At later stages of formation of discontinuous chip segment, there always exists a special slipline along which maximum shear strain rate has peak values in the shear zone of the plastic field, and fracture of the chip is found to take place eventually along this slip-line.
Distributions of stress and effective strain along the slip-lines and thier variations during the segment formation as well are obtained by using the generalized Hencky's equation for isotropic strain-hardening material and the assumption of equivalence of plastic work.
While the variation of shear stress and effective strain with cutting time is simple, gradual increase, the normal stress undergoes a great change in its magnitude and distribution.
Around the stage of crack initiation, the normal stress near the cutting edge turns to tensile from compressive stress in early stages.
Comparison of the stress and effective strain distributions for different rake anglesat the stage of fracture initiation shows that the larger the rake angle, the highar the tensile stress near the cutting edge for lower effective starin or shear stress. Thus the Bridgman effect appears to play an important role for the initiation of chip fracture, as has been pointed out by previous workers.
Whether taking crack initiation at cutting edge or initiation of gross slip of chip segment as the condition of chip fracuture may yield different criteria for the fracture. The later condition appears to be strongly influenced by elastic strain energy stored in the tool-work system.

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The major findings of this study are as follows. There are two regions of cutting speed and feed rate, i.e., normal and abnormal regions. In the former the actual roughness is approximately given by the formula expressed by the tool shape and the feed, while in the latter it is much rougher than expected from the formula because of the disturbances due to built-up-edges. The effect of the rake angles on the surface roughness can be neglected practically except when the feed rate is extremely low.
What is worthy of attention is that the surface roughness increases as the feed rate decreases, when the feed rate is less than approximately 0.05mm/tooth. Run-outs of the cutting edges are detrimental to the surface quality. According to the experiment and calculation, the axial runout is much more serious than the radial.
Contrary to the case of turning, the surface roughness decreases in most cases as the tool wear proceeds, this being attributable to the fact that the initial nose radius is zero in usual face milling.

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The relation between polishing rate of glass and wear of acrylic resin polishing plate is examined. A stock removal of glass is estimated with the decrease of depth of channel etched in glass surface and wear of plate is in plate surface. And, it is found that wear rate of polishing plate is very large owing to dig on glass surface at initial stage, and then approaches to constant rate at final stage.
The felt polishing plate which has been used on low polishing speed is applied as high speed polishing plate, and is compared with acrylic resin and shellac plate in the field of wear to be proportional to polishing time. And, glass is polished using some felt polishing plate hardened with shellac.
As a result, a formula concerned with wear of polishing plate has been deduced and coefficent of glass polishing has been calculated. The glass can be polished more satisfactory by shellac immersed felt plate than acrylic resin and shellac plate, and the more shellac is immersed into felt, the larger coefficient of glass polishing is obtained.

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In grinding, some of grooves produced by abrasive on the surface of metal being cut are created only with plastic defomation, the others are composed of two parts produced by only plastic deformation and cutting respectively.
Judging from the deformation processes of the metal being cut, there may be considerable differences in the pile-up stock and work-hardened layer between the two parts of grooves.
It may be important for studying the cutting mechanism of abrasive grain to make clear the differences.
In this report, we discussed the differences paying special attention to the pile-up stock and work-hardened layer near sides of a groove produced by a simulated abrasive.
The results are as follows;
(1) At ploughing-cutting tranditional point the pile-up stock takes a maximum value that has no relation to the interference angle and the maximum value decreases with the increase of cutting velocity.
(2) The depth of work-hardend layer has no relation to the interference angle at the first half of contact between cutting edge and metal being cut and has relation to the interference angle at the latter half of the contact.

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Recently, abrasive belts have been used in various fields of polishing and grinding, particularly in wood-working and stainless steel sheet industries. There are, however, many problems in the belt grinding and the grinding performance of abrasive belts is not well known. So we designed and manufactured an abrasive belt testing machine of contact wheel and constant force type, of which the belt speed is 15003000m/min and the feed of workpieces is 1.810.5 m/min, to clear the grinding performance of abrasive belts.
Belt life was tested with constant force grinding, and it was cleared that there are both the transition period with falling-off of grains from a belt and the steady period with grain wear in an abrasive belt life.
The distribution of grain size and grain shape of abrasive belts and the distribution of successive cutting edge distances were tested.
We made clear that the depth of cut of abrasive belt grinding with constant force is increased in direct proportion to the back-up force and the belt speed and in inverse proportion to the feed when the cutting edge condition of the belt is the same during the test, and the interaction to depth of cut between grinding conditions is not recognized.

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Metal removal rate of ultrasonic electrolytic machining, which is a combined process of ultrasonic mechanical machining and electrolytic reaction, is studied. The experimental apparatus consisted of 1 kW ultrasonic drilling machine makes ultrasonic vibration of a steel tool (cathode) with an amplitude of 40 micron. Abrasive grains of SiC 240 mesh suspended in electrolyte (NaNO₃ 5%, NaNO₂ 5%, NaF 2% mixed water solution) are pumped on the work (anode) and suctioned through the tool. In order to minimize the influences of variable wor king conditions upon the removal rate, feed speed is recorded automatically and electrolytic current is changed.
Low cobalt alloys containing 610% Co are worked unproportionally to the current and get a callo maximum removal rate in the range of low voltage (34V). The local maximum removal rate is caused by combination of three phenomena : changes of mechanism of electrolysis, changes of mechanical property of carbide, alloy surface, and changes of cutting ability of abrasive grain edge.
Effect of electric power consumed for metal removal becomes the largest when the local maximum removal rate is utilized.

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[in Japanese]

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