Poly has it's own issues since it has a such a memory and will not likey stay put on dies with fine detail or sharp corners as it cools. Poly's higher forming temp, also retains heat a lot longer than many thermal formed materials. If they like the way the part looks in ABS, it is not realistic to expect the same detail out of poly-anything.
It may be possible to use water chilling lines in the tool, in an effort to freeze off the material rapidly to circumvent some of the relaxation. The problem with rapid chill is that this can force the need for heater cartridges in the tool to return it to forming temp in a reasonable amount of time. That is a vicious circle and best be worth the additional complexity!
Larger holes do not increase the vacuum pull on the material directly. It increases the speed at which it pulls over time. This is where a combination in lack of surface area that the vacuum can work on, along with specific material attributes, are a detriment to the desired result. Course Sandblasting the tool surface may help keep the material from sealing off so that the vacuum available does act on a larger area by capilary action between the die and material.
DC
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Learn cause and effect through experience. Mastering those relationships is the "Common Sense" ability within the art of any trade. |