I often get asked about the interesting processing claims promoted by machine manufacturers.
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?
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.
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.
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