CNC Machining Glossary: Essential Terms and Definitions

CNC Machining Glossary

A

Absolute Coordinates
A system where all positions are measured from a fixed zero point or origin.
Axis
A direction of movement in a CNC machine, typically X, Y, and Z for 3-axis machines.

B

Backlash
The amount of clearance between mechanical components, such as in the leadscrew of a machine.
Ball Screw
A mechanical linear actuator that translates rotational motion to linear motion with minimal friction.

C

CAD (Computer-Aided Design)
Software used to create precise 2D or 3D models of parts.
CAM (Computer-Aided Manufacturing)
Software used to generate toolpaths and G-code from CAD models.
CNC (Computer Numerical Control)
The automated control of machining tools by means of a computer.

F

Feed Rate
The speed at which the cutting tool is advanced against the workpiece.
Fixture
A device used to securely hold a workpiece in place during machining.

G

G-code
The programming language used to control CNC machines.

I

Incremental Coordinates
A system where each position is measured from the previous position.
Interpolation
The process by which a CNC control calculates the intermediate points between the start and end of a programmed move.

M

MDI (Manual Data Input)
A mode that allows the operator to enter individual lines of code directly into the machine control.

O

Offset
A value used to adjust the programmed position of a tool or workpiece.

R

Rapid Traverse
The fastest rate at which a machine can move its axes when not cutting.

S

Spindle
The rotating axis of the machine that holds the cutting tool.
Stepover
The distance between parallel toolpaths in a milling operation.

T

Toolpath
The path that a cutting tool follows during a machining operation.

W

Workpiece
The material being machined.