In stamping, a press and die apply external force to sheet, strip, tube, or profile stock so the material either plastically deforms or separates to achieve the required shape and dimensions. On the shop floor, we mainly deal with two categories: separation and forming. Separation operations include blanking, punching, trimming, and cut-off, where the sheet fractures along the contour under the action of the punch and die cutting edges. Forming operations cover bending, drawing, flanging, and bulging, where the material plastically flows inside the die cavity and changes shape. In both cases, die clearance, corner radii, and blankholder force settings directly determine part quality.
From a die-building standpoint, clearance is the first thing we verify on the bench. Too small a clearance on blanking or punching accelerates edge wear and can cause secondary shear or die chipping; too large a clearance produces heavy burrs and poor cut-edge squareness. For forming dies, punch and die corner radii control material flow — undersized radii in drawing risk tearing at the die entry, while excessive blankholder force starves the flange of material and promotes wrinkling. We also check punch-to-die alignment and shut height before tryout, since even minor misalignment shows up as uneven burr height or localized thinning on the formed part.
In practice, the process sequence and die structure must match the material grade and thickness. Progressive dies for high-volume work need careful station layout so separation and forming operations do not interfere, and stripping force must be balanced against the blankholder setup. During tryout, we adjust pressure and clearance incrementally and inspect burr height, thinning, and springback rather than relying on the nominal die drawing alone. For more mold sourcing and die technology information, visit MoldSo at www.moldso.com.