I often see many people getting hung up on the specific percentage fill for first stage short shots… Student In a 4 cavity mold, I usually have to make the part 90% full to create a short shot in all cavities. Is that OK, or does it have to be exactly 95% full? My Response […]
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Routsis Training
Documenting Coolant Temp. without a Temp. Controller…
I encountered this question the other day in a training session… Student Our production facility does not use a temperature controller. Is it still important to document the coolant temperature? My Response In this case, it is even more important. If a temperature controller is present, then you can at least assume that the coolant temperature approximates the setpoint. If […]
Molding of Magnesium…
I received this question during NPE… BD We have a customer who wants magnesium parts. What is the basic principle to metals injection molding? My Response Essentially, materials such as magnesium are effectively alloyed to create a thixotropic material. This alloy can be shear heated like a polymer to create a semi-solid slurry which can be injection molded. The […]
Polishing Actually Removes Metal…
I heard a die setter make this statement recently… Setter Mold makers get all bend out of shape whenever we touch the mold surface. It’s no big deal to polish out a scratch. My Response First off, polishing takes a long amount of time and is a very labor-intensive process. This person has obviously never […]
Mold Temperature and Weld Lines…
I was discussing a processing issue with a technician and encountered this question… Tech The cause of the poor weld line was mold temperature, but I don’t really understand why since the melt flows from the center and should be hot when the flow fronts meet. My Response This is a true, but the strength and appearance […]