Rajput Atul Singh, Kapil Sajan, Das Manas
Department of Mechanical Engineering, Indian Institute of Technology, Guwahati, Assam, India.
3D Print Addit Manuf. 2024 Jun 18;11(3):e1380-e1393. doi: 10.1089/3dp.2023.0028. eCollection 2024 Jun.
Additive manufacturing or 3D printing provides the benefits of individualizing the implant per patient requirements. However, the poor surface quality of additively manufactured biomaterial is a major limitation. Hence, hybrid-electrochemical magnetorheological (H-ECMR) polishing is developed to improve the surface quality of fabricated parts. H-ECMR finishing is an advanced surface polishing operation that avails the synergic action of mechanical abrasion and the electrochemical reaction to enhance the surface quality of the workpiece without hampering its surface topography. Furthermore, the developed H-ECMR finishing process reduces the finishing time and produces a uniform surface quality compared with the conventional magnetorheological (MR) finishing process. However, the surface finishing of the parts having a hole-of-pocket feature through the H-ECMR finishing process is a major challenge as MR fluid gets trapped inside those holes or pockets. A feature-based hybrid H-ECMR finishing process is developed to resolve the issue. In this case, paraffin wax is applied to the holes and pockets before the H-ECMR process occurs. In the present work, bone plates are fabricated through selective laser melting, and their surface quality is further enhanced through the H-ECMR finishing process. Bone plates are necessary to provide mechanical stability during bone fracture healing by adapting to the chemical environment. The final value of 21.37 nm is attained from 9.36 μm through H-ECMR finishing. Pin-on-disk study is carried out on the biomaterial to analyze its wear resistance. The surface topography of the workpiece is analyzed through scanning electron microscopy before and after finishing, and it was observed that a uniform surface is achieved after polishing. Apart from the average surface roughness ( ), other roughness parameters such as skewness ( ) and kurtosis ( ) are analyzed to study the attribute of the surface irregularities.
增材制造或3D打印具有根据每位患者的需求定制植入物的优势。然而，增材制造生物材料的表面质量较差是一个主要限制因素。因此，开发了混合电化学磁流变（H-ECMR）抛光技术来提高制造零件的表面质量。H-ECMR精加工是一种先进的表面抛光工艺，它利用机械磨损和电化学反应的协同作用来提高工件的表面质量，同时又不影响其表面形貌。此外，与传统的磁流变（MR）精加工工艺相比，所开发的H-ECMR精加工工艺缩短了精加工时间，并产生了均匀的表面质量。然而，通过H-ECMR精加工工艺对具有孔或腔特征的零件进行表面精加工是一项重大挑战，因为磁流变液会被困在这些孔或腔内。为了解决这个问题，开发了一种基于特征的混合H-ECMR精加工工艺。在这种情况下，在H-ECMR工艺进行之前，将石蜡涂覆在孔和腔上。在本研究中，通过选择性激光熔化制造骨板，并通过H-ECMR精加工工艺进一步提高其表面质量。骨板对于在骨折愈合过程中通过适应化学环境来提供机械稳定性是必不可少的。通过H-ECMR精加工，表面粗糙度最终值从9.36μm降至21.37nm。对该生物材料进行了销盘试验以分析其耐磨性。通过扫描电子显微镜对精加工前后工件的表面形貌进行了分析，结果发现抛光后获得了均匀的表面。除了平均表面粗糙度（ ）之外，还分析了其他粗糙度参数，如偏度（ ）和峰度（ ），以研究表面不规则性的属性。
