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A customer asked me this question the other day… KL We are using a screw specifically designed for our grade of PP, we have performed the tact temperature study, and have optimized both injection and packing. All these have helped, yet our cycle time is still limited by the screw recovery time, do you have any suggestions? My Response Once the process and screw […]

After answering some follow-up questions from the last post, I decided to clarify the difference between Dynamic cavity balancing and Static cavity balancing with repsect to either injeciton molding or injection-blow molding. Dynamic Cavity Balancing When the mold cavity is filling, the polymer flow front is considered dynamic, or in motion. The balance of two or more mold cavities […]

I received this question over the weekend… Ponce What is the right procedure for performing a cavity balance test for a blow molding machine with an injection, pack and hold? My Response Basically, the procedure is similar to that of an injection molding machine. You would turn off the second and third stage, and then compare the shot […]

During an on-site consultation, I was recently asked this question… George When troubleshooting a Decoupled III process for variations in overall part dimensions, what parameters should we investigate. note: A DIII process has many specific attributes, but the key aspects include a velocity controlled 1st stage fill (90%), 1st to 2nd stage transfer by position, velocity controlled […]

Recently, I was working with a customer who was looking to reduce the cycle time of a particular process… Situation In this case, the customer was buying as many parts as the molder can produce. The ejected parts were sub-gated for part removal while the parts are being dropped onto a conveyor belt. Since the material was a TPO, the parts […]