Recently, in order to realize multi-functionality and intensive processing a new compound multi-axis machine tool has been developed. This machine tool has the potential to realize not only production needs for complex part, but also new machining process. The one of new process is turning with an actively driven rotary tool. But the effect of the tool rotational speed on cutting temperature and cutting force has not been investigated sufficiently. In this paper, in order to investigate the effect of tool rotation during the turning with actively driven rotary tool, an analogical experiment to that machining process was carried out. The cutting method is the same as the oblique cutting process, but the cutting tool moves in the direction perpendicular to the cutting direction. It was found that the cutting force decreased with an increase in the tool moving speed in the direction perpendicular to the cutting direction. In addition, decrease of the cutting force obtained by moving the cutting tool in the direction perpendicular to the cutting direction was larger than that obtained by inclining the cutting edge. With increase of tool moving speed, the helix angle of chips was increased, then it was seemed that the chip flow became smooth, also its flow direction was changed.
The motion of a two stage type Cycloid Ball Reducer is analyzed. The fundamental reduced element of this reducer consists of three components; two surface grooved discs and a train of balls. One of the discs has an epi-trochoidal wave groove on one side surface while other disc has a hypo-trochoidal wave grooves. These grooves are just like a grooved cam mechanism. Also, they are arranged face-to-face with each other, and balls are located which transmit the torque between these discs. Especially, to eliminate the eccentric excitation which is caused by eccentric motion, this newly proposed mechanism has the special transmitting element which locates between the fundamental reduced elements. In this paper, the motion principle is analyzed using the polar complex vectors analysis. Also the design parameters are investigated. It is proved that the proposed reducer has a constant velocity rotation characteristic in motion principle. Then using the prototype reducer, the positioning accuracy and the backlash characteristic have been verified.
In the ultra-smoothness vertical grinding method developed previously, the wheel surface conditions are found to influence largely on ground workpiece surface. Thus the building of wheel surface forming technique is important. In the 1st report, from the point of view, the change of ground workpiece surface and wheel surface with grinding process of silicon carbide ceramic by using #140 resin bonded diamond wheel is examined and discussed. In the report following the 1st report, first of all, the change of macroscopic wheel shape in addition to surface conditions such as cutting edge wear, depth of chip pocket and so on with grinding time is examined. It is cleared that the wheel wear begins to occur at wheel outside edge and proceeds to wheel inside. Wheel life is ascertained to occur due to the contact of workpiece with bond, which is caused from the radial wheel wear. On the basis of the results, trued wheel shape for low rate of radial wheel wear is discussed. The sharp edge in the wheel outside shape is found to be effective for long wheel life in grinding of silicon carbide ceramic.
Drill breakage is one of the dominant factors in micro drilling performance for printed circuit boards (PCBs). PCBs are composite material, and it makes drilling behavior more complicate in the chip formation and evacuating mechanism, which might correlate with drill breakage. This paper presents experimental analysis of a chip evacuation behavior in dependence on drill wear and cutting torque, focusing on copper foils, woven glass fiber and fillers. Evacuated chips during drilling PCBs were observed using a high-speed video camera, and evacuating criteria of chips were discussed. These were examined using φ0.25mm drills at a rotational speed of 16×104min-1. The conclusions obtained are as follows. As regards chip formation and evacuating behavior, a) cutting torque has a strong correlation with chip evacuation. Chip evacuation is getting worse gradually to increase cutting torque through the elapse of drilling. b) When chips are frozen in a deeper hole, it results in drill breakage by the cutting torque beyond drill strength. As regards influence of composite materials, a) glass cloth is one of the dominant factors in drill wear. And drill wear deteriorates chip evacuation. b) External copper foils scarcely affect drill wear, but they bring chips freezing to increase cutting torque. c) Harder filler silica increases drill wear, and chip evacuation deteriorates. Though easy-to-vaporize aluminum hydroxide causes scarcely drill wear, it generates freezing chip evacuation and makes maximum cutting torque increased.
We proposed a fabrication process of an Arrayed Waveguide Grating (AWG) by a casting method using a micro die for the low cost Wavelength Division Multiplexing (WDM) system. We designed and made an optical simulation of the wavelength demultiplexing for the AWG. In order to fabricate the AWG with low cost and high accuracy, we proposed the fabrication process of the micro die by the electro-plating after fabricating the mother shape. We proposed the fabrication process of the mother shape using the SU-8 resist which is the negative resist. By using SU-8 resist, the high cost fabrication process using the dry etching equipments can be deleted. We fabricated the AWG with an UV cure material using the fabricated micro die. As the result, it has become possible to fabricate the AWG with low cost.
TiSiN coatings are widely used for cutting tools due to their higher hardness and higher oxidation resistance. This study aimd to clarify the wear phenomena of a TiSiN coated cemented carbide end-mill in higher cutting speed of hardened die steels. The coating structure was the combination of TiSiN coating as top layer and TiAlN coating as under layer. The wear phenomena of the end-mill were studied by cross-sectional TEM observations on the cutting edge. Both wear and deformation of the cutting edge progressed simultaneously. The top layer of TiSiN coating was effective to restrain both the propagation of cracks and deformation and improved the wear resistance of the cutting tool. In the layer of TiAlN, it was evident that the crack took place perpendicularly to the surface of the cemented carbide matrix and progressed, resulting in the deformation due to the change in direction of the columnar structure in the layer. The diffusion of Co in the substrate into the TiAlN layer through the crack caused to promote the deformation of the layer.
With the miniaturization of semiconductor packages, the surface inspection of the packages for defects such as voids, chip cracks and so on is becoming important. This paper describes a surface inspection of semiconductor packages using image processing technique. The presented inspection method uses 2D brightness distribution which is composed of brightness values of two images acquired under different lighting condition such as side lighting and coaxial lighting. On the 2D brightness distribution, the defect-free areas of part mark area and non-marked area are located in the different areas respectively, and the defect areas are distinguished from those defect-free areas. This technique does not need any reference images and is not affected by surface part marks. In this paper, a method using a color camera under different color lightings is also discussed in order to reduce the acquisition time of images.
A femtosecond laser is a type of ultrashort pulse laser. A focused femtosecond laser pulse induces high-pressure plasma and a shock wave at the surface of a target. In some cases, this shock wave is enough to deform the target plastically. Laser peen forming is a type of sheet metal forming using this deformation by shock wave. The authors adopted laser peen forming for thin-sheet-metal bending. A piece of sheet metal was bent by femtosecond laser scanning. An investigation was conducted into the influences of irradiation conditions and prebending on forming properties. When irradiating in air, bending angles increased with fluence. However, when irradiating in water, the exceedingly large fluence decreased the bending angles. The bending angles were increased by applying prebending during the irradiation. Selection of appropriate prebending directions and irradiation conditions allowed the bending direction to be controlled. Several pieces of sheet metal for springs were bent into various shapes that would be difficult to achieve using the usual press forming process.
A novel process that can fabricate transparent parts was developed for the purpose of improving mechanical and thermal performances of functional and transparent prototypes which is provided through an additive manufacturing technology. The process starts with plastic laser sintering process, which is widely applied to fabrication of functional prototype or rapid manufacturing, and following infiltration of the sinter, which is opaque after the first process, with thermosetting plastic of which refractive index after cure is tuned to have the same value as that of the sintered powder clearly eliminates opacity from the sinter. Experiments using styrene-methacrylate copolymer as powder material and thermosetting epoxy resin were carried out, and the minimum haze of 20% (at 5mm in thickness) was obtained. In terms of mechanical strength, impact strength (unnotched Izod) reached 3.5kJ/m2 meeting standard of that for transparent grade stereolithography parts. In this paper, requirements both in laser sintering and infiltration, and problems to be solved to improve the mechanical strength are also discussed.
Surface texture on the product surface is generally made by etching or sand-blasting. However, these manufacturing techniques have problems related to repeatability of manufacturing and environment pollution. While the performance of the machining has improved to can product the micro parts of micro or nano meter level, which shows the machining is possible to create the surface texture. A method to create the surface texture with regular pattern on the geometric shape is proposed and demonstrated in this paper. This method was conformed by real milling using 5 axis control machine and machined surface texture was measured to compare with designed shape. The results of measuring were shown that this method can create the surface texture of wide area and has a good repetition of machining.
Lure fishing and fly-fishing have been positioned as sports deliberately different from the traditional Japanese fishing-style. In the case of fly-fishing, casting is the element which anglers must master in order to cast a fly, done so by using the weight of a line. This study uses experimental and computational analysis to investigate the dynamic behavior of a fly line. Fly-fishing is constituted by various elements, but the importance that casting holds is extremely large. Fling speed, the casting process and the loop shape of the line while in flight are important for the proper presentation of flies. Moreover, the shape of a fly line is also important for a long cast or controlled cast. Therefore, the most suitable casting method will be clarified from the viewpoint of sports engineering and human dynamics. Anglers usually do “False cast” in the actual fishing field in order to put a fly for long distance and in order to control the line orbit. This technique increases the line speed and the kinematical energy. “False cast” consists of forward cast and back cast. Anglers wait until the line becomes straight forward after the cast, then they start the next cast. Anglers usually change the line orbit while they do “False cast”. Therefore, the line flies appropriate distance. In this paper, a rod, a line and arms are modeled by using rigid bodies and links. The time history behavior of the model is calculated by pseudo angler velocity of the arms. The difference of the line behavior with respect to the time interval between forward cast and back cast is evaluated. It is clarified that there is an appropriate interval.
In recent years inkjet technology has a wide range of application such as Flat Panel Display and Semiconductors. The stability of jetting is a major requirement for industrial inkjet heads. However, air bubbles can cause jetting failures in piezo-driven inkjet heads. The piezo actuators can be used as sensors to detect the acoustic influence caused by air bubbles. In order to analyze the relationship between the air bubbles and the voltage signal from the piezo actuator, a controllable bubble generation method inside the inkjet head is strongly required. In this paper, we propose a bubble generation method by focused THG Nd:YVO4 laser and the secondary Bjerknes forces and obtain bubbles from about 5 micron to 150 micron in radius inside the inkjet head. Using the observation technique with a glass nozzle plate, some interesting bubble migration patterns in the applied pressure field are observed. We consider that the primary Bjerknes forces drive the displacement of air bubbles against buoyancy.
This paper presents a micro hole measuring system using an optical fiber probe. The system is composed of a fiber probe, two floodlighting fibers and two double-light reception fibers in the X and Y directions. The fiber probe has an optical fiber of 30μm diameter with a ball of 50μm diameter on the end. When the fiber probe contacts a hole surface, it is deflected and this deflection is measured by an optical method. In this research, the design parameters of optical system are optimized by using ray tracing, and a prototype of the measuring system is manufactured on trial to verify the simulation results. Then, its measuring accuracies are examined by using the basic experimental apparatus. As a result, it is clarified that the resolution of the fiber probe is better than 15nm.