Many techniques for improving the accuracy of a cutting process simulation using the finite element method have been developed. However, the frictional force and stress between a work material and a tool material cannot be estimated before material cutting when a new tool material and a new work material are developed. This leads to considerable loss of time for the material development. This study aims at developing a method for predicting the frictional-force and frictional-stress distribution on the rake face of a cutting tool before the actual material is manufactured. In this study, electron theory analysis is used and the phenomenon theory using the Langevin equation is proposed. The results obtained from the phenomenon theory agree with the experimental results well. The frictional force is estimated by the theoretical analysis of the molecular orbital method during the cutting process. In addition, the stress distribution is approximated by assuming the real contact area.

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Improvement in the mechanical properties of self-lubricating tungsten carbide bodies that include carbon onion was carried out in terms of microstructure and sintering conditions. Tungsten carbide particles and carbon onion were mixed through ball milling process to achieve homogeneous dispersion. The conditions of electrical current activated sintering were examined regarding temperature, compacting pressure and compaction rate. Ball milling and sintering at the low temperature such as 1500°C resulted in achieving homogeneous microstructure of sintered bodies and leading to higher relative density and Vickers hardness. In accordance with the higher relative densities, surface roughness was reduced because of fewer large voids in sintered bodies. Examination of the sintering behavior revealed that carbon onion performed as lubricative agent for tungsten carbide powders during sintering. Moreover, tungsten carbide sintered bodies including carbon onion showed the similar corrosion resistance as binder-less tungsten carbide bodies.

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In this paper we discuss the basic characteristics and performance of precision washing using ER water (electrolyzed reducing water) electrolyzed with Na₂SO₄ solution (Na₂SO₄ ER water). First, the structure and characteristics of the three-tank system used to produce electrolyzed water as well as how Na₂SO₄ ER water is produced by the system are described. Next, the relationship between the characteristic value of Na₂SO₄ ER water and the electrolytic current, and its difference from those for NaCl ER water and NaOH solution are investigated experimentally. Changes in the characteristic value of Na₂SO₄ ER water with time are also investigated in the same time. Finally, according to the results of washing the surface of precision parts with Na₂SO₄ ER water, C₉H₁₂ solution and pure water, the washing efficiency of Na₂SO₄ ER water is verified.

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Combined loading tests were carried out on secondary hardened SKH51 to examine strength characteristics under combined bending and torsion loading. Tempering temperature at 560°C after quenching temperature at 1200°C was chosen as heat treatment condition. The tests were conducted using torsion testing machine with a special chucking device which enabled to change the stress ratio of bending and torsion. The stress-strain curves were derived from equivalent torsional moment, and the yield and fracture surfaces were analyzed by applying Hill's quadratic function. The yield and fracture surfaces lay inside Tresca's surface. The direction of plastic strain increment did not obey the normality rule. It was revealed by SEM and TEM that bending strain included displacements due to crack and interfacial debonding of carbide. Static toughness increased with increasing shear stress component. The variation of static toughness with stress ratio was divided into three regions on the basis of fractographic fracture aspects; the brittle, the brittle-ductile transition and the ductile regions.

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TiN films are superior in hardness and adhesive strength. However, friction coefficients of the TiN films are higher than those of DLC films. By adding molybdenum disulfide (MoS₂) up to 40%, the TiN-MoS₂ composite films with very low frictional properties could be obtained. In this study, the authors tried to reduce MoS₂ content in the high lubricious TiN-MoS₂ composite films by using a composite target of TiN and MoS₂ for improving the hardness. In addition, Ti interlayer was deposited in order to improve the adhesive strength. The friction coefficient of the composite film with MoS₂ content of 22% showed low friction coefficient which was almost equal to that of DLC film at room temperature and 200°C. The hardness of the newly developed high lubricious composite film was as high as 17GPa. In addition, the adhesive strength of the composite film was improved by forming the Ti interlayer.

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With a technological advance of the industrial product, weld between the different kind metal is demanded. Adove all, demands for welding of the different kind metals, copper and stainless steel, increase. However, forming a welded joint between stainless steel and a copper is difficult because the physical properties of the two metals - such as thermal conductivity and melting point - are different and they do not form an alloy. In this report, laser welding of copper (C1020) plate and stainless steel (SUS304) plate of thickness 1.5mm using a disk YAG laser was examined. The bondable welding conditions were selected, and the structure of welding copper and stainless steel was evaluated by EPMA and X-ray diffraction. As a result, it was found that copper and stainless steel were mixed and were joint by mechanical linking, when laser irradiation position put off in the copper side from 0.1mm to 0.2mm. In addition, it was found that it didn't separate of each component and didn't generate of new alloy in the weld.

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In the industrialized nations, higher wages for workers, a declining number of skilled workers, and other issues have led to a need for the establishment of new high-efficiency and high-reliability production systems capable of maintaining high international competitiveness. This research analyzes the problems in existing cell production systems, defines functions required of more efficient cell production systems, and proposes a production system with the operation support of a robot. The proposed production system has been installed in cable harness assembly. The implementation has resulted in an increase of productivity and a decrease of assembly error ratio.

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Recently, some evaluation techniques have been proposed for five-axis machining centers. In those techniques, the simultaneous three-axis control motions in which the one rotary axis and two linear axes are controlled can detect the positional and angular deviations, and the simultaneous five-axis control motions for cutting the cone frustum of NAS 979 can evaluate various errors. Generally, ball bar instruments are used for the measurement of the displacement between the spindle and the table in those simultaneous multi-axis control motions. Also in the method using a master ball and a linear variable differential transformer, R-test instruments are a possible substitute for ball bar instruments. However, the displacement sensors of those instruments are the contact types. In this study, the measuring instrument for measuring the simultaneous multi-axis control motions is developed in order to avoid collision between the instrument and the five-axis machining center. The proposed measuring instrument consists of a master ball and two noncontact LED/CCD optical micrometers. One micrometer is mounted perpendicular to the other on the base plate. The base plate is fixed on the table and the master ball attached to the spindle is set in the intersection area of the LED light. The measurements of the simultaneous three-axis positioning and the circular motion were carried out on a three-axis machining center. The proposed measuring instrument can precisely measure the motion trajectory in three dimensions.

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