Effects of Bit Shape of Electroplated Diamond Tool Used for Drilling Small Diameter Holes in Glass Plate on Machining Fluid Flow and Chip Discharge

Our laboratory has been exploring the development of tools for drilling holes in glass plates, and the drilling techniques to be adopted for it. A devised tool shape that could prevent the occurrence of cracks at the exit holes achieved high quality through hole drilling of 100 holes or more using only the drilling cycle. However, crack-free drilling beyond this number of holes cannot be performed. This is due to the adhesion of the residual chip on the tool surface when the number of holes increases. Therefore, further improvement of chip discharge is needed to achieve crack-free drilling. In this report, we consider that chip discharge results from the flow of the machining fluid. To investigate the cause of chip discharge, we analyzed the flow of the machining fluid in the hole using computational fluid dynamics and the supposed chip discharge conditions. The results obtained in this study are summarized as follows. (1) In the case of a cylindrical tool, the Z-axis directional flow of the machining fluid did not occur in the hole. This is because the tool does not have bumps to agitate the fluid on the side, and the gap between the tool and the inner surface of the hole is narrow. (2) The plate side widened the gap between the tool and inner surface of the hole. Therefore, the fluid was likely to flow in the Z-axis direction in the hole. (3) For the tool with the plane side bit, the flow entered the hole from one plane side and exited the hole from the other plane side. (4) When the tool end is spherical, the Z-axis directional flow of the fluid occurs at the tool end. (5) The fluid flow of the devised tool weakened as the drilling depth increased. To improve the chip discharge performance of the designed tool, the Z-axis directional flow of the machining fluid must occur in an area deeper than 2 mm.

本研究室では，ガラス板に穴を開けるための工具の開発とその穴あけ技術の研究を行っている．抜け穴でのクラックの発生を防止できる工夫された工具形状により，穴あけサイクルのみで100穴以上の高品質な貫通穴加工を実現した．ただし，この穴数を超えるクラックフリー穴あけはできない．穴数が増えると工具表面に切りくず残りが付着するためである．したがって，クラックのない穴あけ加工を実現するには，切りくず排出のさらなる改善が必要である．本報告では，切りくず排出は加工液の流れによるものと考えている．切りくず排出の原因を究明するため，穴内の加工液の流れを解析した．この研究で得られた結果は以下のように要約される．(1)円筒工具の場合，加工液のZ軸方向の流れが穴内で発生しなかった．これは，ツールの側面に流体を攪拌するための凹凸がなく，ツールと穴の内面との隙間が狭いためである．(2)プレート側はツールと穴の内面とのギャップを広げる．このため，流体は穴内をZ軸方向に流れやすかった．(3)平面側ビット付きのツールでは，流れは一方の平面側から穴に入り，他方の平面側から穴を出た．(4)工具先端が球面の場合，流体のZ軸方向の流れは工具先端で発生した．(5)工夫されたツールの流体の流れは，掘削深さが増加するにつれて弱まった．設計された工具の切りくず排出性能を向上させるには，加工液のZ軸方向の流れが2mmよりも深い領域で発生する必要がある．

International Journal of Automation Technology (IJAT)


Polishing Performance of a Recycled Grinding Wheel Using Grinding Wheel Scraps for the Wet Polishing of Stainless-Steel Sheets

The surfaces of large austenitic stainless-steel sheets, which have side lengths of at least 1 m a sheet thickness of at least 6 mm, used for food tanks and sliding plates in seismic isolation devices, must be finished to a mirror surface. Polishing is performed to improve the surface quality of such sheets and dry machining is typically applied. The problems associated with dry machining are the exhaust heat of machining and treatment of chips. A transition to wet machining is required to solve these problems. In our laboratory, we have developed a wet polishing machine and researched the selection of grinding wheels to develop wet polishing technology for large stainless-steel sheets. In this study, to reduce tool cost and reuse resources, we attempted to manufacture a recycled grinding wheel using snippets of grinding wheel scraps. A polyvinyl alcohol (PVA) aqueous solution was used as the bonding agent for the recycled grinding wheel to reduce environmental load. To overcome the ease of dissolution of PVA in water, we attempted to improve the water resistance of the PVA aqueous solution by incorporating an organic titanium compound. This is one of our efforts to contribute to sustainable development goals. The results are summarized below. (1) A recycled grinding wheel was fabricated by kneading crushed pieces of grinding wheel scrap with a bonding agent. (2) The maintenance of the shape of the recycled grinding wheel was controlled by the concentration of the bonding agent. (3) The recycled grinding wheel with a PVA bonding agent was vulnerable to water. In contrast, the recycled grinding wheel to which the organic titanium compound was added exhibited improved water resistance. (4) The polishing of stainless-steel sheets using the plain PVA recycled wheel was relatively ineffective, but polishing using the recycled wheel with the titanium additive was comparable to polishing with a new grinding wheel.

食品タンクや免震装置のすべり板などに使用される一辺1m以上，板厚6mm以上の大型オーステナイト系ステンレス板は表面を鏡面に仕上げる必要がある．このようなシートの表面品質を改善するために研磨が行われ，通常は乾式機械加工が適用される．乾式加工の課題は加工時の排熱と切りくず処理である．これらの問題を解決するには，湿式加工への移行が必要である．本研究室では，大型ステンレス鋼板の湿式研磨技術を開発するため，湿式研磨機の開発と砥石の選定を検討した．本研究では，工具コストを削減し，資源を再利用するために砥石スクラップの断片を使用して再生砥石の製造を試みた．再生砥石の接着剤にはポリビニルアルコール(PVA)水溶液を使用し，環境負荷を低減した．PVAの水への溶けやすさを克服するため，有機チタン化合物を配合することでPVA水溶液の耐水性を向上させようとした．これは持続可能な開発目標に貢献するための私たちの取り組みの 1 つです．結果を以下に要約する．(1)砥石廃材の破砕片を接着剤で練り合わせて再生砥石を作製した．(2)再生砥石の形状維持は結合剤の濃度によって制御された．(3)PVA 結合剤を使用した再生砥石は水に弱かった．一方，有機チタン化合物を添加した再生砥石は耐水性が向上した．(4)PVA 再生砥石を使用したステンレス鋼の研磨は比較的効果がなかったが，有機チタンを添加した再生砥石を使用した研磨は通常の砥石での研磨に匹敵した．


Helical Micro-Hole Drilling of Chemically Strengthened Glass Using Capsule-shaped Electroplated Diamond Tool

This study investigates the microhole drilling performance of chemically strengthened glass plate by using a capsuleshaped electroplated diamond tool and the helical drilling method. Three different helical pitch conditions were tested to drill holes with a diameter of 1 mm. The number of drilled holes, grinding force, and maximum crack size were measured along with the observation of the drilled holes to evaluate the performance of the microhole drilling. From the experimental results, it was found that as the size of helical pitch decreased, the number of drilled holes increases where the average grinding force generated becomes smaller. By using small helical pitch condition, 43 holes could be drilled but the maximum crack size generated at the outlet side of the drilled hole is not able to achieve the highgrade quality compared to the inlet side. The resultant grinding force generated when the tool tip nearing the outlet side of the glass plate has caused the large crack at a certain position on the outlet side.

Journal of Advanced Manufacturing Technology


Experimental Research on the Compressed Joints with Different Geometrical Parameters

Proceedings of the Institution of Mechanical Engineers. Part B, Journal of Engineering Manufacture


Numerical and Experimental Investigations of the Two-Step Clinching Process with a Bumped Die

Journal of Advanced Mechanical Design, Systems, and Manufacturing


Chip Discharge Performance of Micro-hole Drilling through a Glass Plate using an Electroplated Diamond Tool with Different Drill Bits

This research aims to identify a high-quality, efficient, and low-cost micro-hole drilling process through glass plates that employs an electroplated diamond tool with different drill bits. Three different drill bits were tested to determine how varying the chip discharge volume influences chip discharge performance, which is an important factor that affects the effectiveness of the drilling process. The chip discharge performance of each electroplated diamond tool was experimentally investigated by observing the drilling quality and the number of the drilled holes. From the experimental results, it was found that the drilled chips could not discharge smoothly when the drill bit possesses a small chip discharge volume, leading to the drill bit breaking, which thus limits the number of drilled holes. Furthermore, the changes in thrust force and the crack size were high, and there were also cracks on the drilled glass plate. However, drilling with a drill bit that possesses a larger chip discharge volume resulted in excellent chip discharge performance and increased the number of drilled holes. This type of drill bit is effective in drilling holes through glass plates, with minimum hole defects and no issues associated with chips clogging the hole during drilling.

International Journal of Precision Engineering and Manufacturing


Prevention of chip adhesion by acting non-ionic surfactant physical properties

非イオン系界面活性剤の物性による切りくず付着の抑制

穴加工において，切りくずは穴内に残留しやすく，工具に付着しやすい状況にある.本研究室では先端部を半球形状とした円筒形ダイヤモンド電着工具の側面の一部を削り取り，ここが切りくず排出の役割を担うストレート面付き工具を開発した.この工具は，加工中に生成される切りくずを効率的に排出し，工具への切りくず付着を抑えてい た.しかし，少量の切りくずが穴内に残留し，加工穴数の増加に伴い，切りくず排出領域に付着した.本研究は加工液に含有する界面活性剤の物性に着目し，この物性が切りくず付着に及ぼす影響について検討した.

Journal of the Japan Society for Abrasive Technology


Influence of Sheet Thickness on Mechanical Clinch-Compress Joining Technology

Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering


Comparative Study on Two Compressing Methods of Clinched Joints with Dissimilar Aluminum Alloy Sheets

The International Journal of Advanced Manufacturing Technology


Improved Chip Discharge in Drilling of Glass Plate Using Back Tapered Electroplated Diamond Tool

Previous studies of a through-hole drilling for hard and brittle materials using electroplated diamond tool devised by the authors have led to several challenges such as a restraint of crack size at the inlet and outside, a suppression of chip adhesion on the tool and an improvement of processing efficiency. In this paper, the devised tool was redesigned in order to restrain cracks of the inlet side as well as to improve the chip discharge. The new design of the tool featured a back taper which was expected to bring an effect of restraining crack size by preventing any interference between the tool cylindrical surface and the hole inner surface during drilling process. In addition, the chip can be discharged from the drilled hole through the back taper. Results of the experiment indicated that by providing the back tapered shape, the width of the inlet hole can be reduced slightly as the interference between the glass plate and the tool cylindrical surface was suppressed. Furthermore, the adhesion of chip on tool can be restrained by using the tool with large chip discharge space as the chip was easily discharged to the outside of the hole. Moreover, an abrupt change in thrust force was not detected, and the crack width was found in small size.


Experimental Investigation on the Joining of Aluminum Alloy Sheets Using Improved Clinching Process

Aluminum alloy sheets have been widely used to build the thin-walled structures by mechanical clinching technology in recent years. However, there is an exterior protrusion located on the lower sheet and a pit on the upper sheet, which may restrict the application of the clinching technology in visible areas. In the present study, an improved clinched joint used to join aluminum alloy sheets was investigated by experimental method. The improved clinching process used for joining aluminum alloy evolves through four phases: (a) localized deformation; (b) drawing; (c) backward extrusion; and (d) mechanical interlock forming. A flat surface can be produced using the improved clinching process. Shearing strength, tensile strength, material flow, main geometrical parameters, and failure mode of the improved clinched joint were investigated. The sheet material was compressed to flow radially and upward using a punch, which generated a mechanical interlock by producing severe localized plastic deformation. The neck thickness and interlock of the improved clinched joint were increased by increasing the forming force, which also contributed to increase the strength of the clinched joint. The improved clinched joint can get high shearing strength and tensile strength. Three main failure modes were observed in the failure process, which were neck fracture mode, button separation mode, and mixed failure mode. The improved clinched joint has better joining quality to join aluminum alloy sheets on the thin-walled structures.


Investigation of Grinding Fluid for Prevention of Chip Adhesion in Miniature Drilling of Glass Plate Using Electroplated Diamond Tool


Experimental Study on the Height-Reduced Joints to Increase the Cross-Tensile Strength


Mechanical Properties and Cutting Performance of Electroless Ternary Ni-W-P Coated Cutting Tools


Effects of Geometrical Parameters on the Strength and Energy Absorption of the Height-Reduced Joint


Experimental Investigation of the Mechanical Reshaping Process for Joining Aluminum Alloy Sheets with Different Thicknesses


An Experimental Study on the Compressing Process for Joining Al6061 Sheets


Miniature Drilling of Chemically Strengthened Glass Plate Using Electroplated Diamond Tool

It is well known that chemically strengthened glass plate has excellent strength and hardness properties. These characteristic properties are advantageous for the touch screens used in mobile devices. However, they are detrimental to the process of machining the glass plate. For example, chipping and crack occur around the inlet and outlet of the drilled hole, and the rate of tool wear is significant. Therefore, the surface quality and machining efficiency are low. The drilling process is extremely difficult. In this study, we de- scribe the use of a miniature drilling method to achieve high-quality drilled holes in chemically strengthened glass plate using an electroplated diamond tool with a diameter of 1 mm or less. Using the developed tool with a diameter of 0.5 mm, it is demonstrated that the conventional drilling method can be used to drill a through-hole in the glass plate.

International Journal of Automation Technology (IJAT)


Fundamental Study on Hole Fabrication inside a Hole by Means of Electrical Discharge Machining


Development of electroplated diamond tool for fracture size minimization in miniature drilling of glass plate

ガラス板への高品位通り穴加工を目的とした小径ダイヤモンド電着工具の開発

To minimize fracture size in through-hole drilling of glass plate, this paper examines drilling behavior of commercial tool shape, as well as the availability of a tool shape designed by the authors. The chipping size occurring at the hole edge is related to the form of tool end and the chip elimination efficiency. The designed tool, which is an electroplated diamond tool with a diameter of 1 mm, has a unique shape. The tool shape has a hemispherical tool end and a few straight planes. During drilling, the hole enlarges gradually due to the hemispherical shape of the tool end. The occurrence of chipping at the edge of the exit hole is reduced because the hemispherical shape can reduce the abrupt decrease in drilling force. That is, large chipping and cracking corresponding to the hole diameter can be suppressed. In addition, the straight planes play a role in eliminating chipping, and the adhesion of chips is suppressed. The results of this investigate indicate that the designed tool allows drilling of drilling cycle.

本論文は，ガラス板への小径通り穴加工において，穴縁周りの欠けを小さく抑える工具形状についての検討を行うとともに工具の開発を行った．穴縁に生じる欠けの大きさは工具先端の形状と切りくずの排出性能に関係した．得られた知見から，著者らは工具穿孔部が他に類を見ない形状を持つ小径ダイヤモンド電着工具を開発し，この工具の有効性を調査した．本工具の特長的な点は，工具先端部が半球状であることと穿孔部がストレート面をもつことである．工具先端部を半球形状にすることで，穴は徐々に繰り広げられるような加工となる．この形状により，加工抵抗の急激な変化は抑えられるため，欠けは小さくなった．すなわち，穴径に相当するほどの大きな欠けや割れは抑制できた．そして，ストレート面は切りくずを排出する役目を担い，切りくずの付着を抑制した．本工具1本のみを使用した通常のドリリングサイクルでの穴加工を可能とした

Journal of the Japan Society for Abrasive Technology


Restraint of Thermal Crack on Rake Face of Cermet Tool in Intermittent Cutting


スクエアエンドミルを用いた同時5軸制御加工による中仕上げ加工の高効率化

スクエアエンドミルを用いた同時5軸制御加工による中仕上げ加工の高効率化

In recent years, efficient production by use of CAD/CAM systems draws attention due to the demand of high-variety low-volume. Semi-finishing by square end mill has some problem than finish cutting by ball end mill. However five-axis controll machining with square end mill is more difficult due to the various cusp height and the possibility of the tool gouging. This study aim at proposing a tool path generation method for five-axis controll semi-finishing with square end mill. The method can decide the position and the posture of square end mill without the interference and generate the tool path, which enables to decrease the machining time in consideration of the cusp height.

Transactions of The Japan Society of Mechanical Engineers, Series C

日本機械学会論文集(C編)


Effect of Cutting Point Swivel Machining by Using Tool with Special Chamfer

特殊チャンファ付き工具を用いた刃先移動加工法の効果

Recently, in accordance with the technical development and miniaturization of the information equipments, the demand of optic elements with high precision and miniaturization is increased. The mold is used in the manufacture of the optic elements. Thus, it is needed to machine the mold with high efficiency and high precision. As the material of mold, hard material including cemented carbide and ceramics is used. However, it is a problem of the occurrence of severe tool wear when hard material is machined. To solve this problem, cutting point swivel machining by using the diamond tool with special chamfer was proposed, which has the ability to suppress tool wear and to realize ultraprecision machining. The effectiveness was verified by the microgrooving experiment of SiC. The study aims at investigating the effect of the cutting point swivel machining, and the cutting force and tool wear with different tool rotation speed. As a result, the effect of the cutting point swivel machining is made clear, and the relationship among tool rotation speed, cutting force and tool wear is known.

Journal of the Japan Society for Precision Engineering


マイクロ複雑形状の超精密巧妙加工

マイクロ複雑形状の超精密巧妙加工

Corresponding to diverse consumer needs, high-mix and low-volume production is becoming more important. Unique products matching consumer's sensitiveness tend to be welcome. These products will be something like art and craft products, which require skill and experience to create. This study deals with 5-axis control tool path generation to dexterously and efficiently create such craft-like microshapes, while maintaining the quality. Concerning 5-axis control machining, the way of using ball end mills is generally employed. However, it needs a lot of time to get high quality surface. To solve this problem, a side cutting edge of the ball end mill is positively utilized with its tool axis parallel to the ruled surface. Therefore, a new CAM system is developed to detect the surface to be machined with the side cutting edge, and to generate the collision-free tool paths between the tool and the workpiece. The effectiveness of the developed CAM system is experimentally confirmed by creating a tiny Möbius ring.

日本機械学会論文集(C編)


複合加工機用CAPPシステムの開発

複合加工機用CAPPシステムの開発

Multi-tasking machine tool has a variety of machining functions, which may lead to the reduction in machining time and the machining with high quality, and they have the growing availability. On the other hand, the use of multi-tasking machine tool causes the long process planning due to the functional complexity. There are some CAM systems for multi-tasking machine tool, however they need long working time caused by the mannual allocation of parts to generate tool paths. Therefore, the study proposes the rationalization of the process planning by extracting the machining feature in consideratinf with turning and milling from targeted shape to be machined and by selecting suitable machining method and scheduling machining order automatically. As a result, it is expected to reduce the working time on CAM system, using output data by proposed system. Applying the system to several product shapes containig both turning feature and milling feature, it is confirmmed that NC data can be obtained for each shape without any problem.

日本機械学会論文集(C編)


Dexterous Machining of Complicated Shape Consisting of Several Bended Columns

複数の曲がり円柱からなる複雑形状の巧妙加工

In recent years, manufacturing industries are facing severe competition to achieve products with high quality and low price. It is important to establish a new approach of creating value-added products like objects of craftwork or applied arts, different from traditional way of achieving products with high quality and low price. Manufacturing such value-added products generally needs skill and experience of experts. Thus, the objective of the study is to develop a CAM system for a multi-tasking machine in order to create value-added products, while converting implicit knowledge of experts into a formal knowledge. This kind of manufacturing way is named "Dexterous machining". The study deals with the CAM system to create a complicated shape consisting of bended columns as "Dexterous machining". The CAM system developed in the study can generate the tool path for rough cutting and finishing cutting in consideration of interference avoidance. The effectiveness of the CAM system is confirmed by demonstrating two kinds of bended columns by use of a multi-tasking machine.

日本機械学会論文集(C編)


Highly Accurate Molding Die Machining by Reconstruction of NC Data

NCデータの再構成による高精度金型加工

NC commands are generated by CAM systems to realize high speed and high accuracy machining. At the time, the feed rate in most of NC data may be set to be constant in machining any workpiece shapes. In addition, NC data do not necessarily reflect the workpiece shape correctly due to the variation in the coordinate point values calculated by CAM systems. It causes the reduction in the machined surface quality. The shape recognition in the tool feed direction on the basis of NC data has already been devised. Thus, the study enables 3-D shape recognition to be identified from NC data in the pick feed direction as well as those in the feed direction. After the identification, the feed rate can be controlled according to the identified shape information. The system developed in the study can detect the distinguishing points from the coordinate information in NC data. Then, the points are arranged to generate the smooth tool motion and to control the feed rate for the identified workpiece shape. From experimental result, it is confirmed that the machined surface quality is successfully improved and the machining time is also reduced.


Creation of Microgroove with Two Flat-ends for Hard Materials

高硬度材料への両端マイクロ止り溝創成

High performance and miniaturization are strongly demanded for optical elements and precision parts, where microgrooves play an important role. A non-rotational cutting tool is one of machining means to create microgrooves. However, even non-rotational cutting tool forms slopes at the cutting start and end points, which deteriorate the optical performance. In optical elements and precision parts, the creation of two flat-ends microgroove is expected, where two flat-ends microgrooves mean microgrooves having no slopes at the cutting start and end points. The method to create two flat-ends microgroove has already been devised and applied for soft materials, not for hard materials. In the study, a new method is proposed to create straight and curved microgrooves with two flat-ends for hard materials by indenting and feeding a non-rotational cutting tool. From experimental results, it is found that the proposed method has the potential of creating two flat-ends microgrooves for hard materials.


Fabrication of Microinducer by 5-axis Control Ultraprecision Micromilling


入れ子を有する複雑形状の巧妙加工

入れ子を有する複雑形状の巧妙加工

日本機械学会論文集(C編)


工具姿勢と姿勢変化の影響を考慮した5軸制御CAMシステムの開発

工具姿勢と姿勢変化の影響を考慮した5軸制御CAMシステムの開発


曲がり穴放電加工用極間距離自動制御機構の設計法に関する研究

曲がり穴放電加工用極間距離自動制御機構の設計法に関する研究

This study deals with the design method of automatic discharge gap controller (ADGC) installed on a microrobot which can create long, complicated curved holes by means of electrical discharge machining (EDM). The microrobot has to make a curved hole by both performing stable EDM and moving along a curved trajectory in a workpiece. To realize the stable EDM, the microrobot must be equipped with a function in which its electrode is always kept in an appropriate position autonomously and automatically to maintain suitable discharge gap. The function is accomplished by ADGC. It was proven that ADGC has the ability of achieving the function. However, a design method of ADGC is not established since the relationship between the structures of ADGC, the movement of ADGC, and EDM conditions is not enough revealed. As a first step to solve this problem, this study proposes the ADGC design method based on a simple mathematical model of ADGC and develops a new measurement method to evaluate the performance of ADGC doing EDM. The results obtained in the verification experiments using the measurement method show that the ADGC design method proposed is effective.


5軸制御多数穴あけ加工の効率化

5軸制御多数穴あけ加工の効率化

In case of drilling for a large number of holes, the total process time is composed of the sum of the movement time between a hole and another, and the sum of the drilling time of holes. The former time depends on the drilling order although the latter time is constant. Thus, the difficulty increases with increasing the number of holes in deciding the appropriate drilling order. In addition, it is required to avoid changes in the movement direction because the reverse movement causes the vibration and the degradation of machining accuracy. In this study, the decision problem of the drilling order for a large number of holes is treated as Traveling Salesman Problem. By considering influence of the change in the tool posture, the movement time and the number of the reverse movement are selected as the objective function. In order to optimize the objective function, Simulated Annealing and Genetic Algorithm are applied in the study. As the result of conducting drilling simulation, it is found that SA is superior to GA in this study. The sum of the movement time is reduced to 1/3 by SA, compared to the conventional method. It is also confirmed that the number of the reverse movement is reduced to 3/4 of the conventional method.


領域分割に基づく5軸加工用工具経路生成法

領域分割に基づく5軸加工用工具経路生成法

In recent years, the efficient machining of workpieces with a complicated shape has being increased in terms of realizing the products with compact design and sufficient functionality. 5-axis control machining center is suitable to meet such a requirement. However, it is necessary to obtain adequate tool postures to avoid interference between the cutting tool and the workpiece while machining workpieses with complicated sculptured surface. This study deals with rapid tool path generation for 5-axis control machining to treat such complicated product shapes on the basis of a proposed method. For tool path generation, the product shape is divided into small area. Each divided area is subjected to interference check. This new CAM system can generate automatically interference-free NC data in 5-axis control machining. The validity of the developed system is demonstrated with machining simulation and experiment.

日本機械学会論文集(C編)


複合加工機による鎖形状の巧妙加工

複合加工機による鎖形状の巧妙加工

In recent years, complicated shapes have been required to be machined at a shorter time. Machine tools have become highly accurate and had multifunction as well as the development of CAD/CAM systems. However, there exist a lot of things difficult or impossible to create even by multi-axis control CNC machine tools. Most of them are made by skilled persons of ingenuity and device. In the future, it is predicted that consumer needs are getting more various and that consumers require individual goods matching for their feeling. The study presents the first trial of creating an artistic workpiece by use of a multi-tasking machine tool. Such a machining technology may be called "Dexterous Machining". As an example, a chain-shaped workpieces are selected, which cannot usually be machined in the conventional manner. Thus, a special type CAM system is developed, taking account of the interference between a cutting tool and a workpiece, and by use of the second main spindle. As a result, it is found that the developed CAM system has the potential of realizing Dexterous Machining.

Transactions of The Japan Society of Mechanical Engineers, Series C

日本機械学会論文集(C編)


Direct Measurement of Electrode Movement during Electrical Discharge Machining by Means of Automatic Discharge Gap Controller

International Journal of Automation Technology (IJAT)


Design and Implementation of Automatic Discharge Gap Controller for a Curved Hole Creating Microrobot with an Electrical Discharge Machining Function


5軸加工を考慮した複合加工機用CAMシステムの開発

5軸加工を考慮した複合加工機用CAMシステムの開発

In recent years, highly efficient machining by multi-tasking machine tools attracts the attention since manufacturing industry tends to high-mix low-volume production. An introduction of multi-tasking machine tools results in many advantages. However, the machining operation is difficult due to the complexity of the machine tool structure. Consequently, NC programming for the machine tools requires much time and labor. In addition, the self-interference of the machine tools must be considered. The study deals with the development of an unprecedented CAM system which can achieve the process planning and generate NC programs automatically for multi-tasking machine tools by considering the self-interference and using 3D-CAD data. At the previous study, milling was limited to 3-axis machining. The study deals with the development of CAM system capable of 5-axis control milling in terms of the self-interference avoidance of the machine tools.

日本機械学会論文集(C編)


特殊チャンファ付きダイヤモンド工具の摩耗抑制をした高硬度材の超精密マイクロ溝加工

Recently, in accordance with the technical development and miniaturization of the information equipments, the demand of optic elements with high precision and miniaturization is increased. The die is used in the manufacture of the optic elements. Thus, it is needed to machine the die with high efficiency and high precision. As the material of mold, hard material including cemented carbide and ceramics is used. However, when hard material is machined, it is a problem of the occurrence of brittle fracture and hard tool wear. Tools with chamfer are used in the machining of hard material to reduce tool wear. However, there is a serious problem that the rake angle is not constant along the edge of the conventional R-shape tool with chamfer since the tool shape is like ellipse, it is difficult to machine hard materials with high precision. To solve this problem, a special tool with chamfer is developed. The study proposes a new microgrooving method with tool wear suppressed by the special tool with chamfer. The effectiveness is verified by the microgrooving experiment of SiC.

Journal of the Japan Society for Precision Engineering


Development of CAD/CAM System for Cross Section^s Changing Hole Electrical Discharge Machining ---Formulation of Post Processor---

This study deals with the development of a new CAD/CAM system for fabricating holes whose cross sections change variously. The cross sections of machined holes are generally constant. The limitations in the shapes of holes that can be machined make obstacles in the design stage of industrial products. A new device that utilizes electrical discharge machining has been developed that can create holes with various cross sections to solve this problem. However, it has been impossible to put the device into practical use since there has been no software that has enabled the designed shapes to be easily machined. Therefore, we aimed at developing a new CAD/CAM system for machining the beforehand designed holes with changing cross sections by using the device. As the first step in developing the CAD/CAM system, the post processor in the CAM system is formulated in this paper.

Journal of Advanced Mechanical Design, Systems, and Manufacturing


Development of CAM System for Multi-tasking Machine Tools

Multi-tasking machine tools are very useful to manufacture complicated workpiece efficiently. However, it is very difficult to generate NC data when an operator uses multi-tasking machine tools. Currently, there are some CAM systems for multi-tasking machine tools. However, there are such problems as the manual allocation of parts to generate tool paths, the difficulty of self-interference recognition without a simulator, and so on. Therefore, this study deals with the development of CAM system which can recognize part configurations, calculate tool paths automatically for turning and milling operations, and sort them in machining order, based on 3-D CAD data of workpieces.


Study on an Interactive System for Conceptual and Basic Design of Machine Tool Structure

This paper presents the improvement of design efficiency of machine tool structure in the conceptual and basic design stage. An interactive system has been developed for designing machine tool structure in this study. The key point in the interactive system is that a set of beam elements are assumed to compose the total structure of machine tool because it is easy to analyze the static, dynamic and thermal features. In this interactive system, a conversion procedure also has been developed. By using this conversion procedure, the selected beam structure of machine tool can be converted to an actual structure, completing conceptual and basic design. Consequently, using the interactive system allow, designers can complete the machine tool structure design in a shorter time with higher efficiency. The goal of the interactive system is to assist designers to quantitatively and quickly select a superior machine tool structure.


Creation of V-shaped microgrooves with flat-ends by 6-axis control ultraprecision machining


Interactive Design-Assistance System of Machine Tool Structure in Conceptual and Fundamental Design Stage


5軸制御加工用CAPP/CAMシステムの開発 -3次元微小部品加工への適用-

5軸制御加工用CAPP/CAMシステムの開発 -3次元微小部品加工への適用-

Complicated 3-D parts can be created by using the developed multi-axis control machining centers. 3-D CAD/CAM systems for multi-axis control machining are also developed to save time and labor in preparing NC data. However, operators consume a longtime in process planning since there are few practical computer systems for process planning. It is indispensable to develop CAPP(Computer Aided Process Planning) system for 3-D machining in response to the demands. The study deals with the development of fundamental CAPP/CAM system for multi-axis control 3-D machining. The system developped in the study enables 5-axis control tool path generation in consideration of tool length, the tool posture change and the workpiece fixing direction, based on the tool entrance face concept. From experimental result of creating a micro impeller, it is confirmed that the CAPP/CAM function has the potential of effective multi-axis control machining.


微細構造を有するガラスレンズ成形型の高精度加工に関する研究(第2報) -マイクロフレネル溝を有する非軸対称非球面金型の高精度加工-

In recent years, the demand of optical devices with complicated and highly accurate shape such as Fresnel lens and f-q lens is growing up in terms of miniaturization and improvement of information equipments. Moreover, the demand of glass lenses increases for the purpose of improving its heat resistance and optical performances. The study proposes a machining process for non-axisymmetric aspheric cemented tungsten carbide mold with minute structures, aiming at high precision machining. In the proposed process, the non-axisymmetric aspheric surfaces except for minute structures are at first machined by the spiral form grinding tool path with a spherical resinoid bonded diamond wheel. The machined surface center is corresponding to the center of the rotation axis of ultraprecision machine tool. Afterwards, the surfaces are ground for compensation, based on allover shape measurement interpolated by cubic spline. Then, minute structures are created on non-axisymmetric aspheric surfaces by the grinding with a disk type metal bonded diamond wheel. As a result, it is found that the proposed machining method has the potential of producing a high precision non-axisymmetric aspheric glass lens mold with minute structures effectively.


突出し長さを考慮した3+2軸制御荒加工用工具経路生成

突出し長さを考慮した3+2軸制御荒加工用工具経路生成

In recent years, 5-axis control machining has attracted a wide attention because of having many advantages compared with 3-axis control machining. However, there have been few roughing procedures corresponding to 5-axis control machining. This study especially deals with roughing by 3+2-axis control machining, which performs 3 translational axes machining after determining a suitable tool axis vector by 2 rotational axes movement. For 3+2-axis control machining, the determination of tool axis vectors, tool lengths and tool diameters largely affects the rough machining time. The previous study proposed a method of determining the optimal tool axis vectors and selecting the tool diameters for efficient roughing. In order to improve the method more effectively, this study proposes a new method of searching optimal tool combinations by taking account of shorter tool length. Stiffness of short tool is so high that it can machine workpiece more efficiently. The effectiveness of the proposed method was demonstrated by the machining simulation and experiment.

Transactions of The Japan Society of Mechanical Engineers, Series C

日本機械学会論文集(C編)


Development of Microrobot for Curved Hole Electrical Discharge Machining:- Size Reduction and Performance Enhancement by Improvement of Automatic Discharge Gap Controller -

曲がり穴放電加工用マイクロロボットの開発 -極間距離自動制御機構の改良による小型化と性能向上-

The study deals with the size reduction and performance improvement of automatic discharge gap controller (ADGC) for a microrobot which can fabricate a long curved hole by electrical discharge machining (EDM). The development of curved hole machining method is strongly required so that the pipelines with an arbitrary shape can be made in an arbitrary position. However, such pipelines cannot be fabricated since holes are generally formed by drilling. To solve the problem, the paper proposes a curved hole machining method by means of a microrobot with an EDM function. The microrobot has to have the function of performing the stable EDM in such a limited space as the bottom of a long curved hole, in other words, the function of always keeping the equipped electrode in an appropriate position automatically and autonomously so as to maintain stable EDM. ADGC is key component to realize the function. The prototype of ADGC was developed. However, the prototype was too large to install on a microrobot and did not achieve the full performance designed. Therefore, in the study, ADGC is improved to reduce its size and to achieve its full performance. From the experimental results, it is found that the improved ADGC realizes the full performance designed.

Journal of the Japan Society for Precision Engineering


複合加工機用CAMシステムの研究

複合加工機用CAMシステムの研究

Multi-tasking machine tools are powerful to manufacture complicated workpieces with high productivity. However, NC data generation for multi-tasking machine tools is very difficult in general when using such machine tools. There are some CAM systems for multi-tasking machine tools, however they have such problems as the manual allocation of parts to generate tool paths, the difficulty of self-interference recognition without simulator and so on. Therefore, this study deals with the development of the system which can recognize part configurations, calculate tool paths automatically for turning and milling operations and sort them in machining order, based on 3-D CAD data of workpieces and target shape.

日本機械学会論文集(C編)


断面変化穴放電加工用CAD/CAMシステムの開発(2次元形状用ポストプロセッサの構築)

The study deals with the development of a new CAD/CAM system for fabricating the holes whose cross sections are changing variously. The realizable hole shapes by machining are generally limited. As a typical example, a cross section of a machined hole is constant. To solve the problem, a new device had developed which could create cross section's changing holes by means of electrical discharge machining. However, it was impossible to put the device into practical use, since the software system for the device did not exist which allowed the device to machine an arbitrary cross section's changing hole. Accordingly, the study aims at the development of a new CAD/CAM system to realize such a machining. As the first step, in this paper, the post processor of the CAD/CAM system is formulated to machine 2-dimensional cross section's changing holes. The post pocessor outputs operating program of the device by inputting movement path of the electrode. The results obtained from the experiments show that the post processor can machine 2-dimensional, complicated cross section's changing holes by inputting electrode location data.

日本機械学会論文集(C編)


Elementary Study on the Creation of Cross Section's Changing Holes by Means of Electrical Discharge Machining

International Journal of Automation Technology (IJAT)


6-Axis Control Ultraprecision Microgrooving on Sculptured Surfaces with Non-Rotational Cutting Tool


五軸NURBS補間加工用CAMシステムの開発(一般化ポストプロセッサによるNCデータの生成)

NURBS (Non-Uniform Rational B-Spline) is well known to express free-form curves and surfaces in current CAD systems. Some NC controllers can accept NC data written in the NURBS interpolated format by using G 06.2 code, and NURBS interpolated machining enables us to decrease the amount of NC data, to eliminate the error due to the linear interpolation and so on. Although there are a few post-processors to generate NURBS interpolated NC data for simultaneous 5-axis controlled machining, most of them transform linear interpolated NC data into NURBS interpolated ones by the least square method and so on. Therefore, if the linear. interpolated NC data is huge, the conventional post-processor may require a long calculation time to generate NURBS interpolated ones. In addition, the post-processor lacks general versatility because it copes with a specific machining center. To solve these problems, the study deals with developing a generalized post-processor which can generate NC data without the linear approximation, while considering the axis composition of various machining centers. As the result, it is found that the developed post-processor efficiently generates practical 5-axis NURBS interpolated NC data.

日本機械学会論文集(C編)


Study on Precision Machining of Glass Lens Mold with Minute Structures : Precision Machining of Glass Lens Mold with Fresnel Shape Applying Complex Machining Process

微細構造を有するガラスレンズ成形型の高精度加工に関する研究 -複合加工手法によるフレネル形状ガラスレンズ金型の高精度加工-

In optical devices, the demand of glass lenses with complicated shapes like Fresnel shape is recently growing up for the purpose of improving its heat resistance and optical performances. The study suggests a new machining process for cemented tungsten carbide mold with Fresnel shape, aiming at high precision machining. In the proposed process, the curved surfaces except for sharp edges are at first machined by the conventional grinding method with a disk type metal bonded diamond wheel. Then, sharp edges are created on curved surfaces by fly cutting method with knife edged single crystal diamond tool. Fly cutting method is expected to reduce tool wear due to the intermittent machining process. From fundamental V-microgrooving experiments of WC by fly cutting and shaping, it is clarified that the damage of cutting tool by fly cutting is reduced, compared to shaping. Therefore, complex machining of Fresnel shape by proposed machining method allows sharp edges to create to WC mold. As a result, it is found that the proposed machining method has the potential of producing a high precision glass lens mold with Fresnel shape effectively.


Development of an Electrode Motion Control Device for Curved Hole Electrical Discharge Machining


Creation of U-shaped and Skewed Holes by Means of Electrical Discharge Machining Using an Improved Electrode Curved Motion Generator


五軸NURBS補間加工用CAMシステムの開発(非干渉空間を利用した工具経路の生成)

Nowadays, it is essential to shorten the production time and to make high quality products at low costs since consumer-needs are becoming diversified. To meet this high requirement, it is expected that 5-axis NURBS (Non-Uniform Rational B-Spline) interpolated machining be put into practical use. 5-axis NURBS interpolated NC data are generally defined by transforming linear interpolated NC data into NURBS interpolated ones. Therefore, the approximation error is consequently included in calculated tool paths due to the use of the linear interpolated data. On the other hand, the mainprocessors have been developed, which can generate NURBS interpolated CL data directly from CAD modeling data. It is very useful, however there is a problem of taking a long calculation time to generate CL data since the interference avoidance is considered for each tool path. Therefore, the study develops an useful CAM system, which can automatically generate practical 5-axis NURBS interpolated NC data, utilizing the interference-free space. As a result, the effectiveness of the proposed method is demonstrated from the feasibility experiments.

Transactions of The Japan Society of Mechanical Engineers, Series C

日本機械学会論文集(C編)


A Framework of Compositional Machining Simulation for Versatile Machining Simulation

This paper presents a framework of a compositional machining simulation. Because the machining process involves complex physical phenomena, various fragmented process simulations, such as cutting force, thermal behavior, vibration, and so on, have been investigated. The authors have proposed a concept of the compositional machining simulation which enables a versatile machining simulation. The concept is based on the building block type construction of the various machining process simulators. An association framework and systematic description of fragmental process models are explained. As an example of the framework, fragmented simulations of endmilling process are organized as a multi-aspect simulation.

Journal of Advanced Mechanical Design, Systems, and Manufacturing


5軸制御超精密フライス加工による3次元微小彫像の創成

5軸制御超精密フライス加工による3次元微小彫像の創成

The study deals with 5-axis control micromilling of such a complicated small shape as a human head by use of a diamond pseudo ball end mill. In the fields of micromachining, the milling with diamond cutting tools plays an important role due to the capability of creating 3-D complicated shapes with high accuracy. A wide variety of microstructures have been created with ultraprecision machining centers. Nevertheless, these structures seem to consist of a simple shape. Thus, the study proposes a CAM system for 5-axis control ultraprecision machining to create complicated microparts. 5-axis control micromachining of a BOSATSU was conducted to verify the practical effectiveness of the developed system. Based on the 3-D restored data of BOSATSU, the system can create the complicated statue, taking account of the collision between a tool and a workpiece. From the experimental result, it is found that the CAM system for 5-axis control ultraprecision machining has the potential of accurately producing 3-D small complicated shapes.

Journal of the Japan Society for Precision Engineering


超精密5軸制御加工におけるセッティング誤差の一般化補正法

超精密5軸制御加工におけるセッティング誤差の一般化補正法

The study deals with developing a new method to compensate the initial position error of diamond cutting tool in ultraprecision micromachining by use of a 5-axis control ultraprecision machining center. In the ultraprecision machining, various kinds of errors have large influence on the machining accuracy although they are very small. In recent years, the demand is increasing to fabricate complicated microparts accurately and efficiently by means of multi-axis control ultraprecision machining center. However, the accumulation of various kinds of errors due to the increasing number of motion axes and the setting difficulty of small diamond tools deteriorate the form accuracy of machined microparts. To solve these problems, the study proposes a new method to precisely measure the tool radius and to correctly set the tool, and develops the initial tool setting error compensation system. From experimental results, it is found that the method proposed in the study is effective.


6軸制御両端止りマイクロ溝加工

6軸制御両端止りマイクロ溝加工

In recent years, attention is paid to diffractive optics which have surface appearance like diffraction grating or Fresnel lens. A variety of machining methods are requested to effectively produce metal mold of diffractive optics, consisting of a number of microgrooves with various shapes. One of them is flat-end microgrooves. Flat-end microgrooves mean microgrooves having no slope at the end. The existence of the slope limits the design of microgrooves and causes unnecessary diffraction lights and losses. Thus, the slope is requested to remove. The study deals with the creation of V-shaped microgrooves with two flat-ends by using 6-axis controll non-rotational cutting tools, that is, curved microgrooves with two flat-ends are created on a curved surface. The proposed method shows the effectiveness to create flat-end curved microgrooves on curved surfaces as well as the method of cutting edge detection to set a cutting edge symply and accurately.


多軸制御加工のための効率的荒加工用工具経路生成の研究

多軸制御加工のための効率的荒加工用工具経路生成の研究

In recent years, 3-axis control machining is generally performed in roughing process. However, 3-axis control machining is not efficient in case of roughing complicated shapes, i. e., parts with overhanging shape, because it requires to reset the workpiece. To solve this problem, 5-axis control machining has been developed. However, there has been no roughing procedure in 5-axis control machining. The study deals with roughing by 3+2-axis control machining, which performes 3 translational axis machining after determining a suitable tool axis vector by 2 rotational axis movement. For 3+2-axis control machining, the determination of tool axis vectors and tool diameters largely affects the rough machining time. The study proposes a method of determining the optimal tool axis vectors and selecting the tool diameters for efficient roughing. At first, the method searches candidate of tool axis vectors after calculating machinable area in each tool axis vector, applying the multi-stage decision process. Then, the method determines the combination of tool axis vectors and tool diameters, using a peformance index. The effectiveness of the proposed method was demonstrated by the machining experiment of an impeller.

日本機械学会論文集(C編)


5-Axis Control Tool Path Generation Using Curved Surface Interpolation

JSME International Journal, Series C: Mechanical Systems,Machine Elements and Manufacturing


非一様Bスプライン表現による五軸制御加工用曲線補間CLデータ生成

非一様Bスプライン表現による五軸制御加工用曲線補間CLデータ生成

Most of CAD systems can treat free form curves and surfaces in the mathematical formula called NURBS (Non Uniform Rational B Spline). Some NC controllers can handle NC data written in NURBS interpolated formula by using G 06.2 code. The use of NURBS expression enables us to decrease the amount of NC data, to eliminate the error due to the linear interpolation and to get rid of rapid acceleration and deceleration. However, little CAM systems can create NURBS interpolated NC data for 5 axis controlled machine tools. Therefore, the paper deals with the development of the main processor of CAM system, which creates CL data expressed by six dimensional Non Uniform B-Spline curve. The main processor can generate the CL data directly from CAD modeling data, while considering the interference between a ball end mill and a workpiece and keeping the designated tool posture as long as possible so that the machined surfaces can be smooth.

日本機械学会論文集(C編)


Thermal State Visualization of Machining Workpiece by Means of a Sensor-Configured Heat Conduction Simulation

This paper deals with an adaptive visualization method of the thermal state in machining operation. The visualization is expected to enhance the recognition ability of operators. First, a framework of thermal state visualization is proposed. Then, a sensor-configured heat conduction simulation is proposed as an estimation method of thermal states of the machining workpiece. The method is based on the association of sensed data with the process simulation. As an implementation of the proposed estimation method, a prototype system is developed. After illustrating the configuration of the prototype system, results of a simple example are shown. The results indicate the effectiveness of the adaptive estimation. The influence of measurement points are also evaluated based on the case study. Finally, conclusions and future works are presented.


非回転工具を用いた自由曲面上への6軸制御超精密マイクロ溝加工

非回転工具を用いた自由曲面上への6軸制御超精密マイクロ溝加工

In optical electronics systems, particular optical devices such as mirrors, lenses, diffraction grating, etc. play respective roles. Therefore, many optical devices are combined to consist of a optical system. This causes the problem that the arrangement error of these devices influences the total accuracy of optical system. In addition, new optical devices with multi-function, e.g. diffraction and focusing, have been recently required to miniaturize optical systems and to decrease cost. However, their shape is generally very complicated. Typical example is such a shape as curved microgrooves on a 3-dimensional complex surface. To machine the shape, milling or turning by use of a rotational cutting tool is not suitable for tool interference. In the study, a nonrotational cutting tool is thus employed. In case of machining microgrooves on sculptured surface with a non-rotational cutting tool, 6-axis control is necessary to control tool attitude and tool direction. The study deals with the development of CAM system for 6-axis control ultraprecision grooving. From the experiments of creating microgrooves on a spherical surface and a sculptured surface, it is found that microgrooving on their surfaces is possible by 6-axis control.

Journal of the Japan Society for Precision Engineering, Contributed Papers


Tool Posture Determination for 5-axis Control Machining by Area Division Method

The study deals with a new method to generate interference-free tool posture for 5-axis control machining using a ball end-mill. The 5-axis control machining can produce complicated shapes and parts consisting of overhanging and or sculptured surfaces such as impellers. However, high degree of freedom of 5-axis control machining center causes a fatal problem that other parts except cutting edges of the tool may interfere with other surfaces of the machining object. Therefore, it is necessary to obtain the adequate tool postures to avoid the interference during machining. The interference avoidance is generally performed by the method that cutting points are generated so as to be arranged on the surface to be machined, and then the interference-free tool posture is determined on each cutting point by the geometrical calculations. However, the method has a problem that it takes long time for calculation. To solve the problem, the study proposes a new interference avoidance method of reversing the order of the above procedure, i. e., that of determining a set of interference-free tool postures before generating cutting points. From the machining results, it is confirmed that the proposed method is available to fabricate complicated shapes since the impeller can be machined by using the method.


曲面形状補間を用いた五軸制御加工用工具経路生成法

曲面形状補間を用いた五軸制御加工用工具経路生成法

In 5-axis control machining, it is important to reduce the processing time of generating interference-free tool path between tool and workpiece. Thus, the paper describes a method to determine interference-free tool postures, based on not every cutting point but every tool path. The method generates a ruled surface between an offset curve which sifts a cutting point curve by a tool radius against a surface to be machined, and one of parametric curves on an interference surface. A boundary tool locus which does not interfere with workpiece is generated by rotating the ruled surface, while moving control points on the surface. Tool postures corresponding to a cutting point curve are determined by appropriately selecting the curve within an area surrounded by two ruled surfaces. The curve implies a candidate of interference-free tool paths can be generated at high speed. The effectiveness of the proposed method was demonstrated by machining experiment of an impeller.

Transactions of The Japan Society of Mechanical Engineers, Series C

日本機械学会論文集(C編)


電極運動制御装置を用いた一定曲率曲がり穴放電加工

電極運動制御装置を用いた一定曲率曲がり穴放電加工

The study deals with the development of a new method to machine the curved holes with a constant curvature by means of the apparatus developed by the authors. It is strongly required to machine curved holes for the fabrication of water channels built in a mold. This is due to the achievement of their efficient arrangement, which can improve the productivity in molding by shortening the solidifying time in a molding cycle. However, the efficient arrangement cannot be realized since water channels are generally made by drilling, which causes their shape to be polygonal line. To meet the requirement, the authors developed the device which can fabricate curved holes by means of electrical discharge machining. Though the device is capable of machining various-shaped curved holes, the target shapes were not obtained since the control method and the utilized software were simple. In the study, therefore, a new method employing a vision sensor and its processing software are developed to control the device so skillfully that the curved holes with a constant curvature can be machined. From the experimental results, it is found that the developed control method has ability of accurately fabricating constant curvature curved holes.

ソフトウェアによって電極運動軌跡を制御できる装置を開発し, 加工可能な曲がり穴の形状自由度を向上させたが, 装置の基礎的性能を確認するため, 複雑な処理が必要ない単純な制御による形状的特徴のない曲がり穴の加工にとどまっていた. そこで本研究では, 画像処理センサによる電極運動軌跡の教示およびその再生による加工方式を開発し, これを用いて, 一定の曲率をもつ曲がり穴の加工に成功した.


Creation of Curved Holes with Various Curvatures by Means of Electrical Discharge Machining and Slider Crank Chains


管内走行機構を用いた放電加工による曲がり穴の延長

管内走行機構を用いた放電加工による曲がり穴の延長

The study deals with the development of an in-pipe movable device to extend the length of a curved hole machined by means of the method proposed by the authors. To establish a curved hole machining method, authors have developed the device installed on an electrical discharge machine, which can make an electrode move along a curved trajectory with electrical discharge machining performed. This results in the fabrication of curve holes. However, the length of the curved holes is limited. Thus, the in-pipe movable device is developed to overcome the limitation. The device has a flexible body whose head is equipped with a spherical electrode and whose circumference is furnished with tiny bearings through leaf springs. It can run through a curved hole and make it longer by machining the bottom of the curved hole. From the experimental results, it is found that the device can perform a stable electrical discharge machining and extend the curved hole length.

曲がり穴加工装置を開発してきたが, 原理的に加工できる曲がり穴の距離は限定されていた. そこで, 従来の装置に管内走行機構を導入した高自由度・長距離曲がり穴加工システムを構想した. 本稿では, このシステムに不可欠な管内走行機構を開発し, これを用いて, あらかじめ形成された曲がり穴を延長加工した. その結果, 従来では加工不可能な長い距離を持つ曲がり穴を創成することができた.


曲がり穴放電加工用電極運動制御装置の開発

曲がり穴放電加工用電極運動制御装置の開発

This study deals with the development of a new curved hole machining device which is improved to highly control the curved hole shape. Holes are generally machined with a drill. Accordingly, their shapes are straight. As a result, mechanical design engineers must apply straight holes to products, even when a straight hole is not optimal shape in designing a product. The problem occurs in the design of water channels built in molds and of pipe lines used in pneumatic or hydraulic equipments since it is impossible for drills to make suitable curved holes. To solve the problem, it is required to establish a curve hole machining method. Therefore, the authors have developed and improved new devices to create a curved hole. However, the latest device is not necessarily equipped with high controllability of the curved hole shape since the shape control depends on a troublesome setting of the device's hardware. Thus, the device is improved by introducing servomotors and a personal computer so that it can be software controlled. From experimental results, it is found that the improved device has much higher controllability of the curved hole shape.

スライダクランク連鎖を用いた装置を放電加工機に搭載することにより様々な曲率の曲がり穴を加工できたが, 曲率の制御はハードウェアの設定に依存し, その自由度は事実上低かった. そこで, 従来装置にサーボモータを導入し, 曲がり穴形状をソフトウェアで制御する装置を開発した. 実験の結果, 本装置により従来装置では加工不可能な曲がり穴をソフトウェアの設定どおりに放電加工することができた.


Automation of Polishing Process by Industrial Robots : Polishing Path Generation in Consideration of Surface Curvature

産業用ロボットによる研磨作業の自動化 -曲面の曲率を考慮した経路生成-

The study deals with the automation of polishing process for free-form surfaces by means of an industrial robot. In general, the polishing process has been performed by handwork of skilled workers. Since the polishing environment is extremely inferior and the polishing process is time-consuming and tedious work, the automation of polishing process is strongly desired and the robot systems have been introduced recently. However, the polishing by robots has not necessarily been performed in success. In the study, the polishing path generation is devised to improve the surface quality of workpieces. Thus, the relationship between the surface curvature of workpiece and the contact length of polishing tool is investigated by polishing experiments, which results in the new polishing path generation method. The method is successfully applied to polish an impeller of food and osmetics agitators, which consists of free-form surfaces. As a result, it is found that the new polishing path generation method is effective for polishing automation by robots.


非回転工具を用いた超精密マイクロV溝加工

非回転工具を用いた超精密マイクロV溝加工

The study deals with the creation of ultraprecision microgrooves using non-rotational diamond cutting tools with angle of 90 degrees, which are mounted on an ultraprecision machining center. Machining experiments of micro grooves were conducted to find the optimal value of cutting speed, depth of cut, rake angle, changing the cutting speed from 1mm/min to 200mm/min, the depth of cut from 0.1m to 10m and the rake angle from -5 degrees to 30 degrees. Workpieces were machined with the cutting tool submerged in the cutting fluid to know the influence of cutting fluid supply method. From the experimental results, the adequate cutting condition is obtained such as the rake angle of 10 degrees to 20 degrees, the finish cutting speed of 1mm/min and the depth of cut in rough cut and finish cut of 1m and 0.5m respectively. As the cutting fluid supply method, workpiece submerged in the cutting fluid is effective. Using the cutting condition, fine V-shaped microgrooves are obtained in various materials. In addition, frontlight optical plate and micro Fresnel lens with the designed micro grooves were designed and manufactured by non-rotational diamond cutting method. As a result, it is also found that the non-rotational diamond cutting method enables to accurately and neatly manufacture microgrooves without any burr generation.


Creation of Long Curved Hole by Means of Electrical Discharge Machining Using an In-pipe Movable Mechanism

Journal of Materials Processing Technology


Creation of Ultraprecision V-shaped Micro Grooves with Flat-end

超精密マイクロV形止り溝の創成

The study deals with the creation of V-shaped microgrooves with flat-end. Microgrooves with flat-end play an important role in case of generating intermittent grooves. Microgrooves by use of a rotational V-shaped cutting tool have a long circular arc slope with a large radius when stopping on the way. Thus, a non-rotational V-shaped cutting tool is employed, however, a slope is still formed at the end point of the microgroove. In the study, two new cutting methods are devised so that the V-shaped microgrooves with flat-end can be created. The first method makes use of chip generation whose shape is straight under some cutting condition. The non-rotational cutting tool presses the chips generated perpendicularly against the V-shaped microgroove and cuts the excessive parts of chips over the plane. The second one is to stick the non-rotational V-shaped cutting tool perpendicular to the workpiece surface, to feed it backwards and to remove the swelled parts by feed it to the reverse direction. From experimental results, it is found that the methods enable the creation of flat-end microgrooves.


Development of Movable Drilling Robot inside a Pipeline

配管内面穿孔ロボットの開発

The study deals with the development of a drilling robot traveling inside a pipeline. Aiming at inexpensive anti-corrosion and repair of underground pipes, a new method was established and has been widely employed, in which the internal wall of the pipes is coated with some pieces of material or resin layers. However, the coating method has a disadvantage of closing the inlets of pipes connected to a coated pipe. Accordingly, the inlets must be opened again from the outside of the pipe by means of excavating works, which cause high cost and a lot of waste time, and so on. Thus, a movable drilling robot is developed to make ths inlets again without excavating works. It can move inside the pipe, search the closed inlets to the connected pipes, and drill holes in the closed inlets. The consists of a drilling module for machining holes in the closed inlets, a tool positioning module for searching drilled points, determining the tool position and checking the drilled holes, and a moving module traveling inside a pipe for carrying hte avobe-mentioned modules. From the demonstration experiments, it is found that the robot can move inside the coated pipeline, find the closed inlets, position a tool, machine holes and check the holes.

Journal of the Japan Society for Precision Engineering


往復スライダクランク機構を用いた穴内面フィン放電加工

往復スライダクランク機構を用いた穴内面フィン放電加工

The study deals with developing a new method to fabricate various shapes inside a hole. A hole shape is limited to straight one in the practical machining manner. However, it often happens that the best hole meeting the requirement is not straight but more complex shaped one. In the study, hence, a new device is developed, which can make complicated shapes inside a hole. The device consists of an electrode for electrical discharge machining and some mechanical parts, and is installed on an electrical discharge machine (EDM). The device and EDM move as a reciprocating block slider crank mechanism. Namely, a translational motion of the EDM head can be converted into a rotational motion of the tool electrode. This results in machining the shape similar to the electrode locus. Consequently, if the machining mechanism is applied inside a hole, a semicircular shape can be created inside the hole. Moreover, the use of the electrode with slits makes it possible to fabricate fins inside the hole. From experimental results, it is found that the device has the potential of fabricating the semicircular space and the fins inside a hole.


L-Shaped Curved Hole Creation by Means of Electrical Discharge Machining and an Electrode Curved Motion Generator

The International Journal of Advanced Manufacturing Technology


スライダクランク連鎖を用いた曲がり穴放電加工用電極送り機構の開発

スライダクランク連鎖を用いた曲がり穴放電加工用電極送り機構の開発

This study deals with developing a new method of machining curved holes with a variety of curvature. Mechanical engineers have taken it for granted that drilling is to machine a straight hole. Therefore, straight holes have been used even in unsuitable cases, for example, pipe lines used in pneumatic or hydraulic equipments and water channels built in molds. They cannot be machined in arbitrary shape and arrangement. This prevents the equipments from being minimized and deteriorates the productivity of molding. To solve these problems, it is strongly required that the curved hole machining method. Hence, to machine curved holes, we have developed a new device consisting of a helical compression spring, wires, and pulleys. However, the curvature of curved holes by the device was limited to a certain one. To overcome the functional problem, slider crank chains are introduced in the device. From experimental results, it is found that the improved device can machine curved holes with a various curvature.


曲がり穴放電加工用電極送り機構の開発 -L字形曲がり穴加工-

曲がり穴放電加工用電極送り機構の開発 -L字形曲がり穴加工-


圧縮コイルばねとワイヤを用いた曲がり穴放電加工用電極送り機構の開発

圧縮コイルばねとワイヤを用いた曲がり穴放電加工用電極送り機構の開発


自走式放電加工機構による曲がり穴加工 -電極間距離の自動制御機構-

自走式放電加工機構による曲がり穴加工 -電極間距離の自動制御機構-


Development and Application of Automatic Discharge Gap Controller

極間距離自動制御機構の開発と応用

東海職業能力開発大学校 紀要

東海職業能力開発大学校 紀要


Size Reduction and Performance Improvement of Automatic Discharge Gap Controller for Curved Hole Electrical Discharge Machining


Creation of Cross-Section Changing Hole with a Hemisphere by Means of Electrical Discharge Machining

Manufacturing Systems and Technologies for the New Frontier


Microchannel Array Creation by Means of Ultraprecision Machining

Mechatronics for Safety, Security and Dependability in a New Era


Development of Curved Hole Machining Method -Size Reduction of Hole Diameter-


U-shaped Curved Hole Creation by Means of Electrical Discharge Machining

Initiatives of Precision Engineering at the Beginning of a Millennium


Slanting-hole drilling of glass plate using an electroplated diamond tool

小径ダイヤモンド電着工具によるガラス板への高品位斜め穴加工

The utility of slanting-hole drilling using an electroplated diamond tool of small-diameter devised by the authors was investigated. As with straight-hole drilling, a normal drilling cycle could be adopted with slanting-hole drilling because the unique shape of the tool increases chip discharge. In addition, the drilled hole showed a small degree of chipping without using an underlay board and/or ultrasonic wave instrument. The chipping width was influenced by the behavior of the axial component of the grinding force before completion of the drilling process.

著者らが考案した小径ダイヤモンド電着工具を用いて，ガラス板への斜め穴加工を行い，本工具の斜め穴加工への有用性を調査した．直穴加工時と同様に，本工具の特長的な形状により，切りくず排出のためのステップ送りを採用しなくとも切りくずの排出は良好であり，通常の一方向送りのドリリングサイクルでの穴加工は可能であった．また，座ぐりや捨て座，超音波援用装置などを用いなくとも，工具の食付き側および抜け側に生じる欠けは小さかった．工具抜け側の欠け幅は加工終了間際の軸方向成分の挙動に左右した．

Journal of the Japan Society for Abrasive Technology