Under cuts jump out depends of material

[alexasa]

Is there any table to show how much high in a undercuts is possible jump out depending of each plastic material?
Is there any calculation to determine how many high is possible jump out with out have a big risk to leave the part trap?

 

[MikeHalloran]

The general answer is NO, and NO.

You could do some calculations if you could predict the temperature of the part when the mold opens, and had mechanical properties available for that temperature.

Molding a part with undercuts and getting it out of the mold without destroying the part and/or the mold requires extra attention to the ejection/ stripper mechanism within the mold and to the tiniest details of the part.

Instead of frying your brain with a lot of conjectural calculations that attempt to model stuff you can't control, talk to the one guy who can control it, and has an incentive to do so. I.e., pick a molder, work out the details with him, and pay attention to what he has to say.

Note that the usual mandatory corporate procedure, e.g. designing a part complete in isolation and then putting it out for bid, doesn't work for parts with undercuts or other odd features, because every molder does things differently. This is one time where you really need to develop a real partnership with a vendor, and stick with him.

Tell your MBAs to get stuffed.



Mike Halloran
Pembroke Pines, FL, USA

 

[patprimmer]

Reputable raw material suppliers should be able to provide some information on their specific materials.

Regards

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