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張駿偉 (Chun-Wei Chang)
張駿偉 (Chun-Wei Chang)
Micro resistance welding with in situ micro actuator for micro assembly
Micro resistance welding with in situ micro actuator for micro assembly
結合微致動器之微電阻焊技術於微組裝之研究
結合微致動器之微電阻焊技術於微組裝之研究
Here, micro resistance welding with in situ micro actuators and corresponding two-dimensional (in-plane) and three-dimensional (3D) micro assemblies are proposed, including designs, fabrications, measurements, tests and discussions. Traditionally, resistance welding is a common scheme of assembly in macro scale by pressing two workpieces with current passing through to generate joule heating at contact region due to high contact resistance. There are, however, few studies focused on micro resistance welding with micro actuators in micro world. Under assistance of in situ micro actuators next to welding regions, increasing efficiency of welding energy, providing easy-controlled welding pressure and avoiding manual misoperation can benefit micro resistance welding. The scheme proposed here would be helpful in automation of micro assembly.
Here, micro resistance welding with in situ micro actuators and corresponding two-dimensional (in-plane) and three-dimensional (3D) micro assemblies are proposed, including designs, fabrications, measurements, tests and discussions. Traditionally, resistance welding is a common scheme of assembly in macro scale by pressing two workpieces with current passing through to generate joule heating at contact region due to high contact resistance. There are, however, few studies focused on micro resistance welding with micro actuators in micro world. Under assistance of in situ micro actuators next to welding regions, increasing efficiency of welding energy, providing easy-controlled welding pressure and avoiding manual misoperation can benefit micro resistance welding. The scheme proposed here would be helpful in automation of micro assembly.
First, in-plane micro assembly with electroplated nickel micro structure is proposed to verify the practicability of micro resistance welding and understand the feasible ranges of welding parameters. The calibrated initial contact resistance is shown to decrease with the increasing contact pressure. In addition, stronger welding strength is achieved at a smaller initial contact resistance, namely, a larger clamping force would enhance the welding strength as large as 3.09 MPa at contact resistance of 2.7 ohm here. The input welding energy is also found to be a critical factor. In our tests, providing higher welding energy, such as 1 J, yield also increases to be 100%. In this case, the feasibility of the proposed technique is confirmed.
First, in-plane micro assembly with electroplated nickel micro structure is proposed to verify the practicability of micro resistance welding and understand the feasible ranges of welding parameters. The calibrated initial contact resistance is shown to decrease with the increasing contact pressure. In addition, stronger welding strength is achieved at a smaller initial contact resistance, namely, a larger clamping force would enhance the welding strength as large as 3.09 MPa at contact resistance of 2.7 ohm here. The input welding energy is also found to be a critical factor. In our tests, providing higher welding energy, such as 1 J, yield also increases to be 100%. In this case, the feasibility of the proposed technique is confirmed.
After this feasible study, three-dimensional micro assembly of hinged nickel micro devices by magnetic lifting and micro resistance welding is further developed. Lifting the released micro structure to different tilted angles is accomplished by controlling positions of a magnet beneath the device. Micro resistance welding is utilized for immobilizing the tilted structure. As mentioned, the micro actuators also used to provide necessary pressure. The proposed technique is shown to immobilize micro devices at controlled angles ranging from 14° to 90° with respect to the substrate, which is a difficulty to other techniques. Design parameters such as the electro-thermal actuator and welding beam width are also investigated. It is found there is a trade-off in beam width design between large contact pressure and low thermal deformation. Finally, a lifted and immobilized electro-thermal bent-beam actuator is shown to displace upward about 27.7 μm with 0.56 W power input to demonstrate the capability of electrical transmission at welded joints by this proposed technique. With demonstration and characterization of micro resistance welding by in situ electro-thermal micro actuators, not only the passive micro structures but also the active micro structures which need electrical connections can be assembled with this proposed method.
After this feasible study, three-dimensional micro assembly of hinged nickel micro devices by magnetic lifting and micro resistance welding is further developed. Lifting the released micro structure to different tilted angles is accomplished by controlling positions of a magnet beneath the device. Micro resistance welding is utilized for immobilizing the tilted structure. As mentioned, the micro actuators also used to provide necessary pressure. The proposed technique is shown to immobilize micro devices at controlled angles ranging from 14° to 90° with respect to the substrate, which is a difficulty to other techniques. Design parameters such as the electro-thermal actuator and welding beam width are also investigated. It is found there is a trade-off in beam width design between large contact pressure and low thermal deformation. Finally, a lifted and immobilized electro-thermal bent-beam actuator is shown to displace upward about 27.7 μm with 0.56 W power input to demonstrate the capability of electrical transmission at welded joints by this proposed technique. With demonstration and characterization of micro resistance welding by in situ electro-thermal micro actuators, not only the passive micro structures but also the active micro structures which need electrical connections can be assembled with this proposed method.
[1] C.-W. Chang and W. Hsu (June 2006). A Bio-compatible Microgripper Operated in Aqueous Environment, The 3rd Asia-Pacific Conference of Transducers and Micro-Nano Technology, Singapore.
[1] C.-W. Chang and W. Hsu (June 2006). A Bio-compatible Microgripper Operated in Aqueous Environment, The 3rd Asia-Pacific Conference of Transducers and Micro-Nano Technology, Singapore.
[2] C.-C. Yeh, J. Chung, C.-W. Chang and W. Hsu (January 2007). Micro Assembly by Micro Resistance Welding with Electro-Thermal Actuators, The 2nd Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems, Bangkok, Thailand.
[2] C.-C. Yeh, J. Chung, C.-W. Chang and W. Hsu (January 2007). Micro Assembly by Micro Resistance Welding with Electro-Thermal Actuators, The 2nd Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems, Bangkok, Thailand.
[3] C.-W. Chang and W. Hsu (January 2008). Characterization of microresistance welding with electro-thermal actuator for micro assembly, SPIE Symposium on MOEMS-MEMS, San Jose, U.S.A..
[3] C.-W. Chang and W. Hsu (January 2008). Characterization of microresistance welding with electro-thermal actuator for micro assembly, SPIE Symposium on MOEMS-MEMS, San Jose, U.S.A..
[4] C.-W. Chang, C.-C. Yeh and W. Hsu, "Experimental investigations and characterization of micro resistance welding with an electro-thermal actuator." Journal of Micromechanics and Microengineering 2009, 19, 025001.
[4] C.-W. Chang, C.-C. Yeh and W. Hsu, "Experimental investigations and characterization of micro resistance welding with an electro-thermal actuator." Journal of Micromechanics and Microengineering 2009, 19, 025001.
[5] C.-W. Chang, W. Hsu, "Three-dimensional micro assembly of a hinged nickel micro device by magnetic lifting and micro resistance welding." Journal of Micromechanics and Microengineering 2009, 19, 105026.
[5] C.-W. Chang, W. Hsu, "Three-dimensional micro assembly of a hinged nickel micro device by magnetic lifting and micro resistance welding." Journal of Micromechanics and Microengineering 2009, 19, 105026.
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