Deep Drawing

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Deep Drawing
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Inportant factors of deep drawing

• Properties of the sheet
• ratio of blank dia and punch dia
• clearance
• punch and die corner radii
• speed of punch
• holding force etc

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Deep Drawability

• Limiting drawing ratio (LDR)
• Max D0/Dp ratio
• R (normal anisotropy)
• If R1 sheet is isotropic.

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• For a gage length of l and subscript o and
  f are original and final dimension.
• R can be calculated by measure w0, wf, lf, l0 for
  20 or 15 stretching.
• For rolled sheet R value varies based on the
  direction of rolling.

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• Rbar also depends on grain size and texture.
• Cold rolled Rbar increases with increasing
  grain size.
• Hot rolled Rbar is approximately equal to 1
  since texture has random orientation.
• Ebar is calculated similarly to Rbar. Planar
  anisotropy causes ears to occur.

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Case Study
Beverage cans Page 395/396 of the text book
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Formability of Sheet Metal

• Cupping test Erichson test 1000kg
• Bulge test Hydraulic pressure no friction
  involved
• Forming limit diagram
• Grids are marked on the sheet
• Sheets of several widths

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