This study deals with drilling kinematics by planetary mechanism, adopted tool performances and cutter wear phenomena. Recently lightweight materials such as CFRP or titanium alloy are widely used as structural materials in aviation and aerospace industries for the purpose of mass reduction. Although these materials have characteristics of lightweight and high strength, they are regarded as difficult-to-cut materials. Planetary mechanism drilling is one of effective drilling methods for difficult-to-cut materials. The advantages of planetary mechanism drilling are short machining time, high-quality drilled holes and long tool lifetime. In this study, three types of tools for the planetary mechanism drilling were developed on the basis of kinematics of the cutting edges. Through the experimental results of tool wear or cutting edge observation, cutter performance of the tools and tool lifetime were made clear.

抄録全体を表示

The final objective of this investigation is an invention of theory and technics for multiple precision cylindrical machining with combining ultrasonic vibration cutting on thrust force direction, and superposition superfinishing process. This finishing process is a high efficient mirror machining providing (20-50Hz) low frequent vibration and ultrasonic vibration above 20 kHz to fine abrasive stone. In this report, it is analyzed that high precision cyli ndrical machining as being basic profile can be achieved by vibration cutting on thrust force direction, and that theoretical surface roughness sho uld be formed around this basic cylinder. Cutting phenomenon are observed by some experiments. In the results, it is confirmed that chips on low feed rate and high cutting speed conditions have been cut to pieces as same as analyzing, and that roundness of 1.0μm being near equal to main spindle accuracy and surface roughness of 2.5μmRz for theoretical surface rou ghness 3.4μm are obtained by vibration turning in the case of aluminum alloy. Main cutting conditions are as follows : cutting speed ; v=280∼298m/min, feed rate ; S=2∼50μm/rev, depth of cut ; t=50μm, work material; carbon steel, aluminum alloy, brass, tool frequency; f=21.9kHz, amplitude ; a=9μm, cutting tool material and profile ; carbide K10, (0°,0°,6°,25°,2∼40°,2∼40°,0mm). This report indicates that ultrasonic vibration cutting on thrust force direction can be possibly used for multiple precision cylindrical machining.

抄録全体を表示

A high performance Nd₂Fe₁₄B/Ta thin film permanent magnet (thin film PM), which not only has a high remnant flux density and a high coercive force similar to those of conventional sintered Nd₂Fe₁₄B magnet, but also has higher heat tolerance, was developed. In this report, utilizing this high performance thin film PM, we fabricated a MEMS linear motor consisting of a moving silicon slider including 6μm thick thin film PM, a silicon linear guideway coated with DLC and a two-phased micro coil. In order to increase thrust force, the thin film PM is magnetized with a pole pitch of 0.5mm using a pulsed magnetic field generated by a meander-shaped magnetizing coil. In driving experiments, a 36mm-long stroke, maximum velocity of 1,300mm/s, maximum acceleration of 35.5m/s² and kinetic friction coefficient of 0.14, were achieved.

抄録全体を表示

Many lathe simulators for acquiring skill to fabricate machine parts with a lathe have been already studied and developed. However, there is no simulator for training workpiece centering operation on a lathe, which is known as a high level skill required one. This paper deals with development of a simulator for the operation and its training effect. The simulator developed is composed of the working platform with the clamp-force-adjustment-device, an impulse hammer, a LCD monitor and a PC. A virtual workpiece clamped with a virtual chuck, a virtual test indicator and a virtual hammer are shown in the monitor. A trainee can check eccentricity of the workpiece by using the test indicator and reduce it by adjusting the clamp force and hammering. To confirm the effectiveness of the simulator, skill training examinations by trainees were carried out. As the result, it is found that the simulator improves the centering skill on actual machine operation. In addition, it is clarified that hammering skill is more difficult to learn than clamp-force-adjustment skill.

抄録全体を表示

The productivity of circular shafts with a straight groove and/or a plane surface on outside surface of workpiece was much improved by the development of CNC lathe having a milling spindle. However, for milling of shafts with a large length and a small diameter, workpiece deflection induced by cutting forces causes deterioration of surface quality and chatter vibration. This investigation deals with an analysis of workpiece behavior and optimization of the machining conditions for ball-end milling a shaft with a small flexural rigidity in the direction of perpendicular to the shaft axis. In this paper, to apply a previously developed cutting model to milling of shafts, geometric quantities such as contact region between the cutting edge and the workpiece surface, and distribution of undeformed chip thickness along the cutting edge are analyzed. Cutting forces are calculated by using the cutting model and an energy method. Then, the workpiece deflection is analyzed on the basis of calculated results of cutting forces, and the variation of the above quantities with tool rotational angle are compared with experimental results at various tool locations on the workpiece. It is found that both of the cutting forces and the workpiece deflection take each maximum value at a location where the tool axis reaches close to the perpendicular plane passed the axis of the workpiece. Through the comparison of the results obtained by analysis of resonance frequency of the workpiece and that obtained by impact test using impulse hammer it is shown that the possibility of avoiding the occurrence of chatter vibration.

抄録全体を表示

As manufacturing activities have been getting globalized and product models have become more and more diversified, animated work instructions for assembly sequence have been increasingly employed to assure product quality. However, assembly sequence planning and subsequent animation editing time drastically increases and becomes unacceptably time consuming in the order of factorial as the number of assembly parts grows. To address this problem, a fast assembly sequence and assembly motion generation method have been developed based on assembly constraints and locations of parts in 3D-CAD assembly models. Generated assembly sequences have been automatically translated into animation scripts and eventually employed as animated work instructions in actual manufacturing sites.

抄録全体を表示