6. Tool wear

From the very first press stroke, the tool changes. It acclimatizes at the very start of production (running-in phase), then generally evolves slowly over the course of production until a certain limit is reached, at which point wear accelerates (figure 52 ). Wear can be more or less rapid, depending on the type of degradation encountered. The characteristics of the cut part will then be influenced by this wear, and cutting forces will also change (see § 3.1.2