In stamping, everything starts with the press. Tonnage and stroke length define what you can realistically form or blank, and undersizing a press is one of the fastest ways to wreck a die. For a typical 1.5mm cold-rolled steel sheet, the blanking clearance usually runs between 8% and 12% of material thickness. That range isn't arbitrary—too tight, and you'll see excessive die wear and burr height climb; too loose, and the edge quality drops while slug pulling becomes a real headache. On the die side, the punch and die insert materials matter just as much. For high-volume blanking, SKD-11 or equivalent tool steel with proper heat treatment holds clearance far better than generic stock. Stripper plate design and spring pressure also influence whether the strip feeds smoothly or jams every few hundred strokes.

Drawing operations demand a different mindset. You can't just pick a clearance and run—you need to allocate deformation across each drawing stage based on the drawing coefficient. If the reduction per pass is too aggressive, the flange wrinkles; too conservative, and you waste stations or end up with earring defects. Lubrication selection ties directly into this. A chlorinated EP additive works well for deep drawing stainless, but for plain cold-rolled sheet, a lighter film often prevents suction between the blank and die face. In our shop, we've found that adjusting blank holder force by 5–10% can mean the difference between a clean draw and a torn cup, especially on 1.5mm material with tight corner radii.

None of this exists in isolation. A die that runs perfectly on a 200-ton mechanical press may chatter on a hydraulic press with different ram dynamics. That's why we always trial clearance and draw ratios on the actual production press, not just a tryout machine. Keeping a log of tonnage, material batch hardness, and die maintenance intervals pays off when a job comes back six months later. For more mold sourcing and technical resources, visit MoldWorld at www.moldw.com.