Parametric Optimization of Magnetic Abrasive Finishing Using Adhesive Magnetic Abrasive Particles

1. Introduction

The need for precise surface finish in many industrial components such as vacuum tubes and sanitary tubes is highly desirable which is difficult to attain by traditional methods finishing such as lapping. Conventional finishing methods causes many defects on surface being finished. Such finishing processes should be performed under gentle conditions to minimize the defects. A relatively new finishing process, magnetic abrasive finishing (MAF) is a propelled finishing process where the cutting power is essentially constrained by the magnetic field. It limits the likelihood of microcracks on the outside of the workpiece, especially in hard fragile material, because of controlled less forces following up on abrasive particles. MAF is observed to be a flexible process for finishing interior, outer, flat and complex molded surfaces. The technique can machine ferromagnetic materials, for example steel also non-magnetic materials for example aluminum and brass. Wang and Hu (2005) studied surface finishing of tubular type workpieces by MAF. They concluded minimum Ra obtained was less than 0.3 µm. They used aluminum alloy, stainless steel and brass as work specimens. Yamaguchi et al. (2005) proposed the finishing of SUS304 stainless steel bent tubes using aluminum oxide composite magnetic abrasive with a mean diameter of 80 μm. It contains Al₂O₃ sintered MAPs with particle size lower than 10 μm in an inert gas environment with high pressure and temperature. Particularly, the use of 150 μm iron particles was more effective than 330 μm iron particles. Hanada (2008) proposed MAF of capillary tubes using new spherical magnetic abrasive particles (MAPs) containing diamond particles. These MAPs were developed by using a plasma spraying technique. The experimentation showed that the developed MAPs have good performance as a new MAPs for finishing of capillary tubes. Wang and Lee (2009) ulitized gel abrasive in MAF to polish the steel rod. The authors reported that SR was decreased considerably after 10 min, and SR reduced as minimum as 0.038 μm Ra after 30 min. Sran et al. (2010) described main techniques to fabricate the MAPs and concluded that the sintered magnetic abrasive particles (MAPs) showed better performance than all other types of MAPs. Rahul et al. (2010) investigated performance evaluation of developed MAF set up in terms of percentage change in SR (ΔRa). Response surface methodology was employed for designing the experiments. The minimum SR value achieved was 51 nm. Singh et al. (2011) developed Al₂O₃ based sintered MAPs by sintering machine. Brass as work specimen finished internally. RSM technique was used for process optimization. The best surface finish achieved was 0.05 μm Ra. Patil et al. (2012) employed a mechanical alloying technique to fabricate MAPs. The MAPs contain iron powder and silica. The experiments depict the use of mechanically alloyed silica-based abrasives for finishing of stainless steel 304 tubes. Kang at al. (2013) investigated the finishing of SUS 304 stainless steel bent tubes using MAF. The diamond based sintered MAPs were used finishing tool. It was reported that Percent improvement in surface finish (PISF) was significantly affected by machining time, % of diamond abrasives, rotational speed. Deepak and Bharat (2017) performed MAF of Aluminum 6063 tube with emery as abrasive particles. The authors concluded that PISF increased with increased current, increased grit size up to 180, increased circumferential speed up to 180 rpm. Zhang et al. (2018) polished 316L stainless steel surfaces by MAF with G50 steel grits having average diameter of 500 μm as the abrasives. It was concluded that the surface parallel to build direction has higher polishability as compare to transverse surface. Munyensanga et al. (2018) employed MAF process for polishing AISI 316L stainless steel ball bearing. It was described that the MAF process tend to machine the best surface finish (Ra) with 0.0766 µm value at the optimal finishing conditions.

The available literature reported that considerable research work has been done on various aspects of internal surface finishing by using MAF process. Most of the work has been done on finishing of steel tubes surface, no work has been done on internal surface finishing of aluminum pipes using adhesive bonded abrasives. So commercially available aluminum pipes have been selected as the work specimen to study the effect of MAF with SiC based adhesive bonded MAPs.