Bending strength analysis of micro WC-shaft manufactured by micro electro-discharge machining

Micro electro-discharge machining (micro-EDM) is a critical technology to fabricate high aspect ratio 3D micro-components. However, the surfaces of micro-components manufactured by micro-EDM will exhibit micro-cracks to produce notch effects, and lead to stress concentrate and reduction of fatigue strength. This paper performs micro-bending tests to investigate the influence of various roughness and size on the bending fracture strength of micro WC-shafts manufactured by micro-EDM. The experimental results indicate that the surface roughness, axial surface area, volume, and length of the specimen will affect its bending fracture strength. For specimens with the same size, the mean bending fracture strength decreases as the surface roughness increases, and the bending fracture probability of the specimens also increases (roughness effect). For specimens with the same roughness, reducing the length or axial surface area will increase the mean bending fracture strength, and reduces the bending fracture probability (size effect).

[1]  M. Fujino,et al.  Micro ultrasonic machining and its applications in MEMS , 1996 .

[2]  Jianxin Deng,et al.  Mechanical surface treatments of electro-discharge machined (EDMed) ceramic composite for improved strength and reliability , 2002 .

[3]  H. Brussel,et al.  Micro-electro-discharge machining as microsensor fabrication technology , 2003 .

[4]  Sylvain Martel,et al.  Microelectrode array fabrication by electrical discharge machining and chemical etching , 2004, IEEE Transactions on Biomedical Engineering.

[5]  J. Schweitz,et al.  Micromechanical fracture strength of silicon , 1990 .

[6]  Kai Egashira,et al.  Micro-drilling of monocrystalline silicon using a cutting tool , 2002 .

[7]  Xi-Qing Sun,et al.  Micro ultrasonic machining and self-aligned multilayer machining/assembly technologies for 3D micromachines , 1996, Proceedings of Ninth International Workshop on Micro Electromechanical Systems.

[8]  M. Yamamoto,et al.  Dimensional measurement of high aspect ratio micro structures with a resonating micro cantilever probe , 2000 .

[9]  Dominiek Reynaerts,et al.  Machining of three-dimensional microstructures in silicon by electro-discharge machining , 1998 .

[10]  Y. Gianchandani,et al.  Batch mode micro-electro-discharge machining , 2002 .

[11]  Jow-Lay Huang,et al.  Effect of the electrical discharge machining on strength and reliability of TiN/Si3N4 composites , 2003 .

[12]  B. Yan,et al.  Study of precision micro-holes in borosilicate glass using micro EDM combined with micro ultrasonic vibration machining , 2002 .

[13]  S. Wen,et al.  Size effect on the mechanical properties and reliability analysis of microfabricated polysilicon thin films , 2001, 2001 IEEE International Reliability Physics Symposium Proceedings. 39th Annual (Cat. No.00CH37167).

[14]  Stefan Johansson,et al.  In situ tensile strength measurement and Weibull analysis of thick film and thin film micromachined polysilicon structures , 1997 .

[15]  L. S. Stephens,et al.  Mechanical property evaluation and failure analysis of cantilevered LIGA nickel microposts , 2001 .

[16]  Kenichi Takahata,et al.  High-aspect-ratio WC-Co microstructure produced by the combination of LIGA and micro-EDM , 2000 .

[17]  C. Kuo,et al.  Pin-plate micro assembly by integrating micro-EDM and Nd-YAG laser , 2002 .

[18]  T. Tanaka,et al.  Nano-scale bending test of Si beam for MEMS , 2000, Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308).

[19]  Takahisa Masuzawa,et al.  Wire Electro-Discharge Grinding for Micro-Machining , 1985 .

[20]  Oliver Paul,et al.  Fracture Properties of LPCVD Silicon Nitride Thin Films from the Load-Deflection of Long Membranes , 2002 .

[21]  B. Bhushan,et al.  Development of AFM-based techniques to measure mechanical properties of nanoscale structures , 2002 .

[22]  S. D. Collins,et al.  Removable tubing interconnects for glass-based micro-fluidic systems made using ECDM , 2004 .

[23]  Chia-Lung Kuo,et al.  Precise Micro-Assembly Through an Integration of Micro-EDM and Nd-YAG , 2002 .

[24]  Dominiek Reynaerts,et al.  Microstructing of silicon by electro-discharge machining (EDM) — part II: applications , 1997 .

[25]  Alejandro Pérez-Rodríguez,et al.  Measurement of micromechanical properties of polysilicon microstructures with an atomic force microscope , 1998 .

[26]  C. Vallo.  Influence of load type on flexural strength of a bone cement based on PMMA , 2002 .

[27]  Y. Isono,et al.  Evaluation of size effect on mechanical properties of single crystal silicon by nanoscale bending test using AFM , 2000, Journal of Microelectromechanical Systems.

[28]  Chung-Hsien Kuo.  Modelling and Performance Evaluation of an Overhead Hoist Transport System in a 300 mm Fabrication Plant , 2002 .

[29]  T. Tanaka,et al.  AFM bending testing of nanometric single crystal silicon wire at intermediate temperatures for MEMS , 2001, Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090).

[30]  Y. Isono,et al.  Quasi-static bending test of nano-scale SiO2 wire at intermediate temperatures using AFM-based technique , 2003 .

[31]  N. Shibaike,et al.  Optimization of mechanical interface for a practical micro-reducer , 2000, Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308).

[32]  B. Yan,et al.  Use of micro ultrasonic vibration lapping to enhance the precision of microholes drilled by micro electro-discharge machining , 2002 .

[33]  C. T. Yang,et al.  Micro Hole Machining of Borosilicate Glass through Electrochemical Discharge Machining (ECDM) , 2001 .

[34]  S. Johansson,et al.  Mechanical characterization of thick polysilicon films: Young's modulus and fracture strength evaluated with microstructures , 1999 .

[35]  Paolo Dario,et al.  A sensorized /spl mu/electro discharge machined superelastic alloy microgripper for micromanipulation: simulation and characterization , 2002, IEEE/RSJ International Conference on Intelligent Robots and Systems.

[36]  Dominiek Reynaerts,et al.  EDM texturing of multicrystalline silicon wafer and EFG ribbon for solar cell application , 2002 .

[37]  Feng-Tsai Weng,et al.  A study of the electrical discharge machining of semi-conductor BaTiO3 , 2002 .

[38]  T. Sato,et al.  Fine surface finishing method for 3-dimensional micro structures , 1996, Proceedings of Ninth International Workshop on Micro Electromechanical Systems.

[39]  Kazuo Yamazaki,et al.  High efficiency fine boring of monocrystalline silicon ingot by electrical discharge machining , 1999 .

[40]  R. Aigner,et al.  Fracture strength and fatigue of polysilicon determined by a novel thermal actuator [MEMS] , 2000 .

[41]  Profile measurement of high aspect ratio micro structures using a tungsten carbide micro cantilever coated with PZT thin films , 2000, Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308).

[42]  T. C. Lee,et al.  Processing of advanced ceramics using the wire-cut EDM process , 1997 .

[43]  Kai Egashira,et al.  Ultrasonic Vibration Drilling of Microholes in Glass , 2002 .

[44]  O. Tabata,et al.  Specimen size effect on tensile strength of surface-micromachined polycrystalline silicon thin films , 1998 .

[45]  Y. Meng,et al.  Specimen size effect on mechanical properties of polysilicon microcantilever beams measured by deflection using a nanoindenter , 2001 .

[46]  W. Meeusen,et al.  Design and realization of an optical bi-axial inclination sensor , 2002, Proceedings of IEEE Sensors.