In stamping, we split everything into two big families: separation and forming. Separation covers shearing, blanking, punching, trimming, and slitting — the metal is cut along a contour line. Forming covers bending, drawing, flanging, and embossing — the metal is plastically deformed without fracture. The line between them matters because it dictates die clearance, punch and die material selection, and press tonnage. For a blanking die, clearance typically runs 5–10% of sheet thickness per side; for a drawing die, you're looking at blank holder force and draw radius instead. Get the classification wrong and you'll scrap the first article before lunch.

The three core operations every die maker should know cold are blanking, bending, and drawing. Blanking produces the flat blank — die clearance and shear angle control burr height, usually kept under 5% of thickness. Bending forms angles; springback is the enemy, so we compensate with over-bend or bottoming, often 2–5 degrees depending on material yield strength. Drawing pulls a flat blank into a cup or shell — here the draw ratio (blank diameter divided by punch diameter) rarely exceeds 2.0 in a single pass for mild steel. Each operation demands its own die structure: compound dies for blanking, V or U dies for bending, and draw dies with proper radii and vents for deep forming.

From a quoting standpoint, knowing which category and operation applies tells you the die type, number of stations, and tryout time before you even open CAD. A simple blanking tool might quote at 15–20 hours of design; a progressive die combining blanking, bending, and drawing can easily hit 120 hours plus. That's the difference between winning and losing a job. For more mold sourcing and technical resources, visit MoldWorld at www.moldw.com.