Proceedings of
The Thirty-Eighth International
MATADOR
Conference
held at
National Formosa University,
Huwei, Taiwan
28th
– 30th
March 2015
The University of Manchester
School of Mechanical, Aerospace and Civil Engineering
ii Contents
Organising Committee Professor Lin Li
Professor Wenyuh Jywe Professor Srichand Hinduja
Professor Paulo Bartolo Professor Chun-Jen Chen
Professor Kuang-Chao Fan Professor Ming-Piao Tsai
Professor Wen-Hsiang Hsieh Professor Soek-Hee Lee
Professor Paul Mativenga Professor Jing-Chung Shen
Professor Mike Smith Dr Carl Diver
Dr John Francis Dr Christian Griffiths Dr Robert Heinemann Dr Mohammad Sheikh Dr Andrew Weightman
Contents iii
INTERNATIONAL SCIENTIFIC COMMITTEE Professor J C Aurich, University of Kaiserslautern, Germany Professor D Biermann, Technical University of Dortmund, Germany Professor M Brandt, RMIT University, Australia Professor K Cheng, Brunel University, UK Professor T H C Childs, University of Leeds, UK Professor P Conway, Cranfield University, UK Dr K Cooke, Teer Coatings Ltd, UK Professor B Denkena, Leibniz University Hannover, Germany Professor J R Duflou, Katholieke University Leuven, Belgium Professor F Z Fang, Tianjin University, China Professor D K Harrison, Glasgow Caledonian University, UK Professor B Hon, University of Liverpool, UK Professor X Q Jiang, University of Huddersfield, UK Dr I Kelbassa, Fraunhofer ILT, Germany Professor F Klocke, RWTH Aachen, Germany Professor J P Kruth, Katholieke University Leuven, Belgium Professor M Kunieda, University of Tokyo, Japan Professor A Labib, University of Portsmouth, UK Professor J Lawrence, University of Lincoln, UK Professor Y F Lu, University of Nebraska Lincoln, USA Professor P Maropoulos, University of Bath, UK Professor J Mazumder, University of Michigan, USA Professor J A McGeough, University of Edinburgh, UK Professor A Y C Nee, National University of Singapore Professor R Neugebauer, Fraunhofer IWU, Germany Professor D Pham, Cardiff University, UK Professor R Roy, Cranfield University, UK Dr T S Sudarshan, Materials Modification Inc., USA Professor F J A M Van Houten, University of Twentee, Netherlands Professor F Vollertsen, BIAS GmbH, Germany Professor K Watkins, University of Liverpool, UK Dr H Y Zheng, SIMTech, Singapore Professor M L Zhong, Tsinghua University, China
Foreword
It gives us pleasure to introduce the Proceedings for the 38thinternational MATADOR conference. The Proceedings include 83 refereed papers from several countries. A substantial number of papers are from China, Japan, India and Taiwan, which reflects the increasingly important role being played by the East Asian countries in manufacturing.
Since its inception in 1959, the MATADOR conferences have been held at various locations within the United Kingdom and overseas. The last conference was held at “home’ i.e. Manchester and this conference is being held at The National Formosa University in Taiwan. It is the second time that this conference is being held in Taiwan.
The MATADOR conferences in the 1960s dealt with metal working fundamentals in cutting, grinding and forming and the design of machine tools. Since those early days, new areas of research in manufacturing have emerged which therefore have become part of the conference’s scope as well. A substantial part of this conference is devoted to laser material processing, additive manufacturing, micro/nano fabrication and manipulation. Other areas that are addressed in this conference include metrology and measurement. The conference has continued to attract good quality papers from traditional areas such as machining, design and systems engineering, and innovative manufacturing and design.
We would like to express our gratitude to all the members of the Organising Committee and to those members of the International Scientific Committee who kindly refereed the papers. Our special thanks to Professor K C Fan whose efforts have made it possible for this conference to take place in Taiwan again. Our special thanks to: Ms Janet Adnams and her team for their assistance in organising this conference from Manchester; to Zhengyi Jiang for his assistance in formatting and preparing the Conference Proceedings; Prof. Wei Gao and So Ito for organizing JSPE Affiliation Sessions; Prof. JC Shen and his team for organising the Conference at Formosa University.
We hope you find the papers interesting and stimulating.
Professors Srichand Hinduja and Lin Li Professor Wenyuh Jywe Co-Chairmen Co-Chairman The University of Manchester, National FormosaUniversity, UK Huwei, Taiwan
28th – 30th March 2015
Contents
1 Additive Manufacturing
1–1 Stress distribution and crack propagation behaviour of solid Al2O3-ZrO2 (Y2O3) eutectics prepared by laser engineered net shaping D Wu, L Shi, G Ma, F Niu, Y Zhang, D Guo .................................................................................................................... 2
1-2 Heat dissipative effects on forming quality of filaments in FDM process W Cao, F He, Y Liang, K Wang, H Zhang, S Wang, B Yang ......................................................................................... 11
2 Design and System Engineering
2–1 Three-dimensional input system by pinching gestures for vehicle design K Hoshino, K Hamamatsu ............................................................................................................................................... 17
2–2 Enhanced process verification through manufacturing procedure re-engineering A Jamshidi, J cave, M Chappell, P Maropoulos .............................................................................................................. 23
3 ECM and EDM
3–1 Simulation of powder suspension in electro-discharge machining process using an immersed-boundary lattice Boltzmann method D V Patil, J Sun ............................................................................................................................................................... 20
4 Innovative Manufacturing and Design
4–1 Conformal resist coating technique for TSV manufacturing process by electrostatic spray S Kurokawa, T Hotokebuchi, Y Uchiyama, K Miyachi, Y Kobayashi, T Hayashi, K Matsuo ....................................... 37
4–2 A study on the physical mechanisms in electro-discharge machining process S S Charkraborty, G Mohata, S Ghosh, A K Nath .......................................................................................................... 43
5 Laser Processing
5–1 Carbon nanoparticle functionalisation of laser textured polymer surfaces for chemical and biological speciation R McCann, K Bagga, E McCarthy, A Al-Hamaoy, A Stalcup, M Vazquez, D Brabazon ............................................... 54
vi Contents
5–2 Large area nano-gratings fast fabricated by femtosecond laser on different metal surfaces H Song, S Liu .................................................................................................................................................................. 61
5–3 Experimental investigation and FE simulation of heat affected zone in water-jet assisted underwater laser cutting process of mild steel and titanium S S Chakraborty, Y K. Madhukar, S Mullick, A K Nath, S S Thatoi ............................................................................. 65
5–4 Advanced beam shaping for ultrafast laser micro-processing Oliver Allegre, J Ouyang, W perrie, Y Jin, S P Edwardson, G Dearden ......................................................................... 73
5–5 Controlled fracture of the soda-lime glass with a contact ball lens in Nd-YAG laser thermal cleavage H-H Yean, J Lin ............................................................................................................................................................... 79
5–6 High-rate laser processing of metals using high-average power ultrashort pulse lasers J Schille, L Schneider, L Hartwig, S Kloetzer, U Loeschner ........................................................................................... 88
5–7 Laser micro machining using photonic nanojets T Uenohara, Y Takaya, Masaki Michihata, ..................................................................................................................... 97
5–8 Deposition characteristics and microstructure of Ni60-Ni composite coating produced by supersonic laser deposition J Yao, L Yang, B Li, Q Zhang, Z Li .............................................................................................................................. 102
5–9 2D & 3D flexible laser system for precision cutting, welding and drilling applications M Naeem, A Montello ................................................................................................................................................... 109
5–10 Study on the effect of focal point location and incident angle of laser on the cut quality of thick stainless steel sheet by Yb-Fiber laser S Mullick, S Shrawgi, A Kangale, A Agarwal, A K Nath, ............................................................................................ 117
5–11 Microstructuring of stainless steel with controllable ablation depth by femtosecond laser pulses C W Cheng, X Z Tsai, J S Chen .................................................................................................................................... 127
5–12 Efficient Copper micro welding with fiber lasers using spatial power modulation A Haeusler, B Mehlmann, A Olowinsky, A Gillner, R Poprawe ................................................................................... 132
5–13 Improvement of laser weaving welding system by monitoring reflection return light I Ogura, T Kurita, K Ashida, ......................................................................................................................................... 139
5–14 Laser micro welding of copper on Lithium-ion battery cells for electrical connections in energy storage devices P Heinen, A Häusler, B Mehlmann, A Olowinsky ........................................................................................................ 144
5–15 Cavity pressure dependence on tensile-shear strength of metal-polymer direct joining F Kimura, S Kadoya, Y Kajihara ................................................................................................................................... 154
5–16 Residual stress relaxation of Ti-6Al-4V Titanium alloy based on the variation of damping properties introduced by warm laser peening J Zhou, W Zhu, X Meng, S Huang, J Sheng, J Lu ......................................................................................................... 159
5-17 Analysis of temperature distribution in brake disc with textured surface by laser peening process X Feng, J Z Zhou, J Sheng, S Huang, Y F Mei, W L Zhu ............................................................................................. 167
5–18 Wear behaviour of ZL109 Aluminium alloys textured by laser peening Y Mei, J Zhou, X Feng, S Huang, S Jie, D Mu, Y Zheng, J Lu ..................................................................................... 173
5–19 Research on warm microforming by laser-driven flyer H X Liu, J W Li, Q Zhang, Z B Shen, Q Qian, H F Zhang, X Wang ............................................................................ 178
Contents vii
5–20 Finite element simulation of residual stresses in Ti6Al4V Titanium induced by warm laser peening X K Meng, J Z Zhou, S huang, J Sheng, W L Zhu, Y H han, H S Chen, X feng, C Su ................................................. 188
6 Machine Tool Design and Applications
6–1 Development of machine tools design and operational properties J Jedrzejewski, W Kwasny............................................................................................................................................. 196
7 Machining
7–1 Using Taguchi robust design to ultrasonic vibration assisted turning AISI 1045 W Huang, D-H Wu, Y-S Chen ...................................................................................................................................... 213
7–2 Simulation and experimental study on material removal mechanism and removal characters of ultrasonic machining J Wang, K Shimada, M Mizutani and T Kuriyagawa .................................................................................................... 218
7–3 The effect of cutting speed and tool material on hole quality when reaming C355 Aluminium alloy R Rattanakit, S L Soo, D K Aspinwall, P Harden, B Haffner, Z Zhang, D Arnold ....................................................... 224
7–4 Performance of multi-margin coated tools in one-shot drilling of metallic-composite stack materials under varying feed rate and pecking conditions C-L Kuo, S L Soo, D K Aspinwall, W Thomas, C Carr, D Pearson, R M'Saoubi, W Leahy ...................................... 231
7–5 A basic investigation of micro-grooving on sapphire wafer with diamond tools H Kasuga, A Nemoto, N Itoh, M Mizutani, H Ohmori ................................................................................................. 239
7–6 A mapping-based analysis method for sculptured surface machining Z C Wei, M J Wang, D Y Zhao, X C Sun ...................................................................................................................... 244
7–7 Investigation of relation between straightness and cutting force in CNC turning process T Shansungnoen, S Tangjitsitcharoen ........................................................................................................................... 249
7–8 A study of surface generation in ultra-precision machining of precision Rollers with patterned microstructures C F Cheung, L B Kong, C H Mak, M J Ren, S J Wang ................................................................................................ 257
7–9 Reducing delamination in micro drilling of Carbon composite materials E Pliusys and P Mativenga............................................................................................................................................. 262
7–10 Investigation of different cutting conditions for CFRP routing with multi-tooth tool K-L Li, K-M Li, Y-Y Tsai ............................................................................................................................................. 272
7–11 A new technology to achieve precision machining for CNC machines using Artificial Neural Network G K Nithyanandam, M Franchetti, R Pezhinkattil, ........................................................................................................ 277
7–12 Study on machining-induced phase transformation and residual stress in single-crystal Silicon by Raman spectroscopy and molecular dynamics simulation F Xu, M Lai, Y J Wang, Y Q Zhu, C Chu ..................................................................................................................... 287
7-13 Investigation on position dependency of tool-workpiece compliance D Kono, P Roh, A Matsubara, ....................................................................................................................................... 293
viii Contents
7–14 Machinability of thermo-plastic CFRP by inclined planetary milling H Tanaka, Robert Voss, M Henerichs, , K Wegener ..................................................................................................... 298
7–15 Near-dry and MQL finish machining of mould inserts S Chan, X Xu, ................................................................................................................................................................ 304
7–16 Finite element analysis of machining heat treated titanium alloy Ti54M N Khanna, V Bajpai ....................................................................................................................................................... 312
7–17 Study of frequency correction in ultrasonic horn design Y Liang, J Wie, F He, D Chen, K Wang, H Zhang, L Shu ............................................................................................ 319
7–18 Influencing the process stability for tapping through and blind holes by taps with radial lubricant supply A Steininger, A Siller, F Bleicher .................................................................................................................................. 324
7–19 On deposition and characterisation of TiN-WS2 composite coating and its performance evaluation in dry turning of AISI 1060 steel T Banerjee, A K Chattopadhyay .................................................................................................................................... 331
7–20 Digital technology for splints manufacturing E M Meisel, P Daw, Xun Xu, R Patel ............................................................................................................................ 339
7–21 An implementation of analytical boundary simulation method on cutting force prediction model in five-axis milling G Kiswanto, H Hendriko, E Duc ................................................................................................................................... 347
8 Metrology and Measurement
8-1 A novel miniature laser diode interferometer for precision displacement measurements L-M Chen, K-C Fan, H Zhou ......................................................................................................... ……………………355
8-2 Concurrent measurement method of spindle radial, axial and angular motions using concentric circle grating and phase modulation interferometers M Aketagawa, M Madden, Y Maeda, E Okuyama ........................................................................ ……………………359
8-3 Design and testing of a contact-type micro thermal sensor for defect inspection on nanometric smooth surfaces Y Shimizu, Y Ohba, W Gao .......................................................................................................... ……………………365
8-4 Diameter measurement of micro-sphere based on analysis of two wavelength ranges of whispering gallery modes M Michihata, A Kawasaki, A Adachi, Y Takaya .......................................................................... ……………………369
8-5 Uncertainty of the measurement of radial runout, axial runout and coning using an industrial axi-symmetric measurement machine J Muelaner, A Francis, P Maropoulos ............................................................................................ ……………………376
8-6 The Framework of integrated inspection system based on MBD technology G J Duan, R Liu, X Q Tang ........................................................................................................... ……………………384
8-7 Key technologies for precision management and integrated control in large scale digital alignment F Du, J Jin, M Wang ...................................................................................................................... ……………………388
8-8 Investigation of surface damages in contact and form measurement with a force sensor-integrated fast tool servo Y D Cai, Y L Chen, S Ito, Y Shimizu, W Gao............................................................................... ……………………398
Contents ix
8-9 Removing the effects of linear axis errors from rotary axis ballbar tests J Flynn, A Shokrani, V Dhokia, S Newman .................................................................................. ……………………403
8-10 Tool holder sensor design to measure the cutting forces in CNC turning for optimization of the process D Reyes Uquillas, S-S Yeh ............................................................................................................ ……………………412
8-11 Identification of stable spindle rotation in milling with disturbance observer R Koike, Y Kakinuma, T Aoyama, K Ohnishi .............................................................................. ……………………419
8-12 A scanning electrostatic force microscope for the measurement of material distribution in non-contact condition S Ito, K Hosobuchi, J Zhigang, W Gao .......................................................................................... ……………………426
8-13 Development of an error-evaluation system based on a laser interferometer for linear encoders Y Hori, S Gonda, Y Bitou, A Watanabe, K Nakamura, S Makinouchi ............................................................. ………431
8-14 Development of Orthros, a thickness evaluation system for free curved plate-basic performance based on the measurement principle Y Okugawa, N Asakawa, M Okada ............................................................................................... ……………………435
8-15 Homodyne interferometer using iodine frequency stabilized laser diode T T Vu, Y Maeda, M Aketagawa ................................................................................................... ……………………441
8-16 Comparison of accuracy verification method for X-ray CT K Matsuzaki, O Sato, H Fujimoto, M Abe, T Takatsuji ................................................................ ……………………448
8-17 A transmission characteristics of the low-pass filter using actual measurement data Y Kondo, M Numada, H Koshimizu, K Kamiya, I Yoshida .......................................................... ……………………453
8-18 Design of a texture monitoring system for PV solar cell efficiency via 3-D virtual simulation R Y Chiou, Y Kwon, B Tseng, M Mauk, A Mathews ............................................................................................... …460
8-19 Development of a touch trigger probe M Xiang, R-J Li, K-C Fan, Y-X He ............................................................................................... ……………………467
8-20 Integration of thermal and dimensional measurement- a hybrid computational and physical measurement method D Ross-Pinnock, B Yang, P Maropoulos ....................................................................................... ……………………471
8-21 Elimination of gyro rate offset by using a rotating mechanism for large scale straightness evaluation T Kume, M Satoh, T Suwada, K Furukawa, E Okuyama .............................................................. ……………………479
8-22 Magnetic patterns with index point for high-resolution position sensing system Z H Xu, B H Tseng, C Chang, H S Hsiao, J Y Chang, T S Chin, C K Sung ................................ ……………………484
8-23 Measurement and compensation of pivot point positional error on five-axis machine tools B Yang, M Chappell, J Muelaner, G Florussen, P Maropoulos ..................................................... ……………………491
8-24 A novel method of rotation error analysis on rotary stage based on Abbe principle Y-T Li, K-C Fan ............................................................................................................................ ……………………497
8-25 Development of wearable hand motion capture device in immersive VR system M Tomida, K Hoshino ................................................................................................................... ……………………501
8-26 Liquid crystal sensor for label-free monitoring hydrogen peroxide solution M-Z Zhang, L-W Jhang and S-J Hwang ........................................................................................ ……………………507
x Contents
8-27 An investigation on simulation and identification of diffracted Moire patterns within optical encoders L Zhao, H Ding, K Cheng, S J Chen .............................................................................................. ……………………511
9 Micro/Nano Fabrication and Manipulation
9–1 Microfabrication of three-dimensional structures using nanoparticle deposition with a nanopipatte F Iwata, J Metoki ........................................................................................................................................................... 518
9–2 Large scale periodic structure fabrication by scratching silica-glass-precursor coating S Bolotov, M Hashidume, K Shimada, M Mizutani, T Kuriyagawa.............................................................................. 523
9–3 Study of chipping of micro channel in glass ultra-hard material by micro machining technologies Y C Lin, Z-H Hong, T-P Hung, T-F Chen, Y-S Wu ...................................................................................................... 529
10 Monitoring and Control of Machining Operations
10–1 Cutting force control for multiple repetitive canned cycles in turning operation J Leoro, S-S Yeh ............................................................................................................................................................ 534
10–2 Development of in-situ hybrid 3-D measuring methodology for critical dimension inspection in large-scale robot machining of composite materials L-C Chen, M-T Le, C-J Lin ........................................................................................................................................... 539
11 Welding
11–1 Laser welding of dissimilar materials for electric vehicle batteries M Naeem, A Montello ................................................................................................................................................... 546
11–2 Dissimilar metal laser beam welding between aluminum and copper S Wu , J Zou, R Xiao and P Dong ................................................................................................................................. 552
7-14
Machinability of thermo-plastic CFRP by inclined planetary milling
Hidetake Tanaka1, Robert Voß2, Marcel Henerichs2, Konrad Wegener2 1 Nagaoka Univ. of Tech., 1603-1 Kamitomioka, Nagaoka, Japan 2 ETH Zürich, Rämistrasse 101, 8092 Zürich, Switzerland
Abstract. The study deals with an evaluation of the machinability of thermo-plastic CFRP by means of the inclined planetary milling. The market of thermo-plastic CFRP is developing as the alternate material for next generation automobile. However the thermo-plastic CFRP is also a difficult-to-cut material. The problems of milling the material are not only burrs and delaminations but also melting of matrix material by cutting heat. The drilling methodology for such kind of materials is the inclined planetary milling. The tool rotation axis of the inclined planetary milling is inclined from the revolution axis and a tip of a cutting tool is shifted eccentrically. The benefit of the inclined planetary milling mechanism is reduction of unbalanced mass of eccentricity from that of the helical milling and it improves revolution speed and drilling quality. In the study, the authors evaluated the machinability of the materials and assessed bore quality by means of the inclined planetary milling method. From the experimental result, 2 flutes tool achieved the highest bore quality. In the case of thermo-plastic CFRP, the matrix could be melted by cutting heat and the melted cutting chips were glued and stuck in the flute and that made bore quality worse. Focusing on the cutting edge wear, there were few clearance face wear on the tip of cutting tools. It seems that remained uncut fibers of thermo-set CFRP spring-back and abraded the clearance face of the cutting edge however in the case of thermo-plastic, melted matrix could not retain the fiber orientation and no spring-back effect affected the clearance face.
Keywords: CFRP, CFRTP, Thermo-plastic, Orbital drilling, Inclined planetary milling,
1.1 Introduction
Recently, CFRP (Carbon Fiber Reinforced Plastic) is widely used as structural material in aviation industries because of their advantages such as lightweight and high strength. CFRP is divided into 2 types by mechanical characteristics of the matrix material as thermo-set and thermo-plastic. The thermo-set CFRP (CFRTS) dominates the market for structural materials for aero-space industries because of their properties of higher strength and lighter weight than conventional metallic materials. The thermo-plastic CFRP (CFRTP) is developing in an effort to replace sheet metal forming materials for the next generation automobiles in order to reduce their weight. Those materials are also known as difficult to machine materials in conventional drilling
techniques. The orbital drilling [1, 2] has been realized as one of these solutions. The orbital drilling is similar to helical milling by a machining center. In the case of the orbital drilling a tool rotation spindle with a cutting tool is installed eccentric parallel to a planetary revolution spindle and it rotates independently. The holes machined by the orbital drilling have higher roundness than holes machined by helical milling or conventional drilling. The author has established a cutting model of the orbital drilling and clarified its machinability and proposed the cutting tools having particular cutting edge for CFRP drilling according to the past studies [3-5]. The orbital drilling has a drawback, i.e., delaminations of workpiece by its cutting principle and mechanical vibration. In order to bring solutions to the orbital drilling technique, the authors have modified cutting mechanism principle of the orbital drilling, which named as the inclined planetary milling. Its axis of tool rotation is not parallel to the axis of planetary revolution. The benefit of the inclined planetary milling mechanism is reduction of unbalanced mass of eccentricity from that of the helical milling and it improves revolution speed and drilling quality. It also reduce vibrations by revolution and thrust cutting force, which is generated on a bottom face of a cutting tool. In the study, the thermo-plastic CFRP is focused as a workpiece material in order to compare the machinability to the thermo-set CFRP. The authors developed three type of specialized cutting tools for CFRP milling and carried out drilling tests and endurance tool wear tests based on the inclined planetary milling technique. The cutting force was also measured though out the endurance tool wear test. The drilled workpieces and cutting tools were inspected by visual observation by use of an optical microscope. Bore quality of the workpieces were measured by a roundness measurement instrument. The resin mounted workpieces were also observed to inspect un-cut fibres and their orientation. The progress of tool wear was evaluated by cutting edge profile measurement by the optical confocal microscopy.
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2. Inclined planetary milling
2.1 Principle
The drilling methodology of the inclined planetary milling is similar to helical milling techniques by use of a machining center. Both of them consist of a tool rotation spindle and revolution motion unit. The difference of them is how to realize eccentricity of their mechanisms as shown in figure 1. In the case of helical milling, the axis of tool rotation spindle shifts parallel to the axis of revolution. On the other hand, the tool rotation axis of the inclined planetary milling is inclined from the revolution axis and a tip of a cutting tool is shifted eccentrically. The inclined angle is adjustable from 0 to 3 degrees. In the case of the orbital drilling, the outermost cutting edges penetrate workpiece and the bottom layer is delaminated. On the other hand, in the case of the inclined planetary milling, penetration is caused by the inner cutting edges not the outermost cutting edges because of inclined tool rotation axis. When penetration occurred, the inner cutting edges penetrate firstly then the outermost edges enlarge the drilled hole and the sequence can avoid generation of delaminations and burrs. The diameter of a target bore is controlled by a tool diameter and the eccentricity, which consists of the inclined angle and the tool length from the center of inclination as shown in figure 2.
2.2 Inclination angle.
Control of inclination is necessary to obtain an arbitrary eccentricity of the inclined planetary millig. Figure 2 illustrates schematics of geometrical milling model of the inclined planetary milling with a square end-mill (a) and a ball end-mill (b) where r: tool radius, D: diameter of hole to be drilled, φ: inclination angle and L: distance between tool tip and inclination pivot. For the case of square end-mill, the inclination angle (φ) is calculated by eq. (1) considering with the shape of cutting tool, r, and L and eq. (2) represents for the case of ball end-mill.
(a) Orbital / helical milling
Fig. 1 Differences of interpolated bore milling method
(b) Inclined planetary milling
Fig. 1 Differences of interpolated bore milling method
(a) Square end-mill
(b) Ball end-mill Fig. 2. Schematic of cutting by inclined planetary milling
+−
+= −−
22
1
22
1 sin2
sinrL
r
rL
Dφ (1)
−−
= − rDrL 2
1sin 1φ (2)
2.3 Effective peripheral cutting edge length
The length of peripheral cutting edge depend on the cutting conditions, which restricted according to the cutting principle of the inclined planetary milling. Optimization of the peripheral cutting edge length can
r
D
L
φ
Z
Y
D
L
φ
r Y
Z Tool rotation
Revolution
Feed
Workpiece
299
improve the bore quality by enlargement of cutting tool stiffness as well as reduce manufacturing cost of the tools. Based on the principle of the inclined planetary milling, end-mill type cutting tools are suitable for bore milling and in the study a square end-mill and a ball end-mill are selected to calculate the effective length. The effective peripheral cutting edge length: lpf of a square end-mill is defined as eq. 3 and lpf of a ball end-mill is defined as eq. 4 where fp: feed rate per one revolution.
φcosppf fl = (3)
{ }2
2
1 )cos1(cossinsin Rzrrlrfrl c
ppf −−+
−
+−= − φφφ
(4) 3. Experiment
3.1 Cutting tool design
The authors developed three types of specialized design cutting tool for CFRP milling. The overview of the tool shape is illustrated in figure 3. They have fillet square cutting edge design, the diameter is 5mm including tool center coolant hole and its effective peripheral edge length is 1.5mm. Three types of cutting tools, which have 2, 3 and 4 flutes were developed made of solid tungsten carbide. The helix angle is 30 degrees. Cutting edge of the tools were coated by CVD diamond to enlarge resistance against abrasion by carbon fiber.
3.2 Experimental design
In order to evaluate the drilling machinability of thermo-plastic CFRP, drilling a set of experiment was carried out by use of a 6-DOF parallel kinematic machining center as shown in figure 4 (a), which can perform the inclined planetary milling trajectory tool path motion. In order to perform the trajectory, the cone shape interpolation with z-axis feeding motion (Simultaneous 5-DOF motion) is required. Workpiece setup is shown in figure 4 (b). The workpiece clamping jig and a dynamometer are fixed on a platform. Chips are removed by vacuum unit though the flexible tube, which is fixed near by the spindle unit. A matrix of the workpieces[6] is PA66 and woven fabric orientation. The thermo-set CFRP (Uni-direction) workpieces were also tested as a reference material. The items of experimental objectives are as follows; 1. Observation of burrs and delamination around the bore 2. Observation of cutting tool wear and endurance test 3. Measurement of cutting force during tool wear test The bores on workpieces and appearance of cutting edge of the tools were observed by optical microscope. The cutting edge profile was also measured by an optical
confocal microscope (Alicona, Infinite focus). Cutting force during milling was measured by a dynamometer (Kistler instrumente AG. Type 9254) Total number of bore is up to 1,000 one tool. Cutting force was measured every 500 bores until bore number 200, then every 200 bores until 1,000. Table 1 shows the experimental conditions.
Fig. 3. Schematic of developed cutting tool for CFRP milling
(a) 6-DOF parallel kinematic machining center
(HEXAGLIDE, IWF, ETH Zurich)
(b) Configuration of tool and workpiece setup Fig. 3. Schematic of developed cutting tool for CFRP milling
Cutting tool
Workpiece
Dynamo meter
Flexible tube (to vacuum unit)
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Table 1. Experimental conditions
Cutting speed 90m/min (Thermo-set) 70m/min (Thermo-plastic)
Feed rate 0.25/rev Revolution speed 180 rev/min Inclination 1.433 deg.
Eccentricity: 0.675mm Cutting tools oDA1: 2 flute, Thermo-set
oDA2: 2 flute, Thermo-plastic oDB1: 3 flute, Thermo-set oDB2: 3 flute, Thermo-plastic oDC1: 4 flute, Thermo-set oDC2: 4 flute, Thermo-plastic
4. Experimental result
4.1 Bore quality
The appearance of bore on the workpieces are shown in figure 4. In the both case of thermo-set and thermo-plastic CFRP, smooth finishing was seen in the beginning, however burrs were appeared after 200 bored. Especially, uncut fibers were observed in the thermo-set CFRP frequently. In the case of thermo-plastic CFRP, chip size was larger than thermo-set and melted chips were remained on inside of bore. Sometimes a thin cap shaped burr was remained on the exit side (Fig. 4. (c) and (d)).
(a) Bore exit appearance oDA1 (Thermo-set, 2 flutes tool)
(b) Bore exit appearance oDA2 (Thermo-plastic, 2 flutes tool)
(c) Bore exit appearance oDB2 (Thermo-plastic, 3 flutes tool)
(d) Bore exit appearance oDC2 (Thermo-plastic, 4 flutes tool)
Fig. 4. Bore exit appearances
4.2 Cutting force
There were no difference of the tendency of transition of cutting force during the endurance tool wear test within the three types of cutting tool. For instance, figure 5 shows the transition of measurement of cutting force from bore number 1 to 1,000 selectively focused on 3 flutes cutting tool. The maximum feed force of thermo—set is larger than thermo-plastic due to their fiber and matrix material differences. It seems that the progress of cutting force is rapidly increased until 200 (Thermo-plastic) or 400 (Thermo-set) bores and then gradually increased.
4.3 Cutting edge wear
Figure 6 shows the transition of cutting edge wear observation result. Progression of wear of thermo-set is severer than thermo-plastic. In the case of thermo-plastic, melted cutting chip was adhered and it made flow of chip evacuation worse due to the lower melting temperature of matrix material. Transition of cutting edge profile is shown in figure 7. In the case of thermo-set, cutting edge wear on clearance face is dominant however in the case of thermo- plastic, the wear on rake face is larger than the clearance face and amount of total wear is smaller than the thermo-set. It seems that the big difference of cutting edge wear on clearance face might be caused by the difference of melting
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temperature of matrix materials. The fiber orientation on the inside wall of bore was observed as shown in figure 8. The fiber of thermo-set CFRP was oriented uniformly and spring-back effect of uncut fiber might abrade the clearance face of the cutting edge. However, the fiber of thermo-plastic could not maintain their orientation after cutting due to the melted matrix.
(a) Cutting Force oDB1 (Thermo-set)
(b) Cutting Force oDB2 (Thermo-plastic)
Fig. 5 Transition of measured cutting force
(a) Microscopic image oDA1 (Thermo-set)
(b) Microscopic image oDA2 (Thermo-plastic)
Fig. 6 Transition of cutting edge wear
(a) Tool wear progression oDA1 (Thermo-set)
(b) Tool wear progression oDA2 (Thermo-plastic)
Fig. 7 Tool wear progression
(a)Thermo-set (b) Thermo-plastic
Fig. 8. Fiber orientation on inside wall of bore
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4.4 Circularity
Circularity of the bore of the workpieces was measured by use of a roundness measurement instrument. The transition of circularity was gradually increasing along with the bore number increasing as shown in figure 9. The mean value of circularity of thermo-plastic CFRP is larger than that of thermo-set because of adhered melted chips.
4.5 Discussion
From the experimental results, 2 flutes tool achieved the highest bore quality according to the visual inspection and measurement results of circularity. The tendency of circularity was stable within 30 micro-meter through the bore number increasing. However especially by 4 flutes tool, the circularity changed for the worse up to 120 micro-meter. In the case of thermo-plastic CFRP, the matrix could be melted by cutting heat and the melted cutting chips were glued and stuck in the flute and that made bore quality worse. Focusing on the cutting edge wear, there were few clearance face wear on the tip of cutting tools. It seem that remained uncut fibers of thermo-set CFRP were spring-backed and abraded the clearance face of the cutting edge however in the case of thermo-plastic, melted matrix could not retain the fiber orientation and no spring-back effect
(a) Thermo-set
(b) Thermo-plastic
Fig. 9. Bore circularity
affected to the clearance face by optical microscopy observation.
5 Summary
The thermo-plastic CFRP drilling tests were carried out by the inclined planetary milling tequnique. From the experimental result, following concluding remarks are obtaind.
1. Bore quality of the thermo-plastic CFRP is less
than that of thermo-set by visual inspection and circularity measurement result.
2. Size of burrs of thermo-plastic CFRP is larger than the thermo-set and the burrs consists of melted matrix material generated by cutting heat were observed.
3. 2 flutes tool achieved the highest bore quality. 4. Cutting tool wear were mainly observed on their
rake face not but on clearance face. 5. Melted matrix could not retain the fiber
orientation and no spring-back effect affected to the clearance face.
6 References
[1] http://www.novator.nu/ [2] E.Brinksmeier, Sascha Fangmann, I.Meyer. 2010.
Production Engineering Research and Development. 2:277-283
[3] NEBUKA Teppei, TANAKA Hidetake, and YANAGI Kazuhisa., 2007, Proceedings of Asia symposium for Precision Engineering and Nanotechnology, 309-312.
[4] ISHIBASHI Tatsuya, TANAKA Hidetake, and YANAGI Kazuhisa., 2009, An analytical model for orbital drilling and its applicability to, Proceedings of the Twenty-Fourth Annual Meeting of the American society for Precision Engineering.
[5] Hidetake TANAKA, Shinji Obata and Kazuhisa YANAGI, Optimization of cutting edge configuration and machining conditions in orbital drilling, Proceedings of 4th CIRP International Conference on High Performance Cutting, 2010, p. 201-206
[6] http://www.bond-laminates.com/en/tepexr-materials/composites.html
Acknowledgement
The authors would like to express the gratitude to Mr. Jens Boos and Mr. David Hampl of ETH Zurich for their technical help. The authors are also particularly grateful for the assistance to BOND LAMINATE GmbH, DIXI polytool SA, OC Oerlikon Balzers AG and Inspire AG. The first author would like to thank Mr. Chiaki Takeuchi of NUT.
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