During high-speed cutting, select reasonably matched tool materials and suitable processing for different workpiece materials
The best cutting effect can be obtained only under the cutting conditions such as mode. Cutting tool materials widely used in production
Diamond, cubic boron nitride, ceramic tools, coated tools and TiC (n) - based cemented carbide tools (gold
Ceramic) and powder metallurgy high speed steel (PM HSS) [22, 23, 28, 32531].
In high-speed cutting, with the increase of cutting speed, the cutting force decreases and the cutting temperature rises rapidly, reaching
After a certain value, the increase gradually slows down. Therefore, cutting force and cutting force are the main causes of tool damage in high-speed cutting
Mechanical friction, adhesion, chemical wear, blade collapse, crushing and plastic deformation under the action of cutting temperature
be damaged. High speed metal cutting requires good mechanical properties and thermophysics at high temperature
Performance, adhesion resistance, chemical stability (oxidation, diffusion, solubility, etc.) and thermal shock resistance
And coating cracking resistance [28,53541. In high-speed processing of graphite, due to the high abrasion and brittleness of graphite materials
Property, the intermittent nature of graphite chip formation and the intermittent cutting nature of high-speed milling
Under the action of alternating cutting stress and cutting impact in the process of high-speed milling, early damage and rapid grinding are easy to occur
The tool for high-speed machining of graphite requires high abrasion resistance and impact resistance.

  Shore hardness - when selecting tools suitable for high-speed machining, it is necessary to improve the durability, reliability and safety,

The matching of tool matrix and coating material and tool and workpiece material is comprehensively considered. Suitable for graphite processing
At present, tool materials mainly include diamond tools, ceramic tools, cubic boron nitride tools, cemented carbide tools and
High speed steel. When cutting graphite electrode, the tool wear of all kinds of tools is almost linear with the cutting time
Up 148561. The cutting tool suitable for the hardness of graphite material shall be selected for graphite cutting, as shown in figure L-6.
The service life of various tool materials when processing graphite is roughly as follows:

CVD Diamond Coated Tools & gt; PCD polycrystalline diamond tools & gt; Ceramic tools & gt; Coated carbide tools & gt; Cemented carbide tools & gt; High speed steel 16L,

The service life of CVD diamond coated tools is 8-10 times that of cemented carbide [57l, ceramics is 3-7 times that of cemented carbide
Times [5], cemented carbide is 6.7 times 1561 of high-speed steel.
The allowable cutting speed of CVD diamond coated tools is 2-3 times higher than that of cemented carbide tools, and the cutting edges are sharp
With good consistency and low friction coefficient, high-speed and high-precision thin-walled graphite electrode can be realized at high speed and low feed
Dense processing 157j. PCD polycrystalline diamond tools have the advantages of good heavy grinding performance and low tool cost
It is not suitable for the detailed machining of graphite electrode with complex structure due to the limitation of tool shape and structure. Cubic boron nitride knife
With high hardness and wear resistance, it is an ideal tool for processing superhard carbon graphite composite materials
Improve productivity and machining quality, but there are insufficient tool toughness and easy edge collapse. Therefore, in high-speed milling
It is less used in machining and more used for turning. Ceramic cutters are very easy to be damaged, and the edge often collapses,
Therefore, it is suitable for turning and finishing of graphite; Geometry of precision turning graphite parts with a1203.tic ceramic turning tools
The accuracy can reach 0.002mm, and the surface roughness can be stabilized at RA o.32 GM [591].
Obviously, CVD diamond coated tools are the best for graphite high-speed milling in terms of cutting performance
Cutter. ", However, due to the unstable manufacturing process of tools at present, the price of tools is very expensive, which limits
Its application and promotion in the field of graphite processing are introduced. Therefore, currently, the tools suitable for graphite high-speed milling are still
It is a cemented carbide cutter. The economical coated ultra-fine Grain Cemented Carbide milling cutter is hard due to the high wear resistance of the coating
Alloy matrix has been widely used in graphite processing due to its good toughness and relatively high cost performance. Currently used
Common tool coatings used for graphite processing include AITiN and TiAIN, etc. AITiN has a high surface hardness (4500 ～
4900hv), low friction coefficient and low thermal conductivity, which is higher than TiAIN coating hardness (2600 ~ 2800 HV)
High, so it is more suitable for graphite processing.