276 Modern Metalworking Copyright Goodheart-Willcox Co., Inc. 17.1 Cutting Operations Cutting is the metalworking process in which metal is cut to size for machining. Few conventional cutting operations are used to bring the material to exact size. Sizing is achieved in the forming operations that usually follow. Some cutting techniques developed for volume production are shearing, laser cutting, plasma cutting, waterjet cutting, blanking, punching, and piercing. 17.1.1 Shearing Shearing is a cutting operation used to bring sheet g and plate stock to a specified size or shape. Straight edges are cut on squaring shears. Automated squaring shears use a CNC system to move and cut the material. 17.1.2 Laser Cutting Systems A laser cutting system uses a laser to cut through a variety of materials in different sizes, thicknesses, and shapes. The CNC laser cutting system in Figure 17-2 can handle sheet sizes up to 12′ × 6′ (4 m × 2 m). It can automatically change and align the nozzle. Cutting material with a laser produces superior edge quality, precision, and accuracy. Many laser cut- ting systems use a stationary bed and a moving cutting head. Laser cutting systems typically have multiaxis capability and can cut finished parts in a fraction of the time needed on most conventional machines. 17.1.3 Plasma Cutting Systems Plasma cutting systems, Figure 17-3, use an electric arc and fast-flowing ionized gases to melt and cut metals. The molten metal is blown away by the high velocity of the shielding gases. Metal in sheet form is of little value until it is processed into a useful shape to make parts or products. Metal sheet is commonly given shape using cold forming operations. Cold forming is also referred to as cold working. As the g g name implies, these forming operations are normally done at room temperature. Cold forming gives shape to metal sheet stock by applying enough force or pressure to cause plastic deformation to occur. The following sections explain some of the common cold forming operations. Stamping is a general term used for many press g forming operations. The products that are produced through these operations are referred to as stampings, Figure 17-1. Stamping can be divided into cutting and forming operations. Although the operations are dif- ferent, both can be done on the same machine with only minor modifications. Hamik/Shutterstock.com Figure 17-1. Many parts, such as these automobile body panels, are made by stamping. Stamping can produce complex contours and close tolerances quickly and consistently. Automatic nozzle changer Bystronic, Inc. Figure 17-2. A state-of-the-art CNC laser cutting system with an automatic nozzle changer.