The experimental investigations are carried out with Pyrex glass in regard to the results of theoretical analysis of steady wear which are introduced in 5th report. The main results obtained are as follows :
(1) In relatively low range of sliding velocity υ, wear volumes per unit time are nearly constant, but increase abruptly as υ is increased, in higher range of υ.
(2) The wear rate V_l is minimized at critical sliding velocity υ_c and the relation between V_l and υ_c agrees qualitatively with the results of theoretical analysis in 5th report. Assuming the activation energy Δf to be 20 kcal/mol, calculated value of υ_c is relatively close to that obtained experimentally.
(3) In this experiments, the ratio of the number of elastic contacts to the number of total contacts is analytically obtained to be I.

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Magnetic disks made of aluminum alloy and electroless deposited nickel film have residual stresses due to lapping and plating. This paper reports on theoretical analysis for deformation of disks due to residual stresses. Numerical values calculated by induced equations are in good agreement with flatness values on model disks, which are lapped after electroless nickel plating on one side of the aluminum alloy. Experimental results show that plating stresses and residual stresses by lapping on deposited films depend on the respective values of pH in plating bath and grain size. Depth of worked_ layers on deposited films is extremely small, compared with the case of aluminum alloy. Simulation results on the deformation of 360 mm.diameter plated magnetic disks show that the amont of deformation is 140-200 μm for 50% unbalanced ratio of plating thickness and depth of worked layers on both surfaces.

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In many cases, grinding abilities of grinding wheels depend upon their mechanical properties, Therefore, it is necessary to analyse fracture strength in order to evaluate grinding abilities of grinding wheels, and so in this paper, the relationship between the composition and the fracture strength of grinding wheels is discussed. The results obtained are as follows :
(1) The fracture strength of grinding wheels is influenced with the effective area rate in wheel section area and the equivalent strength of bond in intercrystalline fracture, and is influenced with the effective area rate and the equivalent strength of grain in transcrystalline fracture.
(2) Under the same composition of grinding wheels, the fracture strength varies inversely as the root of the side length of grain (average grain diameter).
(3) In the case that the volume percentage of grain is υ_g, the volume percentage of bond is υ_b, the side length of grain is d₀ and the constants depending on the kinds of grain and bond are K_g and K_b, the relationship between the composition of grinding wheel and the fracture strength is expressed as
σ=K_gυ_g^2/3d₀^-0.5 [1-exp {-1/υ_g^2/3·K_b/K_g·υ_b/3 (1-3√υ_g)}]
or
1/σ=3 (1-3√υ_g)/υ_b·√d₀/K_b+1/υ_g2/3·√d₀/K_g

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For the mirror finishing of Mn-Zn ferrite single crystal, electrolytic buffing was carried out by using two different types of electrolytes; one is HF solution of less than 4%, and the other is 4% HF solution in which abrasives were added. The results obtained were as follows :
(1) In order to get the mirror finished surface of Mn-Zn ferrite single crystal by electrolytic buffing, the higher concentration of HF solution is effective and in the present study, 4% HF solution is the most suitable one.
(2) In case of 4% HF solution, the surface roughness of the pre-finishing surface isomoothed rapidly with the increment of current density.
(3) In case of SiO₂ abrasives added to 4% HF solution, the mirror finished surface is obtained, but the finishing time increased in comparison to the case of 4% HF solution.
(4) In case of ZrO₂ abrasives added to 4% HF solution, the surface roughness is slightly better than the one obtained by using 4% HF solution.

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The twist drill, which has been very widely used for the past hundred years without any significant changes being made to its shape, has been thoroughly investigated with regard to the relation between cutting performance and the shape of the chip produced. The following conclusions are made from this investigation :
(1) When the hole is shallow, chips flow from it in an almost radial direction keeping their shape of a conical spiral. The twist drill is very well designed for this case and shows a very satisfactory cutting performance corresponding to that of a single point cutting tool of a 20° rake angle.
(2) However, when the depth of the hole reaches some value which is found to be predicted from the drill diameter and the feed, some unfavourable phenomena occur such as vibration and an increase in the cutting force. These are attributed to obstruction of chip flow which brings about an increase in chip thickness and/or chip breakage.

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This report will address itself to the following problems about multi-stage production line systems : The allocation ratio of total buffer capacity among the stages; The effect of the number of stages on the relationship between the efficiency and the buffer capacity; The order in which the stages should be placed. To answer these questions investigation on the efficiency and the mean buffer stocks for various system parameters has been carried out by computer simulation based on the analysis developed in the 1st Report. It is to be shown that in order to improve the efficiency for a multi-stage line it is indispensable to install buffers among the stages. For the line having identical breakdown rates and repair rates, the closer to the middle of the line the buffer is, the more buffer capacity should be given to it. Equal allocation of buffer capacity to each buffer does not give the optimum allocation. But, the difference between the efficiency under equal allocation and the efficiency under optimum allocation is not large. For the line having non-identical breakdown rates and repair rates, the higher the stage efficiency is, the closer the stage should be placed to the middle of the line.

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The purpose of the present paper is to analyze the dynamic behavior of a capillary compensated hydrostatic thrust bearing, when a dynamic force and moment are applied to it. Static stiffness and the damping coefficient of the lubricant film are obtained by applying the finite element method, and their propriety is confirmed experimentally. As the first step of the analysis, the relative sliding velocity is assumed to be zero. It becomes clear through the study that the dynamic stiffness of the hydrostatic thrust bearing without insulation grooves is higher than the one which has insulation grooves, and the directional difference of the dynamic stiffness can be ignored in the case of the pad configuration which has four sectorshaped recesses.

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Generally the distribution of re-classification is variant on each sorting, about a same class of works which were automatically measured and classified on their characteristic values. The variation can be forecasted on amount by statistical consideration. For instance, in case of sorting the size of shape, measured and classified work is supposed to have a Gaussian distribution N (μ₀, σ₀²), concluded systematic error of measuring terms, accidental error of machine, and error of shape. Now, pay attention to the class which is classified in the first sorting, these works are supposed to have a uniform distribution with class range. And this class range c is divided into k and thin pillars are set at central location on mean value, and each pillar has distribution of normal population N (μ₀, σ₀²) with variance σ₀². The variation of distribution on repetition sorting is considered to be the area of normal distribution out of the limit of both side of uniform distribution. The propriety of this conception is ascertained by experiences, and recognized of excellent uniformity. From this result, it is elucidated that the probability is easily found out by calculation, of re-distribution of re-sorting with autosortor.

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This investigation was carried out to examine characteristics of sintered compacts which were produced by hot-pressing of spherical powders of high speed steel and to examine whether the products are useful as the cutting tool. When the high speed steel powders are hot-pressed at more than 1280°C, sintering among particles sufficiently proceeds and the fracture of the products occurs not at the particle boundaries but inside the particles. Therefore, this material has a high bending strength, although it is smaller compared to the bending strength of the high speed steel produced by conventional means. As a result, the high speed steel tool produced from powders by the new method has been found suitable as a cutting tool because the wear of the cutting tool is 20% smaller than the tools produced by conventional means.

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Magnetic domain observation technique using 200 kV high voltage SEM was applied on lapped Mn-Zn single crystal ferrites. The surface damaged layer of lapped ferrites was investigated from a magnetic domain structure viewpoint. Surface strain state was found to be closely related to the domain structure. A finer maze domain pattern resulted from high strain state. The maze domain depth can be reduced from the height of spike like domain which was observed on tapar section of lapped surface, and was found to be almost equal to the surface damaged layer depth, evaluated from electron diffraction analysis. Further examination suggests another intermediate domain structure could exist under the maze domain pattern.

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This paper deals with surface roughness produced when pure aluminium in orthogonally cut by a cut-away tool, a low friction tool, a part of the rake face of which is coated with resin, and conventional tools. It is found that surface roughness produced by the cut-away tool is the best and that produced by the conventional tool with the same rake angle is the worst. It is also concluded that the grade of surface roughness is largely controlled by the stress concentration occurred at the tool edge. This conclusion was induced from the fact that the stress concentration might be expressed by the plastic deformation depth under the machined surface and an evident, common relationship between the deformation depth and surface roughness for all tools tested was found.

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This paper presents a solution for self-loosening mechanism of bolt-nut joints under transverse vibration. At the first stage of relative transverse displacement between fastened plates, a bolt-thread inclines in a mating nut-thread with slip on the screw-surface of the nut-thread, producing elastic torsion of the bolt-shank. At the next stage of the transverse displacement, the washer face of the nut slips on the surface of the vibrating plate, accompanying loosening rotation of the nut caused by spring back of the elastic torsion of the bolt-shank. Repetition of these behaviours in each cycle of the vibration, advances the self-loosening of the bolt-nut joint. Above mentioned self-loosening mechanism is analyzed theoretically, considering loci of slip on the screw surface and washer face. The theory is compared with the experiment, resulting that they show fairly good agreement, except small difference which is seemed to be caused by the fluctuation of the frictional coefficients on the screw surface and the washer face.

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In order to elucidate grinding mechanism, it is important to make clear the concept of successive cutting edge spacing on wheel surface. In this paper, Monte Carlo simulations of grinding process are carried out using a wheel model which has a three-dimensional distribution of cutting edge, then the probability distributions and the mean values of the following successive cutting edge spacings are obtained :
(1) the successive cutting edge spacing pertaining to the effective cutting edge,
(2) the successive cutting edge spacing pertaining to the grain depth of cut in the work section perpendicular to grinding direction,
(3) the successive cutting edge spacing pertaining to the finished surface roughness,
(4) the successive cutting edge spacing pertaining to the maximum grain depth of cut,
(5) the successive cutting edge spacing pertaining to the undeformed chip length.
Furthermore, influences of the grinding conditions, the distribution in depth for the position of cutting edge, the distribution of cutting edge tip angle and the elastic displacement of cutting edge on the mean value of the successive cutting edge spacing are considered.

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An investigation has been carried out to study the variation of wear rate of ferrites with variation of the carrier fluid (an olive oil and a kerosene), the sliding speed (0.05-1.0 m/s) and abrasive/carrier fluid ratio (5-50%). When the relatively high viscous olive oil is used, the wear rate decreases rapidly with increasing sliding speed. This seems to be due to increasing load carrying capacity of the oil. The wear rate obtained using the low viscous kerosene is no longer dependent upon the sliding speed. At low sliding speeds, the wear rate depends on the abrasive/fluid ratio, the ratio of 27% gives the maximum wear rate. At high sliding speeds, however, the wear rate is independent of the abrasive/fluid ratio. Surface roughness of worn surface in the olive oil depends on the sliding speed. The dependency is smaller than that of the wear rate. When the kerosene is used, the surface roughness is slightly dependent upon the sliding speed, and the abrasive/fluid ratio at any sliding speed. A discussion was made of the mechanism of abrasive friction. The friction force is the sum of two components, the contact rolling and scratching force of the abrasive F_D and the viscous drag force F_F. F_D is generally proportional to the contact pressure and it is independent of the sliding speed. F_F can approximately expressed as F_F=ηA (V_F/h). The thickness of oil film h estimated with this equation is slightly dependent upon the contact pressure, sliding speed and crystallographic plane of ferrite, respectively.

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