ORIGINAL ARTICLE Toolpath generation and finishing of bio-titanium alloy using novel polishing tool in MFAF process Anwesa Barman 1 & Manas Das 1 Received: 8 February 2017 /Accepted: 1 September 2017 # Springer-Verlag London Ltd. 2017 Abstract Nanofinishing of biomaterials is a necessary pro- cess to lengthen the prosthetic life and performance. Here, Magnetic Field Assisted Finishing (MFAF) process is used to finish biomaterials in the nanometer level. MFAF process uses Magnetorheological (MR) fluid mixed with abrasive particles as the polishing medium. In this study, titanium is used as the workpiece material. A specially designed tool is used to carry out the nanofinishing process. Two types of path planning i.e. parallel and spiral tool path are adopted during finishing. The surface roughness and surface texture differ for each generated tool path. The surface roughness generated from each of the path planning processes is analyzed and it is found that parallel toolpath generates lowest surface roughness (~10 nm) with better surface texture than spiral toolpath. Hence, the parallel toolpath is considered as the op- timum toolpath for finishing biomaterials in MFAF process. Experimental investigations using parallel tool path are carried out to explore the capability of the developed novel tool along with the determination of the optimum range of the process parameters to explore finishing capability. Preliminary experimental study shows that best surface finish and surface topography is achieved using 1200 rpm tool rotational speed, 1 mm working gap, and 6.30 h. finishing time. Keywords Nano-finishing . Biomaterials . MR fluid . Toolpath . Permanent magnet 1 Introduction In this era, the medical industry took a huge leap forward by using biomaterials to make implants. Metals are more favorable as a biomaterial as they are easier to manufacture and more durable as an implant. Titanium and titanium alloys are exten- sively used as biomaterials [1]. The properties of titanium and its alloys are corrosion resistance, inertness, low toxicity, and dura- bility which favored them as biomaterials [2]. Titanium alloy also has better tensile strength and yield strength than other biomaterials [3]. Biomaterials polishing is very important to in- crease the functionality and durability of implants. Different finishing processes are used to finish bio-titanium alloy. Researchers used chemical mechanical polishing process to fin- ish bio-titanium alloys (e.g. [4–7]). Electropolishing is also a very popular method for finishing titanium alloy [8]. Some re- searchers also reported other finishing processes like large area electron beam radiation [9], lapping film [10], ultrasonic vibration-assisted magnetic abrasive finishing [11] for finishing titanium alloy. The surface quality of implants requires mirror finish in the nanometer level [12]. The nanometer level surface finish can be achieved by some of the polishing processes men- tioned above. However, to achieve the required accuracy and better control over the finishing forces, the above mentioned processes are not adequate. Hence, to achieve efficiently con- trolled nanometer level mirror finish with better accuracy, the above mentioned processes are not competent enough. Magnetic Field Assisted Finishing (MFAF) process produces nanometer level surface finish with better control on finishing forces [13] than most of the available finishing processes for polishing tita- nium alloy. Hence, in the present study, this process is chosen as the finishing process for polishing bio-titanium alloy. MFAF process is one of the newly developed processes which utilizes right composition of polishing fluid to provide nano-level finishing. This process generates very less sub- * Manas Das manasdas@iitg.ernet.in 1 Department of Mechanical Engineering, IIT Guwahati, Guwahati, Assam 781039, India Int J Adv Manuf Technol DOI 10.1007/s00170-017-1050-2