As lapping machinability is less than that of grinding, mass production requires it to be increased. We predicted that the quantity of abrasive grains related to processing can be increased by removing burrs at the edge of the upper part of the grain pit on the lapping disk. We have developed Conditioning Soft Stone (Conditioner) using fine abrasive grains and soft adhesive. Grinding tests using the improved disk ground with the conditioner showed that the burrs can be removed, the machinability can be increased, and the life of the disk can be increased by 40%. The conditioner may also be useful for traditional lapping machines.

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Recently, a one-pass type boring machine capable of completing the grinding process with only one stroke has been put into practical use. Realization of high-accuracy machining in this process requires appropriate management of the diameter of the abrasive tool to be used. However, because the form and adhesion posture of the electrodeposited abrasive grain are not uniform, measurements of the diameter may differ depending upon the point at which measurements are obtained. Therefore, even if abrasive tools with the same nominal diameter are used, there may be some differences in the dimensions of the machined hole. Using a non-contact measuring instrument that makes use of a transmitted light beam, we propose a method for determination of the effective tool diameter covering the whole cutting edge zone of the tool. Experiments showed that the proposed method is acceptable.

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The flow characteristics of gas-particle flow and machining characteristics were examined to optimize microblasting conditions. The results showed that: 1) spread of particles increases with increasing mass loading ratio and decreasing supplied air pressure; 2) particle velocity increases with decreasing mass loading ratio and increasing supplied air pressure; 3) removal volume shows a maximum at x/d=8 and increases with increasing supplied air pressure; 4) the relation between removal volume and particle velocity can be expressed well by Sheldon's machining model; and 5) supplied air pressure at the maximum removal volume follows a power law function of mass loading ratio.

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Machining of complex shapes and deep micro-cavities in dies and molds is mostly carried out by the electrical discharge machining process. However, it may not be possible to sufficiently minimize delivery deadlines and reduce the cost of dies and molds. Therefore, precision machining methods using a small-radius ball end mill capable of machining deep cavities in miniature dies and molds is proposed as a substitute for electrical discharge machining. The results of experiments confirmed that long tool life of the ball end mill can be maintained by changing the coating film material and the edge shape of the small-radius ball end mill, and it is possible to obtain the required surface finish in the work pieces.

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