Measurement of the cutting force (thrust force and torque) by micro drilling is important to determine the cutting conditions. However, measurement of the torque is difficult and is associated with many technical problems. Therefore, the micro drilling machine was developed with the force sensor built-in spindle that measures cutting force simultaneously. The structure of the spindle used the air static pressure bearing to detect slight signal. The semiconductor strain gauge was used for detection of thrust power, and the optical sensor was used for detection of torque. The thrust force was less than 0.1 N and the torque was less than the detection sensitivity of 0.05 N･mm. The developed micro drilling machine monitors the maximum and minimum of cutting forces that were set up, and prevents breakage of a drill. In this way, machinability evaluation is possible using this micro drilling machine.

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This paper describes the micro-drilling process of printed wiring boards (PWBs) containing high hardness and high thermal conductive fillers. When processing these PWBs, the drill tools undergo severe wear due to the high hardness of the filler. Therefore, we examined the characteristics of drill wear and derived practical formulas of drill wear from these results. These equations are similar to Taylor's tool life equation. Moreover, we investigated the effects of thermal conductivity on temperature during the drilling process. The temperature around the drill hole was shown to be a complex phenomenon according to increasing filler content of PWBs.

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This experiment was performed to clarify both the rolling friction behavior on cutting sheet glass and scribing phenomenon analyzed by the finite element method (FEM) under six combinations of three different shapes of cutting edge on scribing wheels for cutting sheet glass and two types of rotating pin for fixing the scribing wheel. The coefficient of rolling friction between wheel and glass was measured by fabricating a test device. Penetration depth of the scribing wheel and crack propagation depth from the glass surface were measured. The distribution of stress at the contact area between scribing wheel and glass was estimated by simulation of FEM analysis assuming two-dimensional contact. The experimental results showed good agreement with the simulated stress distribution.

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In this study, a rotation & revolution type polishing (RRP) method is proposed. The shape of the polishing tool can be stably maintained in this method, and the surface roughness can be uniformly polished by the polishing velocity distribution in the polishing area. Here, the principles of the RRP method are discussed, along with the results of simulation of the polishing tool shape. We also checked the polishing characteristics by a simple experimental, and after this experimental we developed a new RRP unit. We confirmed the fundamental polishing characteristics with this new type RRP unit.

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Small size hole generation technology of carbon fiber-reinforced plastic (CFRP) has a number of problems with regard to process cost, machining time, quality, etc., with methods using a drill tool, laser beam, abrasive water jet, etc. Here, we focus on the direct injection type blast using a small grain size as a novel method of small size drilling of CFRP and discuss the development of its processing technology. We investigated the influence of different blast conditions on hole accuracy and quality. Moreover, the removal processing mechanism of CFRP material is discussed based on the experimental results.

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