Most industrial metal fabrication is now done by computer numerical control–CNC machines. CNC programming allows the machines to quickly and precisely manufacture parts to tolerances of thousandths of an inch, at a much lower cost than older manual methods.
Where earlier cnc router machine required a master machinist to painstakingly measure parts to match numbers read from a mechanical drawing, a CNC program uses the drawing itself to precisely position the working end of the tool.
A cam cylinder is a round bar with studs or notches at intervals which move a pin or key as the cylinder is turned. Older music boxes and player pianos used cam cylinders.
Computer numerical control was developed along with the earliest computers, beginning in the late 1940s at the Massachusetts Institute of Technology (MIT). As engineers at MIT were developing computer-aided design (CAD) programs, they immediately saw the advantages of computer-aided manufacturing (CAM). Their work led to today’s CNC machines, which became widely available and commonly used by the 1970s.
Almost any type of tool–lathe, router, cutter, drill, sander–can be controlled by a CNC program. On the most advanced CNC machines, the mechanical part drawing from a CAD program such as AutoCAD™ is uploaded to the CNC machine, the raw material for the part is loaded on the machine platform, and the machine does the rest.