A captive injection molder producing caps and closures in a high cavitational hot runner manifold called me the other day because they were operating outside of their QA parameters.
On one particular line that produces HDPE caps, they were experiencing a problem with the machine if it was stopped for one reason or another. When the machine stopped and sat idle they started to see slow screw recovery times when restarting back up. This caused the machine to go off cycle. They then retracted the screw after running the machine out dry and noticed a ball of semi-melt wrapped around the feed section of the screw. This was the reason for the extended recovery time.
While visiting this customer we had a meeting to brainstorm the problem. It was suggested to try using the UP Grade as a sealant to prevent this ball from occurring. As of the writing of this report, they are currently using UP Grade as I suggested and is working well. This has allowed them to get the machine back on cycle and get right back up into production.
If you’d like more info of how you can use purging compounds to improve efficiency at your thermoplastic processing plant, contact me.