Defects can have different forms and causes in production. In Alples d.d. Company the quality of workpiece edges is very problematic. According to different findings and calculations there are up to 20.8 % edge-related inconsistencies. We seek causes for this deviation in the production itself, which is not always justified. On the basis of the current quality analysis we discovered that we should look for these causes also in the production organization. Causes can, of course, be also elsewhere, for example: tool wear, material quality change, electric power oscillation, carelessness, machine vibration, loosened chuck, temperature change, etc. We do not have an impact on some of them and we cannot prevent them, but we can mitigate them.