Monday, 20 April 2015

Workshop / Blanking and Punching Operation


Blanking and Punching :
Blanking and punching both are sheet metal cutting operations that involve cutting the sheet metal via shearing by a punch and die.

Case – I 
If the part that is cut out is the desired product and remaining part is removed as waste, the operation is called blanking and the product is called blank
 
Case –II
If the remaining stock is the desired part and the material punched out is removed as waste the operation is called punching
 Both operations are illustrated on the example of producing a washer.
 
 

Force required for Blanking and Punching process

            F =StL

                  Where 
                              L = total length sheared ( for circle L = πd )
                              t  = Thickness of metal sheet
                              S = shear strenth of metal sheet

Stripping force -  Force develops due to the spring back of the punched material   that grips the punch.

            SF = 0.02 Lt

                   Where 
                              L = total length sheared ( for circle L = πd )
                              t  = Thickness of metal sheet

Blanking process
Punching process
  • Die is exact     i.e.              Die size = blank size
  • Clearance is provided over punch
  • Shear is provided over Die

  • Punch is exact     i.e.   Punch size = Desired size
  • Clearance is provided over Die
  • Shear is provided over punch


No comments:

Post a Comment