In today’s issue of Cliff’s Chronicles:
What do you think when you see a part with splay, surface bubbles, and streaks? What do you think when a process is running poorly? Something must be wrong with the material, right?
Well, don’t jump too fast to conclusions! Our own Director of Applications Development, Cliff Watkins, has spoken with several customers in recent months dealing with improperly dried resin, and the solutions almost always boiled down to equipment and process fixes.
Here’s the first of three material drying case studies Cliff has encountered:
Case Study #1
Problem – A customer molding high impact PA66 called one day and said their recent delivery was “really wet.” They went on to explain they could only run for four hours before the process went “off the rails.” The successful four hours corresponded to resin that had been dried for four to six hours at 180 oF. Cliff asked about desiccant bed maintenance, air supply hose connections, dry air, and dew point. The dryer was less than three months old. It was a brand new Novatec, so it couldn’t have been the dryer. Nothing else had changed – it was the same old part they’ve always run, just a new mold.
PolySource Investigation – Cliff asked if the mold was still the four-cavity mold he saw on his last visit. No, it was a new 16-cavity mold. Cliff pointed out their brand new dryer had been sized out for the four-cavity process. The tech rep made careful measurements of the hourly pounds being molded. The customer realized they were running four times the pounds from that dryer!
Cliff’s Conclusion – Dryers have throughput rates. Know your dryer!