Warum Schläge an der Kante versagen - nicht nur an der Dimension

In precision stamping dies, edge instability are often found out to be the punch failures instead of overall dimensional accuracy. Although many of the precision punch insert meet the requirements of the drawings in terms of size and tolerance, premature damage still occurs during the trial production or mass production process. Common issues include edge chipping, localized wear, micro-cracks, and unexpected stress concentration along critical contours.

These failures typically occur at the edges. At the edges, cutting forces are highest and material behavior is most sensitive to surface condition, as well as geometric continuity. If the edge quality varies along the profile, even a punch that measures correctly on paper may perform poorly.

In the high-precision ,WAIDA profile grinding machines, the grinding wheel is dressed to match the exact punch geometry. Therefore, material can be removed uniformly along complex profiles.

Solutions

Profile Grinding (PG) addresses this issue by taking into account both size control and ensuring the consistency of the edge shape throughout the entire contour.

Unlike machining processes that only focus on size, PG controls profile geometry, edge sharpness, and surface integrity simultaneously. 

When executed properly, profile grinding can ensures that every section of the punch edge behaves predictably under load.

This results in stable edge conditions, reduced local stress concentration, and improved contact behavior during stamping. For punch inserts with intricate shapes or tight internal radii, PG offers a level of control that is difficult to achieve with wire EDM or milling alone.

In addition, PG has a good impact on die assembly and adjustment. Punches with consistent edge quality require fewer manual corrections during fitting, reducing setup time and minimizing trial-and-error adjustments. For stamping die engineers, it means shorter lead times, more predictable performance, and improved batch-to-batch consistency.

Overall, punch durability is not about dimensional accuracy.  Edge consistency is a critical factor in tool life and production stability. By applying profile grinding to punch inserts, engineers can significantly reduce unexpected failures, extend maintenance intervals, and achieve more reliable stamping results across long production runs.