SGER: High Pressure Dynamic Piercing of Microholes

微孔，直径200-300微米的孔，应用于MEMS，气动传感器和机械手，流体过滤器，燃油喷射喷嘴，生物医学过滤器，喷墨打印机喷嘴，光学孔径，高压孔，测试材料的标准缺陷，微移液器，线粘接导轨和旋转喷嘴。各种微加工方法，如微钻和微电火花加工，可以生产出高精度的这些孔。然而，它们的生产速度往往不足以用于生产线。这项SGER研究的目的是通过高压液体脉冲而不是固体冲孔来制造微孔。研究策略是通过动水压力抑制板材的自然延展性，并在模具角处产生剪切局部化，以形成直孔和无毛刺孔。建议先从铜板开始，然后是铝板和不锈钢板。在这种方法中存在许多科学和技术挑战，包括在中尺度上精确设计和组装工具，动态高压脉冲工具的密封，板材材料在尺度上的动态行为，其中晶粒尺寸和微观非均质性效应不可忽视，以及微摩擦学问题，如板材/毛坯夹头界面的摩擦。在这项研究中产生的知识和理解将有利于微观和中观制造的研究和教学，特别是微成形。

Micro-holes, holes of 200-300 um diameter, have applications in MEMS, pneumatic sensors and manipulators, fluidic filters, fuel injection nozzles, bio-medical filters, ink jet printer nozzles, optical apertures, high pressure orifices, standard defects for testing materials, micropipettes, guides for wire-bonders and spinning nozzles. Various micromachining methods such as microdrilling and micro-EDM can produce these holes with a high degree of accuracy. However, their production rates are often insufficient for production line use. The objective of this SGER research is to create microholes by means of a high-pressure liquid pulse instead of solid punches. The research strategy is to suppress the natural ductility of the sheet material by hydrodynamic pressure and create shear localization at the die corners to initiate a straight and burr free hole. It is proposed to start with copper sheets followed by aluminum and stainless. There are many scientific and technological challenges in this approach including the design and assembly of tooling with precision in the mesoscale, sealing of the tooling for dynamic high pressure pulse, dynamic behavior of the sheet material at a scale where the grain size and micro-hetrogeniety effects cannot be ignored, and micro-tribological issues such as friction at the sheet /blank holder interface. Knowledge and understanding generated in this research will benefit micro and meso manufacturing research and teaching in general, and microforming in particular.