Several Kinds of Wear Types and Improvements Common to Machine Tools

Several Kinds of Wear Types and Improvements Common to Machine Tools

Defects in the work piece are generated when the workpiece is hot-pressed and welded to the cutting edge. This is due to the chemical affinity, high pressure and high temperature in the cutting zone. In the process of processing, the chips are separated due to the cutting action of the front and back rake faces, so that the front and rear flank are always in continuous contact with the chip workpiece, there is a strong friction in the contact area, and there is still a high pressure in these areas. Temperature, due to these physical and chemical effects, leads to the occurrence of wear, which is the main cause of tool wear in the actual process.

Common tool wear has the following forms:

1, flank wear

Normal wear of any type of material can cause blade failure. Normal flank wear is the most popular form of wear because it is the most predictable type of tool failure. The flank wear is generally uniform, and it gradually appears as the machining material wears the cutting edge, similar to the blunt blade.

Several types of wear and improvements common to machine tools when using tools:

Normal flank wear occurs when a hard, fine inclusion or work-hardened material in the workpiece cuts into the blade. Reasons for this type of wear include abrasive wear at low speed cutting and chemical reaction at high speed cutting.

On the other hand, rapid wear of the flank is undesirable, as it reduces tool life and does not reach typical cutting times of 15 minutes. Cutting wear resistant materials such as ductile iron, silicon aluminum alloys, superalloys, heat treated precipitation hardened (PH) stainless steels, beryllium copper alloys and tungsten carbides, and in the cutting of non-metallic materials such as glass fiber, epoxy resin When it comes to strengthening plastics and ceramics, rapid wear often occurs.

The signs of rapid flank wear are similar to normal wear. In order to correct for fast flank wear, it is important to choose a harder, harder, or coated carbide blade grade and ensure that the proper coolant is used. Lowering the cutting speed is also very effective, but this does not meet the production needs, because it will have an adverse effect on the processing cycle.

Cause of flank wear:

● excessive cutting speed (alloy steel and carbon steel containing more than 0.3% carbon)

● The workpiece contains high hard elements (tool steel, die steel)

● Sometimes too low cutting speed will cause abnormal wear of the flank

Solution:

● Reduce cutting speed or feed or apply more wear resistant grades

● Use coolant

● use a larger front blade

2, Crescent Moon

Crescents are commonly found in the high-speed machining of iron-based or titanium-based alloys. They fall into the category of thermal/chemical problems that the insert dissolves into the chips in the workpiece.

The combination of diffuse wear and abrasive wear creates crescents. In the machining of bases and titanium-based alloys, the heat in the chip of the workpiece dissolves the components of the cemented carbide and diffuses into the chips, causing a "crater" at the top of the blade. The crescent will eventually increase enough to cause the flank to collapse, deform, and may even cause rapid flank wear.

Causes of Crescent Moon Formation:

● excessive cutting speed or feed (alloy steel and carbon steel containing more than 0.3% carbon)

●The workpiece material contains high hard elements (tool steel, die steel)

Solution:

● Reduce cutting speed or feed or apply more wear resistant grades

● Use coolant

● use a larger front blade

● Reduce cutting speed or feed or apply more wear resistant grades

● Use coolant

3, built-up edge

Defects in the work piece are generated when the workpiece is hot-pressed and welded to the cutting edge. This is due to the chemical affinity, high pressure and high temperature in the cutting zone. The build-up edge eventually sheds, sometimes falling off with the blade fragments, resulting in micro-collapses and rapid flank wear.

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