Erosive jet micro-machining and vibratory surface finishing: optimization and modeling

拟议的研究涉及两种制造工艺：A) 侵蚀喷射微加工和 B) 振动表面精加工。这两种工艺都涉及通过控制腐蚀来去除材料，并且还可以用于改变金属、陶瓷和塑料的表面特性。侵蚀喷射微加工使用带有磨料颗粒的高速空气喷射（磨料喷射微加工，AJM）或带有磨料颗粒的水喷射（磨料浆喷射微加工，ASJM）。这两种技术都具有巨大的潜力，可以作为通用、低成本、环保的方法来制造小尺寸特征，而这些特征很难用铣削和酸蚀刻等传统技术来制造。潜在的应用范围极其广泛，从航空航天（例如涡轮叶片）到微流体、光电子和微电子中使用的组件。此外，AJM 和 ASJM 不涉及危险的蚀刻化学品，并且不会受到工具磨损、振动或加热的影响。拟议的研究将探索在不使用抗腐蚀掩模的情况下以“直写”模式对玻璃和陶瓷部件进行 AJM 的可能性。这将是降低成本和缩短加工时间方面的重大突破，但需要更加高度关注喷砂区域才能使之成为现实。 ASJM 已经可以制造更小的特征，因为它使用液体磨料浆料射流，我们计划扩展我们在磨料浆料中使用长链聚合物添加剂的现有工作，以增加射流的聚焦。这对于金属部件的微加工研究具有重要价值，特别是那些通常在极端温度下实现耐磨性和高强度的先进超硬材料。使用其他方法很难对这些材料进行微加工。因此，我们计划的另一部分是探索 ASJM 与电化学微加工（ECM，一种集中腐蚀）相结合的可能性，以加快此类金属材料的加工速度。振动表面精加工是一种广泛用于去毛刺、抛光、抛光、纹理、硬化和清洁金属、陶瓷和塑料零件的制造工艺。固体颗粒床（典型尺寸为 1 厘米）通过振动而流化，并形成循环流，部件被夹带进入其中并受到冲击介质的作用。拟议的研究将开发模型来描述局部颗粒撞击速度与许多过程参数（例如颗粒的形状和容器壁的振动）之间的关系。有关颗粒冲击速度的信息对于预测表面精加工的速率和程度至关重要。鉴于仅安大略省就有超过 2,000 台振动精加工机，用于各种行业和应用，例如去除钢板冲压件中的毛刺、金属和塑料铸件中的分型线、高压电气连接器中的硬化和纹理、塑料和金属的抛光以及零件清洁（与 Vibra Finish Ltd. 的 L. Nichol 博士的个人通讯），这可能会带来巨大的好处。此外，该研究的各个方面将适用于涉及侵蚀磨损和流动颗粒介质冲击的各种相关过程（例如磨料流加工、流化床加工、离心盘精加工、抛光和滚磨、拖动精加工）。

The proposed research pertains to two manufacturing processes: A) erosive jet micro-machining and B) vibratory surface finishing. Both processes involve the controlled application of erosion to remove material, and can also be used to change the surface properties of metals, ceramics and plastics. Erosive jet micro-machining uses either high-speed jets of air with abrasive particles (abrasive jet micro-machining, AJM) or jets of water with abrasive particles (abrasive slurry jet micro-machining, ASJM). Both techniques have great potential as versatile, low-cost, environmentally-friendly approaches to the fabrication of small-scale features that are difficult to make with traditional techniques such as milling and acid etching. Potential applications span an extremely wide range from aerospace (e.g. turbine blades) to components used in micro-fluidics, optoelectronics and microelectronics. Moreover, AJM and ASJM do not involve hazardous etching chemicals, and do not suffer from tool wear, vibration, or heating. The proposed research will explore the possibility of the AJM of glass and ceramic components without the use of erosion resistant masks, in a “direct-write” mode. This would be a major breakthrough in reducing costs and machining times, but the blast zone needs to be more highly focused to make this a reality. ASJM can already make smaller features, since it uses a liquid abrasive slurry jet, and we plan to extend our existing work on the use of long-chain polymer additives in the abrasive slurry to increase the focusing of the jet. This will be of significant value in the proposed research on the micro-machining of metallic components, particularly those advanced ultra-hard materials that are used to achieve wear resistance and high strength, often at extreme temperatures. These materials are very difficult to micro-machine using other approaches. Therefore, another part of our plan is to explore the possibility that ASJM can be combined with electro-chemical micro-machining (ECM, a type of focused corrosion) to accelerate the rate at which such metallic materials can be machined.Vibratory surface finishing is a widely-used manufacturing process for deburring, polishing, burnishing, texturing, hardening and cleaning metal, ceramic and plastic parts. A bed of solid particles (typical dimension 1 cm) is fluidized using vibrations and develops a circulatory flow into which parts are entrained and become subject to the action of the impacting media. The proposed research will develop models to describe the relationships between the local particle impact velocity and the many process parameters, such as the shape of the particles and the vibrations of the container walls. This information concerning the particle impact velocities is of fundamental importance to the prediction of the rate and extent of surface finishing. This could be of significant benefit given that there are in excess of 2,000 vibratory finishing machines in Ontario alone, used in a wide variety of industries and applications such as removing burrs in steel stampings, parting lines in metal and plastic castings, hardening and texturing in high-voltage electrical connectors, polishing of plastics and metals, and parts cleaning (personal communications with Dr. L. Nichol, Vibra Finish Ltd.). Furthermore, aspects of the research will be applicable to a variety of related processes involving erosive wear and the impact of flowing granular media (e.g. abrasive flow machining, fluidized bed machining, centrifugal disk finishing, polishing and tumbling, drag finishing).