Design Principle and Failure Mechanism of PDC Cutter

Ⅰ. Selection of PDC cutter material

1. Reasonable selection of PDC granularity

The choice of PDC grain size is related to the processing conditions of the tool. For example, when designing a tool for finishing or ultra-finishing, a PDC cutter with high strength, good toughness, good impact resistance and fine grain should be selected.

Coarse -grained PDC compacts can be used for general roughing. The particle size of the PDC material has a significant effect on the wear and breakage performance of the tool. The research shows that the larger the particle size of PDC, the stronger the anti-wear performance of the tool.

2. Reasonable selection of PDC blade thickness

Usually, the layer thickness of the PDC cutter is about 0.3 to 1.0 mm, and the total thickness after adding the cemented carbide layer is about 2 to 8 mm. Thinner PDC layer thickness facilitates EDM of the insert.

When the PDC cutter and the cutter body material are welded, the thickness of the cemented carbide layer should not be too small to avoid delamination caused by the stress difference between the bonding surfaces of the two materials.

Ⅱ. Geometric parameters and structural design of PDC cutter

The geometric parameters of the PDC cutter depend on the specific machining conditions such as workpiece condition, tool material and structure. Since the PDC cutter is often used in the finishing of the workpiece, the cutting thickness is small, and the PDC cutter belongs to micro cutting.

Therefore, the clearance angle and the flank face have a significant impact on the machining quality. Smaller clearance angle and higher flank face quality can play an important role in improving the machining quality of the PDC tool.

The connection methods of the PDC cutter and the cutter bar of the PDC cutter include mechanical clamping, welding, indexable and other methods.

Ⅲ. Influence of cutting parameters of PDC cutter on cutting performance

1. Cutting speed

The PDC cutter can be cut at very high spindle speed, but the influence of the change of cutting speed on the machining quality cannot be ignored.

Although high-speed cutting can improve machining efficiency, under high-speed cutting conditions, the increase of cutting temperature and cutting force of PDC compacts can damage the tool tip and cause vibration of the machine tool.

When machining different workpiece materials, the reasonable cutting speed of PDC cutters is also different.

2. Feed

If the feed rate of the PDC cutter is too large, the residual geometric area on the workpiece will increase, resulting in an increase in surface roughness; if the feed rate is too small, the cutting temperature will rise and the cutting life will be reduced.

3. Cutting depth

Increasing the cutting depth of the PDC cutter will increase the cutting force and the cutting heat, thereby aggravating the tool wear and affecting the tool life. In addition, the increase of the depth of cut is prone to cause chipping of the PDC tool.

Different particle size grades of PDC cutters for sale have different cutting performance when machining different workpiece materials under different machining conditions. Therefore, the actual cutting parameters of PDC tools should be determined according to specific machining conditions.

Ⅳ. The failure mechanism of PDC cutter

The wear forms of tools mainly include abrasive wear, adhesive wear (cold welding wear), diffusion wear, oxidative wear, and thermoelectric wear.

The failure modes of PDC cutters are different from those of traditional tools. The main manifestations of PDC cutters are polycrystalline layer damage, adhesive wear and diffusion wear.

When using PDC cutter to process metal matrix composites, the main failure modes are bond wear and microscopic intergranular cracks caused by diamond grain defects.

When processing high hardness and high brittleness materials, the bonding wear of PDC cutters is not obvious; on the contrary, when processing low brittle materials (such as carbon fiber reinforced materials), the wear of PDC cutters increases, and bonding wear dominates at this time.

Due to its good processing quality and processing economy, PDC cutter shows incomparable advantages of other cutting tools in the fields of non-metallic materials, non-ferrous metals and their alloys, metal matrix composite materials, etc.

With the deepening of the theoretical research of PDC cutter and the further promotion of its application technology, the status of PDC cutter in the field of superhard cutting tools will become increasingly important, and its application scope will be further expanded.