The importance of sheet metal bends in manufacturing

The unique properties of sheet metal allow it to be used for a vast range of applications. Many industries use sheet metal bending techniques to create custom sheet metal parts and components. The malleability and versatility of sheet metal and the many ways in which it can be formed means that it is able to be used to produce both large assemblies on an industrial scale and limited runs of smaller, highly customized parts.
 
Sheet metal bending is widely used in the automotive industry to fabricate car bodies, frames, and panels. Engineers in the aerospace industry design airplane wings, fuselages, and various other aircraft parts using sheet metal bending. Ducts, vents, and other HVAC systems are made by forming sheet metal. As well as ventilation and heating systems, the construction industry also uses sheet metal bending to produce roofing, gutters, and many other building materials. Even the electronics industry uses sheet metal. Computers and sophisticated high-tech devices are commonly housed in sheet metal enclosures.

V-Bending

V-bending is the most commonly used metal bending technique. A v-shaped punch is lowered onto a piece of sheer metal that is laid across a v-shaped groove in a die. The punch forces the metal workpiece into the die creating obtuse, acute, or 90-degree angles.

U-Bending

U-Bending is much the same process as v-bending, except that the punch and die are u-shaped. This process is used to create sheet metal workpieces with rounded bends.

Edge Bending

Also known as wipe bending, the edge bending process works by forcing a punch downwards against a sheet metal workpiece held in place by a pressure pad. Instead of forcing the workpiece into a die, the punch moves (or wipes) the sheet metal down over the edge of the die to create a bend.

Air Bending

Air bending is a form of v-bending. Unlike the v-bending method, air bending does not force the workpiece into the very bottom of the die. It leaves a gap between the bottom of the workpiece and the die cavity. Air bending allows for more control over the bend angle.

Bottoming

Also referred to as bottom bending, bottoming is a v-bending technique used to solve issues of springback. When using a bottoming technique, additional force is applied to the die after the bend is complete.

Coining

Coining stamps the workpiece between the punch and the die as with v-bending. However, the coining technique involves having the punch penetrate the workpiece, just like coins are imprinted when they are being minted.

Rotary Bending

Rotary bending is sometimes called rotary draw bending. In this process, the workpiece is held by a rotating die and then drawn around the die to form the desired bend. There is often a mandrel that provides internal support and stops the workpiece surface from wrinkling. Rotary bending does not scratch the surface of the workpiece, unlike other sheet metal bending techniques.

The first step in the sheet metal bending process is to create a design that can be used either by CNC machinery in an automated process or by engineers to manually bend the metal. Sheet metal designs are created using specialized CAD sheet metal unfolding software. An engineer may also create a 3D model that can be used to run a sheet metal bending simulation.
 
Often, the sheet metal workpieces will need to be prepared before bending. The metal may need to be cut into certain lengths, sheared, punched, or stamped. An engineer will need to carefully evaluate the thickness of the metal to determine the bending sequence and the angles required. To do this, they need to calculate the k-factor and the y-factor of the workpiece. These calculations are used to evaluate the bend allowance of the material.  
 
Next, the tooling and equipment required will have to be selected. The machinery selected will depend on the nature of the finished product, for example, a press brake with a v-shaped punch and die for v-bending. The sheet metal then needs to be loaded and clamped into the machinery before the bending process can begin. Once completed, the sheet metal is unloaded and inspected for faults or defects.

Engineers need to consider a range of factors when designing sheet metal bends. The material type and the thickness of the material are crucial to calculating the bend allowance. Engineers also need to be sure they use a single bend radius as this will reduce the need for extra tooling work. The bend radius must be equal to or gather than the thickness of the sheet metal workpiece.
 
The tooling selection is also critical. Choosing the right type of machinery will help to avoid issues such as springback, which is where a workpiece will revert partially or wholly to its original form after the bending process. Air bending, for instance, results in less springback than simple v-bending.

To produce quality parts, an engineer must create a highly accurate sheet metal design. Using CAD sheet metal development software ensures that there are no small errors in the design that can become major issues during fabrication. Dedicated sheet metal design software results in clearer, highly detailed plans that can be converted into CNC files.
 
CAD sheet metal designs ensure there are fewer inaccuracies in design interpretation at the shop floor and vendor levels. By using a CAD sheet metal bending simulation there is less time lost in revisions and no need to repeatedly fabricate physical prototype parts.