An innovative method for high-speed micro-dicing of SiC has been proposed using two types of diamond dicing blades, a resin-bonded dicing blade and a metal-bonded dicing blade. The experimental research investigated the radial wear of the dicing blade, the maximum spindle current, the surface morphology of the SiC die, the number of chips longer than 10 µm, and the chipped area, which depend on the dicing process parameters such as spindle speed, feed speed, and cutting depth. The chipping fractures in the SiC had obvious brittle fracture characteristics. The performance of the metal-bonded dicing blade was inferior to that of the resin-bonded dicing blade. The cutting depth has the greatest influence on the radial wear of the dicing blade, the maximum spindle current, and the damage to the SiC wafer. The next most important parameter is the feed speed. The parameter with the least influence is the spindle speed. The main factor affecting the dicing quality is blade vibration caused by spindle vibration. The optimal SiC dicing was for a resin-bonded dicing blade with a spindle speed of 20 000 rpm, a feed speed of 4 mm/s, and a cutting depth of 0.1 mm. To improve dicing quality and tool performance, spindle vibrations should be reduced. This approach may enable high-speed dicing of SiC wafers with less dicing damage.

Ultra-thin dicing blade is usually used to achieve a high precision cutting in semiconductor back-end packaging and assembly. Lots of interactional parameters involving in dicing blade preparation and cutting process bring difficulties to high cutting qualities and good working life of dicing blade. In order to address these problems, this study prepared three kinds of dicing blades and characterized the cutting properties of three dicing blades. It first proposed the abrasive exposure coefficient and tool deviation coefficient to provide parameters for the cutting force model. Then the experimental apparatus was set up to verify the proposed cutting force model. And a series of parameters including feed rate, spindle current, edge chipping coefficient, tool wear amount and grinding performance are used to characterize the comprehensive performance of prepared dicing blades. Finally, the edge morphology was observed under 3D microscope to analysis the hardness of different dicing blades. The theoretical and experimental results indicate that the proposed cutting force model can reflect actual cutting process. There is an inverse proportional function between the shedding of abrasive particles and the hardness of the matrix. The cutting performance of dicing blades is very dependent on the material of workpiece. C-dicing blades presents outstanding comprehensive effects with small chips and good self-sharpening properties.

The effects of the nonuniform cutting force and elastic recovery of processed materials in ultra-precision machining are too complex to be treated using traditional cutting theories, and it is necessary to take account of factors such as size effects, the undeformed cutting thickness, the tool blunt radius, and the tool rake angle. Therefore, this paper proposes a new theoretical calculation model for accurately predicting the cutting force in ultra-precision machining, taking account of such factors. The model is first used to analyze the material deformation of the workpiece and the cutting force distribution along the cutting edge of a diamond tool. The size of the strain zone in different cutting deformation zones is then determined by using the distribution of strain work per unit volume and considering the characteristics of the stress distribution in these different deformation zones. Finally, the cutting force during ultra-precision machining is predicted precisely by calculating the material strain energy in different zones. A finite element analysis and experimental data on ultra-precision cutting of copper and aluminum are used to verify the predictions of the theoretical model. The results show that the error in the cutting force between the calculation results and predictions of the model is less than 14%. The effects of the rake face stress distribution of the diamond tool, the close contact zone, and material elastic recovery can be fully taken into account by the theoretical model. Thus, the proposed theoretical calculation method can effectively predict the cutting force in ultra-precision machining.

Aviation spherical plain bearing often undergoes serious wear due to its extreme and complex working condition. This paper presents a solution of vibration assisted strengthening and surface micro-texture for the wear of aviation spherical plain bearing to achieve the synergistic effects of surface property-improving and appearance-improving. On the basis of analysis the wear mechanism of spherical plain bearing systematically, it attempts to scientifically understand how the vibration assisted strengthening and micro texture can decrease the wear of spherical plain bearing by proposing the distribution function of asperity height and contact theory. The vibration assisted strengthening and micro-texture surface are prepared and the tribological property of friction pairs are investigated on the UMT TriboLab platform. The theoretical analysis and experimental results indicate that the flat-headed distribution of surface asperities is beneficial to improving the contact state and lubricant capability. The vibration assisted strengthening can effectively decrease the friction coefficient of frictional pairs to about 0.11 by decreasing the surface roughness of frictional pairs from about Ra 0.23μm to about Ra 70nm and increasing the micro hardness nearly by 54%. Static load, strengthening times and rotational speed of vibration assisted strengthening have obvious influences on the surface roughness and micro hardness of frictional pairs. Among three textures of micro groove, micro quadrate protrusion and micro quadrate pit, micro quadrate pit obtains a lowest friction coefficient and wear amount. Also the proposed graphene-oil lubricant presents excellent improvement of tribological properties and wear resistance performance of spherical plain bearings.