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Injection Mouldng Number Of Gates

Injection Mouldng Number Of Gates

Injection Mouldng Number Of Gates

(OP)
Hi , All

Designing a part in PP which is much larger than I normally work on. Upshot is I am not sure how many feed points I need to include on the part. The part is 490mm long , with a main wall thickness of 4mm , width is about 80mm , depth is circa 30mm. Part will be subjected to some static loading so I am keen to make sure that the part is filled correctly and that I have no weld lines or weak areas where we can't fill the mould properly. I don't have access to any mouldflow programes , normally I just use my experience , but like I say the parts are normally mcuh smaller. So anyone got an advice , free programes / spreadsheets  or rules of thumb they could point me to.?. Any pointers appreciated.  

RE: Injection Mouldng Number Of Gates


Where/how do intend to feed the part?

Centre fed I would be certain that it would easily fill, and more than likely with a tab gate at one end.

4mm is pretty thick.

You can get flow/pressure charts from material suppliers.

Cheers

Harry

www.tynevalleyplastics.co.uk

RE: Injection Mouldng Number Of Gates

Your material supplier should supply flow path to thickness ratio charts.

These are produced from ideal conditions so subtract 30% for commercial moulding conditions unless you are prepared to pay a substantial premium for the need to use a big press and a slow cycling hot mould.

Also, it depends a heck of a lot on individual grades, so make sure the data is applicable to your grade.

A std medium high MFI PP should do it easily but may warp with a centre gate. A mineral filled grade won't warp as much but won't flow so well either.

Regards
Pat
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