STAMPING BASICS FOR SHEET METAL DESIGN

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STAMPING BASICS


                        Stamping offers precision and good reproducibility for sheet metal. In this, more consideration is given to tooling costs over lifespan of production. 
 

  a)     Blanking:-

            Dimension checks are made at the shear area (punch side) as the die side accuracy is affected.
        1.      Corners-                May be sharp. To reduce tooling costs, radius is specified as ½                    
                                          material thicknesses or .015” min.
        2.      Notches & Tabs-   Width   >= 1.5X  Material Thickness
                                           Length <=  5X    Material Thickness

  b)    Cutoffs:-

           There are three kinds of cutoffs:-
      1.      Straight/Square cutoff (Most Economical)
      2.      Half round or Partial radius
      3.      Full radius (not recommended due to unavoidable “feather edge” burr along the outside material edge.)

  c)     Piercing:-

1.      Min dia of holes   >= 1.2X Material thickness
                              =   2X Material thickness (for stainless steel or high tensile materials)
2.      Edge to hole          =   2X Material thickness (web to prevent bulging of material)

  d)    Forming:-


  1.      Bend Relief-                        (Width = 2T & Depth = T+R) for L shaped features.
  2.      Edge Bulging-                     Formed features from V-bends results in edge bulging. Bend
                                             relief should be provided accordingly.
  3.      Forming Near Holes/Slots-  Hole to form distance =  2.5T + R
                                             Slot to form distance   =    4T + R

  e)     Drawing:-

  1.      Shapes-  Round shapes are easy and economical in drawing. Another option for shape is
                square with adequate corner radii. Cost increases for combinations of basic
                and irregular shapes.
  2.      Radii-     Punch & Die radius = 4X  Material thickness(min)
                Part radius                > 6X Material thickness

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