Many injection molded parts are produced in a short time, therefore it is usually not possible to examine all parts precisely.
For this reason, only a certain number of parts are taken out of production and used for the exact evaluation.
These parts form the so-called sampling size.
There is no general rule how large a sampling size should be.
However, the more parts are inspected, the more likely the results will apply to the remaining and not tested parts.
It is therefore necessary to weigh up the time, financial and human resources against the frequency of a defect in order to determine the appropriate sampling size.