Max Velocity Settings for Thin Wall Molding

A blog reader submitted an entry this morning… Jean Francois We are using a decoupled process. During fill, the pressure is set to a max pressure and should not to be reached. However, when molding thin wall parts with long flow paths, it is common to reach the maximum machine capacity pressure before reaching the expected velocity. […]

Correcting Outdated Process Philosophies

An employee confronted his management with this proclamation he found on a website… I was asked to explain why this was an incorrect philosophy for a 21st century processor.  Outdated Philosophy Plastic is compressible.  We must take the injected shot past its ability to compress so that it acts like a hydraulic (non-compressible) fluid to […]

The Effects Of In-Mold Labelling On Polymer Flow

In a recent webinar, I received this short question… Jeremy Does the use of in-mold labelling have a significant effect on polymer flow? My Response Basically, there should be no significant change in the behaivor of the polymer. Since the polymer exhibits fountain flow, the polymer touching the label surface is stagnant, while the moving […]

Purpose of Grooved Feedthroats

Recently, a webinar participant asked me this question about extrusion… MH Why would I consider purchasing an extruder with a grooved feedthroat? My Response Conveying in the feed zone will only occur if the plastic grips the barrel and slides on the screw.  Whenever it grips the screw surface and slips on the barrel, it […]

Check Ring Drift vs. Repeatability

In a recent e-mail, I received this question from one of our customers… Jim M. Regarding cushion, regardless of dynamic check ring tests (e.g. get 1.3%) if the machine will not hold a cushion, should the culprit be repaired? For example, the gate freeze test shows 7 seconds & the hold time is set to […]