Investigation of the finishing characteristics in an internal tube finishing process by magnetic abrasive finishing combined with electrolysis

In this research, the finishing characteristics in a tube's internal finishing process using the method of magnetic abrasive finishing (MAF) combined with electrolysis has been studied. Electrolysis produces an aluminium oxide film that accelerates the removal of the initial hairline morphology on the surface. Subsequently, the film is removed with MAF. This process significantly minimises the surface roughness in a reduced time. The way the finishing conditions, such as the pole–pipe gap, iron particle size and abrasiveness combinations, and processing time affected the surface morphology in the MAF machining process has been particularly examined. The surface roughness was measured and images of the finished surfaces were recorded to study the morphology changes. Prolonged electrolysis finishing was seen to deepen the oxidation film and pits, which adversely affects the surface. This evidence suggests that the pit residuals contribute to higher surface roughness values.     

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.     

Simulation for the prediction of surface roughness in magnetic abrasive flow finishing (MAFF)

The final machining (or finishing) of precision parts with high level of surface finish and close tolerance is making the application of magnetic abrasive finishing technology increasingly important. Magnetic abrasive flow finishing (MAFF) is a new abrasive finishing process combining the features of abrasive flow finishing (AFF) and magnetic abrasive finishing (MAF). MAFF provides a high level of surface finish and close tolerances for wide range of industrial application. This paper focuses on the modeling and simulation for the prediction of surface roughness on the workpiece surface finished by MAFF process. A finite element model is developed to find the magnetic potential distribution in the magnetic abrasive brush formed during finishing action and then it is used to evaluate machining pressure, surface finish and material removal. The simulation results are compared with the experimental results available in the literature. The simulated workpiece surface roughness shows features similar in nature to the experimental results.     

钛合金管内表面的电化学磁力研磨复合光整试验

针对热挤压成型对钛合金管的内表面会产生微裂纹、褶皱、毛刺等表面缺陷的问题,提出了一种高效率的电化学磁力研磨复合光整加工方法。设计了电化学磁力研磨复合光整加工的实验装置,分别与纯磁力研磨加工和纯电化学加工进行了光整加工试验对比,检测分析了不同工艺加工前后表面的粗糙度、微观形貌、摩擦磨损行为、表面残余应力和能量谱。结果表明:在相同的加工时间内,与单纯电化学加工和磁力研磨加工相比,电化学磁力研磨复合光整加工的表面粗糙度Ra可达到0.2μm,材料去除量和加工效率显著提高;表面显微形貌要明显优于其他两种加工方式;且加工后表面很好地维持了原有材料的化学成分和表面性质;能够使表面由拉应力转变为约–200 MPa的压应力状态,从而获得更好的表面应力状态。     

Surface finishing of cobalt chromium alloy femoral knee components

This paper describes the modification of surface roughness and lay of cobalt chromium alloy femoral knee components by magnetic abrasive finishing (MAF), including clarification of the MAF surface-processing mechanisms. The MAF process creates characteristic surfaces by micro-cutting of abrasive pressed by magnetic particles that nearly conform to the surface, removing large asperities and creating microasperities compared to hand-buffed surfaces. The process enables smoothing the surface on the nanometer scale with critical control of surface lay (e.g., crosshatch angle), altering the contact angle of water by a combination of kinematic behavior of magnetic particles over the freeform condyle surface.     

Ultrasonic assisted magnetic abrasive finishing of hardened AISI 52100 steel using unbonded SiC abrasives

Ultrasonic assisted magnetic abrasive finishing (UAMAF) integrates the use of ultrasonic vibrations and magnetic abrasive finishing (MAF) process to finish surfaces to nanometer order in a relatively short time. The present study emphasizes on the fabrication of UAMAF setup. Using this experimental setup, experimental studies have been carried out with respect to five important process parameters namely supply voltage, abrasive mesh number, rotation of magnet, abrasive weight percentage, and pulse on time (T_on) of ultrasonic vibrations selected based on literature available in the area of MAF process and ultrasonic generator controls. Percentage change in surface roughness (?Ra) for AISI 52100 steel workpiece has been considered as response and unbonded SiC abrasives are used in the work. The experimental results showed that the UAMAF process has better finishing potential as compared to those obtainable by using MAF process for similar processing conditions. The surface roughness value obtained by UAMAF was as low as 22 nm within 80 s on hardened AISI 52100 steel workpiece using unbonded SiC abrasives. Scanning electron microscopy and atomic force microscopy studies were carried out to feel the surface texture produced and to identify finishing mechanism.     

模具型腔自动化磁力研磨光整加工

介绍了自由磨粒磁力研磨光整加工机理,在3_TPT五自由度并联机床上对模具型腔进行磁力研磨光整加工试验,研究了磁感应强度、研磨间隙、磨料粒度以及研具表面形状对模具型腔进行磁力研磨光整加工的影响及其变化规律。     

Study the characteristics of magnetic finishing with gel abrasive

Given the flexible polishing effect in magnetic abrasive finishing (MAF), the precise and mirrorlike surface can be obtained during this process. However, the abrasives are easily flown away from the working area regardless of what abrasives are used in MAF; this situation will reduce the polished efficiency and induce the pollution problem in the environment. Besides, the abrasives cannot recycle after the finishing process. Therefore, a novel abrasive medium, using the silicone gel to mix the ferromagnetic particles and abrasive, was developed to enhance the disadvantages in MAF. Magnetic finishing with gel abrasive (MFGA) was utilized in this study to polish the cylindrical rod of mold steel; furthermore, this cylindrical rod was fixed in a horizontal chuck that could rotate and vibrate in the axial direction. This study focused on the finishing efficiencies and the surface roughness of the workpieces after MFGA. Moreover, recycling times of gel abrasive were also the main effects that need to be approved. The results demonstrated that surface roughness of the cylinder part was reduced to 0.1 μm Ra from an initial value of 0.677 μm Ra within 10 min, and surface roughness could decrease to 0.038 μm Ra after 30 min in MFGA. Surface roughness reduction in MFGA was 3 times of surface roughness reduction in MAF using the unbonded magnetic abrasive as medium. Roughness improvement rate still remained at a high level of 90% when the same abrasive medium (35 g) was used 15 times to finish 15 workpieces; therefore, this result proved that the gel abrasive had excellent ability for recycling.     

反求工程在磁粒研磨技术中的应用

对反求工程在磁力研磨中的应用给予了充分的论证,并找出了二者的结合点,解决了磁力研磨在复杂曲面加工中难以确定磁极运动轨迹的难题,该技术的完善对于实现模具型腔精加工的自动化具有重要的意义。     

模具数字化磁力研磨加工中研磨运动轨迹的研究

介绍了模具制造过程中,模具表面数字化磁力研磨加工的原理和特点,分析了曲面磁力研磨加工轨迹对研磨质量的影响,提出了相应的解决办法。     

Study on cylindrical magnetic abrasive finishing using unbonded magnetic abrasives

The process principle and the finishing characteristics of unbonded magnetic abrasive within cylindrical magnetic abrasive finishing are described in this study. The unbonded magnetic abrasive is a mechanical mixture of SiC abrasive and ferromagnetic particles with a SAE30 lubricant. Iron grit and steel grit, for which three various particle sizes were prepared for both, were used as ferromagnetic particles, each of them being mixed with 1.2 and 5.5 μm SiC abrasive, respectively. Also, the finishing characteristics on surface roughness and material removal as well as their mechanisms were investigated. Experimental results indicate that steel grit is more suitable for magnetic abrasive finishing because of its superior hardness and the polyhedron shape. The variations of material characteristics on the work surface both before and after finishing were also investigated. Si content was increased obviously, however its corrosion resistibility decreased on a surface that was finished via steel grit mixed with SiC abrasive.     

磁粒研磨光整加工的实验研究

通过实验对磁粒光整加工中的关键部件——磁极的形状做了较全面的分析，得到了适合磁粒研磨的最佳磁极形状，解决了在磁粒研磨中经常出现的“磁滞”现象，从而提高了加工效率，改善了工件质量，同时也延长了磁极的使用寿命，为磁粒研磨技术在生产中的应用提供了重要的理论依据。     

模具曲面光整加工中数字化磁力研磨技术

本文针对模具制造过程中模具表面的自动化研磨光整加工的问题，介绍了一种数字化磁力研磨技术。简述了其原理，详细论述了数字化研磨三维加工模型的获得、工艺参数的选择、数字化研磨轨迹的生成方法以及专用和改装的数字化磁力研磨设备等关键技术，证实利用数字化磁力研磨可以对模具曲面进行有效地自动化光整加工。     

小孔内表面磁力研磨加工技术研究进展

磁力研磨加工是提高小孔内表面质量的一种重要光整技术,利用该技术能高效提升小孔类零部件在极端环境下的使役性能。针对小孔内表面的磁力研磨光整加工,按其发展历程对磁力研磨加工技术进行总结,归纳了磁性磨粒研磨、磁针磁力研磨、液体磁性磨具研磨、超声辅助磁力研磨和电解磁力复合研磨等加工方法的技术特点,并分析评述了其局限性。对磁力研磨加工过程中材料去除机理进行了研究,材料主要以微量切削与挤压、塑性变形磨损、腐蚀磨损、电化学磨损等方式去除,材料种类不同,去除机理也不同。其中,硬脆性材料主要以脆性断裂、塑性变形和粉末化的形式去除;塑性材料在经历滑擦阶段、耕犁阶段和材料去除阶段后主要以切屑的形式去除。此外,还对磁力研磨加工过程中的材料去除模型进行了研究,对单颗磁性磨粒材料去除模型和“磁力刷”材料去除模型进行了分析讨论。最后,对磁力研磨加工技术今后的研究发展给出了建议并进行了展望。     

Vertical vibration-assisted magnetic abrasive finishing and deburring for magnesium alloy

The ultimate goal of this project is to develop an efficient finishing process enabling unskilled operators to finish automatically the complicated micro-curved surface and edge surface of the magnesium alloy. The results achieved in the first phase as described in this paper focus on the basic characteristics of the plane and edge surface finishing and deburring of this alloy by the use of vertical vibration-assisted magnetic abrasive finishing process. It demonstrates that realization of efficient finishing of magnesium alloy is possible by the process. The removal volume per unit time of magnesium alloy is larger than that of other materials such as brass and stainless, that is, high-efficiency finishing could be achieved. Micro-burr of magnesium alloy could be removed easily in a short time by the use of the magnetic abrasive finishing process. Furthermore, deburring efficiency considerably increases with vertical vibration assistance.     

Contents

The attempts of researchers to obtain accurate and high-quality surfaces have led to the invention of new methods of finishing. Magnetic abrasive finishing (MAF) is a relatively new type in which magnetic field is used to control the abrasive tools. Surfaces of moulds, for instance, are among those which require very high-surface smoothness. Usually, this type of part has freeform surfaces. In this study, the effect of magnetic abrasive process parameters on finishing freeform surfaces of aluminium parts has been examined. This method was achieved through a combination of the magnetic abrasive process and computer numerical control. The use of a simple hemisphere to be joined on the flat area of the magnet as well as spark machining for forming a sphere at the end of a magnet were performed during experimentation. Gap, rotational speed of the machining head, amount of abrasive powder and feed rate were among the parameters that were tested in experiments. The design of experiments is based on the response surface methodology. Significant parameters and the regression equations governing the process were also determined. The impact of intensity of the magnetic field was obtained using MAXWELL finite element software. In the MAF process, magnetic abrasives play the role of cutting tools. However, the magnetic abrasives are not easily available as these are produced by special techniques such as sintering method, adhesive based, plasma based or gel based. This study presents the basic polishing characteristics of the magnetic abrasives produced by the mechanical alloying process. After the mechanical alloying process fine magnetic abrasives are obtained, in which the abrasive particles adhere to the base metal matrix without any bonding material. In this study, investigation was performed only on the convex area of workpiece. Optimum parameters are gap size of 0.5?mm, feed rate of 10?mm?min^?1 rotational speed of 2100?rev?min^?1 and powder amount of 1.75?g. To help understand the effectiveness of the MAF process, scanning electron microscopy and atomic force microscopy of the machined surfaces have been carried out.     

Modelling and optimisation of magnetic abrasive finishing process based on a non-orthogonal array with ANN-GA approach

ABSTRACT

Magnetic abrasive finishing (MAF) is an advanced precise finishing method that achieves micro-level to nano-level surface roughness. In industries, MAF is highly recommended where zero or negligible post-process surface defects are an obligatory requirement. In the same context, process optimisation is essential for making it commercially viable. This study presents an artificial neural network and genetic algorithm (ANN-GA), a robust modelling and optimisation tool (applicable to any sort of data set orthogonal array design or non-orthogonal array design) that is applied to scrutinise and improve the performance of the magnetic abrasive finishing of stainless steel SS302. In addition, the results from ANN-GA modelling and optimisation have been compared with conclusions drawn from conventionally used Taguchi-ANOVA analysis. An L₂₇ non-orthogonal array design has been opted for as per machining set-up restriction. Abrasive size, voltage, machining gap, and rotational speed were the design variables considered in the present research work. It was found that the parametric design used in this study provides a straightforward, methodical, and proficient method of modelling and optimisation of change of surface roughness or finishing behaviour during the MAF process. Modelling and optimisation done with ANN-GA show a maximum value of (ΔR _a)_max equal to 0.256?µm, which is 7% better than the result obtained from Taguchi-ANOVA analysis.     

混合型磁性磨料在磁力研磨加工中的应用

介绍了一种新型的磁性磨料 ,并对该磨料的加工性能进行了实验研究 ,得到了该磨料的最佳配比。这对磁力研磨技术的生产化 ,以及该技术在模具精加工中的应用具有重要的意义     

磁粒研磨加工技术的研究进展

磁粒研磨加工是一种应用广泛且高效的表面加工技术,具有加工质量高、适用范围广、柔性加工、自锐性好、易于实现自动化等优点,能够有效去除工件表面的划痕、积碳、毛刺和卷边等缺陷.首先,综述了磁粒研磨加工技术的发展与研究,包括磁粒研磨加工技术的提出与发展、数学模型分析和加工参数产生的影响,其中着重论述了加工过程中单颗磨粒的力学模...     

电解磁力复合加工对磁性磨粒性能的影响

利用单纯的磁力研磨工艺加工镍基高温合金等材料时,磁性磨粒失效严重,严重影响了磁力研磨工艺的研磨效果。为了解决这一技术难题,将电化学与单纯的磁力研磨加工工艺结合,通过电解加工在工件表面形成质地较软的钝化膜,再利用磁力研磨对其表面进行加工。对复合加工后的磁性磨粒进行电镜成分分析,得知铝的相对质量分数仅从27.60%降至23.48%,有效地降低了磁性磨粒中研磨相成分的损失,延缓了磁性磨粒的失效时间,提高了磁性磨粒的利用率和使用寿命,从而保证了工件的加工质量。