19-05-2012, 04:56 PM
SHEET-METAL FORMING PROCESS
16sheet metal forming.ppt (Size: 1.65 MB / Downloads: 179)
Shearing
Shearing usually starts with formation of cracks on both the top and bottom edges of the work piece.These cracks meet each other and separation occurs
Process parameters :
Shape of the material for the punch and die
Speed of the punching ,lubrication and clearance
Shearing dies :
Clearance : function of type of material,its temper and its thickness and of the size of the blank and its proximity to the edges
Clearance of soft materials are less than harder grades
Punch & die shapes :
Surfaces of punch and die are flat
Punch force builds rapidly and entire thickness is sheared at same time.
Bending is suitable for shearing thick surfaces
Grain size :
Grain size effects mechanical properties & surface appearance
The coarser the grain the rougher the appearance
Sheet metal formability :
Sheet metal undergoes two forms of deformation
Stretching
Drawing