In this study, a novel precision finishing process for complex internal geometries using smart magneto-rheological polishing fluid is developed. Magneto-rheological abrasive flow finishing process provides better control over rheological properties of abrasive-laden finishing medium that exhibits changes in rheological behavior in the presence of external magnetic field. The finishing fluid used in this study contains SiC and iron particles with a combination of specific volume percentage of glycerin and liquid paraffin as abrasive, magnetizable and base medium parts, respectively. The smart characteristics of magneto-rheological fluid are utilized to precisely control finishing forces to control surface quality. A hydro-mechanical device is used to provide experimental setup in order to investigate the effects of different parameters on surface roughness. This device consists of a hydro-mechanical power unit, abrasive fluid containers, permanent NdFe magnets, workpiece fixtures and a base frame. Experiments were conducted on austenitic stainless steel (AISI304), aluminum (7075 alloy) and copper (unalloyed) with different magnetic field strength, abrasive particle size and finishing time cycles. It is observed that by decreasing magnetic field strength, the surface roughness decreases in all three materials. Besides, with increase in abrasive particle mesh number, surface roughness tends to be higher. However, there is a slight difference observed through different finishing cycle times. The specific applications of this process are finishing fluid guidelines in precise instruments like capillary tubes in drug delivery setups.

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The attempts of researchers in industries to obtain accurate and high quality surfaces led to the invention of new methods of finishing. Magnetic abrasive finishing (MAF) is a relatively new type of finishing in which the magnetic field is used to control the abrasive tools. Applications such as the surface of molds are ones of the parts which require very high surface smoothness. Usually this type of parts has freeform surface. In this study, the effect of magnetic abrasive process parameters on freeform surfaces of parts made of aluminum is examined. This method is obtained through combination of magnetic abrasive process and Control Numerical Computer (CNC). The use of simple hemisphere for installation on the flat area of the magnets as well as magnets’ spark in curve form is a measure done during testing the experiments. The design of experiments is based on response surface methodology. The gap, the rotational speed of the spindle, and the feed rate are found influential and regression equations governing the process are also determined. The impact of intensity of the magnetic field is obtained using the finite element software of Maxwell. Results show that in concave areas of the surface, generally speaking, the surface roughness decreases to 0.2 μm from its initial 1.3 μm roughness. However, in some points the lowest surface roughness of 0.08 μm was measured.

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In order to achieve nanometer accuracies, low vibration in air spindle is vital. Some parameters affecting air spindle vibration could be mentioned as rotational speed, inlet hole diameter, air pocket geometry, air gap pressure and so on. In this study, the air pocket geometry and depth plus rotational speed are experimentally investigated. Three levels of quantity are selected for each parameter. Vibration movements were considered as experiment output. Then, experimental results were analyzed by design of experiment method. The results showed that the air spindle with an air pocket of rectangular shape and 3 mm depth at low rotational speed has minimum vibrations.

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In new developed parts, roughness has become an effective parameter and influences the performance of the entire system. Manufacturing of parts with fine surface finish have been a target for many advanced industries. Sometimes, it is difficult to reach highly polished surface quality by conventional methods. One of the newly introduced methods for obtaining fine finished surfaces is nano‐scale finishing with abrasive particles in magnetic fields. It is a relatively new finishing process that can be used to produce efficiently shiny surface quality for certain parts [1]. In this process, the cutting movement is provided by the magnetic field energy of permanent or electric poles. Magnetic abrasive particles (MAPs) are used to remove chips, and polish the work‐piece surface [2, 3]. The work‐piece is in the shape of a flat plane. An apparatus has been designed and made for machining the upper face of the plane. Nd‐Fe‐B magnets are used to establish the magnetic field. An NC machine is applied to create the rotational movement of MAPs in the horizontal plane and maintain the vertical position accurately. Various experiments have been designed to specify the machining characteristics of the MAF process. In these experiments different effective conditions are determined. Permanent magnets with 1.2 T magnetic flux density are used as magnetic poles. Homogeneous mechanical mixture of abrasive powder (Silicon Carbide) and ferromagnetic iron particles are used as the MAPs. The experimental setup was designed for finishing the aluminium alloy AA–6061. Test results indicated that the finishing parameters affect the material removal rate (MRR) and surface roughness.