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Beginning in the 1950s, engineers began to experiment with Computer Numerical Control (CNC) technology. CNC uses a digitized control system to automate operations. Trained CNC operators program a tool with a set of instructions, ordering the machine to move to specific locations and perform set tasks. 

CNC technology revolutionized subtractive manufacturing, vastly increasing the precision and accuracy of modern machine tools. Today you’ll find CNC routers, CNC lathes, CNC mills, CNC plasma cutters, and numerous other machine shop standards. 

So which one of those tools is a CNC cutter? All of them are CNC machine tools, and all of them cut or grind away at workpieces, removing material to produce new parts. In a sense, all of them are CNC cutters. The term is broad enough to include most CNC machine tools. 

However, most commonly you’ll find CNC cutting machines referring to the family of cutting tools that are bed-based as opposed to turning machines. These include plasma cutting machines, waterjet cutting machines, CNC oxy-fuel cutting, and routers.

Industrial CNC routers are similar to milling machines, in which a cutting head is suspended on a gantry above a workpiece. The router bit is lowered into the workpiece and gouges or drills out a cavity, moving along the workpiece according to the CNC program. Router machines are typically used on non-ferrous materials, particularly wood. 

Plasma cutters use electricity to produce a stream of superheated plasma capable of cutting through metal sheets or pipes. The technique is suitably for workpieces up to six inches thick, and cuts with a cone-shaped pattern. Not surprisingly, plasma cutters are also referred to as burn tables.

Waterjet cutting relies on a small, high-pressure jet of water to cut through a wide variety of materials. For harder materials, the water might be mixed with an abrasive material – sand or grit – which gives the high-pressure stream even more cutting power. CNC water jets excel at cutting even non-ferrous materials – plastics and polyurethane foam are just two of the materials that can be sectioned with waterjets.

Any set up for CNC manufacturing starts with two things – an uncut workpiece, a CNC cutting machine, and a trained operator. Before any cutting happens, the operator will use CAD software (Computer Assisted Design)  and CAM software (Computer Assisted Manufacturing) to design a cutting program for a particular part. After the design stage, a vector file is exported to the CNC machine. That vector file digitally converts the program into G-code, the language of CNC machines. 

G-code programs are capable of cutting complex shapes, and even of switching cutting tools on the tool head for machines that support it. CNC routers and mills might require diamond tools for particularly hard materials or specially-shaped bits for specific cuts. With the right machine, it’s possible to program a complete set of actions that automates the entire production of a given part.

Cutting systems from CNC routers to milling machines produce a huge amount of the industrial fabric of our modern lives. Plasma cutters and waterjets are mainstays in labs and tool rooms, while lathes, mills, and routers are some of the primary machine tools used to make parts for major assembly lines. 

Manufacturers are increasingly turning to CNC technologies to save time and effort and increase automation. Rather than require a single worker for each mill or cutting machine on a factory floor, CNC technology allows a single skilled operator to oversee several machines and a number of processes simultaneously. 

With the number of different CNC cutters available, manufacturers have gained the ability to work with a whole range of materials. Plastics, acrylics, foams, and of course soft steel and other common metals can all be sectioned with the different CNC cutting tools available.

Additive machining has also been adapted to CNC technology. The rise of new technologies like 3D printing use similar programming to subtractive CNC cutting methods and provide many of the same benefits of automation and precision.

The future of machining will look similar to the techniques of the past, relying on a combination of classic cutting methods and new additive processes. CNC technology will continue to play a major role in both methods.