Deep Draw Stamping: Complete Process Guide

Deep draw stamping is a sheet metal forming process where a flat blank is drawn into a die cavity to create a three-dimensional part. It is used to produce everything from kitchen sinks to automotive fuel tanks.

How Deep Drawing Works

A punch forces a sheet metal blank into a die cavity. The blank holder controls material flow to prevent wrinkling. Multiple drawing stages may be needed for deep parts, with annealing between stages to restore ductility.

Key Parameters

• Draw ratio — ratio of blank diameter to punch diameter. Limit typically 1.6-2.0 per stage
• Clearance — between punch and die, typically 1.1× material thickness
• Blank holder force — critical for preventing wrinkles without tearing
• Lubrication — reduces friction and prevents galling

Materials

Low-carbon steel (DC01-DC06), stainless steel (304, 316), aluminum (5000/6000 series), copper/brass. Material formability is measured by the limiting draw ratio (LDR) and n-value (strain hardening exponent).

Common Defects

• Wrinkling — insufficient blank holder force in flange area
• Tearing — excessive drawing stress at punch corner radius
• Earing — non-uniform material flow due to anisotropy
• Surface scratches — inadequate lubrication or die polish