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Fabrication of micro-electrodes by multi-EDM grinding process
Journal of Materials Processing Technology 140 (2003) 332–334
Fabrication of micro-electrodes by multi-EDM grinding process Feng-Tsai Weng a,∗ , R.F. Shyu a , Chen-Siang Hsu b a
Department of Mechanical Manufacturing Engineering, National Huwei Institute of Technology, Yunlin, Taiwan ROC b Department of Materials Science and Engineering, National Huwei Institute of Technology, Yunlin, Taiwan ROC
Abstract In this study, a multi-EDM grinding process is adapted to fabricate micro-electrodes. Equipments such as a wire EDM machine and a traditional CNC-EDM machine are used for machining micro-electrodes. Rod electrodes of copper with diameter 3.0 mm were cut to be 0.15 mm on wire-EDM machine at first step. EDM grinding process was used to grind micro-electrodes to fine diameter bellow 20 m on a CNC-EDM machine at second step. For EDM grinding, rotating mechanisms are mounted on both the WEDM machine and the CNC-EDM machine. A CCD camera is provided for viewing and for on-line dimensional controlling, when micro-electrodes were cutting. Fine electrodes could be processed to a smaller size using proposed two-steps EDM grinding process. Higher L/D ratio could be also achieved by this method. The processed fine electrodes can be used for drilling micro-holes, micro-deep holes, micro-milling, micro-punching, and manufacturing of micro-nozzles. © 2003 Elsevier B.V. All rights reserved. Keywords: KeMulti-EDM grinding process; Micro-electrodes; Micro-nozzles
1. Introduction EDM is considered to fabricate micro-electrodes and micro-parts recently. It is a trend reduce the size of some production to be slighter, thinner, shorter, and smaller. To achieve this may require some special ideas and machining methods. Masuzawa et al. [1] worked by wire electro-discharge grinding to perform micro-machining. EDM process is considered for micro-machining. Many authors proposed micro-machining by EDM [2–6], in order to improve the machining performance and reduce the debris, an electrode rotating mechanism mounted to the EDM machine was proposed by Soni and Chakraverti [7]. In this research, a multi-EDM grinding process is adapted to fabricate micro-electrodes. A similar WEDM system was developed for cutting micro-electrodes in first step as in Fig. 1. Processed micro-electrodes can be taken down and set to a traditional CNC-EDM machine for advanced machining. Copper with diameter of 3.0 mm was cut to 0.15 mm on wire-EDM machine in first step. Advanced EDM grinding process was to grind micro-electrodes to fine diameter bellow 20 m on a CNC-EDM machine in second step as in Fig. 2. The tool wear is small and homogeneous as EDM grinding is taken. Micro-rod copper is selected for proposed multi-EDM grinding method as electrode in grinding process ∗ Corresponding author. Tel.: +886-5-6329643; fax: +886-5-6310824. E-mail address: [email protected] (F.-T. Weng).
0924-0136/$ – see front matter © 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0924-0136(03)00748-9
as it has good wear resistance and high temperature resistance. Energy controlling is very important in micro-EDM machining. Tool wear and processed hole-expansion is proportional to the supplied energy.
2. Experimental equipments and procedures 2.1. Wire electrical discharge machine Wire electrical discharge machine of model type GENS PARK YW-355, was made in Taiwan. The power controller is a transistor R–C circuit. It can provide 2D programmable process ability. The current can be chosen from 0.3 to 30 A, on-pulse duration and off-pulse duration can be chosen from 10 to 2400 s with total 24 sections. 2.2. Electrical discharge machine The advanced EDM grinding process was performed on a CNC-EDM machine, the electric discharge machine employed in experiment was a conventional CNC electrical discharge machine of model type CHMER CD-50 M, which is made in Taiwan. The power controller is a transistor R–C circuit. The current can be chosen from 0.3 to 30 A, on-pulse duration and off-pulse duration can be chosen from 10 to 2400 s with total 24 sections.
F.-T. Weng et al. / Journal of Materials Processing Technology 140 (2003) 332–334
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Fig. 1. WEDM system: wire EDM machine with a developed rotating mechanism, micro-electrode was cut using 0.25 mm wire electrode.
Fig. 3. Micro-electrode can be grind to smaller than 20 m using two-step EDM grinding method. Diameter of micro-electrode at front end is 18 m, and length is about 600 m, L/D ratio is above 30.
Fig. 2. EDM system, a CNC-EDM machine with a developed rotating mechanism.
Fig. 4. Original diameter of electrode is 3 mm, mid-size is 0.15 mm.
2.3. Scanning electronic microscope For on-line dimensional controlling, a surface scanning electron microscope model 5508 (Oxford Microanalysis Group, UK) was used for surface photographing and the investigation of the processing. Main experiment procedures were described as follows: 1. Grinding the electrode to desired size: a developed rotating mechanism is set to the WEDM machine as in Fig. 1. Copper rod with diameter 3.0 mm can be ground to desired diameter about 150 m in this step. Wire electrode is brass. Diameter of wire is 0.25 mm. 2. Advanced grinding: advanced EDM grinding process was to grind micro-electrodes to fine diameter bellow 20 m on a CNC-EDM machine as in Fig. 2. A developed rotating mechanism is also set to the EDM machine, so that the electrode can be turned. Masterpiece on working plane is a aluminum plate of thickness 1 mm. Electrode wear can happen when EDM process take place. The wear is proportional to the discharge energy of the EDM process.
machine by proposed multi-EDM grinding process. In first step, electrode is cut from 3 mm to middle diameter 0.1 mm on WEDM machine. Processed electrode can be taken down and set to a CNC-EDM machine for finishing and grinding, finished diameter is under 20 m. The length of the front end is about 0.6 mm. Aspect ratio is above 30. Fig. 4 shows machined micro-electrode by proposed multi-EDM grinding process. Original diameter is 3 mm. Fig. 5 shows microscope for dimension measurement. Fig. 6 shows machined micro-hole. Masterpiece is copper plate of thickness 50 m. Some electrodes were burn out during experiment owing to the discharge energy is large. This could be improved if power supply of EDM machine can be changed smaller.
3. Experimental results and discussion Through the two steps grinding process, micro-electrode can be grind to 20 m. Figs. 3 and 4 shows micro-electrode
Fig. 5. Microscope for dimension measurement.
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F.-T. Weng et al. / Journal of Materials Processing Technology 140 (2003) 332–334
2. Micro-hole machining has been processed on traditional EDM machine using processed micro-electrode to the copper plate. References
Fig. 6. Machined micro-hole, masterpiece is a copper plate of thickness 50 m.
4. Conclusions 1. Micro-electrode can be fabricated through proposed multi-EDM process. Through a single process may not achieve desired micro-size, this idea of multi-process may.
[1] T. Masuzawa, M. Fujino, k. Kobayasi, T. Suzuki, Wire electro-discharge grinding for micro machining, Ann. CIRP 34 (1) (1985) 431– 434. [2] B.H. Yan, F.Y. Huang, Micro-hole machining of carbide by electric discharge machining, J. Mater. Process. Technol. 87 (1999) 139–145. [3] T. Masuzawa, H.K. Tonshoff, Three-dimensional micromachining by machine tools, Ann. CIRP, 46 (2) (1997). [4] B.H. Yan, F.Y. Huang, Micro-hole machining of carbide by electric discharge machining, J. Mater. Process. Technol. 87 (1999) 139–145. [5] T. Masuzawa, M. Yamamoto, M. Fujino, A Micropunching system using wire-EDM and EDM, in: Proceedings of the International Symposium for Electro Machining (CIRP Sponored), vol. IX, 1989, pp. 86–90. [6] C.L. Kuo, T. Masuzawa, M. Fujino, High precision micronozzle fabrication, in: Proceedings of the IEEE Micro Electro Mechanical Systems, 1992, pp. 116–121. [7] J.S. Soni, G. Chakraverti, Machining characteristics of titanium with rotary electro-discharge machining, Wear 171 (1994) 51–58.
Fabrication of micro-electrodes by multi-EDM grinding process Feng-Tsai Weng a,∗ , R.F. Shyu a , Chen-Siang Hsu b a
Department of Mechanical Manufacturing Engineering, National Huwei Institute of Technology, Yunlin, Taiwan ROC b Department of Materials Science and Engineering, National Huwei Institute of Technology, Yunlin, Taiwan ROC
Abstract In this study, a multi-EDM grinding process is adapted to fabricate micro-electrodes. Equipments such as a wire EDM machine and a traditional CNC-EDM machine are used for machining micro-electrodes. Rod electrodes of copper with diameter 3.0 mm were cut to be 0.15 mm on wire-EDM machine at first step. EDM grinding process was used to grind micro-electrodes to fine diameter bellow 20 m on a CNC-EDM machine at second step. For EDM grinding, rotating mechanisms are mounted on both the WEDM machine and the CNC-EDM machine. A CCD camera is provided for viewing and for on-line dimensional controlling, when micro-electrodes were cutting. Fine electrodes could be processed to a smaller size using proposed two-steps EDM grinding process. Higher L/D ratio could be also achieved by this method. The processed fine electrodes can be used for drilling micro-holes, micro-deep holes, micro-milling, micro-punching, and manufacturing of micro-nozzles. © 2003 Elsevier B.V. All rights reserved. Keywords: KeMulti-EDM grinding process; Micro-electrodes; Micro-nozzles
1. Introduction EDM is considered to fabricate micro-electrodes and micro-parts recently. It is a trend reduce the size of some production to be slighter, thinner, shorter, and smaller. To achieve this may require some special ideas and machining methods. Masuzawa et al. [1] worked by wire electro-discharge grinding to perform micro-machining. EDM process is considered for micro-machining. Many authors proposed micro-machining by EDM [2–6], in order to improve the machining performance and reduce the debris, an electrode rotating mechanism mounted to the EDM machine was proposed by Soni and Chakraverti [7]. In this research, a multi-EDM grinding process is adapted to fabricate micro-electrodes. A similar WEDM system was developed for cutting micro-electrodes in first step as in Fig. 1. Processed micro-electrodes can be taken down and set to a traditional CNC-EDM machine for advanced machining. Copper with diameter of 3.0 mm was cut to 0.15 mm on wire-EDM machine in first step. Advanced EDM grinding process was to grind micro-electrodes to fine diameter bellow 20 m on a CNC-EDM machine in second step as in Fig. 2. The tool wear is small and homogeneous as EDM grinding is taken. Micro-rod copper is selected for proposed multi-EDM grinding method as electrode in grinding process ∗ Corresponding author. Tel.: +886-5-6329643; fax: +886-5-6310824. E-mail address: [email protected] (F.-T. Weng).
0924-0136/$ – see front matter © 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0924-0136(03)00748-9
as it has good wear resistance and high temperature resistance. Energy controlling is very important in micro-EDM machining. Tool wear and processed hole-expansion is proportional to the supplied energy.
2. Experimental equipments and procedures 2.1. Wire electrical discharge machine Wire electrical discharge machine of model type GENS PARK YW-355, was made in Taiwan. The power controller is a transistor R–C circuit. It can provide 2D programmable process ability. The current can be chosen from 0.3 to 30 A, on-pulse duration and off-pulse duration can be chosen from 10 to 2400 s with total 24 sections. 2.2. Electrical discharge machine The advanced EDM grinding process was performed on a CNC-EDM machine, the electric discharge machine employed in experiment was a conventional CNC electrical discharge machine of model type CHMER CD-50 M, which is made in Taiwan. The power controller is a transistor R–C circuit. The current can be chosen from 0.3 to 30 A, on-pulse duration and off-pulse duration can be chosen from 10 to 2400 s with total 24 sections.
F.-T. Weng et al. / Journal of Materials Processing Technology 140 (2003) 332–334
333
Fig. 1. WEDM system: wire EDM machine with a developed rotating mechanism, micro-electrode was cut using 0.25 mm wire electrode.
Fig. 3. Micro-electrode can be grind to smaller than 20 m using two-step EDM grinding method. Diameter of micro-electrode at front end is 18 m, and length is about 600 m, L/D ratio is above 30.
Fig. 2. EDM system, a CNC-EDM machine with a developed rotating mechanism.
Fig. 4. Original diameter of electrode is 3 mm, mid-size is 0.15 mm.
2.3. Scanning electronic microscope For on-line dimensional controlling, a surface scanning electron microscope model 5508 (Oxford Microanalysis Group, UK) was used for surface photographing and the investigation of the processing. Main experiment procedures were described as follows: 1. Grinding the electrode to desired size: a developed rotating mechanism is set to the WEDM machine as in Fig. 1. Copper rod with diameter 3.0 mm can be ground to desired diameter about 150 m in this step. Wire electrode is brass. Diameter of wire is 0.25 mm. 2. Advanced grinding: advanced EDM grinding process was to grind micro-electrodes to fine diameter bellow 20 m on a CNC-EDM machine as in Fig. 2. A developed rotating mechanism is also set to the EDM machine, so that the electrode can be turned. Masterpiece on working plane is a aluminum plate of thickness 1 mm. Electrode wear can happen when EDM process take place. The wear is proportional to the discharge energy of the EDM process.
machine by proposed multi-EDM grinding process. In first step, electrode is cut from 3 mm to middle diameter 0.1 mm on WEDM machine. Processed electrode can be taken down and set to a CNC-EDM machine for finishing and grinding, finished diameter is under 20 m. The length of the front end is about 0.6 mm. Aspect ratio is above 30. Fig. 4 shows machined micro-electrode by proposed multi-EDM grinding process. Original diameter is 3 mm. Fig. 5 shows microscope for dimension measurement. Fig. 6 shows machined micro-hole. Masterpiece is copper plate of thickness 50 m. Some electrodes were burn out during experiment owing to the discharge energy is large. This could be improved if power supply of EDM machine can be changed smaller.
3. Experimental results and discussion Through the two steps grinding process, micro-electrode can be grind to 20 m. Figs. 3 and 4 shows micro-electrode
Fig. 5. Microscope for dimension measurement.
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F.-T. Weng et al. / Journal of Materials Processing Technology 140 (2003) 332–334
2. Micro-hole machining has been processed on traditional EDM machine using processed micro-electrode to the copper plate. References
Fig. 6. Machined micro-hole, masterpiece is a copper plate of thickness 50 m.
4. Conclusions 1. Micro-electrode can be fabricated through proposed multi-EDM process. Through a single process may not achieve desired micro-size, this idea of multi-process may.
[1] T. Masuzawa, M. Fujino, k. Kobayasi, T. Suzuki, Wire electro-discharge grinding for micro machining, Ann. CIRP 34 (1) (1985) 431– 434. [2] B.H. Yan, F.Y. Huang, Micro-hole machining of carbide by electric discharge machining, J. Mater. Process. Technol. 87 (1999) 139–145. [3] T. Masuzawa, H.K. Tonshoff, Three-dimensional micromachining by machine tools, Ann. CIRP, 46 (2) (1997). [4] B.H. Yan, F.Y. Huang, Micro-hole machining of carbide by electric discharge machining, J. Mater. Process. Technol. 87 (1999) 139–145. [5] T. Masuzawa, M. Yamamoto, M. Fujino, A Micropunching system using wire-EDM and EDM, in: Proceedings of the International Symposium for Electro Machining (CIRP Sponored), vol. IX, 1989, pp. 86–90. [6] C.L. Kuo, T. Masuzawa, M. Fujino, High precision micronozzle fabrication, in: Proceedings of the IEEE Micro Electro Mechanical Systems, 1992, pp. 116–121. [7] J.S. Soni, G. Chakraverti, Machining characteristics of titanium with rotary electro-discharge machining, Wear 171 (1994) 51–58.