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The development of fine surface finish with no defects is still a significant challenge for the present industry and the finishing operation in the manufacturing of the precision components is the major problem. It is difficult rather impossible to polish/finish the difficult-to-reach surfaces, internal surfaces, and complex geometries by existing finishing methods. Abrasive flow machining (AFM) is a well-established advanced finishing process that can meet the required finishing requirements. However, the main disadvantages of this process are the surface integrity with low surface finish and high machining times. Magnetically Assisted Abrasive flow machining (MAAFM) is one of the non-conventional machining techniques that can successfully handle these problems. This process was developed in the early 2000s as a technique for deburring, polishing, and radiusing tough to reach surfaces like complicated configurations and edges/boundaries by flowing a magnetic abrasive polymeric medium across them. Magnetic flux density (MFD), extrusion pressure, flow volume, abrasive type, grit size, number of process cycles, medium, and workpiece configuration are the principal machining parameters that control the surface finish characteristics. The medium extruded forward and backward between two vertically opposed hydraulic cylinders across transit created by the workpiece and tooling. Abrasion of workpiece takes place wherever the medium proceeds across the highly confining transit. The major elements of the MAAFM process are the machine, tooling, and the magnetic abrasives containing media. MAAFM has a wide scope of uses in industries including automotive, aviation, precision dies, medicinal, electronics. This article represents a review of current advancements in the area of the MAAFM process and the type of magnetic abrasive particles (MAPs) used.

Organic materials are promising candidates for the development of efficient sensors for many medicinal and materials science applications. Single crystals of a small molecule, 4-trifluoromethyl phenyl isothiocyanate (4CFNCS), exhibit plastic deformation when bent, twisted, or coiled. Synchrotron micro-focus X-ray diffraction mapping of the bent region of the crystal confirms the mechanism of deformation. The crystals are incorporated into a flexible piezoresistive sensor using a composite constituting PEDOT: PSS/4CFNCS, which shows an impressive performance at high-pressure ranges (sensitivity 0.08 kPa

With the rapid development in the industry, applications of finished parts are increasing day by day. However, the surface finish of the parts fabricated by conventional processes could not readily meet the requirements of various applications. Therefore, post-processing is needed to further improve the surface quality. Magnetic abrasive machining uses a flexible magnetic abrasive brush to remove material from the workpiece surface at a controllable rate. This cutting tool sticks to the workpiece during finishing operation and exerts a small force on the surface. In magnetic abrasive machining, the cutting tool neither requires compensation nor dressing. In this paper, the internal finishing of aluminum pipes has been investigated in magnetic abrasive machining tests using silicon carbide-based glued magnetic abrasives. For evaluating the performance of these magnetic abrasives, experimental work according to the central composite design technique was carried out to finish the aluminum pipes. The results so obtained were analyzed to study the influence of process parameters like magnetic field strength, speed of workpiece, abrasive mesh size and quantity of magnetic abrasives on percentage improvement in surface finish and material removal rate. The analysis showed that magnetic field strength was the most effective parameter while finishing the aluminum pipe followed by the quantity of magnetic abrasives. The finishing at optimal condition resulted in a surface finish of 0.07 μm. Further, scanning electron microscopy of the surface before and after magnetic abrasive machining was taken to study the improvement in surface finish. HIGHLIGHTS Magnetic abrasive machining (MAM) of aluminum work specimens have been performed by SiC-based magnetic abrasives The central composite design has been used for planning and execution of experiments The surface finish and material removal rate of the machined work specimens have been analysed as a performance measure of MAM process The high value of improvement in surface finish and material removal rate at optimum machining conditions have been observed Scanning electron microscopy (SEM) has been employed to study the surface topography of machined surfaces GRAPHICAL ABSTRACT

The magnetic field-assisted abrasive finishing parameters used in this study were the distance of the workpiece from the magnetic pole (D), amount of sintered magnetic abrasives (A), speed of rotation of the pole (R), grain size of the abrasive particles (S) and feed to the workpiece (F). The surface roughness percentage change (SRPC) and material removal rate (MRR) of the plane surface workpiece of aluminum are the response quantities. An orthogonal L16 array of the Taguchi method was constructed and is used in this study to analyze the influence of finishing parameters on the surface roughness percentage change of the workpiece. The analysis of variance (ANOVA) showed the extent to which finishing parameters are important. The experimental results showed that for SRPC, the best combination of levels for the given control factors is the distance of the workpiece from the magnetic pole (D) = 4 mm, the amount of sintered magnetic abrasive (A) = 16 g, the speed of rotation of the pole (R) = 600 rpm, the grain size of the abrasive particles (S) = 175 μm and the feed rate of the workpiece (F) = 1.5 m min−1. For MRR, the best combination of levels for the given control factors is the distance of the workpiece from the magnetic pole (D) = 4 mm, the amount of sintered magnetic abrasive (A) = 16 g, the speed of rotation of the pole (R) = 400 rpm, the grain size of the abrasive particles (S) = 175 μm and the feed rate of the workpiece (F) = 6.0 m min−1. The surface profiles and microscopic images of polished and unpolished workpieces show that the magnetic field-assisted abrasive finishing process is very effective in finishing aluminum surfaces.