Factors Affecting the Finishing Characteristics of an Internal Magnetic Abrasive Finishing Process for High Purity Fittings

Author(s):  
Hitomi Yamaguchi ◽  
Takeo Shinmura ◽  
Megumi Sekine

In the case of internal finishing of the bent section of a complex shaped tube, such as found in high purity fittings, by a magnetic abrasive finishing process, the magnetic field at the finishing area and, therefore, the finishing force are hardly uniform over the entire finishing area due to the geometry. This affects the abrasive behavior against the inner surface of the bent section, changing the finishing characteristics of SUS304 stainless steel fittings. In practice, non-uniformities in the surface finish remain at the bent section between the inside, outside, and lateral regions. This unevenness combines to cause difficulties in achieving uniform finishing. Magnetic abrasive is generally supplied with ferrous particles, and the ferrous particles experience greater magnetic force and play a role in pressing the magnetic abrasive against the target surface. This paper studies the finishing mechanism in view of the relationship between the magnetic field, the ferrous particles mixed with magnetic abrasive, and the finishing characteristics. The experiments identify the finishing conditions required for successfully diminishing the non-uniformity in the finished surface, and methods are recommended to satisfy the required conditions. The experiments using the proposed methods show the feasibility of producing a uniformly finished mirror surface.

2004 ◽  
Vol 127 (3) ◽  
pp. 605-611 ◽  
Author(s):  
Hitomi Yamaguchi ◽  
Takeo Shinmura ◽  
Megumi Sekine

This research studies the factors affecting the conditions required for successful uniform internal finishing of SUS304 stainless steel bent tube by a Magnetic abrasive finishing process. In particular, the effects of the magnetic field and ferrous particles were investigated. Local intensification of the magnetic field is accomplished by offsetting the axis of pole rotation from elbow axis. This effect enables local control of the material removal rate, which leads to uniformity in the finished surface regardless of the initial surface conditions. A two-phase finishing process controlling the size of the ferrous particles is proposed to achieve efficient fine surface finishing.


2021 ◽  
Vol 1018 ◽  
pp. 111-116
Author(s):  
Yan Hua Zou ◽  
Hui Jun Xie

The traditional magnetic abrasive finishing (MAF) process, the magnetic flux density at the bottom of the magnetic pole is unevenly distributed, resulting in poor uniformity of the finished surface. Therefore, it is proposed to improve the surface quality by attaching a magnetic plate at the bottom of the workpiece to improve the magnetic field distribution. It is confirmed by simulation that the magnetic field distribution at the bottom of the magnetic pole is effectively improved after the magnetic plate is attached. It is proved through experiments that the magnetic plate-assisted MAF process can obtain a smoother surface. The experimental results show that the surface roughness of the glass lens improves from 246 nm Ra to 3 nm Ra through the magnetic plate-assisted MAF process within 45min.


2020 ◽  
Vol 8 (3) ◽  
Author(s):  
Jason Ratay ◽  
Pei-Ying Wu ◽  
Alex Feirvezers ◽  
Hitomi Yamaguchi

Abstract Nickel-based superalloys have a wide range of high-temperature applications such as turbine blades. The complex geometries of these applications and the specific properties of the materials raise difficulties in the surface finishing. Magnetic abrasive finishing (MAF) has proven effective in finishing the complex geometries. In MAF, the magnetic properties of the workpiece, tool, and abrasive play important roles in controlling finishing characteristics. This paper presents the effects of nickel coating on the abrasive behavior during finishing and resulting finishing characteristics of Ni-based superalloys. The Ni-coated diamond abrasive is more attracted to the magnet than the Ni-based superalloy surface. As a result, fewer Ni-coated diamond abrasive particles, which are stuck between the magnetic-particle brush and the target surface, participate in surface finishing. Because of this, coupled with the reduced sharpness of abrasive cutting edges due to the coating, Ni-coated diamond abrasive cannot effectively smooth the target surface in MAF. However, the Ni coating is worn off during finishing of the hard, rough, additively manufactured surface. Then, the diamond abrasive participates in finishing as uncoated diamond abrasive and facilitates the material removal, finishing the target surface.


Machines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 75
Author(s):  
Huijun Xie ◽  
Yanhua Zou

The magnetic abrasive finishing (MAF) process is an ultra-precision surface finishing process. In order to further improve the finishing efficiency and surface quality, the MAF process using an alternating magnetic field was proposed in the previous research, and it was proven that the alternating magnetic field has advantages compared with the static magnetic field. In order to further develop the process, this study investigated the effect on finishing characteristics when the alternating current waveform is a square wave. The difference between the fluctuation behavior of the magnetic cluster in two alternating magnetic fields (sine wave and square wave) is observed and analyzed. Through analysis, it can be concluded that the use of a square wave can make the magnetic cluster fluctuate faster, and as the size of the magnetic particles decreases, the difference between the magnetic cluster fluctuation speed of the two waveforms is greater. The experimental results show that the surface roughness of SUS304 stainless steel plate improves from 328 nm Ra to 14 nm Ra within 40 min.


2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Mehrdad Vahdati ◽  
SeyedAlireza Rasouli

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.


Author(s):  
R. S. Mulik ◽  
P. M. Pandey

Magnetic abrasive finishing (MAF) is a finishing process in which surface is finished by removing the material in the form of micro-chips by the magnetic and abrasive particles in the presence of a magnetic field. In a finishing process, forces have direct influence on the generation of finished surface and accuracy of the workpiece. The magnitude of force or torque is also of importance as the surface integrity is affected. In the present research work, new design of electromagnet which gave relatively lesser force and torque as compared to conventional annular electromagnet was used to perform MAF. The measurements of normal force and finishing torque were carried out at different processing conditions using Kistler’s dynamometer and were found in the order of 24 N and 8 Nm respectively. The experiments were planned using Taguchi’s L16 orthogonal array and supply voltage to electromagnet, rpm of electromagnet, finishing gap and abrasive weight percentage at four levels were considered as process parameters. Supply voltage to the electromagnet and finishing gap were found to be the significant factors affecting finishing force and torque in this work. The scanning electron microscopy (SEM) study of the finished workpiece showed that there was no surface or subsurface damage due to very low finishing force and torque.


Author(s):  
Anant Bhardwaj ◽  
◽  
Krovvidi Srinivas ◽  
Rajiv Chaudhary ◽  
◽  
...  

Magnetic Abrasive Finishing is a significant process for finishing up to the micro-level. However, with the advancement of technology and hybrids like Viscoelastic magnetic abrasive Finishing and Magnetic abrasive Flow machining, it has become a nano finishing process. To improve the finishing process, the researchers have made a Model and tested the feasibility of the wind turbine magnet in Finishing. The Maxwell simulations were done for the cylindrical Specimen of Brass, Steel Aluminum. The simulations results were in accordance with the fact that the proposed wind turbine magnet may be used for the simulations.


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