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Micro-cutting edges are often used for the die cutting of functional films and paper containers. A hardening process is needed here because the ridgelines of micro-cutting edges require not only we...

Laser hardening process attracted attention because of its ability for a local heat treatment method without cooling solution. The local heat treatment with small power density can result i...

Bamboo grows naturally in Japan as an underutilized forest resource, and its fibers have high specific strength and stiffness, so much so that they are called natural glass fibers. In this study, a method for manufacturing a self-adhesive compact material by pressurizing and heating 100% bamboo fiber after extraction using a machining center, without losing the composition of bamboo, is proposed. This molded body is made of a 100% natural material and has a low environmental impact even when landfilled, contributing to the growth of bamboo for use as a raw material. In this study, the formation conditions for maximizing the tensile properties when forming platelets were investigated. First, an analysis of the variance was conducted using the orthogonal array test design to identify the factors affecting the objective variable and determine the contribution of each factor. In addition, estimates of the objective variable for the molding conditions were obtained from the Gaussian process regression model in a Bayesian optimization. Furthermore, as a result of comparing the maximum values of the properties of the molding conditions between the analysis of variance and the Gaussian process regression model, the values of the tensile properties were improved in the Gaussian process regression model.

The importance of micromachining using small diameter end mills and the dies used for them has been increasing in the machining of small parts. However, the reality is that there are various requirements to improve the machining surface, machining accuracy, machining efficiency, and tool life. Therefore, this paper discusses the possibility of satisfying these requirements by high-speed up cut milling in side cutting. The goal of this study was to solve the aforementioned problems, by conducting a detailed analysis of the machining phenomena in order to understand their mechanisms. In particular, the effects of high-speed cutting using a high-speed air-turbine spindle with highly stiff rolling bearings were analyzed. Moreover, cutting experiments were conducted by measuring the cutting force and flank wear of the tool, to reveal the differences in the cutting phenomena relative to the cutting direction in high-speed micro end milling. Description of the machined surface and the measurement of its profile were also included in the discussions. On the basis of the results, high-speed up cut milling is a better choice than down cut milling, furthermore, a high-feed rate further increases machining efficiency and improves tool life.

Shaft parts are important parts used in almost all machines including automobiles. In addition, extremely high reliability is required since a shaft failure is directly linked to a fatal machine trouble. Therefore, a hardening process is usually conducted to improve strength and wear resistance. In this study, we propose a new laser heat treatment method to produce high-quality and high-accuracy shafts with high efficiency, low cost and low environmental impact. We will also develop a technique to derive the appropriate laser irradiation conditions quickly and systematically for shafts with various shapes and dimensions. There are the other hardening techniques including the electric furnace method and the induction method. These methods require post-processing for deformation correction, whereas the proposed method uses a laser to achieve thermal deformation-free hardening, eliminating the need for the post-processing. As a result, an improvement in yield can be expected due to a reduction of the products that cannot be corrected after heat treatment, which had to be waste disposed with conventional methods. By using our method, the entire circumference of the shaft was hardened by using a ring-shaped laser beam and a cylindrical inner mirror. Here, the ring-shaped laser beam was formed by high-speed scanning of a spot shapelaser. In the present paper, the details of this system were introduced and some experimental results were described.

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.

The number of people with cancer of the large intestine has been increasing steadily. According to the global cancer observatory, its prevalence is second among all cancer types in world statistics over the past five years. Early detection and treatment of diseases by colonoscopy can enable complete recovery. Nevertheless, conventional colonoscopes require extremely high skill of the doctors who use them. Moreover, their invasiveness in the colon is high. Therefore, many robots to facilitate colonoscope-related operations have been developed recently. Unfortunately, no practical system exists which can truly overcome the proven effectiveness and lower costs presented by conventional colonoscopes. We therefore propose a novel autonomous propulsion mechanism for colonoscopy named the “Funicular Flexible Crawler.” It is suitable for propulsion through narrow spaces because it is driven by multiple small diameter crawler units connected to a flexible shaft. Experimentation with a large intestine phantom confirmed that the flexible crawler can run from the rectum to the cecum. As described herein, this propulsion mechanism is applicable for self-traveling colonoscopy.

A laser hardening process has received much attention because of its ability as a local heat treatment method without requiring a cooling solution. A local heat treatment with a small power density...

In small and precision die and mold making, small-diameter end mills are often used through rough to finish machining processes. However, higher-efficiency machining technology in die and mold manu...

Currently, carbon fiber reinforced plastics (CFRP) are being increasingly adopted in various fields. Thus, machining CFRP with high accuracy and high efficiency is required. In addition, machining stack materials composed of CFRP and titanium alloys is required. Therefore, in this study, a novel end-mill electroplated with a cubic boron nitride (cBN) abrasive, which has high thermal resistance, is proposed. In order to evaluate the influence of the base metal shape of the proposed end-mill on the machining process, several cBN-electroplated end-mills with different rake angles or chamfers were fabricated and used to cut CFRP. In addition, in order to evaluate the abrasive shape, a blocky abrasive was also electroplated on the end-mill. The results indicate that the negative rake angle is useful to restrain the progression of tool wear. However, in order to obtain the element of cutting and grinding, it is required that the rake angle should be positive. Moreover, the reasonable width of chamfer is effective for restraining the increase in CFRP temperature. Further, a sharp shaped abrasive can more effectively generate a CFRP with a sharp edge compared with a blocky shape abrasive.

A natural resource, bamboo, is widely distributed in Asia. Bamboo grows faster than other renewable natural material. Further, bamboo fibre has high specific strength and stiffness. We draw attention to this bamboo as a sustainable and environmentally superior material. We propose a sustainable manufacturing system using bamboo. A self-adhesive fibreboard has been fabricated by end-milling and hot press forming. This paper describes the environmental evaluation of this system using life cycle assessment.

In recent years, the performance and miniaturization of portable information devices have rapidly advanced. The build-up process is often used in the manufacturing of printed wiring boards (PWBs) for high-density circuits. At present, CO2 laser beams are generally used in the build-up process to drill blind via holes (BVHs) that connect copper foils. However, Cu direct drilling is problematic in that it produces a copper overhang as a result of copper and resin, with different decomposition points, being melted simultaneously. Overhang could cause an adverse effect in plating the hole for connectivity. However, only few studies have investigated Cu direct processing for drilling BVHs. At an actual production site of PWBs, the number of processing holes is enormous, which leads to neglecting the quality of each processed hole. Therefore, we focused on pulse drilling, which involves laser irradiation using short multiple pulses to reduce the thermal effect. Pulse drilling could reduce overhang compared to single pulse irradiation; however, it lengthens the total processing time. Pulse irradiation after BVH formation would be unnecessary, since it could cause thermal damage to the hole and lengthen the processing time. Therefore, during pulse irradiation, it is essential to distinguish whether a BVH is formed. We observed the value of the motion graph, which was acquired from the high-speed camera images. The motion graph shows the luminance value of an image at a given time of the video. Based on the peak time of the motion graph during each pulse, we proposed a method to distinguish BVH formation during multiple pulse drilling.

In recent years, the recycling of resources has become important because of the aggravation of global environmental concerns. In light of this, it is necessary to minimize the resource needs of current production systems. This concept is called sustainable development. When this concept is applied to machine tools, the assumption is that small parts should be processed using small machines. Additionally, the diversification of consumer needs and the ephemeralization of product life cycles are progressing in industry. As a result, the overall production system has changed from high-mix low-volume production manufacturing, to variant types in variable quantity. In this background, the cell production system is receiving attention as a production system that can achieve variant types in variable quantity. The cell production system also requires miniaturization and process consolidation of machine tools, which has given rise to the need to consolidate heat treatments, especially as part of the process consolidation of machine tools. Laser beams have proved to be effective heat sources when integrated into heat-treatment processes, such as quenching and tempering on machine tool tables. On the other hand, In the case of the thin plate, it is well known that the deformation of a plate occurs due to laser irradiation, as named a laser forming. The laser forming is also effective to generate the complex shape without a press die set. Thus, we propose that the hybrid process of laser heat treatment and forming of thin plate with a small power semiconductor laser, and demonstrate that the proposed method makes it feasible to generate the hardened sheet metal products with a compact machine tools. Moreover, considering the power consumption in laser quenching and forming process, we investigate an appropriate laser irradiation condition from a view of reducing the environmental burden.

There has recently been an increasing demand for miniaturization and multi-functionalization of electronic equipment due to developments in information technology (IT). The semiconductor package printed wiring boards (PWBs) used in the central processing units (CPUs) of various electronic devices have brought about many advanced features. While the micromachining of Si wafers and integrated circuits has improved, advanced processing technologies for micro-drilling in PWBs are also required. Consequently, demands have been made to miniaturize PWBs and fabricate highly dense electrical circuit layers. To make these demands a reality, it has been necessary to decrease the diameter and distance between the wall surfaces of through holes. However, problems have emerged in that the drilling tools bend and break during the drilling process, and heat occurs damage around the drilled holes after the drilling process due to the increased drilling aspect ratio between the depths and diameters of holes. Method of step-feed drilling are generally considered to be effective ways of solving these problems. However, alternation short stroke motions by the spindle axis are needed to do the step-drilling process and these motions cause various kinds of vibrations. A machine tool was constructed with a novel counter-balance mechanism on the spindle driving Z-axis and investigated a model to estimate the appropriate balance mass for the step-drilling process. The results were compared from the frequency responses of the proposed model with these from experiment, and found that vibration could be controlled with the counter-balance mechanism. The results demonstrated that the proposed vibration-proof method could reduce vibration in high-speed step-micro-drilling motions and to improve quality of the drilled holes and the efficiency of the micro-drilling process in PWB manufacturing fields.

Superior performances of carbon fibre-reinforced plastics (CFRP) such as light and higher strength are attracted attention as an alternative material of metal. An application as a printed wiring boards (PWBs) material focuses on its higher thermal conductivity adding to the above properties. The PWBs need so many micro-drilled holes. However, CFRP is well known as one of the difficult-to-cut materials. In the present research, the fundamental micro-drilling phenomena of CFRP were revealed through an experimental approach. This study describes characteristics on micro-drilling, 1 mm or less in diameter, of a CFRP plate using a high-speed spindle. To investigate them, cutting forces such as a thrust force and torque were measured by high-resolution dynamometers and a drill temperature during drilling was monitored by a thermography. In particular, diamond-coated tools were prepared in order to improve tool life. As a result of comparison with conventional non-coated tools, some unique tendencies are...

In recent years, the performance and miniaturization of portable information devices have rapidly advanced. The build-up process is often used in the manufacturing of printed wiring boards (PWBs) for high-density circuits. At present, CO2 laser beams are generally used in the build-up process to drill blind via holes (BVHs) that connect copper foils. The Cu direct-laser method is often used in this process, which irradiates laser to drill the copper foil and insulation layer simultaneously. Cu direct-laser involves a complex phenomenon because it drills copper and resin, with different decomposition points, at the same time. However, only few studies have been made in this field. This report focuses on monitoring Cu direct-laser drilling with a high-speed camera. We drilled holes with four different laser power outputs, 25 W, 50 W, 75 W, and 95 W and measured the size of the drilled holes. During the drilling process, the camera captured the emission of scattering materials in the PWBs. We have processed the images obtained from the camera to observe the scattering material. As a result, we found out that changes in the amount of scattering occur on four occasions: when the outer copper foil is drilled through, when the drilled depth reaches the inner copper foil, when the increase rate of the hole diameter is reduced, and when the inner copper foil is drilled through. Based on these results, the suitable laser irradiation time can be determined for different drilling conditions.

Research is currently ongoing for composite materials using natural fiber with a small burden on the environment. We have been focusing on bamboo because of its fast growth, renewability, flexibility, low cost, and high specific strength. We previously proposed a novel hot press fabrication method for binder-free green composite products made from bamboo fibers extracted by end-milling with a machining center. We can use this method to form three-dimensionally shaped products, especially hemispherical shells, by using two kinds of dies. However, this method is complex and takes longer than one-step hot press forming. In the present report, we propose a new method that uses bamboo powder with a particle size of less than 500 μm. Our new method uses one-step hot press forming and is quicker than the previous method at making a hemispherical shell shape. The new method was successfully used to manufacture hemispherical shell-shape products.

Recently, there has been an increasing demand for miniaturization and multi-functionalization of electronic equipments due to the developments in information technology (IT). Thus, the miniaturization of printed wiring boards (PWBs) and fabrication of highly dense electrical circuit layers are needed to realize the miniaturization and densification of the semiconductor package PWBs. Micro-drilling technology has been attracing attention to machine the electronic micro-through holes with an ultra-high-speed spindle, more than 160 krpm. However, problems have emerged; the drill tool bends and suffers breakage in the drilling process and the heat damage around the drilled hole after a drilling process occurs due to the increase in the drilling aspect ratio between hole depth and diameter. In general, a step feed drilling method is considered an effective way to solve these problems. However, short stroke alternating motion in the spindle axis is needed to do the step drilling process and its motion causes various kinds of vibration. We constructed a machine tool with a novel counter balance mechanism in the spindle driving Z-axis and investigated a model to estimate a proper balance mass for the step drilling process. We compared the frequency response results from a proposed model with the experimental ones, and discussed a control on vibration due to the counter balance mechanism. The results demonstrate that a proposed vibration proof method was found to reduce the vibration in high-speed step-micro-drilling motion and to improve the drilled hole quality and the efficiency of micro-drilling process in the PWB manufacturing fields.

Since demands for Carbon Fiber Reinforced Plastics (CFRP) are increasing, the number of the studies on machining of CFRP is also increasing. However, since there are already reports on a trimming of a surplus portion or a drilling, we focus on a face machining and a generating the step shape with several cutting tools. Problems in the machining of CFRP include an occurrence of the burr and delamination. Therefore, in this report, we investigate these problems in face milling. And, the machining behavior (Cutting temperature, Cutting force) during the machining is estimated.

Nowadays, resource saving technologies have become important because of increasing global environmental problems. Moreover, demand is increasing for the manufacturing and machining of small mechanical parts because of the downsizing of electronic mobile devices. Thus, one requirement has emerged that these small parts have to be fabricated by smaller machine tools to reduce the environmental burden. Here, when we look at the heat treatment process, it is found that most small parts are generally treated with a large size furnace as well. Therefore, we focus on compact machine tools to develop the clean and energy-saving technology in the manufacturing fields. In the present report, we consider an in-situ laser heat treatment technology integrated on the table used for compact machine tools. In particular, we perform the entire laser hardening of a small thin plate with a small power semiconductor laser, which is an attempt to harden a whole steel sheet. However, thin plates deform during the laser hardening process, which is called “laser forming.” Thus, we discuss an effective irradiation path to prevent the deformation of plates while quenching the entire plate. Moreover, considering the power consumption in the laser quenching process, we investigate an appropriate laser irradiation condition.

Data-mining methods using hierarchical and non-hierarchical clustering are proposed, which could help manufacturing engineers determine guidelines for deciding end-milling conditions. We have constructed a novel system that uses clustering techniques and tool catalog data to support the determination of end-milling conditions for different types of recent difficult-to-cut materials. In the present report, we especially focus on the cutting speed to estimate the performance of this system. A comparison with the conditions recommended by famous tool makers in Japan, reveals that our proposed system can be used to determine the cutting speeds for various difficult-to-cut materials. That is, milling experiments using a square end mill under two sets of end-milling conditions (conditions derived from the end-milling condition decision support system and conditions suggested by expert engineers) for difficult-to-cut materials (austenite stainless steel; JIS SUS310) showed that the catalog mining method is effective for deriving guidelines for deciding end-milling conditions at the beginning of the manufacturing stage.

In order to investigate the effects of a new surface modification method, ‘the substrate quenching after coating’ on the rolling contact fatigue strength, TiN coated steel specimens and CrAlN coated steel specimens were processed by this method and the thrust type rolling contact fatigue tests were carried out for these specimens. In the process of the substrate quenching after coating, two types of quenching methods, furnace quenching and laser quenching, were used.For the furnace quenched specimens, the delamination initiation life of CrAlN coated specimen was longer than that of TiN coated specimen. This reason could be explained by the difference of the oxidisation of CrAlN and TiN in their furnace quenching process. For CrAlN coated specimens, the delamination initiation life of the laser quenched specimens was longer than that of the furnace quenched specimens. After the initiation, the delamination of the furnace quenched specimen grew much faster than that of laser quenched specimen. These...

This paper proposes a novel process strategy for micro-cutting edge fabrication. Micro-cutting edges need a hardening process for the ridgeline parts that requires abrasive resistance, as well as edge sharpness and shape accuracy, based on their applications. Micro-cutting edge shapes also vary greatly in ridgeline profile and section. The proposed method is shape fabrication after laser hardening, which easily addresses these issues. In the present paper, effects of the proposed method are discussed and the results of a demonstration test are introduced.

Manufacturing systems have been evolving to accommodate the production of various types and volumes of products, as with the flexible manufacturing system (FMS). However, with FMS, it is difficult to change the layout of a factory and to cope with any problems that may arise. Therefore, the importance of automated guided vehicles (AGVs) is increasing because AGVs can flexibly adapt to changes of equipment in a factory. However, there has not yet been much research on systems that can respond to a large number of indefinite elements. One response to this issue might be a mimetic solution, which is the application of knowledge from one field to another. We feel that knowledge of traffic engineering, dealing as it does with the transport of passengers, could be applied to the conveyance mechanisms of AGVs. This paper describes an autonomous conveyance system for AGVs based on taxi transportation strategy. The system focuses on knowledge of a flexible taxi system in traffic engineering. We chose taxis because they operate with higher flexibility in terms of traveling routes and arrival/departure points compared with railways and buses. In this study, the waiting mode of taxis was applied as AGV rules and then tested to determine the effect of the proposed system. We came up with an equation to identify the best way of determining the waiting position. Moreover, AGV collisions are of extreme importance when AGVs run for real: if a collision occurs, we have to change the factory schedule and fix the AGV. However, in the past we have never taken account of an AGV collision, and so here we do. Two assessment functions are treated: matching time, which is the period of time elapsing between when a load is received and when a load is generated, and conveyance efficiency, which is the total distance the AGV travels divided by the total distance the AGV carries the load. Results showed that the proposed system (applying the waiting strategy of taxis as AGV rules) is effective at reducing the matching time and intersection of AGVs without any decrease in conveyance efficiency.

Recently, the development of electronic devices, such as smartphones, has meant that printed circuit boards (PCBs) have become complex multi-layer ones to provide both multiple functions and be compact. Blind via holes (BVHs) connecting the layers of the multi-layer board are processed by using a CO2 laser. The many benefits of direct processing by CO2 laser include a lower disconnect of the hole position as a result of the base drilling process in the inner layer circuit pattern. Also, efficiently dissipating heat from components improves the quality of the product as digital home appliances are increasingly compact, lightweight, and thinner. Using PCBs raises the radiation performance by the addition of alumina filler at the insulated layer. However, adding alumina filler means that laser processing is difficult, processing efficiency is reduced, and debris on the surface around the drilled hole increases. We consider what causes the changes in the processing hole by changes in the alumina filler content on the basis of data on drilling phenomena gathered with a high-speed camera. We found that the insulating layer material didn’t effect the diameter of the drill hole per laser spot diameter. The cross-section processing is done in a cone initially, and the truncated cone is then processed. And, we found that the hole depth and processing overhang was reduced, and the amount of scattering increased with the amount of alumina content filler.