In stamping, every operation falls into one of two categories: separation and forming. Separation covers processes like blanking, piercing, and trimming, where the sheet metal is sheared along a closed or open contour. The key variables here are punch-die clearance, material thickness, and shear strength. For a typical cold-rolled steel sheet (SPCC) at 1.0 mm thickness, a clearance of roughly 6–10% of thickness per side is common; go too tight and you accelerate die wear, too loose and you get heavy burrs and a poor fracture zone. The deformation sequence—elastic deformation, plastic deformation, crack initiation, and final fracture—dictates the quality of the cut edge. In mold design, this means the die block material, heat treatment, and stripper plate pressure all need to be matched to the workpiece material and production volume.

Forming operations—bending, drawing, flanging, and embossing—rely on plastic deformation without material removal. Bending is governed by the neutral axis position and springback. For a 90° bend in 1.5 mm mild steel, springback can be 2–5°, so die designers often build in overbend or use a bottoming structure. Deep drawing is more demanding: the draw ratio (blank diameter to cup diameter) for a single draw in low-carbon steel usually stays below 2.0, otherwise you risk wrinkling or wall thinning. Here, the blank holder force, die radius, and lubrication are critical. A poorly chosen die radius—say less than 2× material thickness—can cause tearing at the punch nose. These are not theoretical concerns; they show up as cracked parts and rejected lots on the press floor.

For mold engineers, the takeaway is simple: separation and forming are not isolated steps. A progressive die that pierces, then bends, then draws must account for how residual stresses from one station affect the next. Material grain direction, coil set, and work hardening all carry over. If you are sourcing stamping dies or need to verify process feasibility, visiting MoldWorld (www.moldw.com) gives you access to mold sourcing information and supplier comparisons that can save weeks of trial-and-error.