This question arrived via email yesterday… John Why is there water running through the barrel of an injection molding machine? My Response The basic purpose of the water is to cool the feedthroat to avoid bridging. The feedthroat is the area of the barrel where the material passes through from the hopper the screw. If this area gets too hot, the material may […]
Monthly Archives
June 2010
How Colorant Affects Shrinkage
I received a detailed question via email the other day, I will do my best to convey the nature of the question in this blog… Kevin I am running as part in acetal and am having difficulty in maintaining the same dimensions as natural when running colorant: When molded with natural: overall length = 49.33 […]
Should Quality Learn About Processing…
I received this question during a seminar last week… MH When you suggest including everyone in the injection molding training initiative, are you suggesting I include my quality technicians? My Response Definitely, the more quality knows about production, the better off you are. They usually don’t need to know all the technical information… but an increase in knowledge will always […]
Common Gate Sizings…
One blog reader asked this question… Larry Would you please give me the guidelines for runner and gate sizing with respect to nominal wall thickness? My Response Below are some common guidelines… An edge gate should be approximately 1/3 of the part thickness at the mold cavity. The fan and flash gate should taper […]
Back Pressure Setting…
I received this follow-up question the other day… Kevin Once I optimize my rear temperature, what back pressure should I use? My Response Back pressure serves two important roles… 1) to help ensure proper material mixing. 2) to help ensure a homogeneous melt compression in front of the screw. Your back pressure should be high enough to provide […]