Chapter 26 Oxyfuel Gas Cutting 403 Copyright Goodheart-Willcox Co., Inc. Parts can be simple or complex shapes. Cutting systems have one or more torches mounted on a motor-driven beam. A computer controls the movement of the beam over the parts being cut. The beam on which the torches are mounted extends across the cutting table. The material to be cut is placed on the cutting table. The torches are adjusted to a consistent height. Higher-end cutting systems can automatically adjust the torch height. A programmer enters the part shape into the computer using CAD (computer-aided design). The cutting path is determined by the software being used and confi rmed by the programmer. The cutting path is a set of movements the torches will follow to cut the desired part. Cuts may be simple, straight cuts or may be complex shapes. A computer controls motors that drive the beam and torches over the cutting area. The computer also controls the speed of the torch movement, which is the cutting speed. Another type of system moves the cutting table under the cutting torches. In this system, the computer controls motors that move the table. Torches are lit and adjusted following the same steps as for a manual cutting torch. Advanced cutting systems can light and turn off the torches as part of the program. This saves time and money. This same motor-driven beam-mounted cutting system is used with plasma arc cutting torches. Plasma arc cutting torches are mounted on the beam instead of oxyfuel cutting torches. Exercise 26-4 Machine Cutting Use any available cutting machine. 1. Obtain a piece of mild steel that measures at least 6″ × 6″ (150 mm × 150 mm). The piece should be at least 1/4″ (6.0 mm) thick. 2. Refer to the procedures for setting up and adjusting your cutting machine. 3. Make cuts as directed by the instructor. 4. When the cuts are completed, shut off the drive motors and turn off the torch(es). Shut down the cutting outfit. Inspection: The edges of the finished part should be smooth. Slag should not be present.