Surface Polishing of an Inconel 625 Bar by a Super-Fast MAF Process for a Solenoid Valve Stem Used in a Hydrogen Tank

This study explores a super-fast magnetic abrasive finishing (MAF) process for polishing the surface of an Inconel 625 bar workpiece for a hydrogen solenoid valve stem. The Inconel 625 bar was chosen to replace the existing STS 316 bar material, previously used for a hydrogen solenoid valve stem. The cylindrical surface of Inconel 625 bars was polished by a super-fast MAF process with high rotational speeds of 1000, 5000, 15,000, and 25,000 RPM and a super-strong magnetic field of 550 mT. The polishing characteristics of this process were evaluated according to the type of abrasives, rotational speeds of the workpiece and processing time. As a result, a super-smooth Inconel 625 bar was successfully achieved, with a surface roughness (Ra) reduced from 0.31 μm to 0.02 μm under the optimal conditions (15,000 RPM, CNT particles (0.04 μm), PCD diamond abrasive (1 μm), Fe (#200), 0.5 g of light oil, and 16 min of processing time). Also, the Ansys analysis results showed suitable strain, equivalent stress, and safety factor of the Inconel 625 bar. This confirmed that, after a super-fast MAF process, an Inconel 625 bar is feasible for application in Hydrogen (H2) tanks instead of a conventional STS 316 bar

Magnetic Abrasive Finishing of Beta-Titanium Wire Using Multiple Transfer Movement Method

Titanium is often used in various important applications in transportation and the healthcare industry. The goal of this study was to determine the optimum processing of magnetic abrasives in beta-titanium wire, which is often used in frames for eyeglasses because of its excellent elasticity among titanium alloys. To check the performance of the magnetic abrasive finishing process, the surface roughness (Ra) was measured when the specimen was machined at various rotational speeds (700, 1500, and 2000 rpm) in the presence of diamond paste of various particle sizes (0.5, 1, and 3 μm). We concluded that the surface roughness (Ra) was the best at 2000 rpm, 1 μm particle size, and 300 s processing time, and the surface roughness of β-titanium improved from 0.32 to 0.05 μm. In addition, the optimal conditions were used to test the influence of the finishing gap, and it was found that the processing power was superior at a gap of 3 mm than at 5 mm when processing was conducted for 300 s

Magnetic Abrasive Machining of Difficult-to-Cut Materials for Ultra-High-Speed Machining of AISI 304 Bars

This research proposes an optimized magnetic abrasive machining process that uses an ultra-high-speed system to perform precision machining on a workpiece. The system can process several microns of material, either for machining surface roughness or for machining a workpiece for a precise micro-diameter. The stainless steel workpieces have been machined using an ultra-high-speed magnetic abrasive machining (UHSMAM) process. The experiments were performed analyzing the accuracy of the machined workpiece diameter, using response surface methodology. The results obtained after machining have been analyzed to determine the effect of different process parameters such as machining speed, machining time, machining frequencies, inert gas in/out, magnetic pole types, and magnetic abrasive mesh size for the individual workpiece, as well as to study various interaction effects that may significantly affect the machining performance of the process. The obtained outcomes of the analysis for different workpieces have been critically compared to understand the effect of the considered process parameters based on the resulting mechanical properties. Regression analysis was used to confirm the stability of the micro-diameter and the processing efficiency. Atomic force microscope (AFM) micrographs were also obtained to study the surface morphology of the precision-machined workpiece

Ultra-High-Speed Magnetic Abrasive Surface Micro-Machining of AISI 304 Cylindrical Bar

The ultra-high-speed magnetic abrasive machining (UHSMAM) process is a surface improvement technique, which has been widely used to minimize the surface accuracy and change the precision morphology of difficult-to-machine materials. Surface integrity plays an important role in the machining process, because it is used to evaluate the high stress and the loaded components on the machined surface. It is important to evaluate the plastically deformed layers in ultra-precision machining surface of material. However, the usual plastic strains in the ultra-precision machining surface are significantly difficult to consider. In this paper, an ultra-high-speed magnetic abrasive machining technique is used to improve the surface accuracy and dimensional accuracy of an AISI 304 bars. Additionally, the subsequent recrystallizations technique is used for measuring the plastic strain on machined surface of AISI 304 bars. The purpose of this paper is to evaluate the effects of an UHSMAM process on the plastic strains and the strain energy of the machined surface, and to evaluate the residual strain in the plastic deformation of AISI 304 bars materials by analyzing a plastically deformed layer. The results showed that the plastic strain of the material did not change after machined by an UHSMAM process. Based on the results, an UHSMAM process could significantly improve the surface roughness, micro-diameter, and removal weight of AISI 304 bars effectively. The surface roughness Ra of AISI 304 bars was improved from 0.32 µm to 0.03 µm for 40 s of machining time at 80,000 rpm of workpiece revolution speed

Machining the Surface of Orthopedic Stent Wire Using a Non-Toxic Abrasive Compound in a Magnetic Abrasive Finishing Process

The orthopedic stent wire is one of the critical medical components, which is mainly used for the replacement of physically damaged parts in the human body. Therefore, a smooth surface and lack of toxic substances on the surface of this component are highly demanded. In this study, a magnetic abrasive finishing (MAF) process was carried out using a non-toxic abrasive compound (a mixture of iron powder, diamond particles, cold cream, and eco-friendly oils) to achieve high-quality surface finishing of orthopedic stent wire. The surface roughness (Ra) of the stent wire was investigated according to various processing parameters: different rotational speeds (500, 1000, and 2000 rpm), diamond particle sizes (1.0 µm), and three eco-friendly oils (olive oil: C98H184O10; grapeseed oil: C18H32O2; and castor oil: C57H104O9) within 300 s of the finishing time. The results showed that the surface roughness of the wire was reduced to 0.04 µm with a rotation speed of 1000 rpm and a diamond particle size of 1 µm when using grapeseed oil. SEM microimages and EDS analysis showed that the MAF process using a non-toxic abrasive compound could improve the surface quality of orthopedic Ni-Ti stent wire with a lack of toxic substances on the surface finish

A Review on Surface Finishing Techniques for Difficult-to-Machine Ceramics by Non-Conventional Finishing Processes

Ceramics are advanced engineering materials in which have been broadly used in numerous industries due to their superior mechanical and physical properties. For application, the industries require that the ceramic products have high-quality surface finishes, high dimensional accuracy, and clean surfaces to prevent and minimize thermal contact, adhesion, friction, and wear. Ceramics have been classified as difficult-to-machine materials owing to their high hardness, and brittleness. Thus, it is extremely difficult to process them with conventional finishing processes. In this review, trends in the development of non-conventional finishing processes for the surface finishing of difficult-to-machine ceramics are discussed and compared to better comprehend the key finishing capabilities and limitations of each process on improvements in terms of surface roughness. In addition, the future direction of non-conventional finishing processes is introduced. This review will be helpful to many researchers and academicians for carrying out additional research related to the surface finishing techniques of ceramics for applications in various fields

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

Development of a New Ecological Magnetic Abrasive Tool for Finishing Bio-Wire Material

This study proposes a new wire magnetic abrasive finishing (WMAF) process for finishing 316L SUS wire using ecological magnetic abrasive tools. 316L SUS wire is a biomaterial that is generally used in medical applications (e.g., coronary stent, orthodontics, and implantation). In medical applications of this material, a smooth surface is commonly required. Therefore, a new WMAF process using ecological magnetic abrasive tools was developed to improve the surface quality and physical properties of this biomaterial. In this study, the WMAF process of 316L SUS wire is separated into two finishing processes: (i) WMAF with ecological magnetic abrasive tools, and (ii) WMAF with industrial magnetic abrasive tools. The ecological magnetic abrasive tools consist of cuttlefish bone abrasives, olive oil, electrolytic iron powder, and diamond abrasive paste. The finishing characteristics of the two types of abrasive tools were also explored for different input parameters (i.e., vibrating magnetic field and rotating magnetic field). The results show that ecological magnetic abrasive tools can improve the initial surface roughness of 316L SUS wire from 0.23 µm to 0.06 µm. It can be concluded that ecological magnetic abrasive tools can replace industrial magnetic abrasive tools

Effect of Environmentally Friendly Oil on Ni-Ti Stent Wire Using Ultraprecision Magnetic Abrasive Finishing

Nickel-titanium (Ni-Ti) has been widely used to make shape-memory actuator wire for numerous medical industrial applications, with the result that it frequently comes into contact with the human body. High-quality and nontoxic surfaces of this material are therefore in high demand. We used a rotating magnetic field for an ultraprecision finishing of Ni-Ti stent wire biomaterials and evaluated the finishing technique’s efficacy with different processing oils. To create nontoxic Ni-Ti stent wire, the industrial processing oils that are generally used in the surface improvement process were exchanged for oils with low environmental impacts, and processed under rotating magnetic fields at different speeds and processing times. The processing performance of the different oils was compared and verified. The results show that ultraprecision magnetic abrasive finishing that uses olive and castor oil improves surface roughness by 66.67%, and 45.83%, respectively. SEM and energy-dispersive X-ray spectroscopy (EDX) analyses of the finished components (before and after processing) showed that the material composition of the Ni-Ti stent wire was not changed. Additionally, the magnetic abrasive tool composition was not found on the surface of the finished Ni-Ti stent wire. In conclusion, the environmentally friendly oil effectively improved the diameter of the Ni-Ti stent wire, demonstrating the utility of olive and castor oil in ultraprecision finishing of Ni-Ti stent wire biomaterials

Development of an Inner Finishing Method for Brass Cone Pipe via a Movable Manual Electromagnet in a Magnetic Abrasive Finishing Process

This paper describes the development of a movable manual electromagnet with an adjustable flux density to improve the inner surface smoothness of a cone pipe using a magnetic abrasive finishing process. This method is fabricated to reduce further the roughness of the internal surface of the conic shape, which was modeled as an electromagnet oscillating in the work zone with a ball roller. Statistically significant improvement in the process was achieved using unbounded magnetic abrasive, light oil, flux density, controlled feed rate, and constant rotational speed in the experiment. The ball transfer equipped on the top of the electromagnet pole plays an essential role in spinning over the outer cone pipe during the experiment and helps reduce friction while the workpiece fluctuates. Furthermore, the flux density can be changed to control the magnetic force and select the most acceptable option. In addition, a procedure for finishing has been designed for finishing a cone pipe, and we sought to understand how the flux density affects the material in removal exterior roughness. As a result, the flux density is clarified, and a higher flux density achieves excellent removal of surface roughness of the inner deformed pipe from 1.68 μm to 0.39 μm within 24 min