Glossary · CNC and machine tools
Feed rate
Also known as: Feed, F word
German: Vorschubgeschwindigkeit
In machining, the feed rate is the speed at which the tool moves relative to the workpiece along the programmed path, typically given in millimeters or inches per minute, or per spindle revolution.
- CNC
In one sentence
The feed rate is the speed of the tool relative to the workpiece along its path, programmed in CNC with the address letter F.
Example
The finishing pass is programmed with G01 and F150, so the cutter moves at 150 mm/min along the contour.
How it applies
- Programming: The feed rate is programmed with the address letter F and is modal: it stays in effect until a new value is programmed. Whether F means per minute or per revolution depends on the active G-code, which varies by control.
- Operation: Operators can scale the programmed feed with the feed override on the control panel, for example to run in a new program carefully.
- Process: Feed rate, Spindle speed and depth of cut together determine surface quality, Tool wear and Cycle time. Cutting data usually come from the tool manufacturer and process tests.
- Documentation: Setup sheets should state the unit of every feed value. Instructions that tell operators to use the feed override for testing should name the operating mode and any safety conditions from the machine's Operating manual.
Feed rate vs. cutting speed
Cutting speed is the surface speed at the cutting edge and results from the spindle speed and the tool diameter. The feed rate is the path speed of the tool. The two are set independently but chosen together.