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 […]
Author Archives
Routsis Training
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 […]
The 80-20 Rule For Available Shot Size
I received this common question via e-mail the other day… MJ I heard that it’s good to have shot size from 20 to 80 percent of the machine’s available shot size. Has this conclusion was tested, or has somebody published a white paper study? My Response Although I am not familiar with studies to validate this specific conclusion, but […]
Open Loop vs. Closed Loop Controls
In a recent webinar regarding Process Documentation, I received this question regarding process controls… Frank During an In-Mold Rheology Test, should we use the closed loop or open loop option on our machines? What is the difference? note: For those new to the industry, open loop process control uses a set pressure to force polymer […]