Sheet metal parts are the parts that are produced by stamping operation by sheet metals. During stamping operation, there are many sheet metal parts defects such as burrs, dents, scratches, wrinkles, fracture, crack & wrong dimension etc. So below are the operation-wise defects, their causes & remedies.
These are the defects which increase increase internal rejections. Increase in internal rejection increase cost of poor quality. So below root cause and action will help in rejection analysis during red bin analysis.
Punching, Blanking & Trimming operation:
Defect: Burr on blank or punching parts
Credit: Google
Causes
Remedies
Cutting edge blunt
Do grinding of punch & die face
More clearance between the die & punch
Maintain adequate clearance
The punch position shifted as per die
Maintain uniform clearance between die & punch
The top of the tool shifted from its bottom
Replace guide post or pillar bush
Die part shifted
Set the die part in the socket & use the dowel pin
Draw operation:
Defect: Wrinkle
Credit : Google
Causes
Remedies
The wrong lubricant used
Change the lubricant
Blank holding pressure low
Increase the blank-holding pressure
Defect: Fractured Rim & bottom in the draw
Cause
Remedy
Blank holding pressure too high
Reduce the pressure
Puching Operation:
Defect: Dent on cutting edge
Cause
Remedy
More play of posts in bushings
Replace bushings
Cutting element shifted
Maintain uniform clearance in die & punch
Press slide not parallel with bed surface
Repair the press
Tool shoes not parallel ( Spacer below tool)
Grind the shoes
Blanking operation:
Defects: Press jerks when blanking:
Cause
Remedy
Cutting force too large No taper on die cutting edge
