Among the nontraditional milling processes, abrasive water jet (AWJ) is a cold machining technique for producing surface textures on a wide variety of materials. This article reports the feasibility study of producing biomedical implant surface pattern on stainless steel 304 using controlled deposition of AWJ milling. Preliminary investigation on the AWJ-milled surface pattern was carried out through the controllable milling parameters such as fluid pressure, stand-off distance (SOD), nozzle feed rate and garnet flow rate. The preliminary observations made in this study were the depth of cut, metal removal rate, and surface roughness for the evaluation of milled surface characteristics. The multicriteria technique, i.e., Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), was carried out for the selection of the process parameter settings through the efficient use of preliminary observations considered in this study. Surface morphology, topography and their features in the AWJ-milled surface pattern of stainless 304 were examined on the basis of selected parameter settings. The result confirmed the feasibility of producing a rough spot groove texture through controlled deposition of AWJ milling operations. Results of this study can be highly helpful for dental implant manufacturing industries in the production of a precise surface pattern on biomaterials.

Electrochemical micromachining (EMM) is an effective technique for creating micro features in difficult to cut materials like super alloys. Nimonic 75 a super alloy is used to fabricate the aero combustor parts as it can withstand hot gases during the gas turbine operations. In EMM process, Nimonic 75 alloy of thickness 500 μm has been machined by applying two combination of electrolytes. A solid tungsten carbide with a diameter of 500 μm has been used as the tool in the present examination. The variable process parameters considered are machining voltage, micro tool feed rate and duty ratio and their influence on performance characteristics namely circularity entry, exit and surface roughness were studied. By using multi-response technique TOPSIS, the best combination of process parameter is found. SEM was employed to observe the morphology of the machined surfaces.

No abstract

Electrochemical micromachining is one among the widely known method for machining micro holes in electrically conductive, hard to cut materials. As nimonic 75 alloy can withstand alternate cooling and heating conditions, it finds application in aero combustor liner. In this study, solid tungsten carbide (500µm) was selected as the tool to produce micro holes in the work-piece (nimonic 75 alloy). As pulsed current, results in more confined dissolution, trials were performed by changing electrical process parameter such as duty cycle, pulse on period and pulse off period and their effect on MRR and dimensional deviation were studied. Employing TOPSIS, lower values of duty cycle and pulse on period was desirable for the production of holes with better geometrical features and the similar was found to be in concurrent with SEM images.