Top 28 CNC Terms You Need To Know

CNC terminology can be a bit tricky to get your head around, but every term has a function and every function is an important part of the CNC machining process.

Keep reading for definitions to 28 of the most common CNC machine terms used…

Automatic Tool Changer: An automatic tool changer will choose a tool to match the task at hand, doing away with the need for manual machining.

Axis: The axis refers to the plane of motion the machine operates on. This commonly includes three axes: the X-axis, the Y-axis and the Z-axis (see definitions below).

Ball Screw: The ball-screw is a drive system component rotated by the drive motor. It provides the means for moving the spindle along an axis.

CAD: Computer Aided Design is a program that allows you to digitally custom design and make 3D products of any shape or size.

CAM: Computer Aided Manufacturing / Machining software is used to control tools during the manufacture of CAD designs. It converts the designs into a language the machine will understand.

Chuck: The chuck is the piece that firmly holds the material being spun. It has jaws that allow it to clamp around the part to remain tight and secure during the routing process.

CNC: A CNC machine is a Computer Numerical Control machine, meaning computer programs and code commands controls the movement of the machine and its cutting equipment.

Depth of Cut: A depth of cut refers to the amount of material that is being removed from a workpiece (i.e., cut out).

End Mill Bits: The end mill is a type of cutter used in CNC machining. This typically includes standard, ball nose and double-ended cutters.

Feed and Speed: A combination of factors that must be pre-set to control the work performed by the CNC tool.

Feed Rate: The speed at which the cutting tool moves along a piece on the X and Y-axis.

G-code: A universal numerical control language that specifies axis points to which the CNC router machine will move.

Headstock: The headstock is where the motor is. This motor controls the main spindle, which is crucial for spinning the material to be cut.

Lathe: A CNC lathe is the main tool used in CNC turning. The lathe holds a raw piece of material and spins it at high speeds while tools positioned around the material cut into it.

MCU: A Machine Control Unit is a microcomputer that stores the routing program and executes the commands into actions by the machine tool. 

Milling: CNC milling is a process that engages rotating cutting tools to remove material from a workpiece.

Plunge Rate: The speed of descent of the spindle on the Z-axis. 

Spindle: A rotating motor that holds tools and is used to machine parts.

Spindle Speed: The rotational speed of a cutting tool / machine (RPM).

Step Down: Distance in Z-axis that the cutting tool plunges into the material.

Step Over: The amount the cutting tool moves away from the previous cutting path as it cuts a new path.

Tailstock: The tailstock provides additional support for the material being turned. The material is held on one end by the chuck, and the other end is supported by the tailstock.

Thread Mill: A thread mill is another type of cutter used in CNC machining. The thread mill is used to produce internal and external threads in a workpiece.

Tool Turret: The tool turret is where a variety of cutting tools are mounted. 

Turning: Like CNC milling, CNC turning is a process that allows for intricate cutting. The turning process rotates pieces in order to accurately cut them.

X-axis: The left to right, horizontal axis that is designed to hold an object in place.

Y-axis: The front to back vertical axis that is at a right angle to the X-axis.

Z-axis: The up and down, vertical axis representing depth. This is associated with the primary spindle of the CNC machine.