Machine tools is also called mother machine, and it is the essential equipment in all kinds of manufacturing industry up to automobiles, aircraft and the information terminal. As requirements for machining tools, high rigidity and low thermal expansion is important to perform high-precision machining, and having high damping is necessary to realize high-speed machining. In addition, recently weight saving is also required to allow energy saving. However, since high rigidity and light weight is difficult to achieve both, so this study aims to achieve these requirements by optimize machine tool structure through topology optimization. To verify the result of the optimization, create multiple models to compare new models and previous model in the static rigidity and dynamic rigidity. As a result of analysis, it was found that the new model has 5 times stronger static rigidity than previous model and has high dynamic rigidity.

For structures of machine tools, weight savings, high stiffness and high damping are important properties. These requirements are not satisfied with only a single material, so composite materials are promising for machine structure. Carbon-fibre-reinforced plastics(CFRP) has high specific stiffness and damping compared to that of steel, but more damping capabilities are required for structural materials of machine tools. This paper proposes a three-dimensional topology optimization method to develop high stiffness and damping composite structures using CFRP and viscoelastic damping materials. To implement optimization algorithm, Abaqus and MATLAB were used. To illustrate the effectiveness of the proposed method, we designed a cantilever beam. The results showed the optimized cantilever beam had higher stiffness and higher damping than the cantilever beam with a single damping layer.

The water driven spindle which has water hydrostatic bearings and the water driven mechanism has been developed for ultra-precision machining. In ultra-precision machining, if the deformation of the spindle is caused during the machine process, the deformation degrades the machined accuracy, accordingly. Water can be used as an effective cooling media for the water driven spindle because of the better thermal properties of water. It is considered that this improves the thermal stability of the spindle because of the large thermal conductivity and the specific heat of water. In this study, we will consider the thermal stability of the water driven spindle experimentally. As a first stage of the study, the change in the temperature of each parts of the spindle is measured experimentally during spindle rotation with various rotational speeds.

A new analysis method for contact problems in mechanical structures is developed in the present research. In the method, linear parameters in contact analysis, such as displacement and force on nodes not on surfaces, are calculated in advance and eliminated in formulation. Since number of unknown parameters is reduced significantly, contact problem is analyzed efficiently and accurately. The effect of developed method is verified by comparing consumer software ANSYS on three-dimensional and three-parts contact analysis. The results by developed method agree with general method calculated by ANSYS and calculation time decrease less than half. Therefore developed method is confirmed to be effective for contact analysis.

This study compares the motion characteristics of 5-axis machine tools with Japanese and European NCs under wing profile machining. Productivity is one of the most important factor in the industrial field. It is known that the cycle time of the machining process typically depends on the manufacturer, control mode, and setting of the NC controllers, even though the identical cutter path is applied. In order clarify the influence of the manufacture and control mode of the NC controllers onto the cycle time and velocity profile of the machining, wing profile machining tests are carried out by 5-axis machining centers with different type of NCs. Identical CL data is used for the tests. Effect of TCP control mode on to the cycle time and velocity profile is also investigated. As the results, it is clarified that the TCP control mode can significantly reduce the cycle time. In addition, it is clarified that the jerk is limited when the European NC is used although the acceleration is limited in case the Japanese NC is used.

Multi-tasking machine tool with multi-turret is attracting a great deal of attention, which can offer higher efficiency and higher accuracy. However, chatter vibration generated during parallel turning with two tools might be one of the bottlenecks for higher material removal rate. To suppress chatter vibration, we proposed unequal pitch turning method in this research. In this method, the upper tool was properly controlled based on optimum pitch angle calculated from spindle speed and chatter frequency. Chatter frequency was identified from estimated cutting force by disturbance observer. From the result of parallel turning test, it is clear that chatter vibration can be suppressed by controlling the upper tool based on optimum pitch angle.

In terms of high speed and high precision as well as energy saving, development of lightweight machine tools applying new structural materials such as CFRP is under consideration. When the weight of the machine tools is reduced, on the other hand, the position response of the table is more sensitive to disturbance force including cutting force. In this case, it is difficult to ignore the influence of mass reduction of the workpiece by cutting, which demand control strategies to play a greater role. In this study, a robust control method for lightweight driving element was considered. By constructing acceleration control system that had disturbance compensation function, it was confirmed by numerical simulation that the influence of mass variation could be reduced.

Although a NC machine tool moves along previously designed machining path, it has mostly controlled with analog feedback loop. As high-speed tracking motion of XY table inspires vibration in the system, people desires feedforward trajectory without arousing residual vibration. In this study, we propose to design intermittent feed drive trajectory in NC machine tool by using vibration manipulation function (VMF) with discrete sampled-data control. We discuss rotational vibration of column on XY table, which is treated as two-mass one-spring model without damper. Rapid accelerated or decelerated trajectory can be designed from serially combined two VMFs with suppressing residual vibration.

Recently, the miniaturization and densification of the semiconductor package printed wiring boards (PWBs) have been demanded by the miniaturization and multi-functionalization of electronic equipment based on development of IT. For their realization, downsizing of PWBs’ micro-holes and fabrication of highly dense electrical circuit layers are also important. For high-speed and precision drilling, we proposed a feed driving system with a right and left coaxial ball screw as a counter balance structure. In this report, we investigated its dynamic characteristic with measuring the vibration. Furthermore, we examined the suitable weight of counter based on the result and application to machine tools.

In the present report, we focus on 5-axis controlled compact machine tool which has idling reduction system. The idling reduction system is the function which can reduce the energy consumption in processing. However, this system has some demerits. Even among them, we investigated the gap of command position at servo-OFF and the injection power at servo-ON. We implemented some experiments to evaluate influence which is caused by feed speed and moving distance of machine tool. From the experiments, we can understand the cause of the gap of command position. Then, we propose new method which can reduce the gap of command position.

Ultra-Agile Advanced Manufacturing System: U-AMS has been developed aimed for agile prototyping for research and development. Then, Super Processing Center (SPC) integrated multifunctional processing units, is invented for the processing machine becoming the core of this system. In this report, the basic concept of SPC and the result of processing of typical processing function were described.

In CNC lathe machine, the relative distance between the workpiece and the cutting tool is changed due to its thermal deformation. In this study, the main cause of the thermal deformation of the lathe machine is investigated with CAE analysis. From experimental result, the conducted heat from the hydraulic unit is highly influential to the change in the relative distance between the workpiece and the tool. Therefore, CAE analysis of thermal deformation by the hydraulic unit as heat source is carried out. From analyzed result, it is confirmed that the main cause of the change in relative distance between the workpiece and the cutting tool is the thermal deformation of the bed.

Recently, because of pollution problems of lubricating oil, water has been attracting considerable attention as a lubricant of hydrostatic bearings. In this study, static characteristics of a shaft supported by a water lubricated hydrostatic bearing using a self-controlled restrictor were numerically investigated. The restrictor proposed in this study can control the mass flow rate using both the balance of pressures acting on the elastic hinge to achieve a very high bearing stiffness. Various design parameters influence the static characteristics of the bearing were discussed numerically, and it was consequently found that the water lubricated hydrostatic bearing using the self-controlled restrictor can achieve nearly infinite static stiffness.

Recently, high-speed milling using micro milling cutter has attracted attention as the method for achieving high efficiency and high precision machining. However, it is very difficult for conventional bearings to satisfy high-speed milling because of large power consumption. Accordingly in this paper, water-lubricated bearings for machining tool were proposed. The proposed bearing is an integrated bearing with thrust and journal bearings for miniaturization and can stably rotate at high speeds. In this study, instability at high speeds and static characteristics of the proposed water lubricated bearings were investigated experimentally and numerically.

Hydrostatic bearings have been widely applied to ultra-precision machine tools and measuring equipment because of their high load carrying capacity, high stiffness and high accuracy of motion. Generally, these hydrostatic bearings uses fixed restrictors such as capillary, orifice etc. to feed pressurized oil into the bearing clearance. Additionally, in a case of nanometer-order of machining or measuring accuracy is required for these equipment, a self-controlled restrictor is used to achieve nearly infinite bearing stiffness. In this paper, an actively-controlled hydrostatic thrust bearing using an elastic hinge and a voice coil motor was proposed, and the static and dynamic characteristics of the proposed bearing were investigated experimentally. It was consequently found that the proposed bearing could achieve very high static stiffness

Thermal stability of the ultra-precision machine tools is highly needed in order to improve the machining accuracy. In general, the spindle of the ultra-precision machine tools is supported by the hydrostatic bearings. Thus, the heat generation due to the viscosity of the lubricating fluid is inevitable. As a result, the temperature change of the spindle is taken place, resulting the spindle deformation. In this study, the power losses and the resultant heat generation of a spindle supported by water hydrostatic bearings is investigated. Furthermore, temperature increases of the spindle and lubricating water are measured. Then an influence of the temperature increase of water on the temperature increase of the spindle is investigated. The result shows that the power losses of the water hydrostatic bearings consume temperature increase of water, achieving minimum increase of the spindle temperature.

Linear ball guide way are widely used in machine tool feed drives. But it has a friction force which varies periodically. If friction force's periodically changing cannot be suppressed by the control system, it appears in positioning deviation and motion error happens. In this paper, we examine the effect of the surface roughness of guide way to the position deviation and friction force in linear ball guide way. So roll the rolling element in varying surface roughness rails and measured friction force experimentally.

Linear positioning table systems with rolling guide are employed by many mechanical systems. However, because it has nonlinear behavior due to the friction force in small load region, a construction of incorporating appropriate compensator control system is required. In this paper, the friction characteristics of rolling guides, that is expressed by a simple model based on Masing's rule, was incorporated in the positioning compensator.This compensation method inhibited the error due to the nonlinear behavior during driving and realized ultra-precision positioning with high tracking performance and practical use.

Requirements are increasing for aerospace-industry aluminum parts desired to be machined with high efficiency from low to high speeds. Important to this machining is a spindle of high rigidity; i.e., high speed rotation of a large diameter spindle. In order to achieve these requirements, technology for efficient cooling of the bearing is necessary. OKUMA has developed a technology for direct cooling of the bearing to which cooling oil is supplied to the inside of the rotating spindle.

In order to generate micro scale texture on the large scale and complex surface, a rotary Fast Tool Servo (FTS) is proposed. The rotary FTS is actuated by the magnetostrictive element (GME), which can be driven without energy supply wire. On the other hand, under a variation of the stress, the GME changes its magnetic permeability. Due to this feature, the GME is adopted as a vibration sensor. In this study, in order to monitor machining status, the GME is employed not only as an actuator but also as a force sensor. In this paper, as an approach to a measurement of the magnetic permeability without contact, the two methods using a counter electromotive force and an induced voltage change occurring in the detective coil are applied. Performance evaluation results confirmed that the developed rotary FTS can detect machining status during GME actuation.

A plastic gear has the advantages that it is light and can be used without any lubricant, and the disadvantages that its strength is low and that it has a large environmental impact. Therefore, the development of a new gear that maintains the advantages while negating the disadvantages has been proposed. The development of sustainable and reproducible natural materials is especially desired in order to address environmental problems. In this study, a method was therefore devised to extract high quality and highly precise bamboo fibers using a machining center. The hot press method was then used to produce a spur gear, which is a machine element with a complicated shape. Therefore, the present paper describes characteristics of the bamboo fiber gears investigated in some experiments. The results of a strength test showed that the bamboo fiber gear can be used as an alternative to the Mc nylon gear. The results of a meshing test showed that the teeth of a bamboo fiber gear underwent transformation because of the meshing load. In addition, we calculated travel value of meshing point by teeth deformation and compared experimental value of travel value with calculated value. Results show that the experimental deformation value is greater than the calculated value.

Porous Metal Mold created by Selective Laser Melting Method is effective as countermeasures against molding defects produced by gas generated from resin. Further, Since it is possible to fill the molten resin at low pressure, it can be expected the effect of low power consumption. In this study, The Effect of Low power Consumption Injection Molding by Porous Metal Mold is investigated based on the condition of Injection molding.

In this study, the evaluation method and compensation of thermal displacement about NC lathe are reported. Besides the heat generation from spindle, feed axis and so on, cutting heat is on of the major factors that influence thermal displacement. The majority of cutting heat is transferred to the coolant and raises the coolant temperature. Hence, replication of heavy cutting condition using pipe heater is proposed. Using the proposed method, thermal displacements of each components of NC lathe were measured and displacement of bed and turret were found to be dominant. Thermal compensation was also conducted to reduce thermal displacement by cutting heat. The stability of compensation was experimentally verified with various cutting heat and the change of ambient temperature.

Super duplex stainless steel, which is one of the difficult-to-cut materials to machine, is excellent in toughness at room temperature and corrosion resistance. It is used in many applications, such as marine structure and petrochemical plant. However, this stainless steel has certain material characteristics, such as low thermal conductivity, a high work-hardening rate, and a high affinity to tools. In this study, the cutting performance of coated cemented carbide tool is in finish turning with super duplex stainless steel. As a result, the tool life and surface roughness are improved with using TiAlN/AlCrN super multi-layer coated tool. And the superior surface roughness is also obtained. Furthermore, this tool clarified that increased tool wear rate when flaking of the cutting edge causes by the oxidation of the tool at more than cutting speed 2.0m/s.

β-type titanium alloy exhibiting super-elasticity and super-plasticity was developed. This alloy has high tensile stress and low young's modulus too. The excellent characteristics of this alloy indicate its likely application in the field of dental implant. However, the characteristics of this alloy is lost by severe heat environment and external force. In this study, the effect of cutting temperature and cutting force on the affected layer was investigated by milling with small ball end mill tool in order to decrease the affected layer by cutting process. The thickness of affected layer indicated a tendency to increase with the cutting speed. And at the cutting speed of 16.0m/s, the thickness of the affected layer exceeded 2.5μm because of increasing of cutting temperature. On the other hand, the thickness of affected layer was 0.7μm at the condition of the environment of high cutting force. Thus, the affected layer influenced by cutting temperature.

The parameters that the effecting wear mechanism of cBN tools on the hardened steel (SCr420) turning was investigated. In the previous report, it was suggested that cutting speed had an effect on volume of crater wear and the cutting fluid had an influenced on rake face of low cBN content sintered compact. In this paper, we investigated effect of binder around cBN particles of sintered compact using coated cBN particles on the wear damage pattern. As the result, it was found that aluminum compound around cBN particle had an effect on wear damage pattern on flank face and rake face of cBN content sintered compact.

In order to achieve high-efficiency and high-precision machining of difficult-to-cut materials like Ni-based heat resistant alloy, it is important to suppress the flank wear and notched wear which occurs in the boundary region of the side cutting edge. This paper describes the damage morphology of polycrystalline cubic boron nitride (PCBN) tools in association with cutting speed and microstructure of Inconel 718. In the high speed turning of fine-grained workpiece in which flank wear is the main factor of tool life, DS1005 has long tool-life compared with conventional PCBN. In case of coarse-grained workpiece, the tool life is mainly determined by the notched wear. IT105 is able to suppress the notched wear, because of the advantage in terms of its mechanical properties.

The fundamental cutting characteristics of the tungsten carbide using a diamond coated carbide drill was investigated. The cutting force (thrust force) and the tool wear behavior were mainly evaluated. The diamond coated carbide drill, which has two flutes, diameter of 1.0 mm, and coating film thickness of 20 Pm, was used. A large flaking of the coating film on the rake face occurred immediately after the cutting onset, and a sharp cutting edge evolved on the ridgeline of the section of the coating film that remained on the flank face. The cutting force decreased with flaking the coating film on the rake face by the evolution of the sharp cutting edge. The adhesion of the workpiece material on the margin region was observed accompanying the progress of the number of drilled holes.

The cutting characteristics of tungsten carbide using a diamond coated carbide end mill was investigated. The influence of tool feed rate on the finished surface properties and cutting force was experimentally investigated. The tungsten carbide (CIS VC-70) with mean grain size of 5 Pm was used as a workpiece material. The tungsten carbide grain on the workpiece surface detached with ultrasmall tool feed rate (0.5 Pm/tooth) cutting, and the finished surface integrity was deteriorated. The difference of the cutting force in the feed rate of 0.5 and 10.0 Pm/tooth was not so significant. The appropriate tool feed rate existed to obtain the satisfactory finished surface and high cutting efficiency.

In high-value-added machining of complicated shapes, machining know-how is indispensable regarding workpiece clamping and fixing, selection of cutting tools and decision of cutting conditions. However, the process planning still depends on skillful experts to achieve complex-part machining. Therefore, in order to realize high efficient machining, it is necessary to formulate the implicit machining know-how owned by skillful experts and to obtain these tacit knowledges. This study focuses on rough machining of complicated shapes as the first step and proposes a method to logically decide workpiece shapes during a machining operation by using topology optimization.

In order to achieve ultraprecision machining, commercial scanning devices for on-machine measurement have been developed to realize corrective machining without removing the workpiece from machine tools. However, the shapes to be machined shift to more complicated free curved surface such as a non-axisymmetric and non-spherical shape. Thus, it takes long time to scan whole surface of the workpiece. In addition, tool setting errors are remarkably larger than positioning errors of ultraprecision machine tools. Therefore, in order to generate efficient scanning paths, a method based on form shaping theory is devised to analyze both the machined surface and the measurement results influenced by the tool setting errors.

On the dental therapy, the orthoprosthesis is manufactured by using the dental CAD//CAM. This can manufacture orthoprosthesis effectively. But, there are some problems that the work materials are hard-to-cut-material and dental technicians have to decide the processing condition. In this study, the process strategy which is high efficiency and keeping long tool life to machine the orthoprosthesis has suggested and demonstrated on the simulation. Therefore, The processes what is used the radius end mill and The contour line process has applied to roughing and semi-finishing and the 5-axis process has applied to finishing. As the result of carried out roughing and semi-finishing, these process staved the cutting by the center of tool edge of ball end mill, the cutting of pushing down and exponential increase of depth of cut. And these process are shorter roughing time than the conventional roughing. But, the semi-finishing is longer than the conventional one.

This study is aimed for processes integration in the processing of the dental prosthesis, and a database of processing technology by the dental technician. Using the modeling interface device which constructed the 3-dimensional position measuring device to the base, to obtain the shape of the workpiece and a trajectory of forming to be subject. By using the data obtained by the interface device to modeling using voxel model, it does save the tooth type impression acquisition skill manual of dental technician using the lost wax casting, as well as the use of as processing data to the machine tool such as the 5-axis machining center.

In this research, we suggest the catalog-mining method which means applying data-mining method to micro-drill catalogs. -We regard the catalogs as mine which includes the knowledge of micro-drilling plenty. - Data-mining method is one of the analytical methods to discover the valuable information from a mass of data and commonly used in the undeveloped field of study. In this paper, we focused on a relationship between diameter and flute length of micro-drill and classified them. By using the classification, we analyzed cutting conditions for catalogs of micro-drill. In addition, we introduced catalogs of multi micro-drill which cut alloyed steel. The result shows that catalogs have different cutting condition in classifying particular flute length. And micro-drills for PCBs which have small diameter and multi micro-drills for alloyed steel have same tendency of cutting conditions.

Recently, production site is a mainstream variant variable production. Accordingly, the importance of AGV is high because the construction of the production line is difficult. And it suggested the AGV transport system which introduced the movement characteristics on knowledge of taxis with a flexibility to the AGV. But, course shape a major impact on the AGV transport. In this paper, we proposed an evaluation method using homology of course shape that affect the transport. As a result, we quantified a course shape by the homology after having considered the number and placement of the pass on the course and was able to confirm the influence that a course shape gave conveyance.

In general, CAM software that is used to generate a tool path of 5-axis controlled machining requires a complicated configuration setting. Therefore, in previous research, using the haptic device that can operate objects in a virtual space, we had developed a system for generating a tool path of intuitive 5-axis controlled machining. However, the previous system has a problem that may occur increase in cutting load in the generated tool path. Therefore, a function to limit cutting amount by using force sense was developed in this research, in order not to exceed the removal amount per unit time that was specified for the used ball end mill. It was confirmed that the improved system could generate a tool path that did not occur over-cutting.

Off-line teaching systems are becoming a mainstream for making robot program instead of teaching playback systems that require worker's operation using a control device. The off-line teaching systems have enabled to make the program on a computer and to simulate the motion of robot for checking the program. However, in order to make an optimal program with consideration of prevention of sudden change in robot posture, avoidances of singularity, and optimization of workpiece placement, the operator must make the program by a lot of trial and error. In this research, we propose a method for optimization of robot motion and workpiece placement. The method is based on manipulability that measures the manipulating ability of robot, and maximizes the manipulability of postures in a robot program. As a result, we confirm the effectiveness of the proposed method by applying it to sealing process.

Finishing machining process for complex deep groove, continuous 5-axis controlled machining process is widely used to keep tool posture against workpiece surface. In such process, a ball end mill moves back and forth to machine both sides of the groove. Then, a problem about drastic reduction of actual feed rate is caused by rapid acceleration on rotation axes. In this research, we propose an automatic planning method for tool posture in narrow grooves machining without rapid motion of the rotation axis. In the proposed method, tool posture candidate without collision for each cutter location is estimated as machinable range on temporal spatial images. Then, a continuous change of the rotation axis is determined in the machine coordinate system.

In this study, we propose a new automatic planning method of tool posture for continuous 5-axis machining, which can avoid collision between spindle shape and machined workpiece surface. In the proposed method, shape of the machined workpiece surface is simulated with voxel representation. Then interference among the voxel shape and took holder and shank shape are estimated by each tool moving step. Then, the interfered tool posture is modified to new tool posture without collision. In the proposed method, we developed a new efficient algorithm to set and detect new candidates of tool posture. As a result, the proposed method can realize both avoidance of rapid tool posture change and reduction of computational time to plan a new tool posture.

The drilling of microholes by electrochemical machining (ECM) using ultrashort voltage pulses was carried out. The tool electrode feed speed was automatically controlled by detecting contact between the tool electrode and workpiece. The automatic feed speed controlling shortened the drilling time. Furthermore, a microhole of 4.5 μm in entrance diameter and 4 μm in exit diameter was successfully drilled in a 5-μm-thick stainless steel sheet with a pulse width of 60 ns using a tool electrode of 3μm in diameter. This is the smallest-diameter hole drilled by ECM, to the best of our knowledge. A microhole of 5.5 μm in entrance diameter and 4.5 μm in exit diameter was also drilled in an 8-μm-thick sheet.

In recent years, surgical operations of artificial joint replacement have been gradually increased for high quality of life, and the shortening fixing period of joint components to bone is strongly requested. Then, giving high osteoconductivity has been artificially given to the joint components surface for promoting the fixation. In this study, the possibility to give an osteoconductivity on titanium surface by EDM is fundamentally discussed. While soaking the EDMed sample in the simulated body fluid for the purpose of the apatite formation ability, the formation of white deposits unlike hydroxyapatite was confirmed on the sample. In this report, the composition of the white deposits was investigated by XRD and Raman spectroscopy. Furthermore, the formation mechanism were experimentally discussed.

Surface finishing technology by EDM has recently progressed, and very small surface roughness can be readily obtained by controlling the electrical discharge conditions or by using metal powder mixed working fluids. In addition, it was reported that EDMed surface using metal powder mixed fluids sometimes had high surface functions, such as high hardness, high corrosion resistance and so on. Therefore, the high functional EDM finished surface is well expected to be applied as a final metal mold surface. In this study, a cheap metal mold steel with low chromium content was processed by EDM with chromium powder mixed fluid. Then the surface characteristics such as surface hardness, releasability of molded resin, and corrosion resistance could be improved by EDM with chromium powder mixed fluid.

We developed the machine that uses a magnetic gear for the transmission mechanism. Magnetic gear makes it possible to transmit the torque without contact. By this mechanism, this machine can avoid breakage of micro drilling tools. If in order to machine the deep micro hole drilling, it is necessary to high-speed rotation of the tool. However, high-speed rotation tool is to the breakage for the resonance frequency of the tool. And it is also necessary to consider the whirling of the tool by its length. In this study, we machined deep micro hole of high aspect ratio by using drilling and micro electrical discharge machining (EDM). We investigate the machining characteristics, that are the machining speed and the electrode wear in micro EDM.

In large-area electron beam (EB) irradiation method, uniformly high energy EB can be obtained without focusing the beam. Large-area EB can be used for melting and evaporating metal surface instantly. Furthermore, the tip of convex shape is often rounded after large-area EB irradiation with remarkable material removal at the tip. This phenomenon is probably caused due to the electrons concentration at the tip. However, electrons behavior near the workpiece surface during large-area EB irradiation has not yet been clarified. In this study, electron track analysis was conducted in order to clarify electrons behavior during large-area EB irradiation. At first, analytical model of the large-area EB irradiation apparatus was built. Then, the EB diameter on the workpiece surface was experimentally measured with different energy density in order to evaluate the accuracy of our analytical model.

Y-TZP is one of the most excellent materials, which is used as a material of dental restoratives. Y-TZP is, however, a difficult to machine material because of its hardness and fracture toughness. We have developed the laser-assisted grinding method, LAM, of Y-TZP. In LAM a laser provides intense localized heat to the workpiece and lowers the material strength. But it is difficult to determine the machining conditions because a number of conditions are involved. In this work, first we have developed the determination method of LAM condition based on a simulation of the laser irradiation to obtain a temperature and thermal stress distribution in a workpiece. Secondly, we have conducted the LAM experiments and confirmed the validity of the proposed method.

We propose processing method of laser drilling and film deposition on hole inner surface simultaneously. The method is laser irradiation from above to the sample of drilled material on film material. In this study, experiments were carried out for the purpose of elucidation of this deposition process. Irradiating the strong light to the sample side while laser irradiation from above to the sample, the processing state was captured by high-speed camera. Also, taking the copper plates from sample later laser irradiation and observing them, the amount of scattered copper was estimated.

In this study, the characteristics of laser cleavage of three different types of the chemically strengthened glass is investigated experimentally. Laser cleavage is a method for separating brittle materials using thermal stress caused by laser beam irradiation. A chemically strengthened glass is protected from the breakage by loading the compressive stress on the surface. An initial crack is induced on the surface of each substrate along the scanning line by the CO2 laser beam irradiation with a wavelength of 10.6 μm. After inducing the initial crack, the laser beam is irradiated along the line induced the initial crack to separate the substrate. As results, the depth of the initial crack in the compressive stress layer was relied on the maximum compressive stress on the surface. Additionally, the adequate energy density to separate the substrate loaded high compressive stress was larger in comparison to separation the substrate loaded low compressive stress.

In this study, a picosecond pulsed laser of 1064 nm in wavelength and 12.5 ps in pulse duration was used as a laser source for joining of glass material, and characteristics of the molten area in micro-welding of borosilicate glass are described. Influence of focusing condition on microwelding of glasses was experimentally investigated by using an objective lens with and without spherical aberration correction, and its molten area was characterized. Also, influence of pulse interval on the molten area of laser-irradiated specimens by focused laser beam with spherical aberration correction was discussed. The usage of objective lens with spherical aberration correction led to a larger molten area inside the bulk material of glass even under the same pulse energy, which related to the efficient micro-welding of glass materials. In addition, an optical system with the spherical aberration correction led to a stable absorption of laser energy inside the bulk glass material, stabilizing the shape of molten area, which resulted in the reliable weld joint. It was also found that shape of molten area after the laser irradiation became larger at shorter pulse interval compared with that in longer pulse interval. Finally, pulling test results showed that breaking strength of the specimens with spherical aberration correction was higher than that without spherical aberration correction. Therefore, it is concluded that the laser irradiation condition at shorter pulse interval and focusing condition with spherical aberration correction led to the larger and stable molten area, which resulted in higher joining strength in micro-welding of glass materials.

A nano-second pulsed laser processing has been normally conducted with laser induced plasma, which leads to the reduction of laser energy absorbed to a specimen. Therefore, material removal characteristics are strongly affected by phenomena of laser induced plasma. It is considered that plasma generation is affected by pulse duration and laser intensity. However, influence of laser parameter on plasma generation has not been sufficiently clarified yet. In this study, the influences of pulse duration and laser intensity on plasma were investigated by measurements of plasma size and transmittance of laser energy through plasma. Finally, effective energy to material and removal characteristics were discussed with calculated actual laser energy absorbed to a specimen.