Bayat Mohammad, Adibi Hamed, Barzegar Amin, Rezaei Seyed Mehdi
Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, P.O.B. 158754413, Iran.
Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, P.O.B. 158754413, Iran.
J Mech Behav Biomed Mater. 2022 Jul;131:105226. doi: 10.1016/j.jmbbm.2022.105226. Epub 2022 Apr 9.
Zirconia bioceramics has tremendous potential in medical applications owing to biocompatibility and high mechanical properties. Meanwhile, thermal damage and surface defects limit the grindability to achieve the desired properties. Therefore, this research provides an investigation of various grinding parameters on heat generation and surface morphology using a diamond wheel. In addition, a triangular and parabolic moving heat flux is used for heat distribution analysis based on FEM-model. The parabolic model more corresponds to experimental compared to the triangular heat flux, with an average deviation of <5% and 6.5% under dry and MQL, respectively. The response surface methodology is applied to extract a statistical representation of inputs and outputs. Dry grinding temperature obtained in range of 200-540 °C, which by applying MQL, it decreased by 16-35%. Increasing cutting depth would worsen the MQL efficiency in force and temperature. Results indicate the impact of cutting depth on temperature and force is greatest, followed by the effect of feed-rate, and that of wheel speed is the least. Thus, the increasing feed-rate should be utilized to preserve the high removal rate. SEM images indicate material removal mechanism is accomplished by plastic and brittle mode. Furthermore, MQL and a combination of low depth of cut could effectively decline the surface roughness and defects formation by decreasing the brittle material removal mechanism in one step. MQL reduced surface roughness by 46% compared with dry grinding, so that its performance increase in higher cutting depth. Because at higher cutting depths, the MQL changes the prevailing chip removal mechanism from brittle to ductile-regime grinding.
由于生物相容性和高机械性能，氧化锆生物陶瓷在医学应用中具有巨大潜力。同时，热损伤和表面缺陷限制了其磨削性能以达到所需性能。因此，本研究使用金刚石砂轮对各种磨削参数对热生成和表面形貌的影响进行了研究。此外，基于有限元模型，采用三角形和抛物线形移动热通量进行热分布分析。与三角形热通量相比，抛物线模型与实验结果更相符，在干磨和微量润滑条件下的平均偏差分别<5%和6.5%。应用响应面方法来提取输入和输出的统计表示。干磨温度范围为200-540°C，通过应用微量润滑，温度降低了16-35%。增加切削深度会使微量润滑在力和温度方面的效率变差。结果表明，切削深度对温度和力的影响最大，其次是进给速度的影响，而砂轮速度的影响最小。因此，应利用增加进给速度来保持高去除率。扫描电子显微镜图像表明，材料去除机制是通过塑性和脆性模式完成的。此外，微量润滑和低切削深度的组合可以通过一步减少脆性材料去除机制，有效地降低表面粗糙度和缺陷形成。与干磨相比，微量润滑使表面粗糙度降低了46%，因此在较高切削深度下其性能有所提高。因为在较高切削深度下，微量润滑将主要的切屑去除机制从脆性磨削转变为延性磨削。
