Monthly Archives

A recent question was received via e-mail… RZ We are encountering cracking at the bosses on a polysulfone part. We press fit inserts on the bosses but we don’t see cracking during insertion. It is not until a day or two later that we see the cracking. Any thoughts? My Response The occurrence of cracking and crazing in […]

I recently received an email from a friend of mine regarding voids… Ron How do you troubleshoot voids in the sprue? My Response The presence of voids in the sprue is very common, but the need to troubleshoot this is unique to sprue-gated parts. Voids in a sprue gate are a little different than a typical sink or void at the […]

I received this general venting question the other day… LG Many of our molds have venting issues as evidenced by either burns or filling problems. I realize that a “flow analysis” done previous to cutting the steel would answer most of these questions.  The gases have to get out… What do you recommend regarding placement, size […]

A recent commenter to our blog just e-mailed me this age old question regarding gate sizing… Larry If a molder is having trouble filling a mold, yet the process is not ‘pressure limited’, would opening the gates solve the problem? My Response I typically ask for more specifics, but in this case it is more about the […]

This e-mail can to me recently regarding the complications associated with the processing of flame retardant materials… Nathan I am processing with PC/ABS C6600 FR grade material and it is difficult to maintain a consistent part quality. Recently I am getting gas marks and gas deposition on the mold surface after processing for a few hours. Proper […]