LAND AND ANGULAR CLEARANCE
The inner walls of a die opening are not usually made straight through as the blanks or slugs tend to get jammed inside, which may result undue stress buildup. This may lead to the breakage of the punch and die.
To avoid such situation the die walls are kept straight only to a certain amount from the cutting edge. The straight wall is called “LAND”.
An amount of 3mm land for stock thickness up to 3mm.
For thicker materials equal to their sheet thickness.
ANGULAR CLEARANCE OR ANGULAR RELIEF:
Generally, soft materials require greater angular clearance than hard materials. Soft thicker materials above 3mm require more angular clearance.
An angular Clearance of 1.5°per side will meet the usual requirements.
In special cases, the angular clearance extends from top to bottom of the die wall completely eliminating the land.
Dies employing an ejector to clear the blanks will have straight walls without any angular clearance, as the blanks do not get accumulated in the die.
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