Are you maintaining a “Three Legged Stool”?

Buzz - Hey Skippy - seat backs and tray tables up and locked please -

Skippy - say what?

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.

Skippy - It goes without saying that we have a difficult marketplace at present.

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.

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 -

Buzz - which are?

Skippy -

A) [quality] sales - to existing and potential customers;
it’s easier to keep a customer than get one;

B) cash flow - you can be making sales and losing money etc.;
it never works out on ‘volume’ and lastly

C) human capital – are the right team members in place?

Buzz - Any suggestions?

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:

1. The existing problems that are currently facing your company?
2. The quality of key managers you presently employ?
3. The strengths and weaknesses of your company as seen through the eyes of your customers and employees?
4. The current climate of the company, such as morale and its status?
5. The planning that has occurred up to this point?
6. The attitudes of key managers toward the turn around and growth?
7. The story board material that presently exists(brochures, literature, selling aids, etc.)?

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.

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.

"Pita" Management

Skippy – Hey Buzz – Happy New Year. Had someone inquire about "Pita" Management:

“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.”

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?

Skippy – why not both?

Buzz – Ok, from a material handling only point of view, it depends on the condition of the material as is extruded -

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 -

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.

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 . . .

Skippy – okay, how about from a raw material variance standpoint?

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..

It sounds like you have two major issues -

The first is COST for quoting, and the second is ACCURACY for material allocations.

Material allocations (probably the more important on a month to month basis):
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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 -

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 -

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
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
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.

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

a) Increase the raw material per measure in each BOM by the same percentage or

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 -

Beginning inventory + Purchases - minus ending inventory is Material Consumed. (Gross)
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.

LOST/Material consumed is the percentage that each Bill of Material should be increased by (average) to predict material allocations more closely.

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Quoting:
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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.

Note that none of this discussion focuses on Regrind availability or max percentage usable. These discussions are beyond the scope of this simple answer.

I hope this simple explanation works. Good luck.

Aluminum Extrusions

Skippy – We heard a question about aluminum extrusions and (potential?) die modifications –

“I have a simple L-shape extrusion that is currently produced by a supplier. We have need for an additional L-shape extrusion with a shorter length on one of the legs. The supplier has stated that a whole new die is needed. Why wouldn’t the supplier be able to use the existing extrusion die by blocking off part of the existing die with a removable plate that covers part of the leg?” [similar to plastics extrusion – S - ]

Buzz - as far as tooling for aluminum extrusions go, the die charge (with any volume) for a new die is probably only around $1200 to $1600. You might be better off if the quantity is small working with a someone to trim off a small amount of aluminum and sell the scrap to recover the cost -

Example -

Normal extrusion costs $.80 per foot

Corrected extrusion costs $.68 per foot

Retail value of aluminum difference $.12 per foot

Recovery cost of scrap aluminum est. max 50% or $.06 per foot

Cost to machine off aluminum portion not needed est. $.10 per foot

$.80 extrusion + $.10 fabrication cost -$.06 aluminum recovery = $.84

versus

$.68 and a die charge of guesstimate - $1600

Difference is $.16 per foot - so until you buy 10000 feet ($1600 divided by $.16 per foot savings) it is cheaper to work with someone to fabricate what you need.

Note - The guesstimate for the foot cost on the current extrusion might be somewhat smaller if you go up in total volume - buying the portion that is normal PLUS the portion that you will have fabricated -

Substitute in your own numbers and see what looks best -

Good luck.

UPdate to saw blades discussion

Here is a site worth looking at for Acrylic sawing tips - although the generalizations lend themselves more to your own trial and error -

http://www.plasticsmag.com/features.asp?fIssue=Jan/Feb-04&aid=3920

For some tool speed suggestions on more exotic plastic materials - look here -

http://www.boedeker.com/fabtip.htm

And as the good old standby for good plastic blade general info including blade component terminology I use

http://www.generalsaw.com/resource/plasticblade.html

Once again, the key to machining plastics in general is to have a tooth chip design which lends itself to cutting or slicing depending on material, holding the material firmly to prevent chatter, adequate tool speed to remove material but slow enough to discourage heat generation (gumming up the works so to speak) and making sure to deal with chip and dust evacuation issues - always including using your protective equipment - eye, ear and nose/mouth protection.

- Skippy -

'Smart Boards' - 80% of the capability at a fraction of the cost

Skippy: If you're like most of us, you have computers, and you may have one of those low cost projectors to show your PowerPoint presentations at your board meetings. Most of us would also love to have one of those several thousand dollar 'Smart Boards' for the conference room or to use on the road with business presentations and brain storming - but the cost . . .

Buzz: well, yes; and?

Skippy: It never fails to amaze me that 'connective thinking opportunities' occure all the time. I was at a school board meeting the other night as an involved parent and was watching a technology coordinator and some teachers delivering an update on integrating computer technology into standard subjects like readin' writin' and 'rithmetic etc. As I watched the demonstration that evening using an inexpensive projector - I thought of this project I saw on the web in the last few days that had to do about gaming technology but hadn't really done anything with yet. I felt I just had to share this with as many business partners as I could this week - Don't you wish we could be as cool as young people like this young man? see:

http://www.ted.com/index.php/talks/view/id/245

His Wii remote hacks and additional programming are here:

http://www.cs.cmu.edu/~johnny/projects/wii/

Buzz: after watching these, I can't help thinking that this would be a good low cost project for one or more high school kids in computer or science class, and the outcome would be a presentation showing "80% of the capability of these white boards (at $2.0-$.30 thousand each for large ones) at a small percentage of the cost" as the author demonstrates. If nothing more, it along with some 'zippy presentation' might spur the school board into further alignment with the technology.

Skippy: Right you are, AND this is one of those times where you just have to wonder to yourself, couldn't this be applied in my business as well; I need to get my 'computer and wrench staff' working together to try this out -

Enjoy

Plastic 'Shrinks' When Heated (?)

Buzz – say Skippy, I’m always amazed at the long list of things to consider when developing a product. I ran into what seemed to be a routine question about ‘plastic product shrinkage’. The situation was that product was produced as usual, sold into the distribution channels and then made its way into various final applications in different areas of the country. After some time in installation, apparently some product was exposed to elevated heat(s) and ended up shrinking, leaving gaps between product pieces. A light examination up the food chain back to the material supplier was done, and the information passed back down was that ‘Plastic Shrinks When Heated’ – what’s up with that?

Skippy - I always liked that line in Star Wars - "Every thing is true; from a certain point of view." I'm pretty sure that the technical folks would not try to have you believe that plastic simply by design "shrinks when heated" - the reverse is actually true - something is happening here, but it is something else.

Buzz – Well there are products that do exhibit ‘shrink’ when heated – what’s the difference with what is happening here?

Skippy – What will we use for the foundational thinking?

Buzz – Lets use these as our working assumptions -

a) Thermoplastic is composed of molecules in polymer chains tangled up together
b) When heat energy is incorporated into a mass of plastic, additional energy is imparted to the molecules in these chains
c) The molecules get excited and the chains begin to move apart from one another and the mass "grows / occupies more space" - more open space is left between the finite numbers of molecules in the chains (the net amount of plastic isn't changing) as the chains untangle.
d) If no other additional source of energy is expended to lock the molecules in an orientation of "apartness" (Read: Stress) while 'cooling', then as the plastic cools and gives up the heat energy, the molecule chains will re-entangle, nestling back together more closely and the air (if that’s what is occupying the space between them) will return to other areas of the environment.

Skippy – Good; now then, here are two examples where ADDITIONAL energy is ADDED beyond the energy to "melt" the plastic and the result is to ENCOURAGE a part being "larger" than what the apparent volume would be -

Example one -

Sheet for thermoforming is extruded and pulled through a roll stack, and as it leaves the stack, the pulling device continues to stretch and "orient" the plastic during the cooling stage.

Buzz - Isn’t thick gage Polyethylene sheet famous for "orientation"? Even to the extent that you specify the amount of "orientation" you expect in the sheet as it is produced so that it will have predictable "sag" during forming?.

Skippy - Yes, the short version on the way to check for correct orientation is to cut some sheet into known dimensional pieces (2" x 10"), lay them on a tray with a little talc on the tray to allow the sheet to slide around easily, and put the tray into a lab oven at a known temperature (different for different types of plastic) and heat the sheet up. Then without adding mechanical stress allow it to cool. This process will allow the sheet to heat up enough to RELEASE the processed in orientational STRESS (additional mechanical energy that is not apparent to the eye) and the sheet will 'shrink' in one or more directions. Repeated re-heatings once the stress is all released will not make the plastic shrink further. It is not the heating that "shrinks the plastic".

Buzz – So the heating releases the STRESS that is holding it bigger.

Skippy – Right. You measure the sheet before and after the heating and cooling and do some calculations and you see the amount of "orientation" that was present between being extruded and after releasing the stretched in orientation.

Example two –

The other more obvious example is "Heat Shrink Tubing" - I'm sure you know what this is - it is extruded tubing of various materials including Polyolefins or PVC that you put over wire connections, add a little heat with a heat gun and PRESTO the tube shrinks into intimate contact to cover the electrical connection. This Tubing is made by extruding and adding additional MECHANICAL STRESS into the part - orientation if you will that once the tubing is heated, will release the mechanical stress - it will not change the mass of plastic, only allow this built in energy to be released - so by design it is to 'shrink when heated'.

Buzz – aha, here’s an excerpt from http://en.wikipedia.org/wiki/Heat_shrink_tubing :

"Heat shrink can also be expansion-based. This process involves producing the tubing as normal, heating it to just above the polymer's crystalline melting point and mechanically stretching the tubing (often by inflating it with a gas) finally it is rapidly cooled. Later when heated, the tubing will "relax" back to the un-expanded size."

Skippy – Spot on. Of course, by design, the product we opened the discussion with is not being designed to 'shrink when heated' and a complete understanding of the temperatures the product sees - in manufacture, in warehousing, in transportation, in job site storage and in application is in order. It seems likely that orientation exists in the product (as it does in most plastic processes) and something between the time it is a plastic product coming out of the line and it is in final installation is allowing the product to anneal and lose some of this orientation. So this much is true -The part is 'shrinking', and it is 'due to heat', but it is probably changing in size by releasing trapped in as produced stresses.

Buzz – Well another thing that was mentioned was that most of the material is shipped in over the road trucks to warehouses all over.

Skippy: As indicated, a holistic examination of the entire delivery system is in order - perhaps some or most of your product is getting warm enough to be self annealing in the over-the-road trucks passing through very hot conditions during the delivery phase, and has released its orientation while in boxes - these then if brought above the stress releasing temp and re-cooled in application can't release any more stress - it's already gone. On the other hand, if there are other parts that are not annealed in the delivery system and installed and they are heated up later (after installation?) it is possible they could be releasing molded in stress or orientation at that time. Look at the system variables just in our own US – products are produced in every corner and shipped coast to coast. Much of these products if routed to or through hot locations can get a good healthy annealing in hot trucks - the unknown to be studied during the product management cycle is for just how hot and for how long.

Buzz – So, another note to the product managers out there; an important item to be considered while developing plastic products is to pay attention to it all the way through to its final use(s). The development cycle should include the entire system from design considerations to installation (in the full range of environmental conditions) including the delivery methods and path of distribution.

Clear plastic lens material

Skippy - hey Buzz - Happy New Year!
Buzz - same to you; another year gone by.
Skippy: seems like we had too much travel in December to post -
Buzz - well yes, but had some good questions to deal with like this one -

"I am looking into plastics and need to know about some plastics that have high UV resistance and are also transparent. So far the only leads I have are Polyarylate and Polyetherimide. If there are other plastic types that also fit this description please let me know.

Also I need the plastic to be crafted into a mostly cylindrical shape, about 12 inches tall, with a circular/ovular opening in the area of 2-4 inch diameter, so a company(s) that do this would also be useful to me. Any information is greatly appreciated, and if further information is needed, please let me know."

Skippy - that's an easy one. Acrylic is mentioned in many products as the material of choice in terms of process-ability (it can be molded or cast [for optical clarity to sharpen the light rays, or fuzziness to spread them out; depends on need] and extruded (and formed as necessary) into lens covers that could slide or snap on etc for ribbon type installations.

Buzz - sounds like the material might need to be machined . . .

Skippy - Yes, 'cylindrical' was mentioned - may be rod or tubing off the shelf that meets the need and if not - well, the material could be cast to very close dimensions, machined and then mechanically and chemically polished. Additionally, the material can be potted (to make water resistant etc.) and cast for items like pool and spa lights, highway markers etc when used to focus, cover and protect LED's; even including the more powerful LED units of today versus the past.

Buzz - Ok, opening up the thinking, there are other applications that come to mind. There are very high grades of crystal clear versions with good UV protection used in the archiving industry for special documents (remember National Treasure?), paintings etc.