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Extruded Plastic Tolerances
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Posted by: KRP

09/05/2003, 11:22:53

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Is there a plastic industry standard for tolerances that covers both flexible and rigid materials such as PVC, TPVs,TPEs, and polypropylene? 






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Re: Extruded Plastic Tolerances
Re: Extruded Plastic Tolerances -- KRP Post Reply Top of thread Forum
Posted by: jalipa

09/24/2003, 08:42:34

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There is a German Standard DIN 16901 that cover metric and imperial tolerance for some plastic materials. It should only be used as a guidline tho'

The tolerances of a plastic part are affected by it geometery, mould fill direction, mould shrinkage and service temperature.

A rule of thumb:-

Tolerance = Dimension x shrinkage x thermal Expansion coef.

(+ common sense)

This gives you an absolute minimum....use the maximum that your tolerance stack up allows.

If you need to go under talk to the material supplier and moulder -- then use metal ;-)

Note:- with "Thin Wall" technology that is now being used you can have amazingly thin sections, but at a high processing cost....talk to an expert on "thin wall" tolerancing.

Hope that helps.

J.







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