Tool Path Generation for Five-Axis Controlled Machining of Free-Form Surface Using Barrel Tool: Control of Contact Point on Cutting Edge

This study aimed to improve the efficiency of free-form surface machining by using a five-axis controlled machine tool and a barrel tool. The barrel tool has cutting edges, with curvature smaller than the radius, increasing the pick feed width compared with a conventional ball end mill of the same tool radius. As a result, the machining efficiency can be improved; however, the cost of the barrel tool is high and difficult to reground. In this study, a method to obtain the cutting points that make the cusp height below the target value is proposed. Moreover, a method to improve the tool life by continuously and uniformly changing the contact point on the cutting edge is proposed. The usefulness of the developed method is confirmed through machining simulations.

Surface Roughness Analysis for Radius End Mill in Cross Feed Direction Both Contour and Scanning Line Machinings

An optimum experimental condition, which realize good surface roughness in cross direction both contour and scanning lines, for radius end mill against some inclined surfaces is obtained and some features is these cutting processes is discussed in this paper. The optimum experimental condition, which consists of cutting type (or feed direction), spindle speed, feed rate, depth of immersion, inclination angle, corner radius of end mill and cross feed, is obtained and the influence degree of these parameters is calculated by using Taguchi method. The experiment is carried out based on L18 orthogonal array. Based on the influence degree and geometric contact status due to unique shape of radius end mill, some feature of radius end milling is introduced. As a result of the contour line machining, a scallop height is very influenced by the inclination angle and the corner radius, and surface machined by bottom edge must not be remained. Regarding the scanning line machining, “go-up” is good for the feed direction. Big corner radius is also suitable because side edge does not contact to workpiece. In other words, the cutting force in radial direction becomes small. Furthermore, the surface roughness of the scanning line machining is smaller than the one of the contour line machining.

Fabrication of Flexible Interposer Using Printing Method

In recent years, flexible electronic devices such as printed electronics are gathering attention. To make flexible connect between one circuit device and another circuit device, interposer is necessary. However, most of conventional interposers are not flexible, because there are made of silicon or glass substrate. To solve this problem, we have been developed fabrication process of flexible interposer. Master mold was fabricated by photolithography process. First, SU-8 resist was coated on silicon substrate with 5μm thickness. Then, photolithography process was carried out to SU-8 resist. After development, pillar shape master molds with diameters of 10 or 20 μm were obtained. After release coating of master molds, hole patterns for vias were transferred by UV nanoimprint lithography. The obtained hole patterns were diameter of 10 μm or 20 μm, and pitch of 21.0 μm and 40.1 μm, respectively. Next, these holes were filled with silver ink by roll press method. Then, sintering process was carried out to evaporate of solvent of silver ink. After that, flexible interposer was obtained. As a result, we have been succeeded in filling the holes array with silver ink. Obtained interposer vias, which were silver region, were 8.2 μm diameter and 3.3 μm height, or 20.3 μm diameter and 5.3 μm height for 10 mm square size.

Resistance Spot Welding in Non-Combustible Magnesium Alloy

Resistance spot welding (RSW) was applied to non-combustible magnesium alloy, AX41 (Mg-4%Al-1%Ca) to investigate its weldability. The similar material joint of AX41 and dissimilar materials joint between AX41 and aluminum alloy, AA6061 were welded. Tensile shear test was carried out to evaluate joining strength in the similar and dissimilar materials RSW joints. In case of similar material joints, the maximum load obtained with tensile shear test in AX41 similar material joint was higher than that obtained in AA6061 similar material joint. Moreover, higher maximum load was obtained in a similar material joint without surface polishing compared to joint welded with surface polishing in AX41. In case of the dissimilar materials joint, the maximum load obtained was almost comparable with AX41 similar material joint, however scatter in joint strength was large. Weldability of the dissimilar materials joint became poor by applying surface polishing.

Light Environment Design Support System Using Light-Guiding Plate With Decorative Cut Surface: Effects of Stripe Pattern Decorative Cutting on Plates Made From Transparent Resin

To increase the transmission efficiency of incoming and outgoing light on the side of a transparent resin light guide, such as an acrylic plate, we created a machined surface that does not become cloudy and transmits visible light well by cutting it with a single crystal diamond tool. When light is guided to this mirror-finished acrylic plate using an LED light source, its uneven brightness or illuminance distribution may be noticeable, depending on the application. To suppress the uneven distribution, attempts have made the luminance distribution uniform by a decorative cut on the acrylic plates for a fine pattern shape. Our research is developing a light environment design support system using an acrylic light-guiding plate with a decorative cut surface. This system consists of a rapid decoration pattern design technique with optical simulation, a decorative cutting technique to satisfy the demanded optical characteristics, and a technique to maintain machining quality. We implemented decorative cutting tests for various stripe patterns by adjusting the cutting conditions for the acrylic plates. Estimation of the decorative shapes was based on the shape of the tool cutting edge and its trajectory. We controlled the decoration shape and dimensions. The tendency of luminance distributions estimated by optical simulation were corresponded with the actual distributions.

Development of the cBN Electroplated End-Mill for High Precision Machining of CFRP

Recently, the demand of carbon fiber reinforced plastics (CFRP) has been rapidly increased in various fields. In most cases, CFRP products requires a finish machining like cutting or grinding. In the case of an end-milling, burrs and uncut fibers are easy to occur. On the other hand, a precise machined surface and edge will be able to obtain by using the grinding tool. Therefore, this research has been developed a novel the cBN electroplated end-mill that combined end-mill and grinding tool. In this report, the effectiveness of developed tool was investigated. First, the developed tool cut the CFRP with side milling. As the result, the cBN abrasives that were fixed on the outer surface of developed tool did not drop out. Next, the end-milled surface of CFRP was ground with the developed tool under several grinding conditions based on the Design of Experiment. Consequently, the optimum grinding condition that can obtain the sharp edge which does not have burrs and uncut fibers was found. However, surface roughness was not good enough. Thus, an oscillating grinding was applied. In addition, the theoretical surface roughness formula in case using the developed tool was formularized. As the result, the required surface roughness in the airplane field was obtained.

Effect of Steady Rest in Cylindrical Traverse Grinding of Slender Workpiece

In the case of traverse grinding of a slender workpiece, the ground workpiece is easily deformed by the normal grinding force due to its low stiffness. To reduce the form error caused by the elastic deformation of the workpiece, a steady rest is widely used. Generally, a steady rest is set to push the ground area of the workpiece. However, the stepped shape error is generated at the contact point where a steady rest pushed the workpiece because the pushing force of a steady rest is decreased after the material of the contact point is removed. In this study, to reduce the stepped shape error of the ground workpiece, we proposed a new method to set a steady rest. In this method, the steady rest was set to push the area where was not ground. In addition, the traverse speed of the workpiece was adjusted to keep the elastic deformation of the workpiece constant. The suitable method to control the traverse speed was estimated by using a beam model that could simulate the elastic deformation of the workpiece during the grinding process. It was confirmed that the new method could improve the form accuracy of a slender workpiece through grinding experiments.

Measuring Optical Properties of Advanced Nano/Micro-Periodic Structures Fabricated by Multi-Exposure Interference Lithography

Functional optical elements based on nano/micro-periodic structures have attracted much attention. Since the fabrication of these dual-periodic structures requires precise control of periodicity, the semiconductor process such as an electron beam lithography has been mainly employed. However, these techniques have problems with expensive and low throughput for industrial applications. Therefore, there remains a need for low cost and high throughput fabrication methods of dual-periodic structures. Then we developed a multi-exposure interference lithography (MEIL) system using rotational Lloyd’s mirror interferometer to overcome these problems. The advantages of interference lithography are a large processing area and low cost. Our developed rotational Lloyd’s mirror setup enables us to a highly precise superposition of multiple interference fringes by multi-exposure. Furthermore, we developed a measurement setup for reflective diffractive elements using a two axial rotating stage and measured the diffraction properties of the fabricated dual-periodic diffraction gratings. In this paper, as a demonstration, we succeeded in the fabrication of high-dispersion diffraction grating with an enhanced diffraction efficiency of the −3rd order light. The fabricated shapes have a periodicity of 1997 nm and 665 nm. Furthermore, it was confirmed that the intensity of the −3rd order light was enhanced by about 10 times compared to the single periodic grating.

Precision Coating of ta-C Films on Quartz Surfaces

Diamond-like carbon (DLC) films have excellent properties such as high hardness, low friction coefficient, high wear resistance, chemical inertness and so on. Because DLC film is considered as an effective coating material to improve their surface properties, this films are used in various applications such as parts for automobiles engines, hard disk surfaces, cutting tools and dies, and so on. DLC films consist of a mixture of sp2 bonded carbon atoms and sp3 bonded carbon atoms. Among them, ta-C film is known as the hardest and strongest film since it mainly consists of sp3 bonded carbon atoms. One of deposition methods to form ta-C is Filtered Cathodic Vacuum Arc (FCVA). The characteristic of this method is that it is possible to remove the droplets and form a high-quality film.. However, even though lots of mechanical components which require ta-C coating have three-dimensionally shapes, it is difficult to coat ta-C film three dimensionally by using FCVA process. At present, researches on 3D deposition of amorphous carbon films on three dimensional components is still insufficient, and investigation reports on the deposition mechanism and characterization of the deposited films are even more limited. In this study, we tried to deposit films on 3D components by the FCVA method and evaluated the microstructure and surface morphologies of films. Although films were coated successfully in the entire surfaces, different properties were showed depending on the location of components. These properties were investigated by Raman spectroscopy and laser microscope.

Free Vibration and Thermal Fluid Structure Interaction Simulation of Functionally Graded Pipe by Modeling As Layered Structure

Functionally graded materials (FGMs) are advanced class of composite materials which can be used as the thermal barrier to protect inner components from the outside high temperature environment. In FGMs, the volume fraction of each constituent can be tailored made across the thickness for desired applications. In this work, the simulation of FGMs in pipes is considered. Despite the wide application of pipes in machinery, those pipes would suffer from many safety problems, such as thermal stress, cavitation, fracture etc. Application of FGMs to the piping systems could lead to some new solutions accounting for safety measures and higher service life. However, the complex phenomena within the fluid structure interaction are hard to describe with the theoretical solution. The visualization of results from simulation will be helpful in understanding the distribution of kinds of physical quantities within the concerned model. For the simulation, FGMs are modeled as the layered structure in the standard finite element method (FEM) package based on FGM constituent law. The free vibration of the FG pipe is simulated and the accuracy of layered model is verified by numerical calculations. Further, based on the layered model, conjugate heat transfer simulations in a heat exchanger with FGMs are conducted.