Study on cutting performance of the hottest diamon

Research on the cutting performance of diamond thick film cutting tools

1 introduction

precision and ultra precision machining technology, as a key technology in modern manufacturing technology, has been widely used in national defense industry, high-tech industry, aerospace and other mechanical processing fields. Diamond cutting tool is an indispensable key element to realize precision and ultra precision machining. At present, the diamond tools used mainly include single crystal diamond tools, sintered polycrystalline diamond tools, etc. Single crystal diamond tools are scarce, expensive, and prone to cleavage, which has been difficult to meet the needs of production development. Sintered polycrystalline diamond tools because the material contains binder, so that the excellent cutting performance of diamond is not easy to be fully developed. Electronic universal testing machine is a universal testing machine for cutting and stretching metal, non-metal and other materials. This skill is relatively mature, solid, compact, zigzag and other physical and mechanical performance experiments. As a new type of superhard material, diamond thick film has many excellent characteristics and is expected to be widely used in the field of precision and ultra precision machining. In this paper, the cutting performance of diamond thick film tools and the influence of cutting parameters on the machined surface roughness are experimentally studied

2 preparation of diamond thick film tools

the preparation process of diamond thick film tools includes not only the deposition of diamond thick film, but also the cutting of diamond thick film, the welding of diamond thick film on the tool body and the grinding of diamond thick film tools, in addition to the deposition of diamond thick film and the use of silicon carbide fiber reinforced Qin alloy matrix composites to manufacture compressor blades. In this research project, a machine clamped diamond thick film cutter is developed. Firstly, the deposited diamond thick film is cut into isosceles right triangle by laser cutting method, and then the diamond thick film is directly welded on the cemented carbide blade to make a right angle square diamond thick film blade. During welding, the bottom surface of the diamond thick film (i.e. the contact surface between the diamond thick film and the deposited substrate during vapor deposition) is used as the blade rake surface, and the rough diamond thick film surface is used as the welding surface, which is helpful to improve the welding strength by using the mechanical embedding of the diamond thick film surface and the solder layer. Figure 1 shows the bonding state of diamond thick film and blade matrix after welding. In the figure, the upper part is diamond thick film, the lower part is cemented carbide blade matrix, and the middle layer is solder layer. Finally, the diamond thick film blade was grinded on the rs12 tool grinder made in Switzerland. The shape of the cutter head and the surface morphology of the front and rear surfaces of the diamond thick film blade after grinding are shown in Figure 2 and figure 3 respectively. When cutting, fix the prepared diamond thick film blade on the tool bar through the machine clamp

Figure 1 bonding state between diamond thick film and cemented carbide blade matrix

Figure 2 cutter head shape of diamond thick film blade

(a) front face (b) rear face

Figure 3 surface morphology of diamond thick film blade after grinding

3 cutting test and analysis of diamond thick film cutter

cutting test of diamond thick film cutter prepared on cg6125a high-precision lathe produced by Shanghai Instrument Machine Tool Factory, Study its cutting performance. The geometric parameters of the tool are: kr=45 °, kr'=45 °, re=0.8mm, go=-5 °, a=10 °. The test piece to be cut is LY12 aluminum alloy rod of f40mm, and oil dripping lubrication method is adopted during cutting. Tr240 roughness tester produced by Beijing Times Company is used to measure the machined surface roughness of the test piece

under the above test conditions, the influence of cutting parameters on the machined surface roughness of the specimen was studied by single factor test method. Since the cg6125a high-precision lathe used in the test adopts stepless speed regulation feed (which can be expressed by the feed rate VF), and the test results show that the actual measured surface roughness value of the test piece is much larger than the theoretical roughness value calculated according to the feed rate F, the feed rate VF (mm/min) is directly used as the feed parameter in the analysis of the test results, but it is not converted into the feed rate f (mm/r). According to the test data, the influence curves of feed speed VF, cutting speed V (m/min) and cutting depth AP (mm) on the machined surface roughness can be obtained, as shown in Figure 4, figure 5 and Figure 6 respectively

Fig. 4 Effect of feed speed VF on machined surface roughness

Fig. 5 Effect of cutting speed V on machined surface roughness

Fig. 6 Effect of cutting depth AP on machined surface roughness

analysis of the test results shows that the machined surface roughness value of the specimen increases with the increase of feed speed VF, cutting speed V and cutting depth AP, but the effect of cutting speed V on machined surface roughness is relatively small. Under the conditions of this test, there is no chip buildup in the cutting process. The maximum speed of cg6125a high-precision lathe is up to 2000r/min. the vibration of the machine tool when cutting near the maximum speed is the reason why the machined surface roughness value increases slightly with the increase of cutting speed. As mentioned above, under the conditions of this test, the theoretical roughness value calculated according to the theoretical residual area height is far less than the actual measured machined surface roughness value. Therefore, it can be considered that the main reason for the increase of machined surface roughness value is the intensification of cutting process vibration due to the increase of feed speed VF and cutting depth AP. Under the cutting conditions of vf=8mm/min, v=176m/min, ap=0.04mm, the machined surface contour of the specimen measured by tally surf4 profiler is shown in Figure 7, and its Ra value is 0.15 m, which meets the requirements of precision cutting

Fig. 7 surface profile curve of the specimen machined with diamond thick film cutter

4 conclusion

under the conditions of this cutting test, when the prepared diamond thick film cutter is used to cut LY12 aluminum alloy, the machined surface roughness value of the specimen increases with the increase of feed speed VF and cutting depth AP, It increases slightly with the increase of cutting speed. Choosing appropriate cutting parameters can machine a smooth surface of ra0.15 M.

author unit: Shenyang Institute of Technology (end)