Micro rotating-structure manufacture has been largely carried out using a variety of processing methods. However, it is difficult to achieve the high-precise machining of the micro rotating structure due to the material constraints and the geometrical limitation of the free-form profile. This paper discusses the fabrication of micro-rotating structure using micro reciprocated wire electrical discharge machining (wire-EDM). To ensure machining accuracy, a gravity takeup for maintaining constant wire tension and a unit for suppressing the wire vibration are designed and fabricated, respectively. Besides, the effects of processing parameters on rotating groove width are investigated by conducting preliminary experiments, showing that high open voltage, discharge capacitance and revolving speed, and low discharge resistance and wire tension cause larger rotating groove width. Nevertheless, the rotating groove width firstly decreases with the reference voltage and feed rate increase in the initial stage and then increases when applying higher values. Based on the preliminary experiments, the proper processing parameters are determined and are used for machining micro bellows core-mould. Ultimately, the micro bellows core-mould is successfully machined by micro reciprocated wire-EDM, exhibiting high machining accuracy, excellent geometric shape and uniformity. Specifically, the machining errors along the axial direction and the radial direction of the micro bellows core-mould are less than 1.4 µm and 2.3 µm, respectively.

This paper discusses fabrication method of the rotating structure using microwire electrical discharge machining (micro-WEDM). A high-speed rotating spindle has been designed and installed to in-house developed micro-WEDM equipment with two axis to enable the processing microrotating structure. In order to realize high-precision processing, a numerical control program creator for micro-WEDM has been developed based on CAD/CAM technology, and the precise processing code can be obtained to complete the microrotating structure. In this study, a central composite design testing with 3-factor and 5-level is used for experimental plan. And the second-order relational model is established by using response surface methodology, which used to examine the influences of three parameters (open voltage, discharge capacitance, and revolving speed of workpiece) on the material removal rate (MRR). Finally, experimental results prove that the parameters have significant effect on the MRR.

This paper develops an array micro-grooves manufacturing method using micro electrochemical machining (ECM) with disk electrode, which is prepared by in-situ micro wire electrical discharge machining (WEDM). This technology focuses on the difficulty of array structure manufacture in micro-electro-mechanical systems (MEMS). A micro-ECM system is built based on the micro-WEDM machine to achieve high precision processing of the array micro-grooves. Since micro-WEDM has good performance in high precision machining of the rotating structure, single and multi-edge disk electrodes can be fabricated in-situ using graphite. The as-prepared disk tool electrode is directly used for micro-electrochemical milling of the array micro-grooves without disassembling away from the device, which avoids the positioning error caused by the re-clamping of the disk electrode. With the advantages of high surface quality and no electrode loss, micro-ECM improves the manufacture performance of the micro-parts. Through wire path optimization, the shape accuracy of the disk edge is improved. After the research of the micro-ECM parameters, the process is improved, and finally, the high precision array micro-grooves are obtained. This method combines the advantages of micro-WEDM and disk electrode micro-ECM milling, and it is convenient for large-scale manufacture of array micro-structures on micro-parts and MEMS.