This paper describes failure processes in plastic rollers that undergo rolling contact, and the effect of initial surface roughness upon wear and rolling fatigue. Experiments were performed with mating cylindrical rollers of high density polyethylene (PE rollers) and chrome-plated cylindrical driving rollers. Surface roughness of the PE roller is affected by three successive transition processes. In the first period, the amount of wear can hardly be measured, although a reduction of surface roughness is noted. During the second period, wear occurs in proportion to the initial surface roughness. In the third period, wear becomes independent of the initial surface roughness, and increases in a manner exponential to load. At the end of this period, small cracks appear randomly, and grow into pits. Roller fatigue life, defined by the time when cracks appear, is shown by an S-N curve. It is found that fatigue limiting stress, represented by Hertz stresses, is about 10⁷ Pa.

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This paper describes APS system-Automatic Programming system for Sequence control-which is a special computer compiler created to simplify and standardize the procedure for designing logic control systems. It is discussed that by the model of a kind of a sequential machine, logic control systems can be generated from the input of the sequence program describing the sequential motions. The concept of APS system and an example application are also reported. The system is now being used in an automobile manufacturer, machine tool builder, material handling equipment manufacturer and computer service center etc. The result of applications to several kinds of machinery shows that the system is an effective tool for the standardization of design procedures.

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Plunge grinding process of the wheel, which has the locally different composition generated in the manufacturing process, is experimentally analyzed. to make it clear how the locally different composition affects the geometrical accuracy in plunge grinding. Also discussed is the effect of grinding conditions upon the geometrical accuracy in such a plunge grinding. The waviness is generated on the work surface due to the locally different composition of wheel, and the waviness generation process is significantly affected by the revolution ratio of wheel to work. The chatter vibration and the chatter mark are also simultaneously recognized in the grinding process. The waviness becomes smaller with lower plunge speed and smaller width of the different composition. There exists the optimum dressing condition under which the waviness becomes smallest.

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In recent years, many cermet tools possessing different cutting performance have been placed on the market. A great deal of cutting test must be conducted on the cermet tools to know their performance. To save the time and materials consumed, it is recommended to develop a new test method to estimate the cutting performance of tools. Therefore, the virgin surface wear test has been developed to simulate the wear process of the tool. The results obtained were as follows. (1) Sliding speed of the specimen was selected to generate the same interface temperature that the cutting edge is exposed at any cutting speed of interest. (2) Good correlation was obtained between virgin surface wear test and actual cutting test at the condition above mentioned. (3) Tool life curve can be estimated by combining virgin surface wear test and actual cutting test conducted in few minutes. (4) Wear mechanisms observed on the flank wear land of the cermet tools can be classified into three types according to the cutting speed (cutting temperature).

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The present study aims at constructing a behind-the-tape reader DNC system, linking a personal computer directly to a regular NC controller unit through a hand-made interface circuit. Therefore, the interface is joined to the output line of the tape reader of an existing NC lathe in order to receive NC command instructions instead of the tape reader. Besides, a DNC program has been developed to make the DNC system easy to use, by taking advantage of abundant peripherals installed in the personal computer. It enables one to easily provide NC programming and to immediately modify, edit and manage it. The completed system worked entirely, and it has been proved that the DNC system can be economically realized.

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A pair of straight-line tooth profile internal gear and approximated tooth profile mating pinion has been developed to provide easy manufacture of highly accurate internal gear. In this paper, these internal gears are actually manufactured by new developed manufacturing methods, and their angular ransmission accuracies are measured. As a result, it is clarified that the approximated circular-arc which is obtained by applying the least squares approximating method to theoretical profile, is the most available for tooth profile of pinion, and that the higher angular transmission accuracies of ISO grade 4 are realized in the trial manufactured internal gears. Straight-line and circular-arc tooth profiles are the most simple forms, so they can be manufactured accurately and easily by the simple manufacturing methods using the conventional machine tools with simple mechanisms and tools. The measuring methods of individual accuracies of these internal gears by measuring the coordinates of tooth profiles are developed, and it is confirmed that the manufacturing errors can be indicated synthetically by this methods.

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In order to develop the free-cutting alloys of Al-Cu and Al-Mg₂Si groups, various studies were carried out, by changing the chemical compositions and quantities. And the results shown below were obtained in the range of this experimental condition. (1) In view of the machinability of Al-Cu group alloys, Al-0.2Fe-4.5Cu-0.5Pb-0.25 Zn-0.35 Si-0.3Bi was regarded as the suitable chemical compositions and quantities. (2) As for the Fe and Zn lements in Al-Cu alloys, the cutting force and cutting temperature were remarkably improved in the case of 0.2%Fe-0.25%Zn as compared with the case of 0 or 0.6%Fe and 0.01%Zn. (3) In the relation among the quantities of Si, Cr, Zn, Fe, and Mn elements in Al-Mg group alloys, A1-0. 3Si-4.5Mg-0.3Zn-0Fe-0Mn showed the best machinability. (4) The machinability of Al-Mg₂ Si group alloys was improved most when the chemical compositions and quantities were Al-1.0(Sn+Pb)-1.5 Mg₂Si-0.5Mn-0.4Cu-0.05Ca-0.2Cr. (5) The addition of 1%(Sn+Pb) showed the large improvement effect for the disposal of chips, cutting force, cutting temperature and cutting ratio in Ai-Mg₂Si alloys.

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One piece compound parallel spring with reduction levers for a measurement of linewidths of LSI photomasks has been manufactured, with dimensions as follows: block lengths; 270 mm×170 mm, thickness; 30 mm. After machining i. e. drilling, spot facing of a raw stock, and vacuum heat treatment to remove any mechanical distortion of the block, a spring system is formed by means of a CNC wire cut electric discharge machine taking as much as 98 hours. A force "F", which should be applied to the levers to maintain equilibrium after a displacement "d" of an output member from a zero force equilibrium is expressed theoretically; this expression gives F=10.56 N when d=10 μm agreeing well with the experimental measurement; F=7.3 N. The ideal ratio; 0.125 also coincided well with the real one which is 0.122. Pitch and yaw in the direction of movement over 50 μm are so small that a clear distinction between air fluctuation and spring deflection was difficult even if an autocollimator is used to detect them. This performance is higher than that of NBS micropositioning stage made of invar whose pitch is; 0.8 arcsec. and yaw; zero arcsec., because this spring structure described here consists of the compound parallel spring to reduce the pitch motion, and yaw movement compensation mechanism with a high degree of symmetry.

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For simple and accurate measurement of the effective circumference of vehicle wheel tires, a vehicle-mount type instrument, which consists of a wheel revolution counter with high discrimination and a photo-electric detector for position marks on the ground, has been developed. The wheel revolution is counted also by photo-electric detection of a mark on the flank of a tire, which causes one pulse per revolution, and by electronic sub-division, to within thousandth of a revolution. Two position marks to define the travelling distance of the vehicle are provided by infrared light beames across the run-way, which cause, when the vehicle crosses the marks, a start pulse or an end pulse for the revolution counting. The effective circumference of a tire, i. e. the travelling distance per revolution, is calculated from the known distance between the position marks and the number of wheel revolutions counted between start, and end pulses. The advantage of this instrument is that a short run-way for measurement, e. g. 20 m or so, suffices to obtain a reasonable accuracy for practical purpose such as calibration of taximeters, which usually requires a straight and flat run-way of more than a kilo-meter. The total error due to this instrument is estimated to be about 0.07% under a measuring condition that the vehicle speed is constant at 40 km/h and the travelling distance for measurement is 20 m. Including other sources of error the effective circumference of a tire of about 2 m can be determined with an accuracy of 0.2% under the above condition.

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The forming mechanism and the effect of toolspacing angles of multi-corner profiled holes are studied theoretically and experimentally, using a variety of spacing type of reamers. In case of the uneven-spaced tool, the imaginary number of teeth (Z_i=360°/α_L), which is given by 360° divided the G. C. M. angle (α_L) of neighboring angles among the teeth, has significant influence on the multicornered shape of machined hole section. Theoretically the imaginary number of teeth and the number of corners of profile generated by the Z_i-teethed tool increase, as the G. C. M. angle become smaller, but in practical reaming, special unevenspace, six-teethed tools, having more than 12° of α_L, can act as Z_i-tool. In particular, the tool with α_L=15° usually acts as the even-space, twenty-four teethed tool under various cutting conditions and twenty-five cornered shape is produced, and variable component of burnishing torque is small during cutting. The roundness error of the shape is much smaller than that of the even-spaced tool. The rigidity of tool shank also affects on the improvement of roundness error. When using the high rigidity tool, multi-cornered profile is not observed on the profile-diagram recorded by the roundness measuring instrument.

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This study is in the series of researches concerned with the mechanism of micro-deformation or fracture in brittle materials. In this paper, stress is analyzed with finite element method in the case of indentation onto the surface of MgO single crystal. Matrix is developed for the calculation which relates stress to strain in the slip process of MgO crystal. Microscopically deformed (slipped) zone is obtained from the analysis. Furthermore, it is discussed where the probability of crack growth is the highest. The main results obtained are as follows: (1) Slipped zone is constructed with a pair of slip bands which intersect with the indented surface at 45°. Its shape is approximately in accordance with experimentally observed one. (2) In the two bands just mentioned, slip occurs in the opposite directions. (3) Cracks are most likely to grow in the region between two parallel slip bands.

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Based upon a measured distribution of tool-chip interface temperature in continuous turning, the transient distributions of temperature and thermal stress within the cutting edge, which may appear during the heating and cooling in interrupted turning operation, are obtained through the three dimensional finite element calculation. The calculated transient temperature is verified to be in good agreement with the temperature obtained experimentally. On the contrary to the common consent, it is found for tungsten carbide tool that the surface layer of the tool-chip contact zone is not cooled down lower than the interior even by water cooling, due to the higher rate of heat conduction within the cutting edge. Two fields of tensile thermal stress, which is almost uniaxial and parallel to the cutting edge, are found to be induced along the side and front cutting edges respectively. The tensile stress is caused mainly by the temperature distribution in planes parallel to the rake face, but not caused by the simple surface cooling as mentioned before. The magnitude of the calculated stress is also proved experimentally to be true and so small (about 300 MPa) compared with the fracture strength of tungsten carbide and the induced impact stress as well that it may not have a direct concern with the initiation of the thermal crack and the edge chipping.

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In order to develop a general-purpose machine design system, the following fundamental researches are requisite. The first is about a model which represents a general feature of machine structure. Then, we must extract rules from the model, which govern important parameters in every design stage. And finally, it is to develop algorithms which aid man's design activity, based on those above rules. In the present paper, the second aspect is mainly dealt with. Conditional equations of machine structure are derived, which are dependent upon the characteristic feature of the model; especially network aspects of it. These conditional equations give the relationships between dimensions in a machine; length, height and diameter of elements and positions between them which are static or dynamic, that is, motion. Further, when they have no dimensions of dynamic position, equations of static dimension are defined as an expanded concept of them. These results will be applied to the above mentioned third aspect to develop a general purpose CAD successfully.

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In this paper the examples of three-component dynamometers manufactured by using the structure of parallel beams are described. And the deformation and the strain distribution of the onecomponent cantilever dynamometer that is the fundamental shape of the parallel-beam dynamometer are analyzed by Finite Element Method. The main results are as follows: (1) If strain gauges are put on the boundary points between the parallel-beam part and the supporting part, the strain output is the largest. The distribution of normal strain in parallel-beam region is in a straight line. (2)If a Wheetstone bridges circuit is constituted of gauges put on those points symmetrically, the cross sensitivity comes to be extinct. (3) The deflection of the loading point is very small and the strain output per unit displacement is larger than that of a ring dynamometer. (4) The parallel-beam dynamometer is designed easily and a three-component dynamometer can be made compactly.

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