If a mould design with four cavity per shot and each cavity having the same dimension and design. By principle the moulded plastic parts should also have equal dimenion. However you will notice one of the cavity will have under size. can any menbers in this group give some comment. Thanks Regards
Rolf pointed out the most likely causes: differences in cavity sizes or uneven filling due to unsymmetrical runners. Another possible cause is different freeze-off time for runners or gates.
One possible way to diagnose the cause is to increase the screw forward time (the time the mold is filling). If the problem is caused by differences in runner size/length/no. of turns, increasing screw forward time should minimize the differences (the lighter parts should become proportionately heavier). But, if the problem is in gate or runner freeze-offs, increasing screw forward time is not likely to cause much difference; in this case look for differences in cavity cooling.
Ernie
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