Świercz Rafał, Oniszczuk-Świercz Dorota
Institute of Manufacturing Technology, Warsaw University of Technology, 00-661 Warsaw, Poland.
Sports (Basel). 2019 Mar 21;7(3):71. doi: 10.3390/sports7030071.
Electrical discharge machining (EDM) is an advanced technology used to manufacture difficult-to-cut conductive materials. However, the surface layer properties after EDM require additional finishing operations in many cases. Therefore, new methods implemented in EDM are being developed to improve surface characteristics and the material removal rate. This paper presents new research about improving the surface integrity of 55NiCrMoV7 tool steel by using reduced graphene oxide (RGO) flakes in the dielectric. The main goal of the research was to investigate the influence of RGO flakes in the dielectric on electrical discharge propagation and heat dissipation in the gap. The investigation of the influence of discharge current and pulse time during EDM with RGO flakes in the dielectric was carried out using response surface methodology. Furthermore, the surface texture properties and metallographic structure after EDM with RGO in the dielectric and conventional EDM were investigated and described. The obtained results indicate that using RGO flakes in the dielectric leads to a decreased surface roughness and recast layer thickness with an increased material removal rate (MRR). The presence of RGO flakes in the dielectric reduced the breakdown voltage and allowed several discharges to occur during one pulse. The dispersion of the discharge caused a decrease in the energy delivered to the workpiece. In terms of the finishing EDM parameters, there was a 460% reduction in roughness with a uniform distribution of the recast layer on the surface, and a slight increase in MRR (12%) was obtained.
电火花加工（EDM）是一种用于制造难切削导电材料的先进技术。然而，在许多情况下，电火花加工后的表面层性能需要额外的精加工操作。因此，正在开发电火花加工中实施的新方法，以改善表面特性和材料去除率。本文介绍了一项关于在电介质中使用还原氧化石墨烯（RGO）薄片来改善55NiCrMoV7工具钢表面完整性的新研究。该研究的主要目标是研究电介质中的RGO薄片对间隙中放电传播和散热的影响。使用响应面方法对电介质中含有RGO薄片的电火花加工过程中放电电流和脉冲时间的影响进行了研究。此外，还对电介质中含有RGO的电火花加工和传统电火花加工后的表面纹理特性和金相组织进行了研究和描述。所得结果表明，在电介质中使用RGO薄片可降低表面粗糙度和重铸层厚度，并提高材料去除率（MRR）。电介质中RGO薄片的存在降低了击穿电压，并允许在一个脉冲期间发生多次放电。放电的分散导致传递到工件的能量减少。在电火花加工精加工参数方面，粗糙度降低了460%，重铸层在表面均匀分布，材料去除率略有提高（12%）。
