Development of Ice-Jet Machining Technology

9312980戈登：这项研究的总体目标是开发一种基于高速水冰微粒混合物(冰喷)的实用成型和研磨技术。所获得的知识将用于设备设计、操作条件的选择和技术能力的演示。初步实验已经在高速水流中产生了一些冰。这项工作中的主要技术不确定性是实际实施中可以实现的冰水比。将研究几种方法，但其中一种是受欢迎的，因为它至少在一定程度上显然会奏效，而且实施起来相对简单。所需的技术可单独或结合使用：(1)冷却水进入喷嘴时的使用；水出来时的减压和混合，使其进入湍流、过冷状态，这将在微秒时间尺度上产生冰。(2)在减压过程中，使用液态二氧化碳或其他低温流体作为气流的一部分，以实现进一步冷却。(3)与传统磨料水射流一样，在水流中夹带冰粒。(4)将水射流(WJ)注入水冰层。第二个不确定的领域涉及冰粒作为研磨介质的有效性。将开发一种形成冰射流的实用程序，并将研究产生的冰射流与各种工程材料的相互作用。实验将在各种工艺变量(压力、温度、流量)以及喷嘴和混合室的各种设计下进行。将密切监测温度变化和生成的颗粒的大小。将确定IJ加工的参数，并确定IJ加工的实际使用范围。这项研究的最终结果将是设计一个IJ加工的中试工厂。预计所开发的IJ将结合激光(高材料去除速率、去除多种工程材料的能力，以及所需的小光束直径)和WJ(清洁度、高持续功率、宽范围的流动横截面、工艺控制简单、最小加热和有限的损伤面积)的优点。这样的功能组合将使开发一种用于材料成型、研磨和清洁的有效、灵活的工具成为可能。IJ的预期用途包括多层电路板上小直径孔(5密耳)的高生产率钻孔、食品加工、超大型金属和玻璃表面的精密研磨以及生物工程/医疗应用。这一努力的成功将产生一种有效和多产的替代激光和水射流加工的方法，这将有助于清洁和抛光硬材料以及高速切割食物和活组织。

9312980 Gordon The overall goal of the research is to develop a practical shaping and grinding technology based on the use of a high speed water ice microparticle mixture (icejet). The acquired knowledge will be used for equipment design, selection of operational conditions, and demonstration of the capability of the technology. Preliminary experiments have yielded some ice in a high velocity water stream. The main technical uncertainty in the work is the ratio of ice to water that can be achieved in practical implementations. Several approaches will be studied, but one is favored because it will clearly work to at least some extent and is relatively straightforward to implement. The desired technology may include the following, individually or in combination: (1) The use of cooled water as it enters the nozzle; decompression and mixing of the water as it emerges, putting it into a turbulent, supercooled state which will produce ice on a microsecond time scale. (2) Use of liquid CO2 or other low temperature fluid as part of the stream to achieve further cooling during decompression. (3) Entrainment of ice particles in the stream as in conventional abrasive waterjet. (4) Injection of a waterjet (WJ) into a water ice layer. A second area of uncertainty involves the effectiveness of ice particle as an abrasive medium. A practical procedure for icejet formation will be developed and the interaction of the resulting jet with various engineering materials will be investigated. The experiments will be conducted under a wide variety of process variables (pressure, temperature, flow rate) and various designs of the nozzle and mixing chamber. The temperature change a nd size of generated particles will be closely monitored. Parameters for IJ machining will be established and the range of practical use of IJ machining will be identified. The end result of the study will be a design for a pilot plant for IJ machining. It is anticipated that the developed IJ will combine the positive features of a laser (the high material removal rate, ability to remove a wide variety of engineering materials, and small beam diameter when desired) and a WJ (cleanliness, high continuous power, a wide range of flow cross section areas, simplicity of the process control, minimal heating, and limited damage area). Such combination of features will enable development of an effective, flexible tool for material shaping, grinding and cleaning. The expected use of IJ includes such fields as high productivity drilling of small diameter holes (5 mils) in multilayer circuit boards, food processing, precision grinding of very large metal and glass surfaces, and bioengineering/medical applications. Success in this endeavor will result in an effective and productive alternative to laser and waterjet machining that would be useful for cleaning and polishing hard materials and for high speed cutting of food and live tissue.