جستجوی مقالات مرتبط با کلیدواژه « magnetic abrasive finishing » در نشریات گروه « مکانیک »

One of the components of the MAF process is the magnetic field that is applied through the field source. This source can be permanent or electrical. In terms of shape, permanent magnets are divided into two main categories: cubic and cylindrical. In the past researches, cylindrical overhead magnets have been used to perform MAF on free surfaces, which is not very efficient due to the time-consuming process. In this research, first of all, the methods of making overhead magnets have been examined to find the optimal magnetic conditions. Then, in order to increase the efficiency of the process, methods to increase the efficiency of the overhead magnet have been investigated. Based on this, the mentioned methods have been discussed and evaluated. According to the results, in the method of using a ball magnet and connecting it to a cylindrical magnet, the magnetism density is significant, and also by grooving the head magnet, the roughness changes on the inclined surfaces of the ferromagnetic workpiece from 21% to It reached 34.4% and in the inclined area with a curvature angle of 90 and 105 degrees of the surface of the ferromagnetic workpiece, a 9% increase in roughness changes occurs.

Magnetic abrasive finishing process (MAF) is one of the latest advanced machining processes. After eight decades have passed since the registration of the magnetic abrasive polishing process, the applicability of this method has been proven in finishing all kinds of surfaces, including flat, cylindrical and free surfaces. In this research, the influence of MAF process movement parameters on the concave surface of cold-worked steel has been investigated experimentally using the response surface method. These parameters include rotational speed, linear speed, gap between abrasive brush and workpiece, magnetic flux density and curvature angle. For this purpose, a spherical head magnet is used and the powder used is prepared by mechanical alloying method. Cold-worked steel is used in the manufacture of roll forming molds, which is used in air engines to shape compressor and turbine blades, and also to investigate the feasibility of the MAF process on the workpiece surface with high hardness and yield stress, such as Cold work steel is selected. According to the results, the optimal value of the magnetic flux density is 0.55 tesla, and with the increase of the distance between the abrasive brush and the workpiece, the surface roughness changes initially increase and decrease after passing the optimal value.

In the process of polishing with magnetic abrasive particles, several parameters affect the smoothness of the final surface of the part. These parameters include properties related to machining conditions, workpiece properties, or abrasive powder properties. The present paper deals with the effect of the kinetic parameters of the MAF process on the convex and concave surface of aluminum alloy experimentally. These parameters include rotational velocity, linear velocity, abrasive brush distance to the workpiece (gap), magnetic flux density, and angle of curvature. For this purpose, a spherical head magnet was used and the powder used was prepared by mechanical alloying method. Also, the two-way zero-degree raster movement strategy is used for the tool movement path. The experiment was designed using miniatub software. According to the results of analysis of variance, it was found that all the main factors or their interaction are effective. Also, the roughness changes on the convex surface are more than the concave surface. On the convex surface, the roughness changes with increasing curvature angle. On the convex surface of the workpiece, with increasing magnetic flux density, there is an increase in surface roughness changes, while on the concave surface, passing the magnetic flux density of 0.53 Tesla, the progression of roughness changes occurs. The effect of velocity on the convex and concave surfaces of the workpiece is the same, and with increasing rotational speed from 125 to 2000 (rpm), the roughness changes of the concave surface of the workpiece increase by 57%.

Magnetic Abrasive Finishing (MAF) is a nano-machining process; due to low machining temperature, this process is categorized as a cold forming process. Therefore, the machined surface is free from thermal damages such as micro cracks, phase changes, burnt area and etc. In this paper, the effects of machining parameters (machining gap, work piece rotational speed and abrasive particles’ type) on work piece surface roughness have been experimentally studied. To achieve this goal a series of experimental tests were conducted on a newly developed setup and workpiece surface roughness was measured. The results of experimental studies were then used to develop a mathematical model for work piece surface roughness using Response Surface Method (RSM). The results show that there is a good agreement between experimental results and model predictions. This model was then used to minimize workipece surface roughness. In the selected range of machining parameters the minimum value of surface roughness is achieved by workpiece rotational speed of 373.73 rpm, machining gap of 2 mm and using diamond particles as abrasive. In addition, it was shown that abrasive particles’ type is the most affecting parameter on workpiece surface roughness. Furthermore, Microscopic results of surface tissue specimens, Shows that magnetic abrasive finishing process the direction and grooves resulting from the grinding process have significantly eliminated and as well as a super-polishing and uniformity surface finish like a mirror to a range of 0.207 µm is obtained.