In the world of manufacturing, metal bending is a critical process that facilitates the creation of various shapes and designs. Sheet metal bending involves deforming the metal across an axis using a punch and die. This article delves into the process and methods of bending sheet metal parts, providing insights into this foundational manufacturing technique.

Most bending parts are made using processes and methods such as air bending, bottoming bending, and hemming. The operation follows the same principle: the punch presses the workpiece into the die. Therefore, the bending machine that performs these processes and methods is called a press brake. In addition to press brakes, Tongkuai also offers swing arm bending machines.

Air Bending:

Air bending is a process where the punch presses the workpiece into the die without pressing it against the die walls. As the punch moves down, the edge of the workpiece bends upwards and forms an angle. The deeper the punch presses the workpiece into the die, the smaller the angle. There is a gap between the punch and the die during air bending. Air bending is also known as path-dependent because each angle requires a specific path. The machine control system calculates the path and corresponding punching force. The path and punching force depend on the die, material, and product characteristics (angle, length).

Bottoming Bending:

Bottoming bending is a process where the punch fully presses the workpiece into the die, leaving no gap between the die, workpiece, and punch. This process is called bottoming. The punch and die must fit precisely. Therefore, each angle and shape require corresponding die components. Once the workpiece is fully pressed, the punch cannot continue to move downward. The machine control system continues to increase the punching force until it reaches the specified value. The pressure applied to the workpiece rises, showing the contour of the punch and die. The angle gradually stabilizes under high pressure, almost completely eliminating springback issues.

Folding and pressing：

The edges of sheet metal are typically fully bent (e.g., box edges), followed by parallel flanging. This makes the finished piece more stable or forms edge protection. Additional parts may need to be inserted into the flanged edge. Flanging and hemming are completed in two steps: first, the operator pre-folds a 30° angle, then reinserts the workpiece and hems the angle. If there is a gap between the edges, it is called flanging. In hemming, the bent edges are completely squeezed together. Flanging is path-dependent, while hemming is force-dependent.

Swing Arm Bending:

The bending swing arm built into the machine is made of C-shaped profiles, with lower and upper bending dies installed on it. During bending, the C-shaped profiles move up or down, or perform small elliptical movements, i.e., flipping. The swing arm bending machine operates semi-automatically, known for its speed and flexibility, even in small batch production. Additionally, through flip bending technology, the same die can be used to efficiently bend multiple radius sizes on a single part.

As a professional metal bending parts manufacturer, Janee Precision Hardware have helped more than 2,000 plants with process solutions and helped them improve production efficiency, reduce costs, and optimize profit plans. Our main goal is to assist you in optimizing production efficiency and profitability in a sustainable way.
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