In any manufacturing process there must be a balance between production volume and costs. That is why a topic of great importance is the wear and tool life under different conditions.
Wear can be defined as surface damage or change the original form or loss of materials after specific working conditions to which they are subjected. This phenomenon is usually on the surfaces of materials with the loss of it and the effect of reducing size and therefore the expense of tolerance.
During work operations, the tools are subjected the following actions:
A. Great efforts located.
B. High temperatures.
C. Chip sliding over the surface of attack.
D. Slipped working tool for the machined surface.
There are three possible types of failures in a cutting tool:
1. Fracture Failure: Occurs when the cutting force becomes excessive at the tip of the tool, causing a sudden failure.
2. Temperature Fault: There is a plastic deformation during cutting due to too high a temperature for the material of the tool, causing softening and loss at the tip of the cutting edge.
3. Gradual wearing: It produces a loss the tool during cutting, reducing the efficiency of it. The speed of wear depends on the materials of tool and the workpiece, the cutting fluid, the shape of the tool, process parameters (such as speed, feed and depth of cut) and the characteristics of the machine tools.
The temperature fatigue failure and result in premature loss of the cutting edge for that reason the gradual wear allows greater use of the tool and linking it with the duration and the economy in the machining process.
gradual wear occurs in two main areas of the tool: In the upper area of \u200b\u200battack a crater on the same (crater wear), formed by the action of the chip that slides on this surface and the flank or incidence surface (flank wear) of the tool created by the friction produced in the cutting area.
(Translate: fracture for fracture, Plastic Deformation and Plastic Deformation, Crater by Crater Wear, Flank Wear on Edge)
progressive wear of the tool can occur in three ways:
• For abrasion occurs when materials drives the tool into contact with it scratching it and worn, removing small portions of it. This action occurs in the wear Flank and crater wear in, but dominates the flank wear.
• On membership: As in the shear zone there is a high temperature, the material cut and welded tool, so that upon separation, part of the tool sheds.
• By diffusion: It originates from the increase in temperature of the tool, so that there is a spread between the crystal lattices of the workpiece and the tool, weakening the surface of it.
The tool life is defined as the cutting time required to reach a criterion of preservation of it. The cutting speed is the most significant factor affecting the duration of a tool. This, along with the work material, the material and shape are key tool in estimating the life.
Some criteria to evaluate the tool life plan may be mentioned here:
1. Visual inspection of flank wear.
2. Try to touch the edge or cutting edge.
3. Sound changes in machining cast.
4. Visual aspect of the chip.
5. Poor surface finish.
6. Increased power consumption on the court.
7. Decreased workpieces.
ING. WILLIAM HEAD LINE MANAGER
KORLOY 
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