Tool life definition – it’s not when the tool breaks
Tool life definition: Tool life is the duration of actual cutting time after which the tool is no longer usable. There are many ways of defining the tool life, and the common way of quantifying the end of a tool life is by a limit on the maximum acceptable flank wear. The term ‘acceptable’ is however subjective, and can vary from process to process. For example, the amount of wear acceptable on a rough milling insert will be more than that on a finish milling insert.
A typical tool life definition for a roughing insert would be the time period for the flank wear to become 0.5 mm. For a finishing insert it will be typically a third of this.
Tool wear is not uniform through the life of the tool. The wear is initially rapid, then settles down to a uniform rate, and finally accelerates at a very high rate till catastrophic failure occurs, which is a fracture of the tool.
Pic. and text source: CADEM NCyclopedia multimedia CNC training software.
