In stamping production, the entire process is built around two deformation categories: separation operations and forming operations. Separation covers blanking, punching, trimming, and slitting, where the material is sheared along a defined contour; forming covers bending, drawing, flanging, and embossing, where the material flows plastically without fracture. For die design, this distinction drives everything from punch-to-die clearance to die block material selection. In a typical blanking die, clearance is set at roughly 5–10% of sheet thickness per side depending on material grade; get it wrong and you trade a clean shear band for excessive burr and secondary finishing cost. Forming dies, by contrast, live or die by springback compensation and corner radius control, and the die surface often needs polishing to Ra 0.4 or finer to control friction and material flow.

The three core operations—blanking, bending, and drawing—each carry their own tooling logic. Blanking dies demand tight punch-die alignment, hardened inserts (commonly SKD11 or equivalent at 58–62 HRC), and a stripper plate that holds the strip flat during shear. Bending dies require careful attention to bend allowance and back-gauging; a 90° bend in 1.5 mm cold-rolled steel typically needs 2–3° of overbend to counter springback, and the die radius should stay at or above one sheet thickness to avoid cracking on the outside fiber. Drawing dies are the most sensitive: draw radius, blank holder force, and lubrication all interact, and a first-draw reduction above roughly 40% of blank diameter usually calls for a redraw station rather than a single hit. Progressive dies that combine all three operations need careful strip layout so that pilot holes and carriers survive every station.

In practice, most production problems trace back to misjudging which category an operation belongs to and sizing tooling accordingly—excessive burr height (often specified at 0.05 mm max for precision parts) points to a separation issue, while wrinkling or thinning in a drawn wall points to forming parameters. Keeping a clear separation-versus-forming checklist at the design review stage saves far more time than debugging on the press. For more mold sourcing and tooling information, visit MoldSo at www.moldso.com.