Achieving the correct bend angle in a bending operation can be very difficult.ДЄmong the various bending methods are wipe bending, V bending, and rotary bending. Items such as tabs and channels are created using the bending process. Bending DiesД«ending can be defined simply as a forming operation in which the metal is deformed along a straight axis. These dies, also referred to as qualifying dies, usually use tension to re-form the part however, compression also can be used. They also help compensate for springback that occurred during the initial forming.ДЄ restrike die operation often follows a drawing or trimming operation. Restrike dies add details such as sharp radii and small embosses. The restrike die's function is to finish forming features that could not be obtained in a previous operation. The main difference is that a restrike die is used after most of the major forming already has been performed. The restrike die operation fundamentally is a solid forming operation. A simple round metal slug is placed into the die and forced to flow into a given shape by compressing it (see Figure 3). Coins (metal currency) are created with the coining process. Coining also can reduce the metal thickness. Because this operation also uses tension to form the part, attempting to solid-form difficult part geometries using thin metal often results in severe failure (see Figure 2).Д¬oining dies create the part's shape by squeezing the metal under extreme pressure. They are used to form simple parts, such as brackets and braces, made from thick, stiff metals that are more wrinkle-resistant than thinner metals. These dies do not control metal flow and cannot prevent the metal from wrinkling or buckling. Solid form/dead hit dies-also called crash forming dies-deform the metal using only a punch and cavity. The metal's thickness and mechanical properties, along with the forming punch geometry, determine the depth that can be achieved (see Figure 1). The die set primarily is composed of a punch and a cavity. Embossing DiesД®mbossing dies use tension to stretch metal into a shallow depression. Common Forming Die TypesДЄlthough many die types exist, this article focuses on those used in the most common forming operations.

Most forming operations involve at least two basic components: a punch, representing the male portion of the die, and the cavity, representing the female portion. This balance between formability and strength often is hard to achieve. It also must be strong enough to satisfy the part's fit and function. The metal being formed must have the ability to stretch and compress within given limits. Successful sheet metal forming relies heavily on the metal's mechanical properties. Most part defects, such as splits and wrinkles, occur in forming operations.

All forming operations deform sheet material by exposing it to tension, compression, or both.

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