During production control has some limits as below:
- An during production control does not cover the average quality of final products. For example, in apparel industry the last process of products is cutting thread ends, it is arranged just before the packaging of products. Untrimmed thread ends is a common minor defects in the fashion filed, but a during production control could not find this.
- It is not enough in itself. A factory might identify some problems, hide them away from the inspector, and then ship them out. This is why an inspection during production should be followed by afinal random inspection, to confirm average quality.
- For sensitive projects, the factory might need some guidance from the beginning of production. This is the work of a technician capable of setting up processes as required.
- In certain cases production takes place on multiple lines or even in multiple factories. One inspector will not be able to get an idea of average quality in one day… He should stay for longer and monitor both production schedule and quality.
- Very often labeling and packing cannot be checked properly. Chinese factories tend to receive packing accessories towards the end of production (because there are always amendment for labeling or packing till the end of production).