In stamping production, the process is classified by deformation behavior into two major categories: separation operations and forming operations. Separation operations, such as blanking, piercing, and trimming, subject the sheet to shear stress until the material fractures along a defined contour—the die clearance is the critical variable here, typically set at 5–10% of sheet thickness per side depending on material grade. Forming operations, including bending, deep drawing, and flanging, keep the material intact and rely on tensile and compressive stress to reshape it. For a die engineer, this distinction drives everything from punch-and-die material selection to press tonnage calculation: separation dies are sized around shear strength, while forming dies must account for springback compensation and blank-holder force.
The three core operations—blanking, bending, and deep drawing—each carry their own tooling requirements. Blanking dies need precise punch-die clearance and stripper plate design to prevent burr height from exceeding 0.05 mm on precision parts. Bending dies must factor in bend radius (minimum 1× material thickness for mild steel) and incorporate springback allowance, often 2–5 degrees for high-strength steel. Deep drawing dies demand careful draw radius and clearance control, with drawing coefficients per pass typically held between 0.5 and 0.8 to avoid tearing. When quoting a stamping project, these parameters directly affect die complexity, number of stations, and tryout time—underestimating springback or clearance in the quote is a common cause of margin loss.
In practice, many parts combine all three operations in a progressive die, so the process plan must sequence separation and forming steps to avoid interference and maintain strip integrity. Reviewing the force analysis for each station before finalizing the die layout saves costly rework during tryout. For more mold sourcing information and supplier comparisons, visit MoldSo at www.moldso.com.