1 Introduction High-speed cutting has become a major development direction of modern manufacturing technology. Because the development and application of high-speed cutting tools directly affect the machining efficiency and processing quality of high-speed cutting, it is of great significance. In addition to the innovation and improvement of tool geometry and cutting angle, the development of tool cutting edge materials is also a key factor in improving cutting efficiency and reducing cutting costs. Since the mid-1970s, industrialized countries such as the United States, Germany, and Japan have successively developed polycrystalline diamond (PCD) cutters and used them for high-speed machining of non-metallic materials and non-ferrous materials, resulting in a significant increase in production efficiency. Cutting costs have fallen exponentially, so they are widely used in the automotive, aerospace, aerospace, and building materials industries.
Table 1 Company Name Country Name Diamond Average Diameter (μm) GE United States Compax-1600
Compax-1300
Compax-1500
Compax-1700 5
10
25
40 Element six
(Original De Beers) Syndite-CTC002, United Kingdom
Syndite-CTB002
Synd ite-CTB010
Syndite-CTB025
Syndite-CTH025 2
2
10
25
25 Sumitomo Electric Industries Japan DA-200
DA-150
DA-100
DA-90 0.5
5
20+0.5
50 Japan Korea CF
CM
CC 2
10
25 East Japan TDC-FM
TDC-98F2M
TDC-GM
TDC-SM
TDC-HM
TDC-SA
TDC-EpM
TDC-EM 1
1
3
7
10
16
20
Development of 36+16 2 PCD Composite Sheets Polycrystalline diamond (PCD) composite sheets consist of diamond particles of micron size uniformly mixed with metal powders of Co, Ni, etc., under high pressure and temperature, on tungsten carbide (WC) substrates. A new blank material that has been sintered. PCD composite sheet not only has superior properties such as high hardness, high wear resistance, high thermal conductivity, low friction coefficient, low thermal expansion coefficient, but also has good strength and toughness of cemented carbide. The PCD compact is also electrically conductive, so it can be cut into the desired cutter head using a wire cutter. The cutter head is welded to the cutter body and sharpened to produce a PCD cutter. At present, there are many PCD composite production companies at home and abroad. The main manufacturers and product brands are shown in Table 1. 3 Dynamic balance of PCD tool Since the PCD tool is suitable for high-speed cutting, the dynamic balance of the rotary PCD tool is particularly important. In dynamic balancing, the maximum allowable speed (nmax) of the tool and the precision level of the dynamic balance (generally controlled at G2.5 level) should be checked in Fig. 1 to obtain the permissible unbalance rate eper value. The following formula is used to calculate the Uper=meper type in the eper - allow the unbalance rate or eccentricity (unit: g · mm/kg or micron) m - tool mass (kg) In order to achieve the dynamic balance of the tool precision requirements, often used to Gravity (removing the proper weight in the appropriate part of the cutter body) allows the actual unbalance of the tool to ≤ the allowable unbalance. 4 Scope of application of PCD tools Due to the superior performance of PCD tools, it is widely used in the processing of non-ferrous metals and non-metallic materials (see Table 2).
Relationship between residual unbalance different equilibrium level of accuracy G in FIG. 1 (rotor or eccentricity) and the operating speed of the
sheet material of the object
2 to be processed non-ferrous metal such as aluminum alloy car, motorcycle: pistons, cylinders, wheels, gearbox, Pumps, intake manifolds, various housing parts and other aircraft, electromechanical: various cabinets, housings, compressor parts and other precision machinery: all kinds of cameras, copiers, measuring instruments and other general machinery: various pump body, hydraulic machine , mechanical parts and other copper-copper alloy internal-combustion ships: various types of shafts, bearings, bearings, pumps and other electronic equipment: various instruments, motor commutator, printed circuit board and other general machinery: all kinds of bearings, bearings, valve body, shell Body and other hard alloys Various seats, cylinders, etc. Sintered products and semi-sintered products, etc. Magnesium, zinc, etc. Various non-ferrous metals Non-metallic woods Various hardwoods, man-made boards, artificial wear-resistant fiberboards and products Reinforced plastic Glass fiber, Carbon fiber Reinforced plastics and other rubber paper rolls, rubber rings and other ceramic carbon rings such as seal rings, plungers and other sintered products and semi-sintered products in the actual selection, should be based on the PCD tool to make With the occasion, the characteristics of the material to be cut, and the specific requirements for processing, a PCD composite sheet with a proper grade and particle size is used as a tool bit. Under normal circumstances, the wear resistance of diamond with high volume concentration or larger particle size is better in the composite piece, and the toughness is better when the volume concentration of diamond is low or the particle size is small.
(a)
(b) Fig. 2 HSK holder 5 HSK holder system In the high-speed rotation condition, the shank positioning accuracy and clamping force of the PCD cutter are crucial. The DIN69893-1 HSK tool holder system is usually used (most of the PCD tools currently used in the automotive manufacturing engine line use HSK tool holders). Because the HSK tool shank system adopts the principle of double positioning and fitting, under the action of sufficient tension, the contact between the HSK 1:10 hollow tool taper shank and the spindle taper hole, the taper surface and the clamping plane is in contact with each other to generate friction and provide a closed structure. Radial positioning and planar clamping positioning prevent any axial turbulence. The HSK tool holder features high static and dynamic rigidity, high torque transmission, precise radial positioning and high tool repeat accuracy. The structure of HSK shank system has A, B, C, D, E, F type, commonly used A, B, C, D type four: A type is automatic tool change type (see Fig. 2a), B The model is an automatic tool change type with inner cooling holes, type C is a manual tool change type (see Figure 2b), and D type is a manual tool change type with inner cooling holes; the shank flange diameter is generally divided into 9 sizes ( They are 25, 32, 40, 50, 63, 80, 100, 125, 160mm). The type specification of the HSK holder is shown in Figure 3.
Fig. 3 Type specification of HSK holder 6 Marked hardness of PCD composite PCD cutter is generally between HV4500 and HV8000, second only to diamond hardness (HV9000), and the hardness varies depending on the manufacturer or brand. . Therefore, how to solve the sharpening problem of PCD tools is the key to processing and using PCD tools. At present, there are two kinds of grinding methods commonly used for PCD tools: The diamond grinding wheel adopts diamond grinding wheel to sharpen the PCD tool, which requires higher requirements for the machine tool used: the machine system has good rigidity, the feeding mechanism has high precision, and there is a micro feeding mechanism. The precision is high, the grinding head oscillates smoothly and without impact. At the same time, it is also necessary to use a suitable diamond grinding wheel. The RS series machine tools produced by Swiss EWAG company, especially the RS15 machine tool, have the characteristics of high precision, many accessories and accessories such as sharpened PCD tools (with HSK tool holder), and are representatives of PCD tool sharpening machine tools. Sharpening of PCD tool with RS15 machine tools, the tool size accuracy of up to 0.001mm, surface roughness up to Ra0.08. Electro-erosion Grinding Method Electro-erosion Grinding is the process of removing PCD by forming positive and negative electrodes between the workpiece (PCD tool) and the erosion wheel (or molybdenum wire) and discharging them between positive and negative electrodes. The PCD removal effect of the electrolytic erosion grinding method depends on the gap between the erosion wheel (or molybdenum wire) and the edge of the PCD tool, the feed speed of the cutting tool, the voltage level, and the current size. Electric erosion sharpening machine features high productivity, dimensional accuracy is generally about .01mm, and the surface roughness is about Ra0.25. The VOLLMER company's QM and QW series machine tools are the representatives of the PCD cutting tools by electric erosion method. Among them, the new products QM110 and QWD760 are five-axis linkage CNC machine tools. The QM110 is a wheel erosion tool, which is used for the electric erosion of PCD tools with a straight edge. QWD760 is a wire erosion sharpening machine, which is used for electric erosion sharpening of PCD tools with various curved cutting edges. According to the adaptability of PCD cutting tools for different machine tools, in general, PCD reamers, boring tools, etc., which require high dimensional accuracy and surface roughness, are ground with a diamond wheel on a machine tool such as RS15; for PCD milling cutters and saws Chips and PCD woodworking tools, etc., were machined with a QM110 or QWD760 machine tool for electric erosion, while PCD tools used to reinforce the floor opening and various curve-shaped PCD tools were machined with a QWD760 machine tool. 7 Conclusion Shanghai Tool Factory Co., Ltd. has introduced advanced production equipment for PCD cutting tools (including PCBN cutting tools) through technological transformation, including RS15 machine tools from Swiss EWAG company, QM110 and QWD760 machine tools from Vollmer of Germany, and HSK knife handles from German SCHENCK company. Balancing machine, ZOLLER CNC tool special measuring instrument, etc. Through the support of existing production technologies, Shanggong has been able to produce all kinds of PCD milling cutters, boring tools, and reamers that are in urgent need of the woodworking industry, printed circuit board industry, and automobile manufacturing industry. It has become the only domestic capable of supporting production with HSK. Tool holders for PCD cutter companies.
