Even the toughest tools have their limits. The main failure modes for tungsten carbide punches and dies are:
Wear: This is the most common, gradual process. The cutting edges of the punch and die slowly erode due to friction and abrasion from the material being processed. This leads to a larger burr on the finished part and eventual loss of dimensional accuracy.
Chipping: This is a more sudden, catastrophic failure. It occurs when the tool experiences excessive impact, misalignment, or a shock load beyond its toughness limit. Sharp corners on the carbide are particularly vulnerable. Using the wrong clearance between the punch and die can also cause chipping.
Gallling (or Seizing): In some cases, especially with softer, sticky materials like aluminum, small particles can weld themselves to the carbide surface. This buildup affects the surface finish of the product and can eventually lead to scoring or premature wear.
Proper setup, maintenance, and selecting the right carbide grade for the specific application are key to minimizing these failures.