/ˌsiː-en-siː/
n. “The automated control of machine tools using computer-generated instructions.”
CNC, short for Computer Numerical Control, refers to the use of computers to control machine tools with high precision and repeatability. Instead of being operated manually, CNC machines follow a programmed set of instructions that dictate exact movements, speeds, and tool actions.
At a fundamental level, CNC turns numbers into motion. Coordinates, feed rates, and tool commands are interpreted by a machine controller, which then drives motors and actuators to cut, drill, mill, carve, or shape material with extreme accuracy.
CNC is commonly paired with CAD and CAM: CAD defines the design, CAM generates the toolpaths, and CNC executes those instructions on physical machinery.
Key characteristics of CNC include:
- Precision: Produces parts with tolerances measured in thousandths of an inch or microns.
- Repeatability: The same program can produce identical parts over and over.
- Automation: Minimal human intervention once a job begins.
- Versatility: Used in mills, lathes, routers, plasma cutters, laser cutters, and more.
- Digital Control: Instructions are typically written in or generated as G-code.
Conceptual example of CNC operation:
// Simplified CNC logic
Read G-code command
Move tool to specified X, Y, Z position
Set spindle speed and feed rate
Perform cutting operation
Repeat until program endsConceptually, CNC is like giving a machine a perfectly rehearsed script. Once the script starts, every move is deliberate, measured, and consistent, regardless of how many times the performance repeats.
In essence, CNC is the backbone of modern manufacturing, enabling mass production, custom fabrication, and complex geometries that would be difficult or impossible to achieve by hand.