Details of a Researcher - Beaucamp, Anthony

Papers - Beaucamp, Anthony

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Virtual pivot alignment method and its influence to profile error in bonnet polishing

Junkang Guo, Anthony Beaucamp, Soichi Ibaraki

International Journal of Machine Tools and Manufacture (ELSEVIER SCI LTD) 122 18 - 31 2017.11

Accepted, ISSN 08906955

© 2017 Elsevier Ltd This paper proposes a measurement and adjustment procedure for virtual pivot errors using the R-test and investigates the influence of virtual pivot errors to the surface profile in bonnet polishing. Initially, kinematic modeling is carried out for describing the location errors of rotary axes and defining overall errors of the virtual pivot arm. Then, the R-test is introduced to measure the three-dimensional displacement of a sphere located at the virtual pivot point and identify location errors. The adjustment procedure for virtual pivot errors is developed by means of mathematical analysis. The measurement and adjustment approach is applied to an ultra-precision polishing machine, on which an adjustment experiment was conducted to validate the proposed method. Based on this, a contrastive polishing experiment on a concave lens is carried out under good and poor virtual pivot errors. The experiment result shows that the maximum form deviation of the polished surface profile is reduced from 241.0 nm to 89.6 nm when good alignment of virtual error is achieved. Analytical simulation based on a material removal model of the bonnet polishing tool and machine is implemented to reveal the influence of virtual pivot errors to polishing quality.

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Comparison of tool feed influence in CNC polishing between a novel Circular-random path and other pseudo-random paths

Ken Takizawa, Anthony Beaucamp

Optics Express (OPTICAL SOC AMER) 25 ( 19 ) 22411 - 22424 2017.09

Accepted, ISSN 1094-4087

© 2017 Optical Society of America. A new category of circular pseudo-random paths is proposed in order to suppress repetitive patterns and improve surface waviness on ultra-precision polished surfaces. Random paths in prior research had many corners, therefore deceleration of the polishing tool affected the surface waviness. The new random path can suppress velocity changes of the polishing tool and thus restrict degradation of the surface waviness, making it suitable for applications with stringent mid-spatial-frequency requirements such as photomask blanks for EUV lithography.

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Modelling the brittle/ductile transition in super-fine finishing of carbides

Anthony Beaucamp

APPLIED MECHANICS & MATERIALS 869 20 - 28 2017.08

Accepted

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Brittle-ductile transition in shape adaptive grinding (SAG) of SiC aspheric optics

Anthony Beaucamp, Peter Simon, Phillip Charlton, Christopher King, Atsushi Matsubara, Konrad Wegener

International Journal of Machine Tools and Manufacture (ELSEVIER SCI LTD) 115 29 - 37 2017.04

Accepted, ISSN 08906955

© 2016 Elsevier Ltd Silicon carbide is a ceramic material with a desirable combination of high thermal and mechanical stability, making it ideal for optical application in aerospace and next generation lithography. It is however notoriously difficult to machine down to super-fine finish when the shape is other than flat or spherical. In this paper, we describe the application of a “semi-elastic” machining method called shape adaptive grinding (SAG), in which an elastic tool is combined with rigid pellets made of nickel or resin, to which super abrasives are bonded. A comprehensive model of the physical interaction between SAG tool and workpiece is proposed, and used to understand the mechanics driving brittle-ductile transition on ceramic materials such as SiC. Machining parameters adequate for optical finishing are then derived from the model and demonstrated on an aspheric silicon carbide workpiece, which was manufactured by reaction bonding and coated with a layer of pure SiC by chemical vapour deposition (CVD). Through SAG processing and final polishing, this aspheric mirror was improved from an initial form error of 40 µm down to 112 nm Peak-to-Valley, with no residual damage visible on the surface.

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Development of drill property prediction system based on drill shape

KAWAI Kimio, BEAUCAMP Anthony, IMAIZUMI Noriyuki, SAKURAI Masatoshi, TAKEUCHI Yoshimi

Transactions of the JSME (in Japanese) (The Japan Society of Mechanical Engineers) 83 ( 855 ) 17 - 00162 2017.01

Accepted, ISSN 2187-9761

<p>In recent years, the drill used to make holes is expected to exert both high machining accuracy and good processing capability. In order to meet those requirements, it is necessary to develop a new drill shape with good properties requested by designers. There is a strong need for a new system to shorten the drill fabrication time, to reduce material costs, and to create new drill configurations by predicting their characteristics. Current drill shape prediction systems cannot comprehensively and mathematically treat drill cross-section shape including the cutting edge, groove and so on. The prediction system would become more practical if the drill specification was mathematically formulated. This study reports the development of a system to predict not only the cross-sectional shape but also various parameters from the information of grinding wheels used in drill fabrication. Furthermore, this study proposes the new system to predict the most suitable grinding wheel setting from the grinding wheel shape and some drill specifications as the reverse process.</p>

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5-Axis Control Finishing for Decreased Tool Wear

Soushi Uchikata, Anthony Beaucamp, Yoshimi Takeuchi

Procedia CIRP (ELSEVIER SCIENCE BV) 63 313 - 317 2017

Accepted, ISSN 22128271

© 2017 The Authors. Published by Elsevier. With increasing global competition, reduction in the machining cost is the most important issue after machining quality. The machining cost consists of various factors. Among them, the cost of cutting tool holds the first place. The reduction or suppression of tool cost results in an increase in competitive force. This study aims at lengthening the tool life, while decreasing the tool wear. Therefore, the cutting edge of a ball end mill is swung around its center by continuously changing the tool axis vector so that the cutting edge may be uniformly used. Taking account of the width of the flank wear of the ball end mill and the surface roughness of the workpiece in the finishing process, the study proposes an appropriate tool attitude and a suitable tool swing rate of the ball end mill. As a result, the machining method with the tool axis vector continuously swung allows for decreasing tool wear due to its dispersion across the entire tool surface. The proposed method can be applied to machining of workpieces with sculptured faces. From the experimental results, it is found that the proposed idea has the potential of saving tool cost.

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More steps towards process automation for optical fabrication

David Walker, Guoyu Yu, Anthony Beaucamp, Matt Bibby, Hongyu Li, Lee McCluskey, Sanja Petrovic, Christina Reynolds

Proceedings of SPIE - The International Society for Optical Engineering 10326 2017

Accepted, ISSN 0277786X

© 2017 SPIE. In the context of Industrie 4.0, we have previously described the roles of robots in optical processing, and their complementarity with classical CNC machines, providing both processing and automation functions. After having demonstrated robotic moving of parts between a CNC polisher and metrology station, and auto-fringe-Acquisition, we have moved on to automate the wash-down operation. This is part of a wider strategy we describe in this paper, leading towards automating the decision-making operations required before and throughout an optical manufacturing cycle.

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Dexterous Machining of Unstable Thin Plate

Yuya Kida, Kohei Toyoda, Anthony Beaucamp, Yoshimi Takeuchi

Procedia CIRP (ELSEVIER SCIENCE BV) 63 324 - 329 2017

Accepted, ISSN 22128271

© 2017 The Authors. Published by Elsevier. In recent years, miniaturization and light weightedness are required for industrial products as well as high functionality. Thin plates are appropriate in terms of weight, however they are usually difficult to produce only by cutting operation due to the deformation by cutting force or vibration of the thin plate. This study deals with the machining of a twisted thin plate, whose height, width and thickness are 50 mm, 30 mm and 0.1 mm respectively, without using any auxiliary tool. Such a thin plate with high aspect ratio is easily broken down by the cutting force. Thus, the machining of thin plate with high aspect ratio is approached by devising a tool path strategy in this study. As the cutting force easily allows for deformation of twisted thin plate with high aspect ratio, two methods are devised with regard to the generation of the tool path, the method with a supporting frame and the peeling method so that the stiffness of the plate can be kept high. Then, the actual machining of thin plate with high aspect ratio, made of aluminum alloy, was realized without any breakage. As a result, it is found that such cutting method allows the possibility of fabricating such a twisted thin plate.

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Development of drill property prediction system based on drill shape

BEAUCAMP, Anthony Tadeus Herve

Transactions of the JSME (The Japan Society of Mechanical Engineers) 83 ( 855 ) 17-00162 - 00162-17-00162 2017

Accepted

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A novel ultrasonic cavitation assisted fluid jet polishing system

Anthony Beaucamp, Tomoya Katsuura, Zensaku Kawara

CIRP Annals - Manufacturing Technology (ELSEVIER SCIENCE BV) 66 ( 1 ) 301 - 304 2017

Accepted, ISSN 00078506

© 2017 Fluid jet polishing is a versatile process used for super-fine finishing of small and complex optical and prosthetic surfaces. Advantages of this process include highly controllable sub-millimetre polishing footprints and absence of tool wear, though the main drawback is very low material removal rate. To address this issue, a novel system was developed in which ultrasonic cavitation causes micro-bubble generation directly upstream of the nozzle outlet. Experimental data shows that these micro-bubbles boost removal rate by up-to 380%, without causing any degradation of the surface finish. This paper reports on the modelling, implementation, and testing of this new polishing system.

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超音波キャビテーションを利用した高速流体噴射研磨

勝浦知也, Anthony Beaucamp, 松原厚

精密工学会学術講演会講演論文集 (公益社団法人精密工学会) 2016 117 - 118 2016.01

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円弧ランダムパスを用いたCNC研磨による研削模様の除去

瀧沢賢, Anthony Beaucamp, 松原厚

精密工学会学術講演会講演論文集 (公益社団法人精密工学会) 2016 615 - 616 2016.01

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Brittle-ductile transition in shape adaptive grinding (SAG)

Peter Simon, Anthony Beaucamp, Phillip Charlton, Yoshiharu Namba

Optics InfoBase Conference Papers FW5G ( 2 ) 2016

Accepted

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Dexterous creation of soccer-ball pattern by using urethane rubber

Kosuke Funatani, Keiichi Nakamoto, Anthony Beaucamp, Yoshimi Takeuchi

International Journal of Automation Technology (Fuji Technology Press) 10 ( 2 ) 239 - 243 2016

Accepted, ISSN 18817629

© 2016, Fuji Technology Press. All rights reserved. It is important to establish new approaches to create value-added products, such as craftwork or artistic goods, that are different from traditional methods of realizing high-quality and low-cost products. Such a production technology is commonly called “dexterous machining.” This study addresses the creation of artistic products by using soft materials with complicated shapes by employing an aqueous solution of sodium acetate to fix a workpiece and to suppress the deformation. Experimental results show that the use of an aqueous solution of sodium acetate has the potential to realize the “dexterous machining” of soft objects.

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Modelling of drill shapes by a novel predictive system

Kimio Kawai, Anthony Beaucamp, Noriyuki Imaizumi, Masatoshi Sakurai, Yoshimi Takeuchi

Proceedings of the 8th International Conference on Leading Edge Manufacturing in 21st Century, LEM 2015 2015.10

Accepted

There is a strong need for a new system to shorten the drill fabrication time, to reduce material costs, and to create new drill configurations by predicting their characteristics. Current drill shape prediction systems cannot comprehensively treat drill cross-section shape including the cutting edge, groove and so on, mathematically. Modelling would become more practical if the drill specification was mathematically formulated. This study reports the development of a system to predict not only cross-section shape but also various parameters from grinding wheels used in drill fabrication.

Shape Adaptive Grinding (SAG): A new process for finishing of ceramics and high-performance alloys

Anthony Beaucamp, Atsushi Matsubara, Samyak Jain, Christophe Bouvier, Roger Morton

Proceedings of the 8th International Conference on Leading Edge Manufacturing in 21st Century, LEM 2015 2015.10

Accepted

Shape Adaptive Grinding (SAG) is a new process for freeform finishing of difficult materials such as ceramics and high-performance alloys. The basic principle of SAG can be described as "semi-elasticity": compliance is achieved with freeform workpieces by an elastic spherical tool, while hard contact is simultaneously achieved by small rigid pellets covering this elastic tool (diamond or cubic boron nitride super-abrasives are embedded in these pellets). In this paper, we present recent developments in the application of SAG to (1) corrective grinding of aspheric silicon carbide optics, and (2) smoothing of high-performance titanium alloy components produced by additive manufacturing.

Finishing of additively manufactured titanium alloy by shape adaptive grinding (SAG)

Anthony T. Beaucamp, Yoshiharu Namba, Phillip Charlton, Samyak Jain, Arthur A. Graziano

Surface Topography: Metrology and Properties (IOP PUBLISHING LTD) 3 ( 2 ) 024001 2015.04

Accepted, ISSN 2051-672X

© 2015 IOP Publishing Ltd. In recent years, rapid prototyping of titanium alloy components for medical and aeronautics application has become viable thanks to advances in technologies such as electron beam melting (EBM) and selective laser sintering (SLS). However, for many applications the high surface roughness generated by additive manufacturing techniques demands a post-finishing operation to improve the surface quality prior to usage. In this paper, the novel shape adaptive grinding process has been applied to finishing titanium alloy (Ti6Al4V) additively manufactured by EBM and SLS. It is shown that the micro-structured surface layer resulting from the melting process can be removed, and the surface can then be smoothed down to less than 10 nmRa (starting from 4-5 μmRa) using only three different diamond grit sizes. This paper also demonstrates application of the technology to freeform shapes, and documents the dimensional accuracy of finished artifacts.

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277 Development of system for new drill creation

KAWAI Kimio, BEAUCAMP Anthony, IMAIZUMI Noriyuki, SAKURAI Masatoshi, TAKEUCHI Yoshimi

東海支部総会講演会講演論文集 (The Japan Society of Mechanical Engineers) 2015 ( 64 ) 277 - 1 2015.01

Accepted

Process mechanism in shape adaptive grinding (SAG)

Anthony Beaucamp, Yoshiharu Namba, Phillip Charlton

CIRP Annals - Manufacturing Technology (ELSEVIER SCIENCE BV) 64 ( 1 ) 305 - 308 2015

Accepted, ISSN 00078506

© 2015 CIRP. Shape adaptive grinding (SAG) is a novel process for freeform machining of difficult materials such as ceramics and hard metals. Despite low stiffness requirement from the machining equipment, due to the "semi-elasticity" of the process (achieved by a combination of elastic tool with rigid pellets), ductile mode grinding can be achieved with high surface finish. In this paper, the SAG process mechanism is investigated by studying how the size and shape of the pellet bonded abrasives evolve over time, measuring grinding forces for various process parameters, and comparing the equivalent chip thickness and specific energy with the observed grinding modes.

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Dynamometric Analysis of Shape Adaptive Grinding (SAG)

Beaucamp Anthony, Namba Yoshiharu, Charlton Phillip

Proceedings of JSPE Semestrial Meeting (The Japan Society for Precision Engineering) 2015 983 - 984 2015

The novel Shape Adaptive Grinding (SAG) process, which uses diamond abrasives bonded in nickel or resin pellets attached to an elastic tool, has been previously demonstrated in finishing freeform ceramic molding dies with surface roughness below 1 nm Ra. In this paper, a dynamometer was used to characterize grinding forces and the results show that contrary to conventional grinding, in SAG the grinding force increases proportionally to the diamond grit size. The chip thickness was derived statistically, and the grinding mechanism was correlated with previous observations of the ductile to fracture grinding mode transition.

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