Bottom Bending (Set Bending)

Bottom bending (also called set bending or coined bending in some contexts) produces highly accurate angles by driving the punch fully into contact with the material against the die walls, eliminating most of the springback that plagues air bending. This method is especially valuable for parts where angle consistency across multiple bends is critical, such as precision enclosure panels and architectural trim.

The tradeoff is that bottom bending requires significantly higher tonnage, often 3 to 5 times more than air bending the same material, placing greater demands on the press brake's capacity and the tooling's load rating. Because the material is fully compressed between the punch and die, the resulting angle is highly repeatable from part to part.

Press brake shops typically reserve bottom bending for critical applications where the extra tonnage and dedicated die setup are justified by the quality requirements.