Straight Punches

What a straight punch does

A straight punch is the upper tool of a press brake with a straight, non-offset body. It presses the sheet into a V-die to form the bend. Gooseneck punches, by contrast, are used for deep, return-bend stiffeners and side flanges, so straight punches suit flanges that do not need that extra clearance.

How the tip radius shapes the bend

In air bending, the corner of the bend forms around the nose radius of the top tool, so the punch tip radius sets the inside radius of the part. Punch tip radii run from about 0.2 mm up to 12 mm or more. The die angle, die radius and the radius at the bottom of the die have no effect on the floated inside radius.

Angles

Punch angles come in acute, 90° and other values, and V-die angles are commonly 88° or 90°. Acute tooling is for bends sharper than 90° and is meant solely for air forming.

Material and load

Press brake punches are commonly made from 42CrMo-type alloy steel with an induction-hardened working surface. Hardness and load ratings vary by supplier, height, radius and angle, so check the maker's load chart before bending.

Match your machine

Browse our clamp-architecture pages for Amada, Beyeler Safran and LVD styles.