Magnetic Abrasive Grains Research Articles

Circular Halbach array integrated using an abrasive circulating system during the ultra-precision machining of polymethyl methacrylate optical material

A novel approach to enhancing the efficacy and surface quality of magnetic polishing involves the incorporation of a magnetic liquid circulation system for abrasive particle regeneration in conjunction with a circular Halbach array. The continuous renewal of abrasive particles within the polishing zone is realised through a conveyor belt that transports new abrasive particles into the polishing liquid solution. This formation of a continuously circulating polishing system ensures uninterrupted magnetic finishing processes and maintains stability throughout the polishing operation. This study extensively explores polishing force distribution, magnetic field distribution and abrasive grain behaviour in the polishing area facilitated by the magnetic liquid solution. The application of the proposed polishing processes to polymethyl methacrylate, an optical lens material, aims to comprehend the characteristics and validate the feasibility of the polishing method. Key influencing factors in the magnetic polishing process, including abrasive grain size, magnetic particle, polishing distance and conveyor speed to surface quantity, are examined through experimental analysis. Results of the experimental polishing processes demonstrate that the utilisation of circular Halbach arrays with circulating abrasives produces a nanometric surface finish. Even in the polishing of polymethyl methacrylate with an initial rough surface (Ra = 464.895 nm), the process achieves an ultra-fine level with Ra below 9 nm without disruption in the material polishing processes of optical lenses.

Study on magnetic-field-based abrasive grains patterning for electroplating diamond wire saws

In this study, the magnetic field-based abrasive grain patterning for the production of electroplating diamond wire saws was studied. During the manufacturing process of the electroplating diamond wire saw, a permanent magnet was used to perform magnetization of the carbon steel wire. In addition, the following two methods were further used to perform partial degaussing on the carbon steel wire. The first method refers to the laser degaussing method, and the second method refers to the electromagnetic degaussing method, followed by performing electroplating on the carbon steel wire that has undergone the degaussing process. The impacts of these two methods on the magnetization characteristics of the carbon steel wire were studied, the magnetic induction strength of the zone of degaussing, range of the zone of degaussing, production speed, etc., in order to reach a conclusion on the methods for degaussing of a carbon steel wire. In this study, a nanosecond laser with a wavelength of 355 nm was used to perform a partial degaussing treatment on the surface of a magnetized carbon steel wire. When the laser fluence is 11.56 J/cm2, the controlled degaussing region of the abrasive grains could be minimized to 83.8 μm.

Application of magnetic liquid slurries and fuzzy grey analysis in polishing nickel-phosphorus coated SKD11 steel

This paper studies the influencing factors on the magnetic material (nickel-phosphorus coated SKD11 steel) polishing process were determined by investigating the distribution of magnetic iron (MIGs) and abrasive grains (AGs) in the working surface of magnetic liquid slurry (MLS). The influence of the factors, namely the diameters of the MIGs and the AGs and working distance (K), on the polishing surface quality was assessed by fuzzy gray analysis. Results showed that the values of the fuzzy gray relationships with the factors were 0.6361, 0.5181, 0.8804, and 0.6464. Result showed that the fuzzy gray relationship point of factors known as K exerted the most remarkable influence on the polishing effect, whereas the effect of MIG diameter was insignificant. The experimental results indicated that MLS containing MIGs with a diameter of 5 μm, AGs with a diameter of 1.5 μm and K = 1 mm should be prepared to create a mirror surface with nickel–phosphorus coated SKD11 steel. An extremely smooth mirror surface with Ra = 0.926 nm is produced under these experimental conditions, leaving no scratches and impurities on the machined surface. The proposed polishing method that uses MLS with MIGs and AGs (which are low-cost and commercially available) is suitable and effective for polishing the surface of magnetic materials with extremely high accuracy.

A new tool developed for ultraprecision milling nickel by using magnetic liquid slurries

In developing a new milling technique that can produce high precision, smoothness, and gloss on nickel workpiece surfaces, a widely used material is in industrial applications, particularly in mold manufacturing, in which the production requires exceptionally high accuracy. In this work, the factors influencing the magnetic material milling process are determined by investigating the distribution of magnetic iron (MIGs) and abrasive grains (AGs) in the working surface of magnetic liquid slurry (MLS). The magnetic liquid slurry (MLS) contained commercially available MIGs successfully applied for milling the surface of magnetic materials with extremely high accuracy. Surface roughness ([Formula: see text] nm) without leaving scratches on the surface after milling.

Development of a New Ultra-High-Precision Magnetic Abrasive Finishing for Wire Material Using a Rotating Magnetic Field.

In this paper, we propose a new ultra-high-precision magnetic abrasive finishing method for wire material which is considered to be difficult with the existing finishing process. The processing method uses a rotating magnetic field system with unbonded magnetic abrasive type. It is believed that this process can efficiently perform the ultra-high-precision finishing for producing a smooth surface finish and removing a diameter of wire material. For such a processing improvement, the following parameters are considered; rotational speed of rotating magnetic field, vibration frequency of wire material, and unbonded magnetic abrasive grain size. In order to evaluate the performance of the new finishing process for the wire material, the American Iron and Steel Institute (AISI) 1085 steel wire was used as the wire workpiece. The experimental results showed that the original surface roughness of AISI 1085 steel wire was enhanced from 0.25 µm to 0.02 µm for 60 s at 800 rpm of rotational speed. Also, the performance of the removed diameter was excellent. As the result, a new ultra-high-precision magnetic abrasive finishing using a rotating magnetic field with unbonded magnetic abrasive type could be successfully adopted for improving the surface roughness and removing the diameter of AISI 1085 steel wire material.

Application of v-shaped magnet in inner surface polishing of tubes

Compared to traditional polishing processes, the magnetic grinding method allows relatively easy polishing of the inner surface of tube fittings. For more than 7 mm thickness SUS304 tubes, the magnetic abrasive grains are subject to a small magnetic force and grinding pressure, leading to the low polishing efficiency. Therefore, a new magnetic grinding and polishing method is proposed, in which the grooved V-shaped magnet is conductive to spontaneous mixing and stirring with magnetic abrasive grains, allowing them continually being replaced for inner surfaces polishing on the tube. This can increase the grinding pressure of abrasive grains to the inner surface and contribute to high-quality surface polishing. Theoretically, it was proved that the grooved V-shaped magnet-assisted polishing tool improves the uniformity of material cutting force in the polishing process. Finally, this method was validated by the experiment with the 7 mm thickness SUS304 tube.

Effects of magnetic field distributions on wire sawing performance

To transport more abrasive grains into the cutting zone, the method of magnetic-induction free-abrasive wire sawing is proposed. A uniform magnetic field is used to magnetize a steel wire and forms a high gradient magnetic field around the wire. The magnetic abrasive grains are adsorbed on the magnetized wire and are transported into the cutting zone, which improves the wire sawing performance. The adsorption of the magnetic abrasive grains is observed using an experimental setup along the wire cross-sectional direction. The results suggest that magnetic abrasive grains are increasingly adsorbed in the paramagnetic region of the wire with increasing magnetic field intensity. Single-wire sawing experiments are conducted on a WXD170 reciprocating wire sawing machine at variable magnetic field intensity and distribution. The results suggest that the change in magnetic field intensity strongly affects the cutting efficiency, kerf loss, and surface roughness. The performance of the magnetic-induction free-abrasive wire sawing under different magnetic field intensities and distributions are compared. The wire sawing performance improves when the uniform magnetic field is evenly distributed in the cutting zone and at the top of cutting zone.

Investigations on the trajectories of magnetic abrasive grains in magnetic induction-free abrasive wire sawing

This study presents a novel method of magnetic induction-free abrasive wire sawing. The ferromagnetic wire is magnetized in a uniform magnetic field, forming a high-gradient magnetic field that separates into paramagnetic and diamagnetic regions. Paramagnetic abrasive grains are attracted to the paramagnetic region and adhere to the wire surface but are repelled from the diamagnetic region. The trajectory of the magnetic abrasive grains is analyzed in a mathematical model and in COMSOL Multiphysics simulations. The results are verified by test investigations on the motions and adsorption of the magnetic abrasive grains using a dynamic microscope system. The detailed grain trajectories are investigated in a numerical model. Because it actively transports grains toward the wire (where they can be transported to the sawing channel), our proposed method achieves more efficient wire sawing performance than traditional free abrasive wire sawing. Such efficient performance is highly sought in silicon wafering technologies, which are commonly used in the solar and semiconductor industries.

Experimental study of the cutting performance of free-abrasive wire sawing in a magnetic field

In view of the low cutting efficiency and large kerf loss of traditional free-abrasive wire sawing, a method of free-abrasive wire sawing in a magnetic field is proposed. Magnetic abrasive grains are adsorbed onto the surface of a magnetised wire by the magnetic force. Therefore, more magnetic abrasive grains are carried into the cutting area during the cutting process. This mechanism is helpful for improving the cutting performances of wire saws. The adsorption mechanism of a magnetically induced free-abrasive grain is described briefly. A series of observation experiments are performed. The results show that the magnetised wire can adsorb magnetic abrasive grains and that the quantity of magnetic abrasive grains in paramagnetic regions of the magnetised wire surface increases with increased magnetic field intensity, thereby verifying the presumed adsorption mechanism. Cutting experiments are performed, and the results show that changes in magnetic field intensity, feed rate of the workpiece, running speed of the wire, viscosity of the cutting fluid and mass fraction of the magnetic abrasive grains have a significant impact upon the cutting performance of free-abrasive wire sawing in a magnetic field.

Polymer/CeO2–Fe3O4 multicomponent core–shell particles for high-efficiency magnetic-field-assisted polishing processes

Novel multicomponent core–shell particles have been developed for use in high-efficiency magnetic-field-assisted polishing processes. The core–shell particles consist of core polymer particles covered by a shell composed of magnetic particles and abrasive grains. The particle preparation process involves agitation of the particle mixture in a dry ambient atmosphere with an appropriate controlled temperature, which is a simple and low-cost technique compared with the conventional sintering and granulation process used for the preparation of magnetic abrasives. Although the prepared polymer/CeO2–Fe3O4 multicomponent core–shell particles exhibit inferior glass-polishing performance compared to CeO2 abrasives without an applied magnetic field, they reveal a markedly higher removal rate in the presence of the magnetic field than that exhibited by conventional abrasives and mixed compounds (Fe3O4 and CeO2). Furthermore, polishing using the core–shell particles with the magnetic field shows the potential to achieve a superior material surface quality compared to conventional polishing.

Adsorption mechanism of magnetic induction free-abrasive grain and its effect on cutting performance of wire saws

This paper proposes a method of free-abrasive wire sawing in the magnetic field. Magnetic abrasive grains are absorbed on surface of the wire by magnetic force, and therefore more magnetic abrasive grains are carried into cutting area. This mechanism is helpful to improve the cutting performance of wire saws. Theoretical modeling of the movement trajectory of magnetic abrasive grains is done in the magnetic field, and it is also verified by observation experiments of movement trajectory of magnetic abrasive grains. Absorption angle, which is used as the indicator of adsorption capacity about magnetic abrasive grain on surface of the wire, is proposed in this paper. The effect of magnetic field intensity on absorption angle is analyzed through computer simulations and observation experiments. Practical experiments and cutting results show that the change of magnetic field intensity has a significant impact on cutting efficiency, surface roughness, and kerf width.

Study on Preparation Technology and Finishing Performance of Magnetic Abrasive Grain

Due to the low efficiency of magnetic abrasive finishing and the difficulty in the making of magnetic abrasive grain, this article compares three different ways of its making, i.e. hot pressed sintering, spark plasma sintering (SPS) and ab-adhesive bonding sintering. SPS is found to have a higher cost, but it makes up the deficiency in magnetic abrasive grain made either by hot pressed sintering or by felt, with high abrasion resistance, processing efficiency and better processing performance.

Study on Preparation Technology and Finishing Performance of Magnetic Abrasive Grain

Due to the low efficiency of magnetic abrasive finishing and the difficulty in the making of magnetic abrasive grain, this article compares three different ways of its making, i.e. hot pressed sintering, spark plasma sintering (SPS) and ab-adhesive bonding sintering. SPS is found to have a higher cost, but it makes up the deficiency in magnetic abrasive grain made either by hot pressed sintering or by felt, with high abrasion resistance, processing efficiency and better processing performance.

Investigation of a New Kind of Magnetic Abrasive Grains Used for Finishing Inner-Hole Surface

Magnetic abrasive grain is a kind of tool for magnetic abrasive finishing (MAF). The lifetime of the grains is the choke point which restricts its finishing efficiency and the surface quality processed by MAF .Therefore, a kind of magnetic abrasive grains based on Cr and Ni elements is investigated. The interrelated experimental results show: the new magnetic abrasive grains is a practical finishing tool with longer lifetime, higher finishing efficiency, better abrasive resistance compared with traditional magnetic abrasive grains. It supplies a power for promoting the development of MAF.

Micro machining of high-hardness materials using magnetic abrasive grains

If processing speed is increased and processing time is lengthened, a magnetic abrasive system can be used as a tool both for finishing and precise dimensional control of manufactured products at the micro-level, and for mirror face processing. In this study, a micro machining system that can change its high rotational speed was developed. Using micro machining with a high speed magnetic abrasive system, the diameter of difficult-to-cut materials with high hardness could be controlled almost linearly by changing the rotational speed, the frequency of magnetic poles, and the size of diamond particles. By changing machining conditions, the surface roughness of the mirror face level could be obtained. To improve roundness, a higher rotational speed improved processing time and dimensional precision, and 20,000 rpm was the optimum speed in this experiment. Roundness was obtained up to 0.15 μm. Before and after the processing, there was almost no change in the WC(tungsten carbide) and Ni components of the material, and there were no remains of mixed-type particles such as iron and diamond on the material.

The Principle of Magnetic Abrasive Finishing under Rotating Electromagnetic Field and Its Application in Surface Finishing of Heavy Crankshaft

Magnetic abrasive finishing (MAF) is a processing technology using magnetic abrasive grain (MAG) under magnetic field to finish surface of workpiece. The magnetic fields used in MAF include permanent magnetic field and electromagnetic field. Two conditions must be taken into consideration in the finishing surface of workpiece. One is the sufficient cutting force; the other is the relative moving speed between MAG and workpiece. The principle of step-motor rotating magnetic field is used to produce rotating magnetic field (RMF) in this paper. RMF brings MAG to rotate and keeps workpiece immovable. Meanwhile, the coins vibrate within a definite angle range and reciprocate in axial direction so as to process the outer cylindrical surfaces. Yoke iron is made of two halves so that the coins for rotating magnetic field will be keyed to some section of heavy crankshaft, thus realizing cylindrical surface finishing on the heavy crankshaft. MAG are of importance to MAF . Six performance indexes related to MAG are suggested by studying on process parameters.

On simulation of magnetic abrasive finishing process for plane surfaces using FEM

In this paper, a finite element model is developed for the plane Magnetic Abrasive Finishing (MAF) process, by considering the problem as an axisymmetric magnetostatic problem. The model is validated with the available experimental results in the literature. A theoretical model for stock removal and surface roughness is developed by considering the indentation of the magnetic abrasive grain on the workpiece surface. The effect of various process parameters such as magnetic flux density, size of MAP, rotational speed of tool, finishing time, initial surface roughness and shape of abrasive grain on the finishing characteristics are studied. An attempt is made to determine an index of surface roughness for better understanding of the effect of above process parameters on the surface roughness.

Study on the inner surface finishing of tubing by magnetic abrasive finishing

With the development of industry manufacturing technology, fine surface finish is in high demand in a wide spectrum of industrial applications. Presently, it is required that the parts used in manufacturing semiconductors, atomic energy parts, medical instruments and aerospace components have a very precise surface roughness. Amongst them, vacuum tubes, wave guides and sanitary tubes are difficult to polish by conventional finishing methods such as lapping, because of their shapes. The surface roughness of these tubes affects the performance of the entire system, but the finishing technology for these tubes is very scant in manufacturing fields. This project was proposed by a Shanghai Far East pharmaceutial and mechanical factory. They stated that the roughness of the inner surface must be less than 0.3 μm Ra after finishing. An internal magnetic abrasive finishing (MAF) process is proposed for producing highly finished inner surfaces of tubes used in this study. The process principle and the finishing characteristics of unbounded magnetic abrasive within internal tubing finishing are described first. MAF setup was designed for finishing three kinds of materials tubing, such as Ly12 aluminum alloy, 316L stainless steel and H62 brass. Experimental results indicated that finishing parameters such as polishing speed, magnetic abrasive supply, abrasive material, magnetic abrasive manufacturing process and grain size have critical effects on the material removal rate (MRR). How the inner surface micro shape changes course during finishing of an aluminous tube is demonstrated.

220 磁性粒子と研磨材スラリー及び磁性加工ジグを用いた磁気援用加工法に関する研究 : 磁性粒子と研磨材の粒径が加工量と加工面粗さに及ぼす影響

220 磁性粒子と研磨材スラリー及び磁性加工ジグを用いた磁気援用加工法に関する研究 : 磁性粒子と研磨材の粒径が加工量と加工面粗さに及ぼす影響

Research on cylindrical magnetic grinding. Behavior of magnetic abrasive grain and mechanism of polishing pressure generation.

Research on cylindrical magnetic grinding. Behavior of magnetic abrasive grain and mechanism of polishing pressure generation.