Glossary · CNC and machine tools
Tool wear
Also known as: Cutting tool wear
German: Werkzeugverschleiß
In machining, tool wear is the gradual loss of material and shape of a cutting tool during use, for example flank wear or crater wear, which changes part dimensions, surface quality and cutting forces.
- CNC
In one sentence
Tool wear is the gradual loss of material and shape of a cutting tool, which affects part dimensions, surface quality and cutting forces.
Example
The tool management function counts machining minutes and changes the insert after 45 minutes, before flank wear pushes the bore out of tolerance.
How it applies
- Production: Wear is managed through tool life limits (time, part count), wear offsets, in-process measurement or monitoring of spindle load and vibration. When a limit is reached, the control can switch to a sister tool.
- Quality: Undetected wear increases the Scrap rate and rework. Wear data are a typical input for Predictive quality and Predictive maintenance models.
- Documentation: Work instructions should state how wear is checked, which limits apply and who may change them. When a monitoring system decides tool changes automatically, document its limits and what operators do when it raises an alarm.
Tool wear vs. tool breakage
Wear develops gradually and can be predicted from use. Breakage is a sudden failure; it requires detection (for example a tool breakage check with a probe or load monitoring) rather than planning, and it can create ejection hazards.