Unconventional Applications of Electrical Discharge Machining

放电加工的非常规应用

• 批准号: RGPIN-2014-06529
• 负责人: Koshy, Philip
• 金额: $ 1.97万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=589069
• 关键词: Unconventional; Applications; Electrical; Discharge; Machining

Electrical discharge machining (EDM) is a precision material removal process that utilizes the heat generated from controlled, rapid electrical spark discharges struck between the tool and workpiece electrodes, in the presence of a dielectric fluid. Traditionally, the application domain of EDM has referred to the machining of difficult-to-cut materials, as the thermal mechanism of material removal is not limited by the hardness and toughness of the workpiece material, in contrast to cutting processes that entail plastic deformation. EDM has further been applied in the machining of geometric features such as internal cavities with sharp corners. The process is also used to machine thin/fragile workpieces, on account of the associated forces being relatively negligible due to there being no physical contact between the tool and the workpiece. As material removal in EDM entails localized melting and vaporization at the micro-scale, the generated surface comprises a large number of microscopic, overlapping craters. Accordingly, EDM is one of the very few manufacturing processes with the capability to generate surfaces with a positive skewness. This means that the surface comprises peaks interspersed among relatively wide valleys such that the height distribution is skewed to the right, which makes the surface ideally predisposed towards the novel applications that will be investigated in the proposed research. EDM further offers the flexibility to tailor the size and aspect ratio of the characteristic craters that collectively constitute the texture towards a specific application. This offers the exciting prospect of achieving even conflicting functional requirements, such as a reduction or enhancement of friction, in the same process by appropriately tuning the pulse parameters. In the context above, the objective of the proposed research is primarily to explore innovative, unconventional applications of EDM wherein material removal is not the primary intent per se, but rather a means to the end of engineering the topography of a surface towards realizing a specific functional attribute. In particular, the proposed work will refer to scientific investigations into: (1) the role of an EDM texture in providing nucleation sites for bubbles towards enhancing boiling heat transfer, with applications in the power generation and electronics industries, (2) texturing of automotive piston rings so as to enhance lubricant ingress and retention for reducing friction towards enhanced engine performance and fuel efficiency, (3) imparting an appropriate texture on metallic biomedical implants with a view to facilitating their integration into the bone structure, and (4) the use of EDM for the fabrication of water-repellent, self-cleaning surfaces with applications in the aerospace, marine and automotive industries. The research will further examine the application of EDM in texturing tooling surfaces in order to enhance adhesion between the substrate and a coating, explore the effect of an EDM texture on the drag against a moving fluid, and investigate the mechanism by which an EDM texture could be engineered to increase surface traction.

放电加工 (EDM) 是一种精密材料去除工艺，在存在介电流体的情况下，利用工具和工件电极之间受控的快速电火花放电产生的热量。传统上，电火花加工的应用领域是指难切削材料的加工，因为与需要塑性变形的切削过程相比，材料去除的热机制不受工件材料的硬度和韧性的限制。电火花加工还进一步应用于几何特征的加工，例如带有尖角的内腔。该工艺还用于加工薄的/易碎的工件，因为由于工具和工件之间没有物理接触，相关的力相对可以忽略不计。 由于电火花加工中的材料去除需要在微观尺度上进行局部熔化和汽化，因此生成的表面包含大量微观的、重叠的凹坑。因此，EDM 是极少数能够生成正偏度表面的制造工艺之一。这意味着该表面包括散布在相对较宽的谷中的峰，使得高度分布向右倾斜，这使得该表面非常适合将在拟议的研究中研究的新颖应用。 EDM 还提供了定制特征凹坑的尺寸和纵横比的灵活性，这些凹坑共同构成了特定应用的纹理。这提供了令人兴奋的前景，即通过适当调整脉冲参数，在同一过程中实现甚至相互冲突的功能要求，例如减少或增强摩擦。 在上述背景下，拟议研究的目标主要是探索 EDM 的创新、非常规应用，其中材料去除本身并不是主要目的，而是最终对表面形貌进行工程设计以实现特定目标的一种手段。功能属性。特别是，拟议的工作将涉及以下方面的科学研究：(1) EDM 织构在为气泡提供成核位点以增强沸腾传热方面的作用，在发电和电子行业中的应用，(2) 汽车织构活塞环，以增强润滑剂的进入和保留，从而减少摩擦，从而提高发动机性能和燃油效率，（3）在金属生物医学植入物上赋予适当的纹理，以促进其融入骨结构中，以及（4）使用用于制造的 EDM防水、自清洁表面，应用于航空航天、船舶和汽车行业。该研究将进一步研究电火花加工在纹理化工具表面的应用，以增强基材和涂层之间的附着力，探索电火花加工纹理对移动流体阻力的影响，并研究电火花加工纹理可以产生的机理。旨在增加表面牵引力。