线切割与真空热扩散焊组合工艺制备微模具

采用线切割和真空压力热扩散焊组合工艺制备了高深宽比的三维微结构。分别研究了线切割与热扩散焊工艺并获得了较好的工艺参数用于制备微模具。首先,在脉冲宽度为10μs,脉冲间隔为40μs,线切割电流为0.28A,电压为60V的条件下,对100μm厚的铜箔进行线切割,获得了多层二维微结构。然后,在热扩散温度为850℃,热扩散时间为10h,压力为1.0μPa的工艺参数作用下,对多层铜箔二维微结构进行真空压力热扩散焊接,通过多层二维微结构的叠加形成微模具,并制备了六棱台微型腔模具及微型级联齿轮模具。实验结果表明:三维微模具表面形貌较好,制作结果较理想,与设计模型基本相符。最后,通过超声模压成型分别获得了二阶和三阶的塑料级联齿轮。这些微塑件质量良好,验证了该工艺方法的可行性。

Laminated fabrication of micro-mold based on WEDM and thermal diffusion welding

A 3D micro-structure with a high aspect ratio was fabricated by combining Wire Electrical Discharge Machining(WEDM) and vacuum pressure thermal diffusion welding. The WEDM and thermal diffusion welding were researched, and the better technological parameters were obtained to fabricate a micro-mold. Firstly, a copper foil with a thickness of 100 μm was cut to obtain a multi-layer 2D micro-structure under the conditions of a pulse width of 10 μs, a pulse interval of 40 μs, a wire cutting current of 0.28 A and a voltage of 60 V. Then, the 2D micro-structure of a multilayer copper foil was fabricated by vacuum pressure thermal diffusion welding under the technological parameters in a thermal diffusion temperature of 850°C, a thermal diffusion time of 10 h and a pressure of 1.0 μPa. The multilayer copper 2D microstructure was connected together by vacuum pressure thermal diffusion welding to fit into a six frustum pyramid mold and gear molds with two-stage steps and three-stage steps, respectively. Experimental results indicate that the 3D micro-mold with good surface quality is an ideal fabrication and fits to design models. Finally, based on ultrasonic powder molding, two-stage and three-stage plastic gears are respectively obtained. These micro plastic parts show good quality, which verifies the feasibility and usability of laminated micro molds.