Do you think processors are stuck with mold makers building in shrinkage factors according general rules of thumb?
For example, published shrinkage of ABS is around 6/1000 in/in. I recently had a mold built, whose boxed dimensions (as verified during validation metrology)did average out to about 7/1000 in/in. But the shrinkage seemed quite feature-specific. For example, in this medical device part, shrinkage along length dimensions of a spike could vary from 2 to 11 thousands in/in. Also, shrinkage pattern of inner diameters in ports and and other areas made by core pins seemed to vary. This is a 2-shot mold. The 2nd-shot TPU, landing on ABS substrate and forming around a core pin, actually had its inner diameter increase after shrinkage. I think this is because the structure became a thinner doughnut during shrinkage, pulling the I.D. away from the center of the circle. But the mold maker had assumed all of the diamters would simply decrease after shrinkage. So the core pin was made pre-large originally, and now we have to make it pre-small (since I.D. will increase). Do you think the effort would
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