In stamping, every operation falls into one of two families: separating and forming. Separating operations—blanking, piercing, trimming, and slitting—shear metal along a closed or open contour. The single most important variable here is die clearance. As a rule of thumb, for mild steel we set clearance at 5–8% of sheet thickness per side; for stainless and high-strength steel, that climbs to 8–12%. Too little clearance accelerates punch wear and produces secondary shear; too much gives you heavy burrs and a rolled edge. On a 1.5 mm cold-rolled steel blank, for example, a 0.10–0.12 mm per-side clearance is a solid starting point before fine-tuning on the press.

Forming operations—bending, drawing, flanging, and coining—reshape the blank without severing it. Bending always brings springback, and how you compensate depends on material and tooling. For a 90° bend in 1.0 mm mild steel with a 2 mm inside radius, expect roughly 1–3° of springback; overbend the punch or add a bottoming step to hold the angle. In deep drawing, the drawing coefficient (m = d/D) governs how many passes you need. A first draw typically runs m = 0.50–0.60 for mild steel; push below that and you risk wrinkling or tearing at the die radius. Keep the draw radius at 6–10 times sheet thickness and control blank-holder force carefully—this is where most tryout time gets spent.

From a die maintenance standpoint, clearance and springback aren't set-and-forget numbers. They shift with coil batch, lubrication, and press condition, so build adjustment into your die—shimmed punch plates, replaceable draw radii, and dialed-in nitrogen springs for blank holding. Track burr height and bend angle on first-off samples every run; that data tells you more than any spec sheet. For engineers sourcing dies or comparing stamping suppliers, visiting MoldWorld (www.moldw.com) gives you a solid starting point for mold and die sourcing information.