This study deals with the technology of high speed end milling of hardened steel by a high speed milling machine with an air bearing spindle. In a previous paper, it was shown that use of such machine enables stable machining to be carried out. Nowadays most of high speed milling machines are equipped with ball bearing spindles. But basic feature differences of high speed end milling of hardened steel when using air bearing spindle and ball bearing spindle, have not been clarified. In this paper, static and dynamic stiffnesses of high speed milling machines with a different type of spindles are discussed. Basic features of high speed end milling of hardened steel, vibrations, surface roughness and tool lives are also discussed. The main results are as follows: (1) The static and dynamic stiffnesses of the air bearing spindle and the ball bearing spindle are obtained by experiments. (2) The features of high speed end milling are obtained by experiments for each type of spindle machines. (3) In a high speed milling machine with an air bearing spindle, the static and dynamic stiffnesses are lower than those of a machine with a ball bearing spindle. But under comparatively high spindle speed conditions, tool lives are longer and surface roughness are better than those in case of a ball bearing spindle machine.

抄録全体を表示

In the micromachining research field, there are great demands to reduce the start-up and shut-down time of film deposition system, to reduce running costs, to produce thick film of polysilicon, and to enable the high-speed polysilicon film deposition. However, no such polysilicon film deposition system which fulfills the above-listed demans can currently be found. Therefore, in order to meet these demands, the authors designed new LPCVD which is characterized by spot-heating using a lamp and produced a prototype of this apparatus, and actually operated this apparatus to study its characteristics.

抄録全体を表示

The purpose of this study is to analyze the thickness deviation conditioning effect of the polishing by a polishing pad. The quartz crystal unit that oscillates directly with more than 100MHz requires the polishing, of thickness less than 17μm and the thickness deviation 0.3μm (a wafer) within. The working became possible with the composite plate that attached quartz wafer (a diameter 76mm) and a standard plate. However, it is difficult to do wide area a highly precise polishing. The action of a polishing pad is important to grasp the dynamic behavior of polishing pad that is able to reproduce the condition of polishing. It became possible with 4 elements of Burgers model of a visco-elasticity. The thickness deviation conditioning effect that calculated it from the dynamic character and vibration analysis confirmed the appropriateness from the comparison with an experiment value.

抄録全体を表示

This paper deals with a machining device for a local area on a large workpiece called Local Machining Station (LMS). It consists of a small machine tool, a reference plane with displacement sensors, extendable legs and adhesion pads. By adhering on a workpiece with the pads and pressing the LMS with a robot, the stiffness of the system is improved. Because the movement range of the mobile machine tool is restricted within the reference plane, higher positioning accuracy can be easily obtained by the LMS method. A prototype with five degrees of freedom is a mechanism which consists of a parallel mechanism and an xy stage. A small electrode feeding device for electrical discharge machining (EDM) on the xy stage is installed as a mobile small machine tool in the prototype. The tool electrode is positioned in a local coordinate system for a worlpiece by using holes which have been machined as references. Some holes are machined by EDM on the workpiece. The accuracy of measured interval between two holes and the center of the machined holes with the LMS are better than that with a robot.

抄録全体を表示

In this study, the plate shaped workpiece is constrained in a special method whereby it is supported at four selected points at the bottom surface. From experiments, it has been found that this special fixture configuration results in less amount of flatness error than that caused by side clamping mechanism. The flatness error is, however still dominantly influenced by the cutting heat. The objective of this research is to find an optimum method on fixture design for plate shaped workpieces, which can ensure that the machining flatness error is minimum as caused by the moving cutting heat source imposed by finish face milling cutter.

抄録全体を表示

The newly developed cutting force and temperature measuring system with high response speed and fine resolution can monitor cutting process as well as tool wear during high-speed endmilling of hard materials. The system enables us to precisely determine a transient cutting force and temperature action which is generated by each cutting edge of an endmill tools with various rake angles and helix angles. It is found that the cutting force and temperature in high-speed endmilling are sensitive to the helix angle rake angle and tool wearing process. When the helix angle and rake angle are 60 degrees and - 15 degrees respectively, the cutting force and the flank wear of each cutting egde generated is smaller than those for other angles of helix and rake.

抄録全体を表示

Magnetic head made of polycrystalline ferrite sintered by HIP method is widely used in an audio and video installation. Work damage such as a chipping induced by slicing of ferrite gives rise to the deterioration of an electro-magnetic property of the magnetic head. Micro-crack growth modes of ferrite by an indentation and scribing tests with an diamond indenter are examined in detail by SEM microscopy and by an acoustic emmission method. It is found that micro-crack growth modes are very different among the ferrite materials with same hardness of physical property. Chipping at groove corner yielded by slicing of ferrite with a diamond blade is closely related to micro-crack growth of a grain. AE signal generated by scribing is useful for evaluating the slicing of ferrite.

抄録全体を表示

The study deals with the curved hole machining. In the field of injection molds and casting die, the temperature control of molds is much required in order to obtain products without any defects occurring in molding process. It is almost accomplished by regulating flow rate and temperature of coolant which runs through cooling holes of molds. Recently, the great development of computer technology comes to allow various physical phenomena in molding process to be simulated, which can show us the best arrangement of cooling paths. However, the paths cannot help being formed like broken lines consisting of a series of straight holes since cooling holes are conventionally machined by drilling. Therefore, it is difficult to realize the best arrangement of cooling paths determined by computer simulation. To solve this problem, a new method for curved hole machining mechanism with an electrical discharge machining (EDM) function was devised. The mechanism performs EDM by itself in the limited space such as a bottom of curved and long hole. It mainly consists of a helical expression spring and helical extension ones made of shape memory alloy (SMA), and makes it possible to control a discharge gap automatically without any actuators. The mechanism is called Automatic Discharge Gap Controller (ADGC). From experimental result, it is found that ADGC has potential of performing stable EDM due to the self-dischage gap control.

抄録全体を表示

Although a simulator is sometimes useful for training the operation of man-machine system, its application to machine tool operation has been hardly studied so far. In this paper, the authors propose a method for high efficiency skill training of small-diameter deephole drilling by using the simulator developed previously. For the training system, a function to display an ideal operation pattern and difference from that of a trainee graphically has been added to the simulator. A new index for evaluating the skill level has been also introduced by using this difference. As the results, it is found that 10 to 15 times of training using the simulator improves trainees' skill. In addition, the training by the simulator with emphasized sensory display together with the normal simulator is highly effective to overcoming saturation of skill level.

抄録全体を表示

CAD system for designing dental crown has been developed as a step to attain stable and sufficient supply of prosthetic teeth, which will be serious social requirement in The 21st century. In the report, a concept for modifying standard crown model and a process for crown designing by combining functions and operations of the design, were proposed. Then CAD system equipped with CAD function to assist the design process and design data has been developed and rapid crown designing has shown to be realized.

抄録全体を表示

One of the major problems in manufacturing is obviously to reduce cost. In order to do so, various activities such as TQM, TPM and JIT, etc. are often carried out. But many companies recognize that these activities do not necessarily guarantee cost reduction even if they have successfully been implemented. In the worst case, manufacturing cost rises with the introduction of such activities. This is such an important issue in manufacturing, but strangely in the literature, there have been no papers which have addressed themselves directly to the methodology of manufacturing cost reduction. The purpose of this paper is to develop a good method that establishes a cost reduction program scientifically and systematically, first, by investigating various production losses and classifying them into causal losses and resultant losses, secondly, by looking for the relationship among the losses, processes generating cost and the cost factors and finding connection between various kinds of loss reduction and their possible cost reduction, thirdly, by clarifying if the know-how on each loss reduction is available and obtaining it if not available, and finally by estimating the cost of reducing or eliminating each identified loss and putting priority to the loss items for total cost reduction from the viewpoint of cost and benefit. This method has been coined as cost deployment. This is a very powerful tool to identify right losses to reduce cost. A simple algorithm to establish a cost reduction program based on the cost deployment is presented and one case study is given at the end of the paper.

抄録全体を表示

In the progressive press-working, a belt-like sheet metal part is transferred in a series of pressing machines. Punching, bending and cutting operations are successively applied to the part during the transferring process and products in the final shape are fabricated. Manufacturing process planning of the part, especially planning of the bending sequence is the most critical task in designing the press-working line. Preferable bending sequences of a sheet metal part can be determined by successively applying bending simulations to the geometric model of a blank. Three acceleration methods of the simulation based bending sequence planning are proposed in this paper. (1) Bending operations in the progressive press-working must comply some topological constraints of a part. These constraints can be used as a filter for excluding infeasible bending sequences. (2) The same geometric computation for checking the bending feasibility is repeated many times in the bending sequence planning. This redundancy can be eliminated by properly saving and reusing the previous computation result. (3) In order to realize the stable part positioning, two parallel and symmetrical lines of a part are often bent simultaneously. Consideration of such simultaneous bending in the planning process can reduce the search space of the solution. Based on the methods, an experimental bending process planning program is implemented and demonstrated.

抄録全体を表示

This paper presents a new design style which is called "Global Design" based on designers' collaboration across time and space, and proposes the "Activity Chain Model" for the knowledge medium which realizes "Global Design". This model not only represents design product information such as drawings which is obtained as a result of design processes but also represents dynamic design process information including evolution histories of design product information and design rationale by recording design activities and links between the activities, and enables designers to share the design process information. The model can provide causal explanations based on subjective constraints as well as teleological explanations for the design rationale, and can be used with less difficulty in capturing the design rationale. This "Activity Chain Model" is implemented in a system called "POET Knowledge Media" which realizes interactive searching for the design process information by navigating "Activity Chains" and facilities to support capturing the design rationale. Evaluation of the system through a design simulation shows effectiveness of this model in capturing, storing and transferring the design rationale in cooperation with product information handling tools such as 3D-CAD systems.

抄録全体を表示

Determination of tolerances is very important during product manufacturing in order to maintain low cost while achieving a consistent level of product performance. However, with optical products, precise, quantitative prediction of tolerance sensitivities, optical performance, and productivity in a mass production environment have been very difficult in the design stage, The purpose of this study was the development of a statistical tolerancing system for optical products based on computer simulations (called Virtual PT System). The development of the mass-production simulation system was already reported in the first paper. As the second step of this study, the development of the complex sensitivity analysis system, which is based on the stepwise multiple regression method are reported in this paper. This system analyzes the error data and the MTF data output by mass-production simulation system, and output analysis result of the statistical complex tolerance sensitivity. Furthermore, this paper reports the effect the sensitivity analysis result confirmed by the mass-production simulation.

抄録全体を表示

This study proposes a new coordinate measuring machine (CMM) based on a parallel mechanism consisting of closed loop link mechanism. The use of this mechanism will potentially improve the stiffness, accuracy and efficiency of the CMM. This report describes link layout design for isotropic measuring resolutions. Moreover, error analysis was performed to obtain tolerances of various mechanical parameter errors. The obtained main results are as follows. (1) When three straight lines between three spherical joints and a probe tip are perpendicular to each other, the measuring resolutions become isotropic. (2) Overlapping between the struts and those lines, the resolution variation is minimized. (3) Increase of the base radius and decrease of the stage radius and the probe length reduce the resolution variation. (4) Maximum measurement error varies in proportion as the measuring length is multiplied by the parameter error.

抄録全体を表示

In case of plastic injection molding process, stable molding is the most required and pressure profile deviation under injection velocity control is used for a judgment factor of stable molding. Formerly pressure profile is controlled only during hold process (pressure controlled stage) and is not controlled during injection process (velocity controlled stage). To achieve the stable injection process, Pressure Profile Trace Control is developed. This control is able to trace the original pressure profile at good part produced by controlling pressure directly. To control pressure directly with fully electric injection molding machine, the force control of electric servomotor has to be used. Force control of electric servomotor is developed for various areas, especially robot application. But there is a little application at injection molding area. Simple closed loop force control was not able to get good result. To improve the functionality, learning system is introduced for force control.

抄録全体を表示

This paper describes.a measurement of surface flatness along a circle with no standard. For the measurement, distances of the space between two unknown surfaces located almost in parallel are measured along a circle. One of the surfaces is rotated around the center of the circle and the distances are measured again. This procedure is repeated many times. The profiles of two surfaces along a circle are calculated from these data. Validity of this measuring principle was proved by computer simulations and simple measuring experiments in the former paper. In this study the principle is applied to measurement using a Fizeau interferometer with He-Ne laser. For the purpose, a high precision mirror and a metal-coated glass are used for the upper and lower reflection surfaces respectively. Their profiles are unknown. The distances between two surfaces are obtained by the interference fringes. Fourier transform method is used to obtain the distances smaller than one fringe. Two profiles are calculated from the data. Profile measurements are carried out four times using four different metal-coated glass plates as the lower surface and a precise mirror as the upper surface. The measured profiles of the precise mirror obtained by these procedures agree well with a deviation of about 2nm.

抄録全体を表示