Today's KNOWLEDGE Share : Differential Shrinkage Driven Warpage Problem
Today's KNOWLEDGE Share
How to experimentally spot a differential shrinkage driven warpage problem ?
If you are molding a relatively uniform thickness part and suffer from warpage, there is a nice trick to experimentally separate the contribution of differential shrinkage from other sources of problems (differential cooling, anisotropy).Just make parts that are roughly full (say, 99% full), with zero packing (no pressure, no time). By not packing, you avoid packing one area better than another (for instance overpacking the gate area vs. distant areas). As a result you have a lighter part, with sink marks all over and voids, but with essentially NO DIFFERENTIAL SHRINKAGE. If this "short shot" is flatter than your packed part, you have experimentally demonstrated a strong contribution from "uneven packing", i.e. differential shrinkage.
Learn about all this in detail in my online course on the packing phase.
Learn about all this in detail in my online course on the packing phase.
source:Vito leo
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