I received this question today… AJ A co-worker told me voids are actually not filled with air or gas. Is this true? Could you explain what voids really are? My Response Your co-worker is correct. Voids are sections in the center of a part where material shrinks away from itself and leaves what appears like a […]
Monthly Archives
April 2010
Feedthroat Temperature Differences…
I received this question the other day from an experienced molder… Cindy We have 2 different brands of machines. On one brand, the feedthroat temperature is 85-90ºF, yet the other brand has a temperature of 150-190ºF. Is this difference OK…? and could you comment on what effects the higher temperature will have on the process? My Response Regarding the Machine […]
Screw Flight Diameter Along the Screw
I received this question as a follow-up question regarding a different blog, and decided it warranted it’s own entry. MJ Does the screw have the same diameter in the front, middle and back screw flight diameter? My Response The typical injection molding screw has the same outer diameter along the entire length of the screw. When measuring […]
Packing With High Pressure Molding
During a recent consultation, I was asked this question… Engineer Could you explain how to pack-out a thin-walled part which requires a large amount of pressure to fill? My Response In such a case, the pressure to fill the part is typically very high… therefor, the pressure at transfer is also high. In such a case, […]
Conditions For The Dynamic Check Ring Repeatability Test
I received this questions from one of our advanced blog readers… Milan Before I perform the dynamic check ring repeatability test, must I optimize the screw recovery, decompression, back pressure, and feed zone temperature. note: The Dynamic Check Ring Repeatability Test monitors the ability of the check ring to mold consistent short shots by weighing and comparing the part […]