Cutter wear and life

Cutter wear and life

Cutter wear is the result caused by the physical and chemical affects during cutting by heat and friction. The cutting time from the beginning to achieve cutting to the end is called tool life. Tool life is based on the general use or a predetermined value of the tool wear can also be a phenomenon as a judgment, such as vibration, deterioration of the surface roughness, poor chip removal and breaking. When tool life is ended, we should re-grind, translocation or abandoned. Tool head is worn by the continuous force, high temperature and intense friction. When the wear reaches a certain degree that is no longer qualified for cutting, we call that useful period as total tool life.

Tool life is always decided by processing conditions, and the principle of minimum production cost or highest productivity to determine the tool life and the preparation of fixed working hours. It is very complicated and lots of reasons to influence tool life,

there are several major factors to affect tool life:

  1. Match up for tool material and work piece material
  2. Cutting speed
  3. Cutting thickness
  4. Width of cutting

The increasing of cutting speed may shorten the working time, and improve the accuracy of surface, but the tool wear rate will increase, and that is the tool life will be shortened. The formula between tool life and the cutting speed is as below,

VTn = C
  • T:the actual cutting time of use(min)
  • V:the cutting speed(m/min)
  • N: constant (tool material, work piece material and cutting conditions)
  • C:constant (refer to the cutting speed in one minute)

Tool wear includes wear and damage

Tool breakage usually happens suddenly, the caused reasons are:

  1. Improper tool shape of geometry
  2. Over load of cutting
  3. Trembling or vibration shock
  4. Cutting temperature exceeds the limits of its high-temperature hardness
  5. The tool itself has some micro-cracks, defects, etc.

the main reasons for tool wear:

  1. Fuser
  2. Curettage
  3. Proliferation

Common tool wear:

  1. Cater wear
  2. Thermal deformation
  3. Thermal cracking
  4. Nose wear
  5. Depth of cut notching

Tool wear process

  1. Initial wear:
    This stage of wear is caused by cutter, which make the surface rough and not plain, microscopic protrusions at the cutting action be polished first, followed by surface grind a wear band, then reduce the pressure, the wear rate stabilized.
  2. Normal wear and tear:
    Tool make the wear surface increase evenly, the wear situation is more stable, this stage for the validity of the tool for processing, the tool should be used during this period.
  3. Severe wear and tear:
    In this stage, cutters become blunt, the cutting force increasing , cutting temperature rise, the tool quickly lose cutting ability, tool wear reached this stage, the tool material loss is too large. We should avoid cutter to reach this stage.


。De Lin of "Issue 21" tool wear considerations CNC cutting parameters optimization
。Journal of Machinery Industry 291 tool breakage explore