In some cases the customer is responsible for the part design and their don't follow the rules of plastic development. So when the drawing with the tolerances included is made by a designer who does not know what he is doing and what he's dealing with this has to fail.
In some cases the customer is responsible for the part design and their don't follow the rules of plastic development. So when the drawing with the tolerances included is made by a designer who does not know what he is doing and what he's dealing with this has to fail.