SpringerLink — “Cutting tool materials”

1.Flank wear

Flank wear is the most ideal wear state because it is quite predictable and reliable. At the same time, a clear relationship is established between flank wear and the achievable tool life. However, if flank wear occurs too quickly – similar to typical flank wear but in a very short time – it may cause problems.

At lower cutting speeds, the main causes of flank wear are abrasion and erosion. Hard tiny carbide inclusions or work – piece material particles that have undergone strain hardening cut into the cutting tool. Then, small pieces of the coating come off and cut into the tool flank. Eventually, the cobalt leaches out from the matrix. This reduces the adhesion of carbide grains, causing them to come off as well. At higher cutting speeds, diffusion wear is the main cause of flank wear because higher cutting speeds generate higher temperatures on the cutting edge, creating favorable conditions for the occurrence of diffusion wear.

Flank wear is similar to relatively uniform wear on the cutting edge of the tool. Sometimes, the metal from the work – piece covers the cutting edge, increasing the visible size of the wear mark. Flank wear occurs in all materials. If the cutting edge does not fail first due to other types of wear, it usually fails due to flank wear.

Some corrective measures to reduce flank wear are to lower the cutting speed (in some cases, increasing the feed rate can also help), select a more wear – resistant and harder carbide grade, and use coolant correctly.

Improvement methods:

Reduce the cutting speed.
Select a carbide material grade that is more wear – resistant.
Use the correct cooling method.

2. Crater wear

Crater wear is the combined effect of diffusion – decomposition wear (at higher cutting speeds) and abrasive wear (at lower cutting speeds). The heat generated by the workpiece chips decomposes the tungsten carbide particles in the matrix, and carbon infiltrates into the chips (diffusion), thus forming a “crater” on the rake face of the cutting insert.

Ultimately, the crater will become large enough to cause the flank face of the insert to crack or may lead to rapid flank wear.

Crater wear refers to the shape/appearance of a crater or pit that appears on the rake face of the cutting insert. Crater wear is most common when machining abrasive workpiece materials or materials with a hard surface.

To minimize crater wear, it is advisable to use coatings containing a thick alumina layer, apply coolant, use a free – cutting geometry that can reduce heat, and decrease the cutting speed and feed.

Improvement methods:

It is advisable to use a thicker alumina coating.
Use cutting fluid. Reduce chip interference.Reduce heat.
Lower the cutting speed and feed rate.

3.Cutting edge breakage

Any overview of basic wear patterns must cover cutting – edge fracture. Catastrophic fracture of the cutting edge is not a wear pattern but a harmful and dangerous phenomenon caused by improper use of the tool.

Cutting – edge fracture means that the selected cutting conditions are too severe, resulting in excessive mechanical loads acting on the cutting edge, which the tool cannot withstand.

Improvement methods:

Apart from common flank wear, other wear failure mechanisms should also be noted.
Reduce the feed rate and cutting depth. Increase the stiffness of the technological system.
Select cemented carbide materials with better toughness and strong cutting – edge groove shapes.
Use inserts with chip – breaking grooves during high – feed cutting.

SpringerLink — “Cutting tool materials”

1.Flank wear

Improvement methods:

2. Crater wear

Improvement methods:

3.Cutting edge breakage

Improvement methods:

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