Computer Numerical Control (CNC) machining is a manufacturing process in which computer inputs are used to control machining tools such as drills and lathes. It is used across many industries for a variety of prototype and end-use parts.
The process starts with a digital 3D design, created using CAD software, which a computer can translate into a series of instructions to the machine’s cutting tools. These instructions are known as G-code. Once the G-code is sent to the machine, very little manual supervision is needed, since the machine knows when and where to cut and performs the machining autonomously. This results in significant time and cost savings when compared to traditional machining, in which a skilled machinist cuts the workpiece using manually operated cutting tools.
Machining is a subtractive process, which means the equipment removes existing material instead of introducing new material. Unlike additive manufacturing, in which a 3D printer deposits material in layers to form an object, CNC machining involves cutting sections away from a formless block known as the “workpiece.” Excess material is discarded or recycled, eventually leaving behind a completed part. More complex CNC machines, those with a greater number of axes, are capable of cutting the workpiece in more complex ways, producing parts with more intricate geometries.
CNC machining is a widely used manufacturing process thanks to its versatility, accuracy, consistency and wide range of compatible materials: although aluminum alloys are the most common material for machining, numerous other metals and plastics can also be used.