8. How to calculate Weight tolerance of a molded part?

We understand that with plastic parts, weight is the best method of controlling the process capability. Is there a guideline or standard for defining the tolerance?

The most common method is:

Shot to shot weight variation calculated as (three standard deviations) divided by

(average weight) must be less than 1% and should be less than 0,5%. In general it is possible to achieve 0,1-0,4% weight variation using scientific molding.