In this report, it is analyzed that the precision machining of ceramics can be done by using a new ultrasonic super-position vibration cutting of ultrasonically vibrated ceramics (USVC). And this analytical results can be confirmed by the experiments using a new vibration cutting devices with the 50 Hz electro-hydraulic power device, ultrasonically vibrated tool and ceramics. The experimental conditions are as follows : Cutting form ; constant load cutting, frequency of ceramics f_w ; 29.5 kHz, amplitude a_w ; 0-8μm, audio frequency of tool F ; 50 Hz, amplitude A ; 0.17 mm, ultrasonic vibration frequency of tool f ; 19.6 kHz, amplitude a ; 16 μm, load P ; 0.49, 0.98, 1.96 N, tool ; diamond tool # 300, # 600, # 1000, # 1500, cutting speed V ; 200 mm/min ( V <2πAF), dry cutting, cutting time ; 6 s, work material ; glass, zirconia, alumina, silicon nitride, work size ; 5×5×5mm. The main results are as follows : (1) By using this new cutting process, cutting amount of 25 mm²×0.02 mm is obtained. This cutting amount is about infinity times compared with 25 mm²×0 mm in a_w= 0 μm conventional cutting. (2) Cutting surface roughness of 1-6 μmR_max are obtained. It is found that smooth machined surface roughness can be produced. (3) And more, it is found that tool and machined surface temperatures are not rise owing to low load and low speed of above cutting conditions. (4) Therefore, it is considered that adding the high frequency vibration stress to ceramics which has weakness in tensile stress and cut it by pulsating cutting force are key points for precision cutting of ceramics efficiently.

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The aim of this paper is to clarify the influence of additives to a boring bar on the dynamic characteristics and chatter stability of the boring bar. In this study three types of the boring bar are provided, the side faces of which are cut off and filled with the additives ; i. e., polyurethane rubber, composite of steel and epoxy resin, and solder. The results which are obtained by the shock excitation tests and the cutting tests are as follows : (1) For the boring bars provided, the effective damping ratio ζ of the boring bar is affected significantly by the additives, on the other hand the effective stiffness k is almost independent of those. (2) The boring bar to which the solder is added has a higher performance index kζ and the chatter stability than the others. (3) It becomes clear that the suppression effect of the additives on the chatter stability can be evaluated by the product ρδ of the density ρ and the logarithmic decrement δ of the additives.

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This paper experimentally describes the grinding characteristic of segmental wheels in creep feed grinding. In creep feed grinding, grinding temperature increases rapidly and thermal damage such as a burn occurs on a workpiece. As one of prevention methods of the thermal damage, a segmental wheel which shows an excellent cooling effect has been developed. This wheel has 24 pieces of soft grade segments which are attached on the circumference of an aluminium disk. As a result of applications of the segmental wheel to creep feed grinding, the followings became evident. (1) The segmental wheel has the effect of reduction of both total grinding force and grinding temperature. (2) Self-sharpening is activated and grinding characteristic of the segmental wheel is kept good without dulling of cutting edge. (3) Grinding ratio and ground surface roughness in the case of a segmental wheel is almost the same level as those in the case of a straight wheel.

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This paper describes a theoretical analysis on the elastic deformation of a specimen connected with the bar used for a load cell in impact test. Reflected and transmitted stress waves are considered in the analysis. Equations for calculating the stress and strain in the deformation are derived from strain waves. As results, the deformation behavior is affected by the reflection and transmission coefficients. The effects of coefficients are remarkable in the low impact rates. It is clarified that the lower limit of the impact rate in this method should not be estimated by the length of the bar, but by the rate during stable deformation.

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In this study, unsintered, pre-sintered and sintered low purity alumina ceramics were machined with various tools to clarify the machinability, the optimum tool materials and the optimum cutting conditions. The main conclusions obtained were as follows. (1) Machined with alloy steel tool, the machinability of the pre-sintered ceramics becomes better with the decrease of pre-sintering temperature, but that of unsintered ceramics (white body) was extremely poor. (2) In the case of carbide tool K 01, the tool life in machining white body was the longest, and the machinability of pre-sintered ceramics becomes poorer with the increase of the pre-sintering temperature. (3) In the case of ceramic tool, the 1000-1100°C pre-sintered ceramics showed the best machinability within a certain cutting speed range. So far as dry machining, the above combination and conditions showed the highest productivity. (4) When the pre-sintered ceramics were wet machined with sintered diamond tool, the tool life becomes extremely long, and higher cutting speed can be used than in the case of full-sintered ceramics. The productivity of wet cutting is much higher than that of dry cutting. (5) In machining the low temperature pre-sintered ceramics, the tool life increases with the increase of feed rate and clearance angle, and with the decrease of rake angle.

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In this paper, the grinding characteristics in cylindrical plunge grinding under the cryogenic condition by using reversible properties of rubber materials are discussed comparing with the conventional process. The main results obtained are as follows : (1) Under the cryogenic grinding, transient and spark-out times are reduced compared with the conventional process and normal grinding force increases with the increase of dynamic elastic modulus of rubber material. (2) The method of cryogenic grinding makes it possible to grind normally rubber materials which are impossible to do in the conventional process in order to have an effect upon grinding temperature. And, this method prevents the over-cut by expanding with heat and increases the cutting ratio. (3) In this process, the finely powdered chips are generated and the loading on grinding wheel can be prevented. The saw-toothed type abrasion pattern generated on ground surface by the conventional process disappears and its surface roughness is improved remarkably.

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On the honing of fine ceramics, the influence of concentration and grain size of the diamond stick on honing performance is investigated theoretically and experimentally. The workpieces are alumina Al₂O₃, silicon nitride Si₃N₄ and silicon carbide SiC, which are sintered under atmospheric pressure. The results are as follows. The effects of concentration and grain size on the cutting ability can be expressed by a simple equation. This equation can explain the tendency of experimental results. The diamond stick of lower concentration of grain is superior in the cutting ability, but it cannot have the higher finishing ratio. On the other hand, since the stick of higher concentration has many grits on its working surface, it is superior in finishing ratio but inferior in the cutting ability. Therefore, SiC and Si₃N₄ which have poor machinability should be honed with the stick of low concentration, but then the high finishing ratio cannot be obtained. For Al₂O₃ having good machinability, the stick of high concentration should be used to obtain the high finishing ratio. The stick with fine diamond grains improves the surface roughness, for example, #1 200 stick can make the surface of Si₃N₄ to the mirror finish, but it is not economical for material removing.

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The purpose of this study is to make clear the form grinding process, where the grinding action of wheel varies in different positions on the wheel surface along wheel width because of the difference of cutting depth of wheel. Grinding process of circular groove with a formed wheel is experimentally investigated, analyzing wheel wear, grinding force, stock removal, surface roughness and so on. Main results obtained in this paper are as follows : (1) Generated profile of circular groove is different from one of dressed grinding wheel because of wheel wear, elastic deformation and residual stock, which also changes with the grinding length. (2) The ratio of wheel wear to grinding length in steady wear region is directly decided by cutting depth of wheel, while it has no relation to radius of wheel profile. (3) Under the constant stock removal rate in circular groove grinding, deeper cutting depth and slower feed rate lead to lower steady wheel wear rate.

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Various problems of constructing and processing polyhedra represented by the hierarchical tree structure of convex components have been approached by the authors for several years. To decompose a polyhedron into the smaller components may be necessary in the processes of constructing the structure. A method for this type of problem, which is based on the idea of utilizing the boundary edge line loops between used and unused faces for making the convex hull of the original one, is presented for the case of a polyhedron with holes. The main feature of this method is as follows. (1) The polyhedron can always be decomposed uniquely. (2) No vertex is newly produced. (3) The number of newly created components may not become so large.

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This paper is concerned with a shape data processing method for 3-dimensional structural analysis based on solid model. The objective of the paper is to propose a data model for FEM analysis and a program structure of the pre/post processing system using the model. The main features of the data model are ; (1) The object to be analyzed are represented as a set of solid models corresponding to each finit element and the conditions and/or the computed results are as their attribute ; (2) Total shape data can be preserved by a renaming procedure in splitting operation, and the cyclic sub-division operations for selective parts can be performed in the system. The proto-typed system connected with NASTRAN is organized using Euler operators in shape processing and is proved to be effective through case studies.

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This paper presents a fast visible surface algorithm for free form bodies. Conventional algorithms for such objects require a lot of computing time as well as much memory capacity. The proposed algorithm approximates the objects with many small triangles. It makes use of a special triangle data structure which preserves topological information between neighboring triangles and requires comparatively small memory storage. By employing the segment chain method, the algorithm exhibits much faster characteristics compared with the Watkins' algorithm.

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This paper describes a method of representing three-dimensional objects required in industrial products. The object is defined by mutual combination of segments. The segment must be defined by the intersection of curved surfaces which are formularized by single-valued function. The segment shape can be defined by mutual combinations of the simplest solids (e.g. block, cylinder). The simplest solid is treated as the standard shape. The standard shape is a restricted shape. It is analogous to the case of a segment shape. Namely, a sphere is not a standard shape, but a hemisphere is a standard shape. This modeling method is concise and does not require a large amount of data. The calculation of modeling can be done at high speed.

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A new style of CAM system which consists of hierarchical modules was developed, and as a basic geometric model for the system, the Cell-Constructed-geometric-Model (CCM) was proposed. These enables us to decompose the CCM into the several Machining Face Groups (MFG) which are created by the same cutting operations, to determine various information about machining, to generate cutter path for each MFG and to check and distribute NC data to machine tools in an interactive way. The CCM which is based on a rational Bézier interpolation, is efficient to make and edit the MFG, and to generate cutter path. In this paper, the structure and functions of these hierarchical modules and an example of the processing are described. And the concept and contribution of the CCM to these modules are also shown.

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For the development of the FRP bolt, it is essential to analyze the stress distribution in the screw thread of FRP bolt and to examine theoretically and experimentally the reinforcing effect of fiber arrangement on the static as well as fatigue strengths of the thread. This paperdescribes the results of a study on the reinforcing effect of fiber in the FRP screw thread. For the two-dimensional glass-epoxy composite model of M 8 thread magnified in 10 diameter, finite element analysis of the stress distribution in the thread, static shear test and fatigue test were made. The arrangement of the long fiber along the screw thread was found effective for the increase of the strength of thread.

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This paper describes the experimental results on the relation between the size of the contacting surface between a steel ball and an optical flat made of cubic zirconia and the applied force between them. The diameter of the circular contacting surface is measured by the method of total reflection of polarized light which has been developed by one of the authors. A polarized light beam is projected on the hypotenuse of a cubic zirconia prism which is in contact with the steel ball, and the reflecting light from the ball surface is intercepted by an analyser. Thus, the contacting surface is observed as a dark image in bright backgroud. The systematic error caused by an electromagnetic field appearing outside of the reflecting surface which is accompanied by total reflection is estimated theoretically and the corrections are made on the measured values. As a result, the corrected values agree with the calculated values from the Hertz's formula in the range of an applied force larger than 1 N, but do not agree in that smaller than 1 N.

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It has been said that the internal gears have a higher surface durability as compared with the external gears. Nevertheless, experimental study on the load capacity of internal gears has been extremely few. In the present paper, a new type of four square internal gears running test machine has been developed for investigating the load capacity of internal gear pairs experimentally. And some experiments on the conventional involute tooth profile internal gears have been performed by this testing machine. It is confirmed from these experimental results that the fatigue strength of internal gears increases remarkably with increasing the surface hardness of the internal gear by heat treatment.

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The study deals with the development of a new type face gear and the application. The face gear can be easily hobbed by use of a conventional narrow gear hob without any special attachment. Geometrical dimensions and form of face gears are analysed, and face gears were actually produced. The face gear meshing with involute spur gears or helical pinions has advantages of easy setting and smooth mating. Together with applications to robot hand, radial-feed screw cutting device and reel for fishing, the automatic circular index table developed in combination with two different face gears is explained, making use of features of the face gears.

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As mentioned in the 1st and 2nd reports, the new types of pockets and restrictors are effective for facilitating the manufacture and for improving the performance of the hydrostatic lead screw. The working fluid used in the previous reports was lubricating oil. However, air is desirable when using the lead screw under conditions where contamination by oil must be avoided. In the present report, the problem of pneumatic hammer resulting from the use of air is analysed. To avoid the occurrence of pneumatic hammer, the mass of air stored downstream of the restrictor was decreased by the following modifications of design ; (1) decrease the diameter of the supply holes, (2) decrease the working clearance, and (3) increase the pressure ratio to almost unity. The maximum thrust stiffness measured was about 11 N/μm, where the supply pressure of air was 0.2 MPa(gauge), the working clearance was 12 μm, and the pressure ratio was 0.9. From the measurement of the thrust stiffness, it is shown that air can be used as a working fluid of the improved hydrostatic lead screw.

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The count variance of light scattering single particle counters is investigated experimentally. Since in the present state of the art it is impossible to feed a fixed number of sample particles repeatedly to a counter, an alternative way of evaluating count variance is proposed. In this method, count data are collected by two counters operated simultaneously in parallel and then analized statistically. It is shown that for actual airborne particles count variance can be notably larger than that for mono-disperse polystyrene latex particles the size of which is well above the threshold level of the counters. Therefore, if sampling error is assumed to be the only cause of count variance, there is possibility of underestimation of the count variance. The origin of this phenomenon is also discussed.

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The experimental considerations are performed to clarify the fatigue behavior of the bolt tightened up to the plastic region in the joint. The T-flange joint is treated as an example of bolted joints. The experiments are executed as the co-operative investigation by six bolt makers and a laboratory of the university. Firstly tension tests, tightening experiments, and fatigue tests of the bolt-nut joint are done in order to examine the mechanical properties of the bolt. Secondly the fatigue tests of the T-flange joints are performed in the same loading condition and in the three different tightening conditions - (a) elastic region tightening, (b) elastic limit tightening, and (c) plastic region tightening. As a result, the failure probability is found to be least in case (c), and greatest in case (a). These results coincide with the estimation from the stress measurements for the bolt in the T-flange joint. On the other hand, the difference in the behavior of the preload loss during fatigue tests are not so remarkable between three tightening conditions. Finally it is concluded that the bolted joints in the plastic region tightening have the more safety against fatigue because of higher preload, i. e. lower load amplitude on the bolt.

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