</span> - I'd like the the final color of the additive to be the same color as the final plastic parts. I head down to the store and ask the two guys behind the counter "who's the painting expert? I have a special project I would like to ask you about."<br /><br />One of the two steps forward to volunteer. I share that I have an experiment that requires adding some pigment to a 'white' liquid additive for plastics and need a color matching process - just like the kind you put into the paint you sell - I was wondering if you would color match this piece of plastic, then <span style="font-style:italic;">squeeze out the special color stuff you would normally add to a gallon of white paint -</span> <br /><span style="font-style:italic;"><br /><span style="font-weight:bold;">and just sell me the special color stuff . . .</span></span><br /> <br />Skippy - Seems easy enough.<br /><br />Buzz - yes, <span style="font-style:italic;">seems.</span> The paint expert tells me to “Hold on now, the special color stuff is VERY expensive - its, well . . . <br />its SO expensive . . .”, and as he is trailing off, it seems apparent that he doesn't even KNOW how much a single cartridge of any particular color is.<br /> <br />“Hang on.” he says and heads to the back. I guess the gal he was talking to was his mom who probably cuts all the checks. He tells her the tale in shorthand - "This guy wants to buy some color for paint; without buying the paint . . . what should I tell him?"<br /> <br />After just a few seconds thought she stage whispers back <br />"Gee, that special color stuff is VERY expensive. <br />Its, well, so its SO expensive I don't even KNOW how much <br />a single cartridge might be . . . <br />Hmm, what to charge him - $25.00? $50.00?"<br /> <br />By this time, the silence in the place is deafening; everyone in the place is listening . . . you know, like the old commercial where someone says "Well, EF H*TTON is my broker and he says . . ."<br /> <br />Skippy - This doesn't seem to be moving along very well.<br /><br />Buzz - Exactly, so I decide to sweeten the offer – “How about,” I say, “if I BUY a gallon of white paint, and you MATCH the piece of plastic I have, but give me the special color stuff "<span style="font-style:italic;">on the side</span>" like so much salad dressing and I'll mix it myself . . .”<br /><br />BINGO! NOW we're cookin’ with gas. Our paint expert jumps right into action and does the color match on the plastic piece lickety split and <br /><br />'Mom' jumps back in with two suggestions -<br /> <br />a) he (me) will have to buy a small container for the special color stuff (“Gee whiz, if I have to I say, ok.”) and<br /> <br />b) "Don't sell him a gallon of the tint base if he isn't really going to mix it - sell him a gallon of the flat ceiling white - he might actually use that." (Again I say "Ok” - after all it's much (get this) ... <span style="font-weight:bold;">CHEAPER</span> than the tint base . . .)<br /> <br />Skippy - So how does the check out go?<br /><br />Buzz - Well, it comes time to tally the damages. "How much is the gallon of paint going to cost me?", I inquire. "$21.00" is the reply. "Ok, so how much" I press, "is the small container for the special color stuff?"<br /> <br />"Well, that will be another $.99", comes the reply. <br /><br />"Now, (finally) how much is the special color stuff going to cost me?",<br /> <br />"Well, that's <span style="font-weight:bold;"><span style="font-style:italic;">FREE</span></span> because it's part of the cost of the paint . . ."<br /><br />…<br /><br />Skippy - (speechless, sharp intake of breath)<br /><br />Buzz - Wait for it, it gets <span style="font-style:italic;">better</span>. <br /><br />I think about the process for a moment or two and then ask - <br /><br />"<span style="font-weight:bold;">If I have any paint left over from the project, can I bring it back?</span>"<br /><br />…<br /> <br />Ok now all you RHPS fans - you know you're thinking ANTICI –<br /><br />…<br />…<br />…<br /> <br /><span style="font-weight:bold;">PATION</span> . . .<br /><br /> <br />“<span style="font-weight:bold;">Sure, </span><span style="font-style:italic;"> just bring back any unopened cans for a refund . . .</span>” he says.<br /><br /> <br /><span style="font-weight:bold;"><br />True story - only in America</span><br /><br />Just our two cents<br />Skippy and Buzzeagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.com0tag:blogger.com,1999:blog-245063825711416652.post-60147297902074892152011-02-13T10:12:00.001-05:002011-02-13T10:20:46.089-05:00Need advice on managing regrindBuzz - Morning Skip - it's been a while since we posted here - lots of things going on in various forums and hopefully as this spring unfolds we can get back onto a regular contribution schedule, but for now, another important question cropped up on use of regrind -<br /><br /><span style="font-style:italic;">"We realize every heat cycle deteriorates the integrity of plastic resin. We have a few parts that can be made from 100% regrind. These parts require very little strength or cosmetic requirements. How do you manage regind of regrind? What do you do with the runner and sprue composed of 100% regrind? Regrind a second time, sell? It seems it can become a material management nightmare quickly. THANKS"</span><br /><br />Skippy - Morning Buzz - well let's go through a couple thoughts- <br /><br />a) some materials "live on" despite being regrind better than others <br /><br />Buzz - right, and some materials can have a small amount of "sweeteners" to add as processing aids in subsequent passes through a machine. Size reduction equipment is likely to yield better "flow" and better process stability <br /><br />Skippy - exactly so - next<br /><br />b) work to establish a "use ratio" of "regrind aka sprues and runners and less than acceptable parts and start up scrap" that is slightly larger in intent than generation aka use a goal of 21% "regrind" when you generate a total of 20%. <br /><br />Buzz - the obvious advantage in controlling a steady "process" is that this keeps things very close and as you get better, you may find that you need to reduce the percentage of what you classify as regrind as you get better - <br /><br />Skippy - spot on, so to continue, <br /><br />c) Generally "100% regrind" is still suspect for process "ability variability" unless it is (continually) well blended - keep an eye on aspect ratio (size of and percentage of each size) in the mixes and gravity induced separation - <br /><br /><br />Buzz - thinking this one through -- ask if the runner and sprue are say 20% of the shot weight, then use these as the "regrind" portion of an 80/20 mix with 80% being the "first pass" material and the 20% being the "second pass regrind". <br /><br />Skippy - Right; just like mapping a "virgin and regrind" process, only a tiny percentage of the material on a descending basis remains and keeps moving forward as the "regrind of the regrind" becomes a portion as "regrind". <br /><br />just our two cents - <br />Skippy and Buzz<br /><br />for more on this discussion see it here:<br /><br />http://www.linkedin.com/groupItem?view=&srchtype=discussedNews&gid=155135&item=42931513&type=member&trk=EML_anet_ac_pst_ttleeagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.com1tag:blogger.com,1999:blog-245063825711416652.post-71519509179777499222010-11-07T12:10:00.001-05:002010-11-07T12:12:33.504-05:00Rule of Accuracy - source unknownSkippy: hey Buzz - sharing a little nugget -<br /><br />"When working toward the solution of a problem, it always helps if you know the answer."<br /><br /><br />Buzz: "Corollary - Provided, of course, that you know there is a problem."eagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.com1tag:blogger.com,1999:blog-245063825711416652.post-10070140887740650972010-06-22T11:53:00.005-04:002010-11-07T12:09:47.848-05:00"Key Plastic Extrusion Indicators"Skippy – hey Buzz – the hot summer months are finally here. We were involved in a question having to do with “extrusion performance indicators”:<br /><br /><span style="font-weight:bold;"><span style="font-style:italic;">What are your Key Performance Indicators for your plastics production process?</span></span><br /><br />---------------- <br /><br />Buzz – well, here are a few thoughts from a profile extruder's point of view - <br /><br />First, consider the intended outcome in an environment bounded by these four statements: <br /><br />a) The extruder is responsible for continuously pumping plastic at a prescribed temperature and pressure <br />b) The cooling station (water, air, vacuum, etc) is responsible for continuously holding the plastic in the intended shape until cool <br />c) The take off unit is responsible for continuously pulling the extrudate down line through the "magic foot" represented by the interaction of the extruder and the cooling station <br />d) The cut off device is responsible for intermittently cutting good parts to length <br /><br />Skippy – sounds like a pretty simple explanation of “extrusion” –<br /><br />Buzz – well it is; and for a complex set of interactions, it is often best to “categorize” information in a way that reduces the over all complexity. When it comes time to troubleshoot a problem, <span style="font-style:italic;">for every production related symptom, ask yourself two questions and answer them; <br /></span><br /><span style="font-weight:bold;">1) which piece(s) of equipment is the one responsible for this condition? <br />2) What minimum change or correction must be made to achieve maximum desired improvement result? </span><br /><br />Buzz - Here’s an example – based on one of our tenets – the greatest good an operator will ever do is to be a great OBSERVER -<br /><br />The operator reports that he has been making boxes of product for some time now. In the last couple of boxes he has observed the following –<br /><br />a) the part is still in spec, although he has made some “minor” adjustments to the take off speed<br />b) the boxes of product all contain the right amount of product and weigh the same as they have been for some time for full cartons – again because the parts are all in spec<br />c) a box normally takes about 55 minutes to run off – <br />d) the last box took 65 minutes to complete without a break or any casual loss<br /><br />What is happening at the line?<br /><br />Skippy – hmm – well you didn’t mention a cut off device, so we can eliminate that –<br /><br />Buzz – right<br /><br />Skippy – the parts are continually in spec, so the “magic foot relationship” is being maintained – it is therefore unlikely that the cooling station is the culprit -<br /><br />Buzz – right<br /><br />Skippy – once again, all we sell is time; and it took 10 minutes more to make a box of product<br /><br />Buzz – yes . . .<br /><br />Skippy – well the take off is responsible for that line speed and the direct measure of what gets done in a given amount of time in terms of product, so we must have been SLOWING the take off over time –<br /><br />Buzz – yes right. So what ELSE is going on?<br /><br />Skippy – well the parts are the right size, and a full box still weighs the same, as we drop the take off speed, therefore the extrusion output must have been dropping over time as well –<br /><br />Buzz – bingo – and what could be causing that?<br /><br />Skippy – well a couple of things, but upon a closer inspection at the extruder, it appeared that the pressure was up, the melt was hotter etc, so it was concluded that the screens might be being blocked over time by debris – which was verified during a screen change. After the screen change, the line was brought back up and the proper speed on the takeoff was yielding good boxes again at 55 minutes . . .<br /><br />Buzz – perfect –<br /><br />Skippy – but that was so EASY – <br /><br />Buzz – yes you are correct. Once you categorize your information and step through it logically, things “fall into place pretty easily”. Good work.<br /><br />This has been working for us for nearly 30 years - the measure of "how well" we are doing (since in the end, all we all sell is TIME) is the number of good units at the correct/reasonable cost produced in that time; insuring both we and our customer profit and continue to exist. <br /><br />Just our two cents <br />Skippy and Buzzeagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.com0tag:blogger.com,1999:blog-245063825711416652.post-16885812844560639302010-04-17T21:27:00.006-04:002010-04-17T21:37:16.052-04:00"Bananas and Monkeys"Skippy - hey Buzz; why does it seem that so many of the questions coming in are more about the myths from the past rather than the facts?<br /><br />Buzz - well in answer - how about we share this "oldie but goodie" -<br /><br /><span style="font-weight:bold;">"Bananas and Monkeys"</span><br />________________________________________<br /><br /><span style="font-style:italic;">Original source unknown. </span><br />________________________________________<br /><br />Start with a cage containing five monkeys. <br /><br />Inside the cage, hang a banana on a string and place a set of stairs under it. <br /><br />Before long, a monkey will go to the stairs and start to climb towards the banana. <br /><br />As soon as he touches the stairs, spray all of the other monkeys with cold water. <br /><br />After a while, another monkey makes an attempt with the same result - all the other monkeys are sprayed with cold water. <br /><br />Pretty soon, when another monkey tries to climb the stairs, the other monkeys will try to prevent it. <br /><br />Now, put away the cold water. Remove one monkey from the cage and replace it with a new one. The new monkey sees the banana and wants to climb the stairs. To his surprise and horror, all of the other monkeys attack him. <br /><br />After another attempt and attack, he knows that if he tries to climb the stairs, he will be assaulted. <br /><br />Next, remove another of the original five monkeys and replace it with a new one. The newcomer goes to the stairs and is attacked. The previous newcomer takes part in the punishment with enthusiasm! <br /><br />Likewise, replace a third original monkey with a new one, then a fourth, then the fifth. Every time the newest monkey takes to the stairs, he is attacked. <br /><br />Most of the monkeys that are beating him have no idea why they were not permitted to climb the stairs or why they are participating in the beating of the newest monkey. <br /><br />After replacing all the original monkeys, none of the remaining monkeys have ever been sprayed with cold water. Nevertheless, no monkey ever again approaches the stairs to try for the banana. <br /><br />Why not? Because as far as they know "that's the way it's always been done around here." <br /><br />And that, my friends, is how company policies are made.eagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.com0tag:blogger.com,1999:blog-245063825711416652.post-1162686987378443972010-04-04T12:24:00.025-04:002011-03-29T23:01:32.646-04:00Of Acme Threads and Diamond DustSkippy – hey Buzz – it’s finally April – nearing Uncle Sam’s initial harvest date – er um Tax Day - <br /><br />Buzz – yup; lots of snow in the Northeast really hammered costs, productivity and profitability in February and March. Of course, that will all be just a dull memory by the time the tax implications for that roll around NEXT year –<br /><br />Skippy – we’ve had some questions coming in across a variety of topics, and thought that this one might be of interest to a number of the new users of the “old timers” tooling systems –<br /><br /><strong><em>“We have a variety of pipe and profile tools that have been around since the dark ages (60’s and 70’s). Our engineers keep designing around them, but although still ‘functional’, we’re having a lot of trouble getting these tools to seal (leakage) and to come apart at ends of production runs. They have something on them called “Acme threads” and we’re wondering why we are having so many disassembly issues?”</em></strong><br /><br />Buzz – ah, <strong><em>Acme Threads </em></strong>– strong ‘translation’ threads that were used to help convey large standardized tooling pieces together to assemble flow paths for polymer. These flow paths were on the way out generally from screw tips and breaker plate areas towards spiders/pins/shells for tubing or profile tooling and or adaptation between the gate and custom die lands. Not only good for tooling assembly back in the day, but known in some circles for generating a fair amount of industrial ‘diamond dust’ as well. <br /><br />Skippy – ‘translation threads’ and ‘diamond dust’?<br /><br />Buzz – yes; first, the translation of rotational energy (spinning) into horizontal movement allowed the operator to precisely align precision flatly ground faces or sealing surfaces between two pieces of tooling creating a sealed flow path between the two pieces. By CAREFULLY conveying the two pieces of tooling together until the very flat ground sealing surfaces were touching, the tooling could seal between the two surfaces without having to torque tools together with a variety of bolts.<br /><br />Skippy – sounds easy enough – what sort of problems are these folks facing?<br /><br />Buzz- well, by design the Acme threads are perpendicular to the flat sealing surfaces and by nature do require having a small amount of clearance in the threads for things to move smoothly. As with all threaded objects used in heated plastic tooling, a bit of molybdenum disulfide or copper-based 'anti-seizing' compound on the threads is always a good idea. Anyway, to continue, the flat section beyond the threads of the male portion of the tooling must extend further than the receiving flat area near the end of the threads area on the female portion so that the two don’t bottom out on thread early with the sealing surfaces not having coming into contact and creating the seal by touching each other. Also it is a good idea that the outside “corner” intersection be undercut and or knocked off at the outside edges of both the sealing face of the male and female portions. This additional clearance allows the two sealing surfaces to make contact BEFORE the corners can connect or binds up prior to the sealing faces touching (which never should).<br /><br />Skippy – sort of like in the picture where "A" bottoms out against "B" before we run out of threads to look more like "C"? (Click on the picture for a larger view)<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUXj_Smwaym0peyOGTqxllmBjqkLcUH245vLZCjk1xFObRUJy9wXpzRMm_BLFsrg7MsVeYvpZPz9OCxFP0yh7cQarad3MSvd2MNJLdlb7op5-Sd9DRI0zjAOdsUzB6-8wR9xMI2k5cLRr8/s1600/Threads+2.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 200px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUXj_Smwaym0peyOGTqxllmBjqkLcUH245vLZCjk1xFObRUJy9wXpzRMm_BLFsrg7MsVeYvpZPz9OCxFP0yh7cQarad3MSvd2MNJLdlb7op5-Sd9DRI0zjAOdsUzB6-8wR9xMI2k5cLRr8/s320/Threads+2.jpg" border="0" alt=""id="BLOGGER_PHOTO_ID_5456824501197266146" /></a><br /><br />Buzz – yes and note further that when the sealing surfaces need to be “freshened’ by grinding flat again, they have to remain perpendicular to the Acme threads and the same rules to “corner interference” have to be observed.<br /><br />Skippy – sounds like a robust system of assembly – so what about the “diamond dust”?<br /><br />Buzz – well, Acme threads aren’t the easiest threads in the world to generate on tooling, and require a fair amount of design planning and tooling execution. These kinds of assembly threads are “designed for the ages” and as such, once successfully implemented are committed to tooling that is going to be around for a long time. Often this tooling is made from materials that will ultimately be hardened and treated to become long lasting tooling. Occasionally the tooling will be hardened almost into “spring steel” to be resilient against plastic and operator maintenance as well as ‘abrasive wear’ -<br /><br />To continue; try as they might, most extrusion companies utilizing Acme threads aren’t able to avoid some small amount of leakages or incomplete clean ups in tooling over the life of these tools – and plastic (particularly something that will burn and degrade like PVC) eventually finds its way into areas of the tooling in or around the flat sealing surfaces and threads. Sometimes, edges are “shoe-shined” during clean up, sometimes a small leak occurs, and a small amount of PVC will turn to carbon and coat a small area inside the threads or clearances area. <strong>It is this small amount of carbon flake that may eventually cause a BIG problem.</strong><br /><br />Skippy – how can a small flake of carbon cause any trouble?<br /><br />Buzz – well, remember that the goal of the “sealing surfaces” is to be conveyed towards each other slowly until they are in intimate contact – <em>there is no room left in this impossibly small space left between two surfaces that are “flat” </em>and so, plastic even under pressure takes the easier path out – though the intended flow openings in the tooling – not between the two flat sealing surfaces. However occasionally, a couple of circumstances (read moons coming into alignment) can conspire to create a very unique set of circumstances – and interesting by products -<br /><br />Say that an operator is extremely busy and hurries the process of assembly – rather than slowly turn the tools sealing surfaces toward each other, they insert a bolt into the portion they will be rotating into place and “spins it up” like starting an old fashioned crank on a Model “T”. Beyond the scope of this discussion, threads are ramps enabling accumulation of leverage – and so as the operator spins the tooling, they are progressively adding energy while increasing the speed of the rotating mass; the heavy metal parts spin faster and faster, gaining inertia . . .<br /><br />form a picture in your mind now, that at the same time, a small flake of carbon, previously hanging innocuously in a corner of the tooling, falls down between the quickly approaching <em>impossibly flat </em>sealing surfaces – and suddenly the moment of ‘impact' occurs.<br /><br />Skippy – what happens in those milliseconds?<br /><br />Buzz – well – huge torque is going to be applied from the accumulated inertial mass in the rotating piece. This is applied to the impossibly flat surfaces with a small piece of carbon trapped in between. As the crushing pressure of the accumulated spinning mass begins to focus in the single point of contact represented by the carbon, the carbon begins to be squeezed and smeared. The torque continues to carry the moving tool forward towards having the sealing faces touch, and yet, we still have inertia tearing forward with energy having yet to be expended and absorbed. The carbon, which by now has been transformed into a low quality industrial diamond, is now caught between the face and is continuing to be pushed and ground inexorably onward by forces in the rotating “spring steel” still hurtling forward. The diamond dust is harder than the steel, and as such is encouraged by the onslaught to plough into the steel faces, displacing steel material to the sides and perhaps behind it as it is gouged further and further into the seal face(s). Eventually the spring rebounds, but with not enough force to unlock, having spent some energy during the diamond formation phase, and rebounds back, and then forward again, back and forth like a SlinkyTM until finally coming to rest. Again, all this happens in only a fraction of a second . . .<br /><br />Skippy – and so here we are with the two faces perhaps near enough but not really touching each other as intended with a small bit of diamond dust, ground like a fallen meteor skipping across a Kansas corn field embedded in one or both of the faces?<br /><br />Buzz – you’ve got it. Sadly, the damage billing isn’t ready for final tally yet – eventually, we have to take the tooling apart, and it is going to take Herculean effort – not to mention a huge “cheater bar”, perhaps our burliest operator and a heat source to get the steel spring twisted enough toward “off” to encourage the spring to back away by crushing AGAIN over the diamond dust as it is unwound – it is not uncommon during the disassembly to find plastic leakage, and perhaps even MORE carbon trapped in the tooling against the next assembly.<br /><br />Skippy – the tooling will have to be cleaned up again, and the sealing surfaces are likely to require grinding and lapping to be brought back to “flat and perpendicular” again as well –<br /><br />Buzz – yes – most houses go through much of this process, without really even realizing it has been going on – you can bet that when you walk into an extruder and look at the sealing surfaces on Acme threaded assemblies and see ‘eyebrows’ gouged into the faces – diamond dust was being made along with plastic parts – and not of much positive value at all . . .<br /><br />Just our two cents –<br />Skippy and Buzzeagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.com0tag:blogger.com,1999:blog-245063825711416652.post-42367421758460845412010-02-13T19:20:00.005-05:002010-02-13T19:25:34.939-05:00SNOW[shhhshkkt]<br /><br />[flump]<br /><br />[shhhshkkt]<br /><br />[flump]<br /><br />[shhhshkkt]<br /><br />[flump]<br /><br />Skippy: - sorry for the delay on our next posting - we've had about 45 inches of snow over the last 14 days after a couple of trips out to important industry shows in Atlantic City and Atlanta -<br /><br />Buzz: - right; but the good news is that we're getting good "mileage" on the snow blower -<br /><br />Hope to be back soon with our next article - hopefully this weekend -<br />Skippy and Buzzzeagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-46594667360546218252010-01-24T20:30:00.006-05:002010-01-24T20:41:27.137-05:00Drop Test on PVC ProfilesSkippy - hey Buzz - here is another typical extrusion scenerio -<br /><br /><span style="font-style:italic;">“Using <span style="font-weight:bold;">ASTM D4495</span> to test rigid PVC profiles from extrusion. The problem I’m having is that very few of the profiles are failing . . .<br /><br />The standard calls for room temperature conditioning, and when a 10 lb weight strikes the profiles, even from a height of 30 inches, no damage is done as far as failure, denting yes, no cracking . . . <br /><br />I’ve even increased the weight to 14lbs and nothing. Any ideas”</span><br /><br />Buzz - As the standard points out<br /><br /> (<span style="font-weight:bold;">http://www.astm.org/Standards/D4495.htm</span>),<br /><br /> results obtained by use of this test method can be used in two ways: <br /><br />a) As the basis for establishing impact-test requirements in product standards, and or<br /><br />b) To measure the effect of changes in materials or processing. <br /><br />Skippy - isn't drop dart impact testing by profile extrusion houses done in foot pounds per mil (so two different wall thickness samples from the same materials would be subjected to different pass/fail drop heights/weights but the same overall criteria?)<br /><br />Buzz - yes and is used to determine the limits of acceptable ductile or brittle failure modes - mention made above is that "only a few are failing". Actually at the maximum for acceptable failure mode - none should fail - perhaps the testing is at too high a standard to be appropriate (just beyond what would be "acceptable") or the testing isn't destructive enough if you are hoping for failure more often or every time?<br /><br />Skippy - Additional questions requiring study come to mind given the presented information <br /><br />- Are you testing for ductile or brittle failure<br />- is your calculation for inches of height per pound correct<br />- how long is the product resting between production time and testing <br />- would the application benefit or call for an annealing process involved to relax stress<br />- how thick is the product in mils<br />- what tup shape are you using<br />- etc<br /><br />Buzz - Perhaps just as important, after the drop dart testing, are you giving it a more "<span style="font-weight:bold;">real life</span>" type '<span style="font-weight:bold;">whammo</span>' testing - the kind of test when a worker punches through it with a nail, or drops it from the truck, or off a roof, in hot and more importantly cold weather; etc?<br /><br />Also, we are assuming that dimensions and aesthetics are acceptable and accounted for in the testing at current (measured and reproducable) run conditions - aka you should be doing this testing to failure on parts that are in all other ways acceptable - if not, when or as you make additional changes, your test results may be suspect or worse, value-less.<br /><br />Just our two cents -<br />Skippy and Buzzeagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-32516790145364398702010-01-17T21:47:00.003-05:002010-01-17T22:00:07.194-05:00Extrusion of PETG - more thoughtsSkippy - hey Buzz - we never did actually give a "heat profile" to start up the PETG in the last discussion -<br /><br />Buzz - yes, correct. Why? Well, mostly to see if these comments were helpful in the event that they did in fact have a start profile capable of <br /><br />a) getting melt to the tooling and<br />b) keeping a steady state melt coming<br /><br />No mention of the current melt temperature or current heat profiles or equipment, rates, tooling etc was given, (we are also assuming that adequate drying was in fact occuring) and PETG doesn't have too much in the way of "hot guts" anyway -<br /><br />Skippy: so we pulled up a little short in the actual "heat profile" part of the answer on purpose since they didn't mention the equipment, screw/barrel etc being used. Suffice it to say that achieving the recommended melt temperature on heated (and controlled heating) screws and tooling is necessary; more information is required to make a more specific recommendation. <br /><br />Buzz: Yes, much will depend on the screw length/diameter and screw design and intended rates and draw-down. The first couple of zones can be used to keep the melt cooler (but this again depends on screw design) and it is generally wise to keep barrel cooling OFF during start up to avoid freezing material along the screw and creating melt blockages.<br /><br />Skippy: Typically, processors successful at extruding tubing and profiles from PETG use an "efficient" screw design to keep the melt and unmelt seperate until near the end of the transition area - particularly with thin re-granulated clean dry scrap. And generally (as indicated by Eastman) high compression screws like those designed for HDPE will generally not be suitable for PETG copolyester since excessive melt temperature and poor melt strength usually result - <br /><br />Just our two cents<br />Skippy and Buzzeagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-86806644287348124282010-01-06T23:40:00.008-05:002010-01-10T19:42:26.187-05:00PETG tubing questionSkippy: Hey Buzz; Happy 2010!<br /><br />Buzz: Howdy Skip - same to you. Glad to get 2009 behind us and start moving forward again -<br /><br />Skippy: - right. To kick off the year - how about a quick processing question - the material? PETG or glycol modified PET for us extruders -<br /><br />The question goes:<br /> <span style="font-style:italic;"><span style="font-weight:bold;">"Can anyone recommend a heat profile for extruding a PETG Tube 3" in Dia with a wall of 1 mm? Experiencing too much sag between the Die and the water tank in a vac sizer."</span><span style="font-style:italic;"></span></span><br /><br />Buzz: the real answer of course is a heat profile that yields the correct clarity, and the least adhesive version of the material with the most hot guts you can get. This would of course also have to take into account the type of screw, compression, screens, tooling die pressure drop and other items. Not to mention that a heat profile while extruding at rate may or may not be the same as during string up, etc etc etc -<br /><br />Skippy - well, yes, hopefully a dialog will ensue that will prompt a few more details. Do we have any thoughts that we can share assuming that the heat profile that is being used now is correct (and it just seems too hard to handle?)<br /><br />Buzz: - you bet - although we can not be sure by the question as asked is whether we are asking in this way due to a surface issue, control of ovality or inability to string up. Will assume the worst - <br /><br />There are a couple of more important questions for glycol modified PET -<br /><br />1) What is the DRAW DOWN of the material - draw down orientation can be very useful; we used to produce our tooling approximately 50-80% greater than the size of the drawn down part for 'some' dependable orientation between the pin/shell and the calibration kiss. <br /><br />2) Do you have an open air passage to the inside of the tube through the pins (perhaps through one or more spider legs) to allow air pressure inside the tube as you string it up?<br /><br />3) is your tank in a position to give you the best shot at string up and running? Normally, you have the tank on center line in both plan and elevation to balance out "kiss", but this material is ADHESIVE versus just COHESIVE at correct melt temperature, so the KISS has to be at the last possible instant - you can’t just rub it all over and around the entrance of the sizing; it will want to set up too quickly, so you need a fair amount of draw down. <br /><br />4) What is the nature of your calibration design - wafers, solid sleeve, rifled sleeve etc. as well as the surface texture - smooth, glass beaded, chromed etc. <br /><br />Skippy: What about this "sag" business?<br /><br />Buzz: At the same time as you are drawing down, the tube is wanting to "sag" due to gravity; recognizing, planning and depending on the "sag" that you mention for good clarity can be advantageous - so for this reason, the vacuum sizing tank as a whole is inline from a plan and elevation view as well as level for start up but after the string up, you will run it LOWER (still level; drop BOTH ends) than the die and backed away to point that still allows a kiss, but minimal contact prior to going down the "barrel" of the tubing calibration unit - and the tube does some controlled "sagging" as it falls from the die face down to a lower level calibration entrance level, then is pulled in evenly into the calibration unit.<br /><br />Skippy - Cool; any more pointers?<br /><br />Buzz: Assuming you are using a vacuum tank, I prefer a vacuum chamber that is 2' or less to get the line up into a tube quickly. Mount a fogging sprayer in the lid of the tank that can be used to spray the material with a mist of water (which will harden it pretty quickly at low speeds). You use this during the vacuum chamber sealing and water fill, then turn it off once a regular vacuum is achieved. <br /><br />Skippy: What about gasketing?<br /><br />Buzz: Be sure to have an adequate seal at the down stream exit of the vacuum chamber - one sealing material preferred is a silicone rubber (smooth orange) that is pretty friendly to sticky PETG. Use a few test swatches - you are looking for a supple material that will stretch to seal off as pulled downstream but doesn't stick and release. In general, the gasket material might ben1/8" thick and cut about 1/4-3/8" smaller on center than the OD of the final tube depending on suppleness. It is extremely important to cut the inside circle of the gasket on center with the supports and the tube itself. The seal material should be supported on BOTH sides of the seal with semi rigid to hard supports. The UPSTREAM support ring should be the OD of the tube plus a smidgeon (maybe 1/8" but not more than one thickness of the seal material larger than the final tube OD). Not larger than one times the thickness of the seal material, or the seal can be sucked upstream through the support easily. The DOWNSTREAM support ring should be the OD of the tube Plus 3 times the thickness of the seal material and a smidgeon more, so as not to be pinched too tightly by the tube when it is pulled round and the friction between it and the tube pulls it evenly down stream to minimize drag/release marks.<br /><br />Skippy - gee the gasket and tube sealing technique described there sounds like a good practice on just about any tubing -<br /><br />Buzz - Right!<br /><br />In addition, you will need cooling that is MEASUREABLE in gallons per minute depending on line speed and calibration design for duplication in the future (see another post about water use across a plant), and a water level that has the cooling around the calibration deep enough to prevent air being cavitated into the cooling stream turbulence.<br /><br />At string up, use a bit of silicone mold release on the shell and pin face that is clean to avoid material sticking to these surfaces and melting into "drool". Try to control your pin/shell temperatures to the extent that you can cool down the shell slightly to below the melt temperature which will result in a duller looking matte surface (melt fracture as the material slows down at the wall) at string up. This will give you a little more in the way of "hot guts" with a material that is very soupy at melt. When the Shell is a bit colder than the Pin, the material will bloom AWAY from the pin face once trimmed off. Spray a bit of silicone mold release on the pin face, then work to string up the line through the calibrator and avoiding touching the die face with the PETG as you pull it into the calibration towards the take off. Some of the sticky material may have stuck to the Shell face during the bloom once you get the line strung, you can scrape the face of the shell as necessary to clean up any material (being careful not to cut the material off the pin etc). <br /><br />Skippy - is it hard to handle down line towards the take off?<br /><br />Buzz: Once you are pulling the material down line, twist the material as you pull it into a 'rope" in water that has been brought up to the bottom edge of the calibration. The transition point is so abrupt that it will harden very quickly at this point; the twisting into the rope keeps it straight -<br /><br />This next part is a little tricky - it takes a time or two to get the hang of it; read and visualize it a couple times before trials:<br /><br />Once in the take off, you need to seal up the vacuum chamber -<br /><br />a) move the tank forward to an adequate "kiss point", and<br />b) will open the drain to the chamber slightly (only a crack - this will help prevent pulling too much vacuum too quickly) and you<br />c) will apply vacuum to the calibration chamber, while you <br />d) turn the water misting/fogger lightly on (don't blow it out the face of the die) to set the tubing up as a "tube" while you simultaneously use a wet rag in the exit side seal area to "seal" the vacuum chamber around the rope until the "tube" arrives and is sealed with the gasketing. You do turn on the general fill water to be bring up the water level as well - just enough to fill but not flood out the front and hit the die - the light vacuum being maintained with the wet rag at the back and the drain cracked should allow you to make a "tube" in the sizer and keep water from going forward to the die - <br /><br />Skippy: So . . . you want to be pulling enough vacuum to encourage the air pressure in the tube to expand it to fill the calibration unit and be raising the general water level to coincide with covering the tube when the mostly filled tube gets to the rear seal. Once you have good vacuum and the tube covered, close off the drain, bring your water level on up and level out your vacuum in the chamber?<br /><br />Buzz: Perfect! Get things up to rate, drop your tank slightly and move the kiss back to a sweet spot and run with it. <br /><br />These thoughts should get you up and running - good luck.<br /><br />Just our two cents -<br />Skippy and Buzzeagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-66520022930384153812009-12-11T07:51:00.003-05:002009-12-11T07:58:01.932-05:00Extrusion Surging - potential trouble areasSkippy: Good morning Buzz! The last go around, we talked about feed throat cooling. <br /><br />Buzz: Right; it is more important than many operators give credit to to have a feed throat temperature control ‘plan’ that is measurable and repeatable for this key area on an extrusion since it can impact<br /><br />a) Zone One (feed section) of the barrel overall temperature variation and the machines controls for (potential over) compensation and<br />b) Moisture content of hopper flood fed In-rush of material – aka too cold in a humid production environment could sweat out moisture to end up falling into the feed stream<br /><br />Skippy: The generic improvement suggested was adding a gallons per hour meter to the feed throat cooling loop. It could be necessary depending on larger machinery for say sheet etc running thousands of pounds per hour to require a gallons per minute meter, but that will be rate dependent. <br /><br />Buzz: Yes, make an observation(s) at the line running in control as to water flow at various usage rates and select a gage that has the RANGE of use occupying same about the middle 50% of the gages working range. <br /><br />Skippy: Let’s not forget safety issues –<br /><br />Buzz: Of course, it’s a good idea to start the water flow at a small rate at start up so as not to flood the feed throat with water (which will turn to STEAM – OUCH) if you heat up the line and forget to have the feed throat coolant on until the barrel has potentially over-heated that area. Your set up procedure should include having the gage OPEN at start up to allow pressure relief as the system is started up then closed down to the range of coolant flow necessary for operation. <br /><br />Skippy: also, as a reminder, remember to add a measurement process to your processing records for each rate requirement which can be impacted by incoming material temperatures (from cold boxes off of freezing trucks in the winter to preheated and dried materials) and shear generated during extrusion.<br /><br />Buzz: Again, it is important to measure the flow OUT of the feed loop – keeping the loop filled, and at a constant temperature pulling out only a given amount of heat once equilibrium is achieved is key –<br /><br />Skippy: ok, so having dealt with the feed throat area, what is this we continue to hear about “Hammer Rash”?<br /><br />Buzz: You mean “hoppers that have been terribly abused and mercilessly beaten” in the interests of improving flow?<br /><br />Skippy: Exactly.<br /><br />Buzz: Well, we’ve always tried to avoid “reinventing the wheel”. There IS a lot of good information out there on the internet and discussions about material handling always get around to HOPPER FLOW. <br /><br />In a general search on the internet for some good information about hopper flow, we’ve found a number of good sources and among them, found <span style="font-weight:bold;">AJAX EQUIPMENT’s</span> site at<br /><br /><span style="font-weight:bold;">http://www.ajax.co.uk/index.htm</span><br /><br />Where there are a number of excellent articles and videos describing typical problems with feed related issues. For anyone interested in improving flow related issues in hoppers for plastics - check it out!<br /><br />Skippy: Great - With a good grounding on hopper related issues and potential corrections, we can turn to another big element in feed related surging – material presentation to the screw –<br /><br />Stay tuned –<br /><br />Skippy and Buzzeagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-37587168953967523662009-12-03T09:34:00.006-05:002010-01-10T19:43:00.893-05:00Feed Throat Cooling - SurgingBuzz: Good morning Skip - we've been having some discussion in other formums about "screw and barrel wear and it's possible affect(s) on surging". <span style="font-weight:bold;">To that end, we have gotten a lot of good feedback, and are in process of organizing it into a better report out format and to give credit where we should.</span><br /><br />In going over the material, I couldn't help noting that the overlap of experience will indeed be of great value to the "newer" extrusion techs. <br /><br />Skippy: - Well, there IS a lot of good training material out there, but sometimes in the editing process it can become so terse, abbreviated, or worse situational as to be little to no help to our "newer" team mates. <br /><br />Buzz: - right; for instance, one of the thoughts central to the surging discussion comes back to the simple <span style="font-weight:bold;">"feed throat cooling"</span>. This important area should be cool enough to allow material not to stick in the feed throat on the way into the feed section of the screw, but not so cold as to <br /><br />a) be cooler than the dew point in the plant resulting in water condensation on and in the throat being carried down into the extruder and<br />b) be cold enough to impact temperature sensing devices on zone one controls.<br />c) warm enough not to pull heat unnecessarily out of pre-conditioned (heated or dried or both) hopper materials.<br /><br />Skippy: you bet. I remember once dealing with a problem on a particular make of extruder that used TWO thermocouples per barrel zone - one in the approximate center of the barrel, and one a scant few thousands of an inch from the barrel wall. The <span style="font-style:italic;">idea</span> was that the comparison between the net change of the two was call for 'control intervention'.<br /><br />Buzz: what happened?<br /><br />Skippy: It was the darnest thing - in real operation, with regrinds in the material mix and a drying system in place (and feed throat water not under very good control,) we were finding that the net temperature of the mix delivered was moment to moment changing in the feed section and disturbing the thermocouple nearest the wall only a couple of degrees. However, with this 1-2 degree change happening so fast, <span style="font-weight:bold;">the machine interpreted huge swings in temperature average range occurring.</span> The machine controls in response would apply heat and then (water) cooling in a progressively expanding band of ripples which would throw the machine into real dismay. The output eventually would surge (at best) or stop with melt blockage on the screw (at worst).<br /><br />Buzz: Was there a fix?<br /><br />Skippy: - you bet. We put a small 1/2" long metal dowel in the bottom of the hole, and THEN the thermocouple to move it out just a bit from the wall. In this way, the mass of the measured area was not so quick to be "affected" by a momentary change in the mix. The problem was solved and never occurred again. This repair was actually applied to all additional similar equipment in the plant to overcome the same problem.<br /><br />Buzz: what about the feed throat water? <br /><br />Skippy: Well, the material was CAB and very hydroscopic. We used a lot of cold water cooling baths, and found that under the right circumstances, our chilled water could be applied too liberally to the feed throat and actually sweat water out of the air into the feed section. Water in clear materials ends up looking like "moisture" trapped in the material, so you can mistakenly be looking for a dryer problem where none really exists. Water driven out in the feed section as steam ends up going up the hopper stack and re-hydrating dried materials and can come back down through the throat again etc - all in all not a good process to support.<br /><br />Buzz: what was your approach?<br /><br />Skippy: <span style="font-weight:bold;">The global answer was to equip each feed throat with a gallons per hour meter on the OUTPUT side of the loop. </span> In other words, you want to trap the water in the feedthroat and only let out enough volume at what ever temperature you are putting in at what ever rate you are running (since many plants approach it differently) to yield a net temperature that is measured (on the same place of the feed throat each time)as part of the operations once or twice a shift after start up and steady state. <br /><br />The temperature of the feed throat can be different for different materials and will be affected by different hopper dryer temperatures, rates and shear heat curve in the barrel etc. of course, so a "once size fits all" temperature isn't correct, but a one process variable fix to get to a repeatable measurable temperature is -<br /><br /><br />Buzz: - good stuff.<br /><br />Anyway, over the next day few days, we will be consolidating more of this excellent input from the various groups for a report out for all how have contributed - stay tuned<br /><br />Skippy and Buzzeagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-28860798515982690382009-11-25T12:48:00.006-05:002010-01-10T19:43:38.869-05:00Worn screws/barrels and extruder surgingBuzz: Oh yes, Skippy; another thought on the discussion so far about extrusion screw and barrel wear and "surging".<br /> <br />As you know, we have been involved with extrusion companies in two broad camps -<br /> <br />a) those that religiously measure and rebuild screws and replace barrels when they expect wear to be too much of an impact on reliable extrusion, and<br /> <br />b) those that have machines that you can rattle the screws around in worn barrels to a good degree <br /><br /><strong>and yet because they can continue with process updates and changes produce product profitably, these companies couldn't care less about the thought of "measuring the wear" and moving directly to repair/replacement.</strong><br /> <br />Skippy: - but how can this be? If both can achieve steady state extrusion with a wide variety of virgin and regrind materials in new and worn equipment, and both can exhibit machine conditions where "surging" exists - there must as Paul Harvey says be a "the rest of the story" -<br /><br />Buzz: well yes. We have some thoughts on this that we would like to share with our readers and use to develop some discussion on solutions as well as discuss why this TYPE of question is so difficult - once we've had a little tryptophan er um TURKEY to help marshall our thoughts, we shall continue.<br /><br />Skippy: - what direction is the discussion likely to go?<br /><br />Buzz: well, I'd like to see us confirm that there is essentially no right or wrong answer here, but <em>due to the system or environment in which it is answered, it could go either way.</em><br /><br />BECAUSE of that, perhaps it is time for us to spend a few sessions in a much more compressed time span talking about a number of the other extrusion variables that can contribute to "surging" as well, how to spot them, how to eliminate or at least control them, and certainly the importance of being aware of them. In this way, our readers hopefully will jump in with additional thoughts and our dialog will be that much more productive -<br /><br />Skippy - can't wait - see you in a day or two . . . Happy Thanksgiving to all!<br /><br />(to be continued)eagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-88083844405417160432009-11-14T23:07:00.009-05:002010-01-10T19:44:39.749-05:00Worn Screw/Barrel - Extruder Surging - more thoughtsSkippy: Our first stab on this question was put out there and a question came back on our preliminary thoughts below - concerning whether this was seen on single or twin screws. Others have observed more wear at the start of the life cycle on singles - <br /><br />Buzz: Oops, engaged fingers faster than brain. The intent is not to be aggregating total screw and barrel wear as being a one side or the other phenomenon; regret it appearing to be so one sided - to continue;<br /><br />In singles, we did see wear in a brief spike at the beginning of each screw and barrel rebuild for a short duration while all of the items "wore in" so to speak (remember, we were looking at situations where multiple screws and materials went into each machine). <br /><br />Skippy: What happened after this initial break in period?<br /><br />Buzz: We would observe a long period of wear which would be fairly predictable when on lines committed to more or less one material, and then accelerate nearer the end as the wear began to accumulate enough to cause significantly greater changes to process 'output' and we applied more and more resultant torsion to the screw and barrel interfacial region with other process variables. Our feeling was that since the screws were captive at the hub and near the gate, the torsion resulted in a greater arc in the "bend" to the screws and opened up the clearances at an accelerating rate in the 'middle' of the processing area.<br /><br />Skippy: Did machine size or rate expectations play into this at all?<br /><br />Buzz: Other factors coming into play did include the over-all rate as a percentage of "top end" capability since the observations were made on 2 1/2 and 3 1/2" machines and our goals did include increasing rates to "gain contribution per hour." I guess the anecdotal way to communicate this concept is the same as saying that when painting, using an 18" roller versus a 9" doesn't double the output at the same intended quality with out other factors being affected.<br /><br />The other major difficulty area for our data may have been the constant change from one material to another, the various screw designs with and without various mixing elements in differing locations down the screw. Rather than having to overcome "wear" in one part of the screw and barrel with ONE screw and barrel, things were changing up and down the inter-facial area probably from just after the feed section until well into the metering sections from a number of the combinations. <br /><br />Skippy: so in the end, wear begins to accumulate and . . .<br /><br />Buzz: Well, once we began to be confronted with the results of leakage back over the flights, and the corresponding reduced outputs etc, the natural tendency was to try to put a toe or two out over the edge without leaping into the abyss - increase screw speed. <br /><br />Skippy: Hmm. Most find that dealing with the resultant increased shear, and "residence" time for a portion of the material along with the general increase in melt temperature requires rethinking how to pump the material down a screw and barrel (with increasing wear) in differing manners versus suffering the resultant degradation, adhesive versus cohesive, flow related and sometimes aesthetic issues related to a hotter melt.<br /><br />Buzz: Right. This tug of war over the abyss was generally continued until we would be delivering sufficiently high rate, continual output in terms of <span style="font-style:italic;">rate</span> but dealing with stratified material coming out of the metering section in the 'plug flow' transformation at the breaker plate after the screw tip with a lower level of melt homogeneity. Instead of relying on the breaker plate and screens to simply help move ribbon to plug flow, we found ourselves relying on these to play an increasing role in melt mix distribution as well. <br /><br />Sorry, all this once again is beyond the scope of this discussion. The short course was that it was (well past?) time for a screw and or barrel rebuild or replacement; and remember first that as processors, we need to look holistically at all the the interelated variables and manage them as just that - a whole.<br /><br />Skippy: What about twin screws?<br /><br />Buzz: A couple of things; on twins - yes we saw the most amount of wear at the end of the process since the forces exerted in the conveying mechanism were significantly different and other control options like screw tempering and differing feeds like starve versus flood feeding in combination with screw rpm and fusion rate modifications with the raw material supplier on formulations gave us a good many more options over the life of the screws and barrels -<br /><br />Just our two centseagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-39346876528660828492009-11-14T22:40:00.008-05:002010-01-10T19:45:06.392-05:00Breaker Plate clean up suggestionBuzz: - Hey Skippy, the holidays continue to close in on us and we had a quick question on breaker plate maintenance -<br /><br />[Flex PVC user] "Is there an energy efficient way to clean breaker plates?"<br /><br />Skippy: As a big believer in (M)inimum (N)ecessary (C)hange or correction should be applied for (M)aximum (D)esired (R)esult, how about this -<br /><br />Assuming that you are pulling and tidying them up "hot" after running flex PVC (even highly loaded), an operator with sufficient vocational prep time should be able to <span style="font-weight:bold;">use compressed air and have them spic and span by simply pulling them clean most of the time.</span> This does require a little practice with experienced personnel and the appropriate non scratching tools - most houses make brass tooling available specifically for this type of clean up. Once fully cleared, they should be dipped in an acid neutralizing solution, rinsed, air dried to remove moisture and either stored with/in a light lubricant, or preheated and reused on the next line -<br /><br />Buzz: there are of course all sorts of other cleaning methods - (old) salt baths, fluidized beds, ultrasonics, etc . . . <br /><br />Skippy: Yes of course. Generally plants with processes requiring breaker plates to convert ribbon to plug flow also have a supply of compressed air on hand as part of the operations, and may need to avoid the extra expense of these additional energy consuming devices. You may need to re-engineer your tooling with one or more die "swing gates" or multiple breaker plate positions on a push through system to keep the line up and running again during clean up/change over with a minimum of lost time. The activity to avoid appears to be pulling the plates out and leaving them to cool down, <em>then</em> trying to "clean them" in an "energy efficient manner"; which seems like the start of a wasteful process - <br /><br />Just our two cents -eagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-64048656557483064562009-11-13T19:37:00.005-05:002010-01-10T19:45:27.578-05:00Plastics in the news - cutting through the noise -Welcome one and all - our list of visitors is growing, and we are always interested in new discussion topics.<br /><br />Interested in keeping up with a wide varitey of plastics information worth investigating? <br /><br /><strong>Check out <span style="font-weight:bold;">Matt Defosse's</span> blog at Plastics Today!</strong><br /><br />http://www.plasticstoday.com/blog/4942<br /><br />Skippy and Buzz -eagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-78489096243315855802009-11-12T18:54:00.005-05:002010-01-10T19:46:14.033-05:00Worn extrusion equipment and surgingSkippy: Hey Buzz - happy almost Thanksgiving - we saw an interesting question in another plastics forum -<br /><br /><span style="font-style:italic;"><br />"<span style="font-weight:bold;">Can a worn extruder screw cause surging?</span> I've heard this for years but can't see how a linear variation with a period of a minute or two can be caused by a slow radial change over many weeks or months or even years. If anyone can come up with a reasonable and technically sound explanation, I would like to see it. ALG"</span><br /><br />Buzz: - Well Skippy, I tend to agree with most that the slow evolution of “wear” is not likely to create a situation where we have good melt pumping on Tuesday, only to have it fall apart on Wednesday. Screw melt pumping conditions DO change over time with wear, and particularly when aggressive screw and screw tip cooling are employed to “throw material around” in profile tools. <br /><br />Skippy: To be fair, don't we have to acknowledge here that there are a number of critical process areas that contribute perhaps as much to "surging" based on material delivery (aspect ratio of material components, mix of materials, conveying method/stability, existence of fines, drying temperature, air flow, residence time in the dryer, feed throat temperature control, zone 1 and or 2 temperature control, etc etc etc) to the feed section of a screw that are ignored or not very well understood in too many shops?<br /><br />Buzz: Of course, although that conversation is way beyond the scope of this particular discussion and will be investigated more fully in the future. On the other hand, in custom plant environments where screw and barrel wear were faithfully measured by quarter on extrusion lines that ran a variety of materials from week to week (aka not just one material from beginning to end of each screw/barrel rebuild life) we observed the following –<br /><br />The most amount of wear from quarter to quarter occurred at the END of the screw and or barrel life measurement period, not at the beginning. (by production hours)<br /><br />R&D staff tend to prefer to “run in new items on new screws and barrels” and in short order, the “process” is/was not as "stable" to established run conditions in future runs and required “tweaking”<br /><br />Many US firms have gotten caught in the trap of increasing rates to “increase contributions per hour” (false economy of course if no new sales fill the new empty machine time) at the expense of significantly closing the ‘window of process ability’ with any particular brand of elements<br /><br />Skippy: I'm wondering whether the economic climate we're experiencing contributes in any way as well -<br /><br />Buzz: well, we have observed that batch to batch variation in raw materials from manufacturers quite frankly (despite their “certifications” on lab materials) DO exist, sometimes in great measure and<br /><br />Business conditions (and perhaps lack of cash flow?) in custom extrusion in poorly run shops affects the run to run use of varying raw material virgins and regrinds – <br /><br />Skippy: How does that affect running an extrusion line?<br /><br />Buzz: Well sometimes, rather than running a standard mix of regrinds back into product from the beginning of the run until the end, some houses accumulate and “rev the meter” from nearly 0 to nearly 100% which further requires "tweaking" in general to re-achieve proper melt thixotropy with varying amounts of regrind.<br /><br />This can result in some rather aggressive approaches to achieving a stable melt pumping mechanism at the correct melt temperature and pressure to have the material “be one” with the intended tooling flow paths – <br /><br />Skippy: So all that translates to what?<br /><br />Buzz: In the case(s) above, we find that the requirements for process adjustment in a process where we KNOW that all else (listed in the opening above) is in good working order and under “control” end up being “justified” due to “changing outputs”. The bottom line is that although a good deal of data can be accumulated in “screw and barrel wear” verus "surging" it is meaningless, unless the contribution to wear can some how be tied back to the requirements for any number of the destabilizing run approach problems above in the plant as well.<br /><br />Your question is an excellent one, because many shops quite frankly do not do a very good job of monitoring, mixing, drying etc the input of raw materials and then “change the process and blame the extruder” aka worn barrel and screw.<br /><br />Skippy: is this likely to be a standard answer for extrusion in general?<br /><br />Buzz: Quite frankly, we would guess that the pipe folks who will routinely rebuild screws and change out barrels on an “X” pounds schedule on lines running the same product 24/7 for months on end would have a totally different answer than the “custom gang” but that's just our two centseagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-20283372100921335282009-08-07T17:03:00.003-04:002009-08-07T17:07:20.610-04:00More on Vacuum Tank help -Skippy: Say, we thought a bit more about the response in the last post, and hadn't realized we didn't ask a couple more 'broad brush stroke" questions - <br /><br />a) are you using a color concentrate with the PE and PP that is being exuded out from the melt and being deposited/captured/coating the calibration unit or plugging vacuum holes and slots? This could be insulating the calibration unit and preventing efficient heat transfer - may need to be checked on a regular basis if the colorant system and or process can't be modified to eliminating this "plate out" effect. A rubberbanding or thinning/stretching effect in the calibration unit due to this insulating of the calibration could intermittently look like folding at the front of the calibration unit - rather than a constant haul off down the line - <br /><br />b) we didn't really discuss the travel method, and assumed that the take off unit was capable of overcoming the normal calibration drag and pulling the part at a constant rate of speed - without belt/cleat slippage or obvious motor speed problems. Depending on the drive makeup, one thing to check is that the take off is operating at approximately 70-80 percent of it's rated motor speed in the correct gear reduction range if applicable at the correct haul off rate. <br /><br />c) is the output of the extruder constant? as we had assumed; - if not could be a host of issues - check by cutting off 10 to 60 second pieces of hot melt at the die -several in a row, cool the mass and weigh on an accurate (gram?) scale to see what if any variation is occuring at the extruder. It is important that the sample size be large enough to overcome the inherent error in your "by hand" cut off of the samples - <br /><br />Buzz: and d) we were also assuming that the calibration unit had previously been checked for obvious damage, nicks, blocked ports, correct coolant and vacuum hook ups etc. and that the Vacuum tank itself was in correct running order with adequate coolant into and out of the system - sorry for not thinking of those items as well earlier - <br /><br />Good luck -eagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-46082940820802677212009-08-06T07:37:00.003-04:002009-08-06T07:48:11.342-04:00Need Help Extruding Rigid Tubing Using a Vacuum TankBuzz: You know Skip, we are working on extrusion materials from the last NPE show, but we often get questions that show the need for making sure just the basics are covered as well - like this one:<br /><br />"We just got a vacuum tank and have had several jobs tool really well on it. On the past few jobs, we are getting a fold in the wall of the tubing that we cannot seem to work out. Materials are PP, PE and Nylon. I know that we are probably missing something simple. Any suggestions or resources that can help me trouble shoot?"<br /><br />Skippy: Oh boy, I hope that our 30 years of extrusion experience can be of some benefit. We do this for a living, and would be glad to come in and help - Note these comments are not meant to criticize, but we will assume nothing -<br /><br />Mentioned in your post:<br /><br />"We just got a vacuum tank and have had several jobs tool really well on it. On the past few jobs, we are getting a fold in the wall of the tubing that we cannot seem to work out. Materials are PP, PE and Nylon. I know that we are probably missing something simple"<br /><br />Buzz: Let's talk about a couple of these elements to see if you are in fact "missing something".<br /><br />Skippy, ok, A) You got a new vacuum tank. Was this the only addition to the line, or did you get some new tooling with it to make particular parts as well? You mention the first few jobs ran "well" - were they in the same materials? Using the same tooling? Do you have a program in place to tear down the machine from job to job and a set up sheet that has been gone over to be sure that all processing conditions are "correct"? Are you running more or less lines now that in the past (see calibration - aka water)<br /><br />Buzz: right, then B) Suddenly, you are having problems with the extrudate folding over in the wall of the extrudate - is it in one area only, or all around the tube - A fold usually indicates one of several things -<br /><br />1) The wall balance versus the "draw down" is not correct. <br /><br />When you shear off some material coming out of the die at rate, the parison (tube shape) pushed out should flow out roughly horizontally for a small way (until gravity kicks in). <br /><br />Question? Do you clean the machine up totally from material to material (clean means all plastic out of the tooling to bare metal, pull the screens, pull the screw and clean all down to the metal?) If not, you might have material hung up in the barrel or at the tip of the screw, in the screens or breaker plate that isn't moving. Since the screw is imparting ribbon flow that must be converted into plug flow through the breaker plate, if you interrupt this plug, erratic and generally uneven flow through the balance of the tooling may occur. You might also have material caught up in one or more spider legs - causing whacked out flow that an operator is trying to correct with pin/shell relationships -<br /><br />Once the material flows through the gate adapter in plug flow, through the spider and pin/shell in even distribution and assuming that your tooling is approximately 5 degrees above the correct melt temperature, then you should be delivering a "tube" out of the tooling that is ready for draw down and calibration -<br /><br />Skippy: Good point, but it also might be <br />2) Die Gap - this is the distance between the Die Face and calibration. Assuming that the wall is even, then we would want the Die Gap to be even from every point on the die to every point on the calibration. Since the tooling is larger than the calibration, you need to back the tank AWAY from the die so that "draw down" can occur. The correct distance away will be somewhat variable based on<br /><br />a) the melt temperature and "stiffness" of the melt"<br />b) the wall thickness versus the cross sectional area<br />c) the lot of material - yes I know that your materials should be fractional melt, but since they are "fractional" even a small change can affect the apparent "stiffness" of the melt at any given temperature.<br /><br />In the materials that you mention, it is not uncommon for the OD and ID of the tubing tooling to be larger (in some cases up to 60% or more) than the final size of the tubing so that the material can be drawn down prior to entering the calibration. Are you using common tooling for all of the materials, or do you have different pins and shells for different sizes of tubing from different materials?<br /><br />Also the die gap is established by making sure that the calibration and extrusion centerlines in both planes (side view and top down) are straight in line with one another. Vacuum tanks, takeoffs and cutting devices are notorious for vibration and will "creep" along the floor if able - is the line "in Line?" if not, you are perhaps not applying cooling evenly down line. <br /><br />Buzz: yes sir, and doen't forget <br />3) Lubrication - two of the materials - PP and PE have an affinity to move from being cohesive to adhesive as they get hotter - generally, most custom extruders use a lubricant (water or other proprietary) systems to lubricate the material as it enters the calibration. Is this system working correctly? Nylon is VERY sensitive to moisture - is your drying system capable, is the (lack of) moisture level very well maintained? It goes without saying that PP, PE and Nylon all require different pins and shells and draw downs to make the "same" size tubing. Anyone that tries to run all three from the same tooling perhaps can by sacrificing rate or quality. Best to optimize for each material and go clean to clean between materials on machines.<br /><br />Skippy: yup, and this is key - <br />4) Calibration cooling - is it dependable and repeatable? Is it actually working? Your vacuum tank calibration cooling might be hooked up to <br /><br />a) well water; coming up out of the ground, it is likely to be around 55 degrees all year round - good system if dependable in terms of gallons per minute<br /><br />b) city water; likely to change temperature with the seasons - 55 or so in the winter to possibly 75 degrees of more in the summer. Again, are you sure that your supply in gallons per minute is known and repeatable?<br /><br />c) some sort of internal water recovery system (cooling tower, chiller); do you do preventative maintenance on the system, again do you know day to day what the temperature and actual gallons per minute availability is<br /><br />Once the supply of water is maintained, then it has to be APPLIED to the calibration in a known manner. I like to put gallons per minute meters in line supplying my calibration - for a couple of reasons - <br /><br />a) once we know for instance that 7 gals per minute at 55 degrees on a part running 150# per hour at "X" feet per second through the calibration at 300# per thousand feet is running WELL, I note that as being critical to being repeated in the future.<br /><br />Buzz: ok, all together now, b) are we ready for "silly?" <br /><br />We often encounter plants with a problem like this, where everything is running well as in a) above, and then the process "goes south". I always ask what is "new at the line" - "Nothing" is generally the reply. Then I ask "what else is new in the plant?" and we find out that three other lines were being started at the same time, and the SUPPLY of water which was capable of giving me 7 gal per minute with valve open 1/4 is now being diverted into filling three more lines. A quick check on my gal per minute meter shows that at my line, we've dropped to 3 gals per minute and the parts are "folding" (too hot). I open the supply valve at my line from 1/4 to say 1/2, bringing my supply back up to 7 gal per minute and line settles out. Don't forget that when the other three lines eventually settle into production and turn their valves from FULL to fill to 1/4 to run that we will suddenly have TOO much water (check the gage) and have to make an adjustment again. One of these gages on every line allows each operator to know what effect others are having on his line, and what to do to get back in control rather than just "trying zone three for 5 degrees" etc.<br /><br />Skippy: wow, just goes to show you that laying down the foundations is really important. Other simple thoughts include making sure that the water application in the tank is even - water rings get plugged up with rust, shavings, dirt etc, and make sure water is cooling all sides evenly.<br /><br />Buzz: We haven't really talked much about how to set up the calibration, the materials of construction to seal around the tube after the calibration and from compartment to compartment etc, but have been focused on the "fold" probably happening with either uneven flow out of tools or uneven cooling in the Calibration.<br /><br />Once again, we can be called upon for additional help, training etc in your plant as required.<br /><br />Just our "two cents" -eagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-9690783509756040372009-07-29T07:15:00.007-04:002010-01-10T19:56:28.899-05:00- Bigger in your customer's eyes on a small budget -Skippy: How do you act bigger with critical customer follow up without breaking the budget?<br /><br />Buzz: As a small to medium size business (or even a small consultant group) you probably realize that in addition to the discipline of an active Customer Relationship Management program spitting out follow up activity, you have actionable follow up as well.<br /><br />Skippy: Of course, plenty; from having meetings and teleconferences transcribed to keeping on top of customers critical time sensitive contacts to ordering supplies remotely, etc.<br /><br />Buzz: Check out <span style="font-weight:bold;">www.microtasking.net</span> For a nominal charge, just about any customer or vendor follow up activity can be handled once or on a recurring basis on your behalf <span style="font-weight:bold;">- think and be big on a small budget -</span>eagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-51758966005046159792009-07-01T12:00:00.003-04:002009-07-01T12:06:52.229-04:00Profile extrusion info from NPE 2009Skippy: Hi all - just back from a productive outing at NPE in Chicago -<br /><br />Buzz: - I heard the show numbers were really down -<br /><br />Skippy: Well yes, it did seem that the number of plastics personnel there were highly diminished from what we had observed the last 10 shows in a row back to 1979, but on the other hand, the folks that were there appeared to have a real reason to be there. <br /><br />Buzz: and so the quality of the contacts was likely to be good?<br /><br />Skippy: Right. I have a bag full of materials that are coming back from the variety of disciplines we are constantly going through - profile extrusion, thermoforming, injection molding both conventional and low pressure structural foam, and fiberglass composites. <br /><br />There seemed to be a bigger focus on this show from the vendors on pooling the products (training, controls, common sense shop info etc) into more system wide solutions rather than just selling the newest loader, calibration, etc.<br /><br />I will be assembling some of the materials regarding the profile extusion elements first and posting soon -eagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.comtag:blogger.com,1999:blog-245063825711416652.post-53143531678476326202009-02-10T22:25:00.000-05:002009-02-10T22:35:42.491-05:00Are you maintaining a “Three Legged Stool”?Buzz - Hey Skippy - seat backs and tray tables up and locked please -<br /><br />Skippy - say what?<br /><br />Buzz - Well the travel in today's market is so bumpy and most of us don't have the luxury of having a 'Captain Sully' in the cockpit that it seems prudent to have seating that is firmly grounded.<br /><br />Skippy - It goes without saying that we have a difficult marketplace at present. <br /><br />Buzz - Yup, most companies (unfortunately) are in full blown ‘survival mode’; the mode consists mainly of gouging out ‘costs’ so as to live to fight another day. <br /><br />Skippy - It is important to keep in mind though that doing this without enough introspection is akin to sawing legs off the stool you’re sitting on. You’ll want to maintain at least a ‘three legged stool’ with the three pillars necessary to provide stability over unknown terrain - <br /><br />Buzz - which are?<br /><br />Skippy - <br /><br />A) [quality] sales - to existing and potential customers; <br />it’s easier to keep a customer than get one;<br /><br />B) cash flow - you can be making sales and losing money etc.; <br />it never works out on ‘volume’ and lastly<br /><br />C) human capital – are the right team members in place? <br /><br />Buzz - Any suggestions?<br /><br />Skippy - Rather than focus only on cost cutting, an honest internal assessment should be part of the operations mode at this most important time – does your team have a good handle on:<br /><br />1. The existing problems that are currently facing your company?<br />2. The quality of key managers you presently employ?<br />3. The strengths and weaknesses of your company as seen through the eyes of your customers and employees?<br />4. The current climate of the company, such as morale and its status?<br />5. The planning that has occurred up to this point?<br />6. The attitudes of key managers toward the turn around and growth?<br />7. The story board material that presently exists(brochures, literature, selling aids, etc.)?<br /><br />Buzz - Sounds like an assessment of these key factors prior to the coming rebuild is critical to take advantage of better company re-positioning and perhaps re-branding. <br /><br />Skippy - right; and consider an independent audit. An outside consultant’s report can sometimes be not only revealing but also thought provoking. It may open the eyes of the most astute leadership. You must be prepared for real hidden problems that you might have missed. Moving forward before conducting an independent assessment can be deadly to your rebound and future growth.eagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.com1tag:blogger.com,1999:blog-245063825711416652.post-4270063132904375052009-01-31T14:02:00.000-05:002009-01-31T14:07:02.112-05:00"Pita" ManagementSkippy – Hey Buzz – Happy New Year. Had someone inquire about "Pita" Management:<br /><br /><span style="font-style:italic;">“Hi In the molding process when you allow raw material to flow fluently from the extruder at the beginning or end of work you get what we call here a "Pita" It is a big round and hard melted raw material. This raw material is out of the stock but not handled by the shop order and due to that after a while cause mismatch in stock. I would like to hear how do you handle that in your plants and if you have any suggestions for me. Thanks in advance.” </span><br /><br />Buzz – Happy New Year as well. Hmm, this question could be looked at two ways – are we talking about the handling, use or disposal of the “pita” or the raw material allocation and subsequent quote effects side?<br /><br />Skippy – why not both?<br /><br />Buzz – Ok, from a material handling only point of view, it depends on the condition of the material as is extruded - <br /><br />In custom shops running multiple materials, it is often that the barrel was given a light coating of a petroleum based product to seal the pores of the barrel. It is a given that your tooling was likely coated with something as well and that you have de-"greased" it etc as you hung and heated up - <br /><br />A new run of material will pick this up and it is not in your best interest to have petroleum or silicone based products introduced back into your run mix from internally generated scrap - pitch it. <br /><br />On the other hand, once you are up and running, with a good melt temp, the material can be handled at nearly the correct make up consistency, cool the material by mass quickly, remove water if present and run through granulator being careful to have the resultant regrind not too gummy/sticky - if you generate enough of this due to jamb ups, string ups, etc you may want to consider a "hot granulator" designed to take excess material at or near melt temp . . . <br /><br />Skippy – okay, how about from a raw material variance standpoint?<br /><br />Buzz – well, the amount of shop generated regrinds and virgin is a problem that is easy to overcome in your MRP or ERP process with a little examination of your particular system, some history analysis and a slight 'adjustment percentage' to your allocation table from the BOM.. <br /><br />It sounds like you have two major issues - <br /><br />The first is COST for quoting, and the second is ACCURACY for material allocations. <br /><br />Material allocations (probably the more important on a month to month basis): <br />------------------------------------------------------------------------------------------------------------------ <br />Assuming that you have a costed bill of materials for each product, each would call for "X" pounds or kilos of plastic per some measure - thousand feet, 100 meters etc. Unless you have a VERY sophisticated MRP system, you probably have variances month to month in virgin to regrinds before any losses - <br /><br />There are several losses that occur that belong in the BOM but generally are excluded until the problem becomes so large that it is hard to miss - <br /><br />1) "Pita"s or start up scrap or jamb ups etc are all "losses" unless recaptured as I indicated in the original reply. If they are ground up and re-run, no loss exists and no variance is expected. For this exercise, we will assume that they are always losses <br />2) scrap that is lost in and around the granulator - it is rare that material isn't spilled on the floor and swept up, or vacuumed up when cleaning a granulator and going from one material to another or regular maintenance - what happens to it? Unless you re-wash, dry and reuse, again, loss <br />3) In extrusion, and vacuum or thermoforming versus injection molding, saw shavings, and tool cut offs end up on the floor as saw dust, trims etc. These can be or are losses as well unless recovered. <br /><br />The closest MOSTLY correct answer is to do a scrupulous study by product - measure all inputs, all saved product, all by product wastes and losses as above, then calculate the % of loss as a measure of the total amount of material consumed and either <br /><br />a) Increase the raw material per measure in each BOM by the same percentage or <br /><br />the NEXT most correct answer is to do a scrupulous monthly study on the weights of all final products (net) by raw materials, and using the following formulas - <br /><br />Beginning inventory + Purchases - minus ending inventory is Material Consumed. (Gross) <br />Material Consumed - net weight of all saved parts for shipment is Actual Material Used for Product and what ever is left is what was LOST. <br /><br />LOST/Material consumed is the percentage that each Bill of Material should be increased by (average) to predict material allocations more closely. <br /><br />-------------- <br />Quoting: <br />-------------- <br />This same exercise for a year would probably yield that your losses in aggregate are likely in the 1-3% range in a fairly clean well run shop. In this case, you would want to increase the raw material cost component in your quotes by the same or slightly more (slightly more is more likely to leave a little wiggle room until you find all the losses) than the aggregate loss. In this way, you know you aren't going to automatically get a "SURPRISE" loss in margin of 1-3% at year end. <br /><br />Note that none of this discussion focuses on Regrind availability or max percentage usable. These discussions are beyond the scope of this simple answer. <br /><br />I hope this simple explanation works. Good luck.eagertaskhttp://www.blogger.com/profile/09754013618764662396noreply@blogger.com0