This article breaks down the core stamping process categories—separation and forming—with real operational details for mold engineers and sourcing professionals.

In everyday die shop practice, stamping is broadly split into two families: separation processes and forming processes. Separation covers blanking, punching, trimming, and shaving—where the material is deliberately fractured along a contour. The critical parameters here are clearance, which typically runs 5–10% of material thickness per side for mild steel, and the cutting edge condition. A worn punch or die radius will produce excessive burr height and a poor shear zone ratio, which directly affects part flatness and downstream assembly. For precision blanking, we often switch to fine blanking with a V-ring impingement, achieving a fully sheared edge of 100% versus the conventional 30–50% shear band. This matters when the customer specifies tight edge requirements on gear blanks or valve plates.

Forming processes, on the other hand, include bending, deep drawing, flanging, and stretching. A common pitfall in bending is springback—for a 90° bend in 1.2 mm DC01 steel, the springback angle can range from 2° to 5° depending on the die radius and material yield strength. To compensate, we either overbend by adding a corrective angle in the die, or use a bottoming operation with a relief groove. In deep drawing, the limiting drawing ratio (LDR) for low-carbon steel is roughly 2.0–2.1 without intermediate annealing. Exceeding that causes wrinkling at the flange or tearing at the punch nose radius. Real-world dies often incorporate draw beads to control material flow, and we adjust blank holder force from 20–30% of the drawing force to stabilize the process window.

For mold sourcing and quoting, understanding these boundaries is non-negotiable. A simple blanking die for a 2 mm thick part might quote at 8–12 weeks with a tool life of 500k–1M strokes, while a complex forming die with nitrogen gas springs and sensors can push lead times to 16–20 weeks. Always confirm the material grade, edge quality class, and production volume before finalizing the die design—these variables shift the cost by 30–50%. If you need reliable stamping die suppliers or want to compare process capabilities, visit MoldWorld at www.moldw.com for a vetted list of mold makers and sourcing leads.