we have a part which is 220mm long x 100mm wide, it incorporates 2 living hinges along the 220mm length, the part has varying thicknesses, from 1mm thick to 3mm.
problem, we have some depression in the thicker areas and the length is out by 2mm, not shorter though longer, the width of the part is perfect.
the living hinges are ok though a little stiff, hinge thickness is 250um.
material we have used is a polypropylene,
I was hoping someone would have the knowledge to help us remedy the over length and depressions we are getting.
any advice on a appropriate material would also be appreciated.
Hi Rick, the images will show all I hope, the length is reduced to a more tolerable dimension, since changing plastic, still not 100%, should be 200 long. still have problem with depressions, which will be something intolerable.
the gate it self is 10mm x10mm, I can get the drawings to you if that helps.
BTW thanks for helping I didn't know where to turn.
Hello!
If the part is too long, try reduce cooling time. i had same problem on similar tool, and i had to reduce cycle time for almost half, from 50s to 33 s. open the mold as soon it is possible, so the part start shrinking when its hot. And reduce holding pressure time, but you will have biger sink marks, i dont know how much it is aceptable. Boris
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