In this study, the effects of dry, oil mist and wet cutting methods were investigated in turning wear resistant cemented carbides to achieve a systematic understanding of the machining characteristics of cutting and tool wear in environmentally conscious machining. The turning and orthogonal cutting were carried out using the PCD tool. The main results obtained are as follows: (1) In mist or wet cutting, the tool wear was effectively reduced on the flank where the thickness of the removal stock was large, due to the lubricating property. (2) In mist or wet cutting, the residual stock was increased for the lubricating property. Therefore a removal of grains contained in the cutting tool was suppressed and the tool wear was not severe. (3) The flank angle in the worn tool edge became negative, and the magnitude of that angle increased as the thickness of removal stock became large. In mist or wet cutting, in the tool edge where the thickness of removal stock was small, the magnitude of that angle became smaller than that in dry cutting, resulting in an increase of the tool wear width.

抄録全体を表示

A testing method for judging the suitability of powder metals in layer manufacturing of 3D products by the selective laser melting method is proposed. In the test, the laser beam to be used in the 3D fabrication is scanned only once on a powder bed, and the longitudinal and cross-sectional shapes of the solidified part are examined. In the present study, pulsed YAG laser with an average power of 50W is used. When the solidified part is not continuous due to balling (pure Al, Al alloy and 18-8 stainless steel), 3D fabrication is not possible. Among the powders which solidify continuously, those with round (Ni based alloy, CuP and Sn) and crescent (Ti, Fe based powder) cross-sectional shapes result in high product densities (greater than 90% of relative density). When the cross-section is in a V shape (Pure Cu and Fe), 3D parts with relatively low densities are obtained. Some attempts are made to improve the formability of Al and Cu.

抄録全体を表示

The object in this report is to establish “Mild-Cooling Air Machining Method” that removes cutting heat by two ways, one is mild-cooling air jet spray on just cutting point and the other is cooling water, using water flow in passage made in cutting tool. In this report, the same experiments are curried out as reported in the first report by use of the heat removing method of combination with both holder cooling and mild-cooling air jet. The experimental results indicate that the flank wear width W_b and the ten-point average roughness R_zjis are made better in accordance with the decrease in the tip temperature difference T_c. Mild-cooling air machining method is more effective than using mild-cooling air jet or holder cooling method. The method to calculate heat flow rate released around the tool edge Δq is established by evaluating tool temperature distribution. Experimental equation for predicting W_b is proposed as a function of Δq, and it's accuracy is verified. It can be also confirmed that time constant of tip temperature rise is in proportion to T_c.

抄録全体を表示

The innovative system of milling-combined laser metal sintering is developed, combining a laser-assisted metal sintering and a milling process. In this process, the periphery of the sintered layers is machined by end mill in each several sintering steps. Smooth surface is obtained after the one process. Applying to the mold manufacturing process, it halved the lead time required in the conventional machining processes.
To get the accurate dimensions and a smooth surface required to the injection mold in this method, relation between the energy density of the laser and the sintering surface density is evaluated. In the range of the energy densities bigger than 4.1J/mm², approximately 100% density is obtained. Also, the milling condition of sintered body is decided by evaluating the relation between the surface roughness and cut volume per tooth.
When processing a sample by the developed Milling-Combined Laser Metal Sintering system, dimensional accuracy of ±0.03 mm and the surface roughness of Rz20μm are obtained. And it confirmed that a mold manufacturing time is reduced by half than the conventional machining process when applying this process to the injection mold manufacturing.

抄録全体を表示

The scribing of glass by a CO₂ laser is much more effective compared to the conventional mechanical technology in use because the strength of the cut glass is improved since microcracks and particles along the cut edge are lessened. However, the crack depth of laser scribing is limited because the inner compressive stress region under the cooling area prevents median crack growth. This fact was shown by the experimental and thermal stress analysis with two dimensional FEM in our previous study. In this study, the glass was masked partially on the scribing line so as not to generate an inner compressive stress region and we found that the median crack depth of laser scribing was deeper in the experiment. Thermal stress analysis of this phenomenon was conducted by using a three dimensional FEM. As a result, the stress distribution and the phenomenon of which the median crack grew deeper corresponded qualitatively well. It has been supported that the model of laser scribing mechanism proposed in our previous study is valid.

抄録全体を表示

This paper describes how to removal residual of metal ion which is in the semiconductor device using electrolytically oxidized water. First, it evaluated about the influence of the electrolytically oxidized water on the epoxy-radical board which is the substrate material of the semiconductor device. Next, as for the copper plating surface on the epoxy-radical material and the oxygen-free copper board, it experimented on the etching using electrolytically oxidized water and hydrochloric acid solution. Moreover, it did experimental reviewing about the relation between the specific of electrolytically oxidized water and the etching speed of copper plating. As results of the study, following could be identified. (1) Dilute NaCl electrolytically water doesn't have a bad influence on the surface of epoxy-radical material like hydrochloric acid solution. (2) Electrolytically oxidized water has the etching ability which is higher than hydrochloric acid solution to copper plating surface. (3) The etching speed of electrolytically oxidized water depends on the specific value. The bigger the value of ORP/pH is, the bigger the etching speed becomes. (4) The etching speed of electroplating is big compared with electroless plating.

抄録全体を表示

This paper describes on high accuracy contour grinding. We focused on problems in the current CAM systems in order to improve the machining accuracy and the quality of ground surface. The changes of curvature in workpiece profile were attracted attention because the ground workpiece profile changes with tool path and grinding force. Therefore, the grinding tests with monitoring the grinding force were carried out for three type models with different variety of curvature. The workpiece profile after grinding was evaluated by reflected light images test. As a result, considering the responsibility of machine tool, it was clarified that the smooth-continuation model shows the best quality of ground surface.

抄録全体を表示

Micro-fabrication technologies have recently developed dramatically and fabrication methods have become much-needed with which devices on the order of micrometer can be fabricated precisely. In particular, methods of fabricating MEMS and microscopic optical devices as typified by a photonic crystal are in huge demand. In this study, we propose a novel stereolithography method using evanescent light instead of propagating light to realize a 100-nanometer resolution. With this method, we intend to establish the nano-stereolithography with higher accuracy and flexibility. In the second report, we performed the fabrication of in-plane lattice structures, which is strongly required as diffraction grating, diffractive optics, photonic crystals, etc. Theoretical and experimental analyses suggest that the proposed stereolithography method using evanescent light has a potential to fabricate micro three-dimensional objects with a resolution of sub-micrometer.

抄録全体を表示

This paper describes a development of 5-axis dry electrical discharge machining (dry EDM). The machining characteristics in the processing of a spherical cavity were compared between 3-axis and 5-axis machining in order to investigate the effect of the 5-axis dry EDM. It was found that the processing time of 5-axis machining was nine times shorter than 3-axis machining. Since the end surface of pipe electrode was uniformly worn in 5-axis machining, it was easy to compensate for the tool electrode wear and improve the machining accuracy. Error of the processed shape from the target shape increased when the pitch used in finishing was larger than 60% of the tool electrode diameter due to the edge wear of the tool electrode. Hence, the machining accuracy was improved by optimizing the pitch of the tool path and compensating for the tool electrode wear using the simulation developed.

抄録全体を表示

The reciprocating motion type ball reducer has been developed to realize the non-backlash element for the positioning mechanism. This type ball reducer consists of an input rotor with half speed reciprocating cycle wave groove, a fixed internal rotor, many reciprocating motion sliders with freely rotating balls, and an output rotor with wave groove. Both of the input rotor and the output rotor have the wave groove just like a "trochoidal-wave" on these cylindrical surfaces. This reducer generates the reduced rotation using the differential motion. Especially, the input rotor generates the half speed cycle reciprocating motion; it is different from the conventional reducers. It is similar to the grooved cam mechanism which has a translating follower. These sliders are allocated in a uniform angular pitch. And these are preloaded structurally to eliminate backlash. Also these grooves conform to the loci of each ball attached on the linear motion slider. In this report, this reducer is introduced, and the motion principle is analyzed using polar complex vectors. Also, the design parameters are investigated using the pressure angle evaluation method.

抄録全体を表示

The multi-point method using more than four displacement sensors requires selections from non-unique filters deriving out-of-roundness from sensor outputs in the case of the conventional calculation technique using inverse filtering with frequency analyses. This paper analyzes propagations of sensor noises in the calculation process of out-of-roundness estimation, and shows that the calculation technique of multi-point method using pseudo-inverse matrix optimizes the calculation process and minimizes propagations of random noises occurring in sensor outputs without laborious calculations in search of the optimized filter.

抄録全体を表示

In this paper, we describe improvement of compensation sequence and results of the motion compensation for the versatile micro robot. In order to provide microscopic operation, the unique locomotion mechanism which is composed of four piezoelectric actuators and two electromagnets is proposed. Here two legs arranged on cross each other are connected by four piezoelectric actuators so that it can move in any directions, i.e. in X and Y directions as well as rotate at the specified point precisely with the manner of an inchworm. Moreover the combination of particular wave forms of piezoelectric actuators can provide “arc trajectory motion with facing center”, that is important for the micro manipulator to keep its tip end within the microscopic view area. In previous report, we have proposed the competitive compensation method supported by CCD camera based tracking system and confirmed the effectiveness from several experiments. However, we have also confirmed that we could not compensate straight motions in forward, back, right and left directions because of the assembling error of the four piezoelectric actuators and two electromagnets. In this report, we propose the unique mechanistic model which allows the assembling error to improve the compensation method. In the compensation experiments, we succeed in reducing the motion errors and confirm the effectiveness of newly developed compensation method. The design procedure, basic performance and biomedical application of this tiny robot are also discussed to open the new field for micro-robotics in precision region.

抄録全体を表示

Curvature is known as an important geometrical property for curve generation in engineering applications. Many methods have already been proposed to control the curvature distribution of curves, but most of them are for planar curves. This research proposes a new scheme for controlling curvature distribution of planar and space curves, based on discrete curves. Discrete curves, such as discrete Clothoid, have an ideal curvature distribution, because discrete geometry models have a high degree of freedom. For application to practical CAD/CAM, a parametric curve with a controlled curvature distribution can be generated based on a discrete curve with an almost ideal curvature distribution. A G² curve consisting of quintic Bezier curve segments has been generated by the energy minimization method. The generated curve passes through the given points and has the given tangent vector, normal vector and curvature on both ends. And the curvature distribution of the generated curve by using the method of this paper shows the smooth change throughout the curve.

抄録全体を表示