What is press brake bending?

The punch is the upper tool; the lower tool is usually a V-die. In air bending, the most common method, the sheet touches the die only on its shoulders and the punch in the middle, and penetration depth sets the angle. In bottoming and coining the punch presses the sheet fully into the die; that takes more force and a tool set per angle.

What decides angle and radius in press brake bending?

Once released, the sheet springs back. How much depends on the material's yield strength, the thickness, the ratio of inside radius to thickness and the die opening; high-strength steel and stainless steel spring back more than mild steel. Angle measurement on the brake or a correction in the program compensates for it. In air bending the inside radius follows mainly from the die opening and the material; if the punch radius is larger, that sets the radius. The die opening also sets the minimum flange length. The bend sequence decides whether a later bend can still be made without the part hitting the tools or the machine. A bend line across the rolling direction reduces the risk of cracking.

How does press brake bending work in practice?

Time follows the number of bends, the number of times the part has to be turned or flipped and, for large or heavy parts, handling. On a manually operated brake that is work per bend; a robot cell shifts the balance between setup time and run time. Each different punch and die combination means a changeover, and the first piece is usually measured and adjusted. How you spread that setup across a batch is an estimating convention; on a one-off with many bends, setup can take longer than the bending itself.

What is press brake bending often confused with?

Press brake bending is not rolling: rolling bends sheet between rollers into a continuous curve, a press brake makes an angle along a straight line. Nor is it cutting the flat pattern: cutting comes first, and an error in the flat pattern can rarely be put right at the brake.