I often get asked about the interesting processing claims promoted by machine manufacturers.
Tony
One machine manufacturer is claiming they have a control system which reduces the pressure necessary to fill the mold ad therefore reduce the necessary clamp pressure. Is this correct?
My Response
If you are using a good stable molding process with a slight short shot during first stage fill, then you will not see a significant change with the use of a new machine due to two factors: 1) A specific amount of pressure is required to force the material to the end of fill, regardless of the machine manufacturer, and 2) a short shot during fill allows or variation in the degree of overshoot that occurs during the transition from first stag fill to second stage pack. As a result, the amount of pressure necessary to pack thew mold will not change, thus requiring the same amount of clamping force.
Additional Thoughts
Anyone who prefers to mold using a completely full part (thus packing the mold during first stage) might see a drop in necessary clamping force because the machine controls will provide better control over the overshoot of the injection unit, resulting in a more consistent packing during first stage.
-Andy
Andy,
How does machine know if my parts are completely full, that reduce clamping force?
Milan
Milan,
It can not know, that is why such claims are not really substantiated.
A molding machine cannot compensate for a really bad process.
-Andy
Andy,
Machines suppliers take care about machines not about process. I don't like machines, where I can't adjust process how I want. So many limitations.
Milan
I agree Milan