Sheet Metal Forming
 • One of the oldest processes - more than 5000 
  years old.
 • Can create light weight and versatile shapes.
 • Carbon steel-most commonly used sheet metal.
 • Low cost, good strength & formability.
                 Sheet Metal Forming
   • Metal forming processes include:
      – Roll forming
      – Stretch forming          – Superplastic forming
      –                          – Peen forming
        Drawing
                                 – Explosive forming
      – Rubber forming
                                 – Magnetic-pulse forming
      – Spinning
       Sheet Metal Forming
 • Stamping operations include:
    • punching  • lancing
    • blanking  • piercing
    • embossing • perforating
    • bending   • parting
    • flanging  • notching
    • coining
          Shearing
 • Most basic operation.
 • Sheet is subjected to shear stresses as punch and 
  die interact.  (Fig. 16.2)
 • Components are punched hole and slug.
        Shearing Mechanics
 • Edges of shear zone are not smooth. 
 • Shearing starts with formation of cracks at top and bottom 
  edges of workpiece.
 • Cracks eventually meet and separation of slug occurs.
 • Cracks generate the rough fracture surfaces. (fig. 16.5a left)
 • Rubbing of sheared edge and wall of punch & die create 
  shiny burnished surfaces.