Create Tabs when Punching Metal Sheet

Most likely you have used tabs, or micro-joints, in one application or another in your shop. Creating tabs is a common punching application. Tabs are used to keep the part attached to the sheet so it can be easily broken free once it’s removed from the machine. The most efficient tab will keep a strong enough bond to the sheet to keep the part stable, but then break cleanly without requiring a secondary operation to clean up burrs. Tabs are used to “shake-a-part” pieces nested in sheet metal as well as to create “mini-nested” pieces for additional manufacturing processes.

	Corner Tab This is the most common shaker tab and is normally created with a rectangle or square punch. Roughly 10% of the material thickness is left in both directions.
	Wire Tab Wire tabs are weak, unstable and do not break cleanly – use as a last resort. Tab width is roughly 33% of the material thickness.
	Equilateral Triangle This standard shape tool creates triangular tabs that break cleanly. Tab width is roughly 33% of the material thickness.
	Inverted Diamond Tool This is a common special shape tool. It creates diamond shaped tabs that break cleanly. Tab width is roughly 33% of the material thickness.
	Inverted Diamond Tool with “Horns” A special shape tool similar to the Inverted Diamond. It creates diamond shaped tabs that break slightly below the edge. Tab width is roughly 33% of the material thickness. (Max Material = 0.080 mild steel / aluminum; 0.060 stainless steel)
	Half Shear Tool This forming tool can create a relatively long tab that breaks off flush to the edge.
	Dash Tool This form-up / form-down tool can create any length of tab. It is normally used on chamfered corners.

For more information on shake-a-part techniques, please contact our Tooling Technicians.

July 23, 2020

Common Ways to Create Tabs

It doesn’t matter what style of tab is used, the key to this process remains the same – keep the sheet stable during the punching machine’s cycle.