This paper describes of development an interferometer for measurement grating and index scales. The interferometer is provided with a photo-electric microscope to detect the edge of the scale grating. Measuring object is fixed on a double-moving table. An upper table is supported by the cross roll guide ways and driven by a laminating piezo-actuator. An under table is supported by the pneumatic half-floating slideways, and driven by lead screw. In this article, the specification, system and specific constructions, heat insulating plan, calibration of laser wavelength, estimate of the errors, and performance are described. The interferometer has the following specifications : (1) Measuring range is 200mm, (2) Fringe counting resolution of primary development is 8nm, secondary one is 4nm, (3) Interferometric light is He-Ne laser, (4) Thermometer is platinum resistance thermometer.
This paper presents a high speed non-circular generating mechanism for a piston-head of a reciprocating engine. An ordinary piston-head has the complicated cross-section whose profile is ellipse with harmonic components, so that it is difficult to machine the workpiece at high speed by the copying lathe which is used generally. In order to solve this problem, an NC-tool positioning mechanism using hybrid system which has both the VCM's feature, long stroke, and the PZT's feature, fast response was developed. And a periodic learning control method was also developed which corrects the NC data in the frequency domain. The PZT is mounted coaxially on the top of the externally pressurized slideway which guides the VCM, and the sum of these two actuators' displacement becomes cutting tool's displacement. On account of sharing the harmonic components of profile, i. e. lower components to the VCM, higher components to the PZT, the piston-head can be machined more than three times as fast as the conventional system at the speed of 3 000 min-1, resulted in the accuracy of ±3μm tolerance.
A new type of STM instrument, named skid-type STM is proposed and a test instrument has been constructed. In the test instrument, two skid-styluses and a measuring stylus are set in a line so that the measuring one is equi-distant from both skids, and the specimen is moved by a 2-dimensional inch-worm mechanism. It is shown that the z-directional errors due to thermal drift and the scanning motion of the inch worm stage can be reduced to 1/10 in the skid-type STM. Although the influence of environmental vibration has not been sufficiently reduced yet and smoothing effect by the trial skid-stylus is not quite enough for specimens like gratings, a possibility of making an STM with a very large scanning area is shown.
This paper describes a development of an apparatus for highly accurate measurement of a thermal deformation of a mechanical part. The apparatus makes possible a real time monitoring a microscopic change of the thermal deformation pattern by using real-time holographic interferometry. One of the most important problems to be solved on a measurement of thermal deformation is how to fix a measuring object. When environmental temperature changes, the spurious interferometric fringes are happened by an unnecessary slip between contact surfaces of the measuring object and its holder, due to thermal expansion differences between them. An adjustable correcting stand utilizing piezoelectric elements is developed for a real time compensation of the spurious fringes. The effectiveness of the correcting stand for a precise and real time measurement of the thermal deformation pattern was confirmed experimentally. An air bath that has an optically stable window for observation of the deformation from outside is used for highly accurate control of the temperature of the measuring object. The interferometric fringes are recorded on a thermoplastic plate for real time monitoring of the changing process of the thermal deformation pattern.
Magneto-optical disk drives have some disadvantages compared with hard disk drives such as low access speed and low data rate. A small light optical head and high speed rotation of the disk would improve the performance, as well as achieving over write. This paper details the development of small-light focusing actuator, which can be used in high speed rotation of disk and make optical head small and thin. The actuator suspension, which raises the frequencies of higher order mechanical resonance, is discussed. And a parallel leaf spring suspension with visco-elastic damping layer is adopted. The vibration characteristics were experimentally evaluated. Results show that the frequencies of higher order mechanical resonance are above 50 kHz. The actuator is driven by a novel moving coil motor which makes the moving part thin and stiff. The design and performance of the motor are clarified.
The adhesive mechanism to flexible surface is more and more important for a medical electrode, the future minute medical machine which moves and inspects in stomach, and so on. In order to investigate the superior adhesive mechanism, the authors take up the suction electrode for electrocardiograph which is now desired to improve and also can be the base of mechanism with its simple structure. The chest suction electrode is constructed with a steel cup and a rubber sphere and can adhere to skin with the suction pressure. But there are many different types of skin, so the suction time varies. If the electrode is fallen off while electrocardiogram running, the inspection becomes impossible. Moreover it is a problem that the skin is engorged and damaged by the suction pressure. To overcome such problems, the paper makes experimental investigations on the influence of the shape and rubber elasticity of the electrode and the elastic characteristics of skin. Based on the results, the authors propose the “flexible over-hemisphere electrode”, and confirm the validity with experiments. The newly proposed electrode could adhere to skin for far longer time than present ones with less suction pressure. Also, the paper tries to analyze the performance with a simple model.
When a number of micro holes are machined in a workpiece, one effective way to reduce machining time is to use small electrode-feeding mechanisms arranged closely to machine simultaneously. An electro-discharge machine with three electrodes is developed combining three pencil-sized electrode-feeding mechanisms using rapid deformations of piezoelectric elements (IDM : Impact Drive Mechanism). The three electrodes are controlled independently by one controller using time sharing system so that the developed electro-discharge machine can machine three micro holes simultaneously. The machining time of three micro holes using the developed electro-discharge machine was as short as that of one micro hole.
In this report grinding characteristics of chloroprene rubber (CR, matrix material) are experimentally investigated in order to obtain fundamental information as to grinding mechanism of aramid fiber reinforced rubber. Main conclusions obtained in this report are as follows : (1) Regular pattern just as file is generated on ground surface of CR, and generative mechanism of the pattern is classified into two distinct types. (2) Tangential force is larger than normal one because of severe friction between bonding material on diamond wheel surface and CR which make much elastic recovery before and after a contact of cutting edge. (3) Height and spacing of the pattern decrease with an increase of mean contact stiffness between surface of grinding wheel and CR by varying setting depth of cut, speed ratio and radius ratio.
In the present paper, piano wire on which spiral grooves are ground continuously is developed and it is used for a multiwire saw as a tool. The spiral-grooves ground round about the wire possess a sort of “abrasive grain carrier effect”. Accordingly, the abrasive grains can easily enter into the part being processed. This report deals with the mechanism of a trial apparatus to make the spiral-grooved wire tool and with the slicing characteristics of the spiral-grooved wire tool. The results obtained through the theoretical analysis and a series of experiments are as follows : (1) Theoretical results considered on the basis such assumptions that a holding effect of abrasive grain in slurry is related to volume in the hollow of spiral grooves are approximately confirmed by experiments (when the grain size is same or less with grooves depth). (2) Machining efficiency used the spiral-grooved wire tool shows two times as much as the normal wire tool. (3) Wear of multigrooved pulley used the spiral grooved wire is slightly larger than the case of ordinary wire. (4) Thickness of the sliced wafer used the spiral grooved wire is as thick as the case of ordinary one.
The grinding of amorphous tape is regarded as extremely difficult due to the loading of the wheel during the grinding process and due to the crystallization of the amorphous tape caused by grinding heat. By taking advantage of excellent grinding performance of endless CBN abrasive belts, a new grinding wheel system constructed of endless CBN abrasive belts (namely a throw-away CBN wheel) was developed. In order to improve the ground workpiece surface waviness and roughness, a Low-frequency Vibration Grinding Method (LFVGM) was creatively put forward. In this paper, both the theoretical analysis and experiment research of LFVGM on improving ground workpiece waviness were carried out. An experiment investigation on grinding performance with a throw-away CBN wheel in continuous-feed grinding of amorphous tape was also conducted. Experiments show that the ground amorphous tape roughness Rmax value is below 0.8 μm by using # 600 endless CBN abrasive belts.
This paper treats the relation among lapping pressure, wear-distance-ratio, mesh number of abrasive sheet and sphericity of balls in the lapping circumstances of ceramic balls, and the new lapping method for ceramic balls are presented. Obtained results are as follows : 1) For green balls formed by CIP the optimum lapping conditions such as lapping pressure, the mesh number of abrasive sheet and others are found. 2) New lapping method for sintered balls using combined lapping tools is proposed, and the sphericity of balls can be considerably improved by this method. 3) The optimum share ratio of normal loads in combined tools is found for the rapid improvement of the sphericity of balls.
It was previously shown that chipping size of the work corner in grinding of ceramics was subjected mainly to the length of the crack extending forward during its process. This paper focuses its attention on determination of the length of the crack in grinding by a wedge-shaped two-dimensional single grain. An analytical model for the crack extension was introduced; the cracks extend under the stress state induced near the grinding point on the work (early stage) and re-extend successively due to the proceeding of the point. It has been shown that the maximum length in the cracks and its trajectory obtained from this model approximately agree with those of the experiment for alumina ceramics and the length is larger than that from the traditional model considering only the early stage.
The nanometer scale imaging of ultra-precision ground surface of silicon nitride ceramics generated by using fine grained diamond wheels has been carried out with an atomic force microscope. The main results obtained in this study are summarized as follows : (1) An ultra-precision mirror surface with a roughness of 6-9 nmRmax can be obtained by using a very fine grain diamond wheel of grain size # 10 000. The roughness of the mirror surface is affected by the protrusion of grain boundary phase out of Si3N4 crystal surface as well as the unevenness of grinding streaks generated by grain cutting edges. (2) There are an infinite number of ultrafine projections with a height of less than 1-2 nm on the ultra-precision ground surface. The height of ultrafine projections existed on the bottom surface of cutting edge streaks is less than 1 nm, which is lower than that on the other ground surface. (3) These ultrafine projections have slightly an anisotropic geometry in the shape and the distribution. It seems that the anisotropy is closely related to the material removal mechanism in grinding.
In centerless grinding, unbalanced parts are difficult to produce with precise accuracy, because centrifugal force caused by the rotation of the unbalanced mass tends to move the part up and down, or to fall from the work support blade. Unbalanced parts are classified into 3 types depending on the position of unbalanced mass. This paper presents criteria to achieve stable grinding conditions for each type of unbalanced part by analysing the balance of the forces working on them.
This work deals with the evaluation of ceramic-fiber reinforced plastics, as a grinding tool for various work materials. The composites were manufactured by mixing continuous alumina-fiber of definite diameters and thermosetting resin as a bond material. The characteristics of FRP tool as a grinding tool (volume fraction of fiber : 60%, fiber diameter : 10-25μm) are as follows : It is strong but fairly flexible so that it does not break up during use. The sharp edge of the tool does not rapidly lose its shape. The evaluation is performed in testing the composites with fibers of various different diameters from 10 to 25μm. The wear of the work and the composites and the surface finish of the work materials were evaluated.
The study deals with the general method of generating NC data from collision-free tool path of 5-axis control machining centers. The use of 5-axis control machining centers, capable of machining complicated workpiece shapes efficiently and accurately, is recently increased. Then, it is inevitable to generate collision-free CL data and NC data rapidly. CL data are generated by the main-processor having the collision avoidance procedure between a workpiece and an arbitrary tool shape, based on the solid modeling technique. The post-processor developed in the study can convert CL data to actual NC data, taking account of the structure of machining centers, linearization, feed rate control and spindle rotation control. The main- and post-processors are experimentally found effective.
This paper establishes a high-speed algorithm to compute three dimensional collision domain of two input domains, such as a workpiece and a tool. When the tip of the tool is located in the collision domain, the tool must collide with the workpiece. Collision domain can well be computed by Inverted Template Method using envelope operation. Studies have been made to develop algorithms for three dimensional envelope operation. In order to save on storage, oct-tree is adopted to describe three dimensional objects. An oct-tree is generated by recursive dividing of cubic cells. The top cell must involve the object to be described and the descendant cells are classified by four cell values ; outside, inside, boundary and unchecked. Among them, only boundary cells are subdivided into eight. The cell value of the output collision domain is determined by matching two cells extracted from each input domains. Matching strategy is most crucial to the speed of envelope operation. We designed three strategies ; Breadth-first, Depth-first and Weighted Depth-first-matching. Comparing the computing speeds among the three, Weighted Depth-first-matching shows the highest efficiency owing to the effect of pruning the unnecessary matching of the oct-trees.