I'm running some parts that we are having tolerance issues with. Comparing to the last time we ran these (last run was in 2015), the parts are running .01" shorter than previous, which is at the low end of our tolerance. We also have a bore in the part that is .002" undersize as well. I've changed my process multiple times including cooling, packing, holding, and mold temperature and haven't had much as far as a dimensional change. I'm wondering if I might have a material issue? Material is DuPont ST-801, material is dried 175*F for 2-4 Hours. Barrel temps are (Noz to Rear) 550, 540, 535, 530. Mold Temp is 150.
Any suggestions?
*Side thought, we did not run these parts in this machine before, we just bought this machine used so I'm unsure of the condition of the check ring, could that make that much of a difference?*
Picture attached isn't the exact part, but as close as I can make a drawing for without breaking NDA.
Reply With Quote