scholarly journals Change in Surface Magnetic Flux Density in EDM of Permanent Magnets-Influence of Internal Temperature and Shape on Machined Magnets

Procedia CIRP ◽  
2013 ◽  
Vol 6 ◽  
pp. 112-116 ◽  
Author(s):  
H. Takezawa ◽  
Y. Ichimura ◽  
N. Yokote ◽  
N. Mohri
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Permanent Magnets ◽  
Magnetic Flux Density ◽  
Internal Temperature

scholarly journals Design of a New 1D Halbach Magnet Array with Good Sinusoidal Magnetic Field by Analyzing the Curved Surface

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2522
Author(s):  
Guangdou Liu ◽  
Shiqin Hou ◽  
Xingping Xu ◽  
Wensheng Xiao
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Permanent Magnets ◽  
Air Gap ◽  
Curved Surface ◽  
Magnetic Flux Density ◽  
Sinusoidal Magnetic Field ◽  
The Magnetic Field

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.

Platform Design for Characterizing Shear Force Produced by Magnetized Magnetorheological Fluid

2019 ◽  
Author(s):  
Ping-Hsun Lee ◽  
Jen-Yuan (James) Chang
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Yield Stress ◽  
Flux Density ◽  
Shear Force ◽  
Permanent Magnets ◽  
Magnetic Flux Density ◽  
Finite Element Method Result ◽  
Mr Fluid ◽  
The Magnetic Field

Abstract In this paper we proposed a platform for measuring shear force of magnetorheological (MR) fluid by which the relationship of yield stress and magnetic flux density of specific material can be determined. The device consisted of a rotatable center tube in a frame body and the magnetic field was provided by two blocks of permanent magnets placed oppositely outside the frame body. The magnitude and direction of the magnetic field were manipulated by changing the distance of the two permanent magnets from the frame body and rotating the center tube, respectively. For determining the magnetic field of the device, we adopted an effective method by fitting the FEM (finite element method) result to the measured one and then rebuilt the absent components to approximate the magnetic field, which was hardly to be measured simultaneously as different device setup were required. With the proposed platform and analytical methods, the drawing shear force and the corresponding yield stress contributed by MR fluid could be evaluated in respect to the magnitude and direction of given magnetic flux density with acceptable accuracy for specific designing purposes without a large, complex, and expensive instrument.

scholarly journals Surface Magnetic Flux Density Patterning in EDM of Permanent Magnets

Procedia CIRP ◽  
2016 ◽  
Vol 42 ◽  
pp. 668-672 ◽  
Author(s):  
Hideki Takezawa ◽  
Naoki Hirakawa ◽  
Naotake Mohri
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Permanent Magnets ◽  
Magnetic Flux Density

scholarly journals Experimental Investigation of Process Parameters of Al-SiC-B4C MMCs Finished by a Novel Magnetic Abrasive Flow Machining Setup

2021 ◽  
Vol 18 (18) ◽  
Author(s):  
Gagandeep CHAWLA ◽  
Vinod Kumar MITTAL ◽  
Sushil MITTAL
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Material Removal ◽  
Permanent Magnets ◽  
Surgical Instruments ◽  
Extrusion Pressure ◽  
Magnetic Flux Density ◽  
Abrasive Flow Machining ◽  
Wide Range ◽  
Number Of Cycles

Abrasive flow machining (AFM) is one of the non-conventional finishing processes used to attain good surface quality and high material removal. However, limited attempts have been made to improve the performance of these processes. This paper presents a novel magnetic abrasive flow machining (MAFM) setup fabricated by adding a magnetization effect in which a nylon fixture and permanent magnets are replaced by a newly fabricated aluminium fixture and coil-type magnets, respectively. Inner cylindrical surfaces of hybrid Al/SiC/B4C metal matrix composites (MMCs) are finished by the MAFM process. One variable at a time (OVAT) approach is used for studying the effect of 6 input parameters, extrusion pressure (Ep), the number of cycles (N), abrasives concentration (C), workpiece material (Wp), abrasive mesh size (M), and magnetic flux density (Mf) upon response parameters, material removal rate (MRR) and change in surface roughness (ΔRa). The experimental results obtained for MRR and ΔRa show a significant improvement from 3.92 to 7.68 μg/s and 0.49 to 0.74 μm, respectively due to the increase of the extrusion pressure from 1 to 9 Mpa. The MRR and ΔRa was reduced from 6.89 to 6.78 μg/s and 0.46 to 0.22 μm, respectively with an increase in mesh number of abrasives from 80 to 400. The variation in concentration of abrasives from 40 to 60 % shows an improvement in MRR from 4.51 to 6.42 μg/s; whereas, there is a negligible effect on ΔRa which comes out from 3.82 to 3.86 μm. The MMCs, which are used for the experimentation shows a decline in MRR and ΔRa from 5.12 to 3.85 μg/s and 0.77 to 0.42 μm, respectively. This happened because there was a percentage change of reinforcement of SiC from 9 to 7 % and B4C from 1 to 3 % in Al-6063. An increase in the number of cycles from 50 to 250 shows a significant improvement in both MRR and ΔRa from 1.79 to 3.75 μg/s and 0.97 to 1.86 μm, respectively. Variation in magnetic effect also significantly improves MRR and ΔRa from 1.35 to 3.17 μg/s and 0.38 to 1.06 μm, respectively, when it is varied from 0.15 - 0.45 Tesla. The work carried out shows an overall significant improvement in MRR and ΔRa by using the MAFM process. The MAFM process finds a wide range of applications in finishing like surgical instruments, mechanical components, aerospace industry, electronics industry, etc. HIGHLIGHTS The hybrid MMCs (Al/SiC/B4C) are finished by novel MAFM setup An aluminium fixture and coil-type magnets play a significant role for finishing the workpiece surfaces An abrasive laden media acts as a cutting tool in the finishing process The OVAT approach is used for investigating the parametric effect The extrusion pressure, number of cycles and magnetic flux density are the significant parameters affecting the MRR and ΔRa GRAPHICAL ABSTRACT

FEM Analysis of Magnetic Field Induced by Martensitic Phase Transformation Around Fatigue Cracks in SUS 304 Stainless Steel

2004 ◽  
Author(s):  
Yuji Nakasone ◽  
Yoshifumi Iwasaki
Keyword(s):  
Stainless Steel ◽  
Martensitic Transformation ◽  
Magnetic Flux ◽  
Flux Density ◽  
Permanent Magnets ◽  
Fatigue Cracks ◽  
Martensitic Phase ◽  
304 Stainless Steel ◽  
Magnetic Flux Density ◽  
Stress Ratios

The present study has attempted to analyze the distributions of vertical magnetic flux density Bz above growing fatigue cracks subjected to various stress ratios R in SUS 304 stainless steel in which plasticity-induced martensitic transformation has occurred at room temperature in air. FEM calculations have been made to obtain Bz distributions above fatigue cracks by using composite permanent magnet models. The martensitic transformation regions around fatigue cracks were modeled as composites of permanent magnets having different B-H properties varying according to the content of α′ martensitic phase transformed. The resultant distributions of leakage magnetic flux density above fatigue cracks obtained by FEM agree well with those obtained by experiments.

Relationship between Magnetic Flux Density and Temperature Distributions of Permanent Magnets by EDM

2012 ◽  
Vol 523-524 ◽  
pp. 322-327 ◽  
Author(s):  
Yoshihiro Ichimura ◽  
Hideki Takezawa ◽  
Naotake Mohri
Keyword(s):  
Magnetic Flux ◽  
Magnetic Materials ◽  
Flux Density ◽  
Permanent Magnets ◽  
Electrical Discharge Machining ◽  
Magnetic Flux Density ◽  
Input Energy ◽  
Machined Surface ◽  
Depth Direction ◽  
Temperature Distributions

It is difficult to machine permanent magnets by traditional machining such as turning, milling and grinding, because of magnetic force. However, electrical discharge machining (EDM), which is a non-contact thermal machining method, has been used for shape machining of magnetic materials. In the EDM process, non-magnetic materials such as copper and graphite are typically used for electrodes. Magnetic materials have a Curie point; therefore, their magnetic flux density reduces when they are heated to a high temperature. Because EDM is a thermal process, it has the potential to control the magnetic flux density of a machined surface. In this study, to clarify the relationship between magnetic flux density and temperature distributions in depth direction of permanent magnest by EDM, internal temperatures of magnets were investigated using a K type thermo couple during EDM. Neodymium magnets were used as work-pieces. The magnetic flux density of a machined neodymium magnet was measured. In addition, the effects of duty factor (D.F.) were also examined. The results showed that the average temperature inside of the magnet is determined by the input energy, depending on the discharge conditions. A decrease of surface magnetic flux density after EDM is affected by the magnitude of the area and the amount of decrease is due to the increase of the internal temperature of the magnet. Therefore, it isn’t determined by the magnitude of the simple input energy.

Non-Contact Actuation of Less-Invasive Bone Lengthening Device Using Embedded Cycloidal Motor Driven by Permanent Magnets from the outside

2012 ◽  
Vol 523-524 ◽  
pp. 722-726 ◽  
Author(s):  
Yuki Matsuzaki ◽  
Yoichi Kadota ◽  
Kazuo Uzuka ◽  
Hideyuki Suenaga ◽  
Ken Sasaki ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Permanent Magnets ◽  
The Body ◽  
Magnetic Flux Density ◽  
Bone Lengthening ◽  
Ring Gear ◽  
Actuation Mechanism ◽  
Surgical Device

This report proposes a miniaturized non-contact actuation mechanism for a surgical device for bone extension operation. The device is embedded inside the body, and the device controls the gap between the bones cut by operation. A small permanent magnet is attached to the outer gear of a cycloidal reducer that rotates a screw of the screw-nut mechanism. This magnet is forced by the external magnetic flux density controlled by the outer permanent magnets’ position. In this research, two pairs of permanent magnet bar were rotated by stepping motors outside the device. The outer gear is constrained in As a result, ring gear of the cycloidal reducer is driven in translational wobbling motion the inner gear is connected to the screw and the output nut position is driven linearly with screw rotation. The dimensions of the fabricated device were 7 mm in diameter and 39.7 mm in length. The output thrust of this device was 2 N.

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