When we do molding testing pr production, it's common to see the dimension is NG. so today we are going to discuss why the dimensions are not in tolerance.

1. Check the drawing, to see if you find the right datum?

2. Check the measuring tool, to see if it's outdated or the accuracy? or the scale is not clear, or the measuring tool not returned to zero?

3. Is the measurement method and reading correct? For example, when measuring the length of a plastic semi-finished case with a caliper, do we measure that the plastic part is perpendicular to the caliper? Is it done that the external measurement point is the maximum point value, and is the internal measurement point the minimum?

4. Is the measured position and the measurement tool we use accurate?

5. Check the mold drawing, the shrinkage fator is right?

6. Check the mold steel, is it machined correctly?

There are many factors to cause the dimensions not in tolenrance. let's pay more attention to each step.