What Is CNC? Computer Numerical Control Basics and How FANUC Fits In
CNC stands for computer numerical control: a computer (the CNC controller) reads a part program and commands motors to move a machine tool along precise paths, so parts are cut, drilled, turned, or shaped repeatably instead of by hand. It applies to almost any machine that removes material or moves a tool under programmed control — mills, lathes, EDM machines, routers, and more. FANUC's role in this picture is specific: it supplies CNC controls, drives, motors, and its own compact machine series (ROBOMACHINE), while independent machine builders integrate FANUC controls into their own machines.
How a CNC machine works
The chain from drawing to finished part runs through four stages:
- Part program — a human or CAM software produces instructions. In the most common form this is G-code: a text list of coordinates, feed rates, spindle speeds, and tool changes.
- Controller — the CNC control reads the program, plans the toolpath, and calculates the motion each axis must make, moment by moment.
- Drives and motors — servo drives convert the controller's commands into electrical power; servo motors turn that into shaft rotation or linear motion.
- Feedback and machine tool — position sensors report actual axis position back to the control, which corrects any error. The machine tool itself (spindle, slides, table, tool changer) is what actually contacts the workpiece.
The controller is the part that makes the machine "CNC" rather than manual. It closes the loop between commanded and actual position many times per second.
Main CNC machine types and what they are used for
| Machine type | Motion style | Typical work |
|---|---|---|
| Milling machine / machining center | Rotating tool, moving axes | Prismatic parts, pockets, faces, holes |
| Turning center / lathe | Rotating workpiece, single-point tool | Shafts, bushings, threaded and cylindrical parts |
| EDM (electrical discharge machining) | Spark erosion, no cutting force | Hard metals, fine details, dies and molds |
| Router | High-speed spindle on a gantry | Wood, plastics, composites, sheet goods |
The same control concepts apply across all of them; what changes is the machine structure and the process.
Core system components
- CNC controller — the interface and brain: program storage, motion planning, operator display.
- Servo drives — power amplifiers matched to each axis and spindle.
- Servo motors — execute the commanded motion.
- Feedback devices — encoders or scales that report real position.
- Machine tool — the mechanical structure that holds and moves the tool and workpiece.
A control is only as good as the machine it is mounted on, which is why the control supplier and the machine builder are usually different companies.
Where FANUC fits
FANUC is a supplier of factory automation and robotics, and its product range includes CNC controls alongside robots, ROBOMACHINE, ROBODRILL, ROBOSHOT, ROBOCUT, ROBONANO, and laser products. Two distinctions matter when reading about CNC:
- As a CNC control supplier — FANUC provides the controller, drives, motors, and related CNC technology that machine tool builders integrate into their machines. When you see "FANUC control" on a mill or lathe, FANUC supplied the control side, not necessarily the whole machine.
- As a machine supplier — under the ROBOMACHINE name, FANUC also offers its own compact CNC machine series. So FANUC appears both as the control inside other builders' machines and as the maker of complete machines.
This is why "FANUC CNC" can mean either the control unit or a FANUC-built machine, depending on context.
Programming inputs you will encounter
- G-code — the standard low-level instruction set for motion, feeds, speeds, and tool changes.
- CAM output — software that converts a CAD model into G-code, often for complex 3D shapes.
- Conversational programming — control-side interfaces that let an operator build a program from menus and graphics instead of typing G-code.
For simple parts, hand-written G-code is common. For contoured 3D work, CAM-generated code is the norm.
Practical next steps
- To learn CNC basics — start with G-code fundamentals (coordinate systems, feed and speed, tool length offsets) and run a simulation or a small desktop machine before touching production equipment.
- To select a control — decide first what machine type and part complexity you need, then check which control the machine builder offers and whether its programming style (G-code vs. conversational) matches your operators' skills.
- To understand a specific FANUC product — treat the control, the robot, and the ROBOMACHINE series as separate product lines, since each has its own documentation and application scope.
The key takeaway: CNC is the control layer that turns a program into precise machine motion, and FANUC occupies two positions in that chain — control technology supplier and, through ROBOMACHINE, machine supplier.