使用磁性粉末去除精密部件上毛刺的加工方法外文翻译@中英文翻译@外文文献翻译

附录 附录 1 英文原文 Journal of Materials Processing Technology 187188 (2007) 1925 Micro deburring for precision parts using magnetic abrasive finishing method S.L. Ko a,., Yu M. Baron b, J.I. Park a a Center for Advanced E-System Integration, Konkuk University, 1 Hwayang-dong, Kwangjin-gu, Seoul 143-701, Republic of Korea b Saint-Petersburg State Polytechnic University, St.-Petersburg, Russia Abstract Using the developed electromagnetic inductor for deburring micro burr, more detail characteristics of the performance are analyzed. Experiments were carried out to verify the influence of each conditions: volume of powder, height of gap, rotational frequency of the inductor and feed velocity. Proper deburring conditions are suggested to satisfy the productivity and the accuracy. In addition to deburring efficiency, the influence to surface roughness is analyzed. To improve the surface roughness and impurity, a method of coolant supply and component of abrasive powder are investigated. It is proved that the continuous flow of coolant and the Fe powder without abrasive is effective for deburring and surface quality. . 2006 Elsevier B.V. All rights reserved. Keywords: Magnetic abrasive finishing (MAF)； Micro burrs； Electromagnetic inductor； Deburring 1. Introduction The quality of precision parts can be evaluated by the surface and edge quality. The geometry of edge is determined by deburring process for removing burr and rounding process, which is necessary for its function. The surface quality is determined by surface roughness and the stress state of the surface. As one of the finishing methods, magnetic abrasive finishing method (MAF) has been used for a long time 13. MAF is based on the magnetization property of ferromagnetic iron and the machining property of abrasives, which is made of Al2O3 and SiC. Along the magnetic flow, which is formed by the magnetic inductor, the magnetic powders will be arranged like brushes and the strength and stiffness of the magnetic brushes can be controlled by the electric current supplied. As a first application of MAF technology for deburring, the burr formed on plane after drilling was tried to be removed. An inductor for removing the burr formed in drilling was produced and analyzed for effective deburring 4. The precise part used as samples in this work contains 510 m averaged burr height . Corresponding author. E-mail addresses: slkokonkuk.ac.kr (S.L. Ko), baronburr.hop.stu.neva.ru (Y.M. Baron), (J.I. Park). and 0.300.40 m surface roughness on surface after piercing operation. In the previous work, electromagnetic inductor for deburring this part was designed and manufactured. Some conditions were applied to evaluate the performance of the inductor 5. The proper powders are selected based on the previous work using the evaluation method to characterize performance of powder 6. The characteristic equation can be obtained from simply developed experiment method, which enables to predict the productivity and powder tool life 6. In this paper, proper finishing conditions are to be recommended for precision deburring. Volume of powder, rotational frequency of inductor, height of gap and the feed velocity of table are the main factors to be determined from the more detail experiment based on the result from the experiment in previous work. As a result, the optimized conditions are suggested to improve productivity. The vibration table is applied to improve the performance, which was verified in previous work also as in Fig. 1. The efficiency for deburring and the surface roughness can be improved using this vibration table 5. In the case of micro deburring for precision parts, improvement of surface roughness during deburring becomes one of the most important task. Most influencing factors for surface roughness are component of powder and the coolant supply method. Fe-powder without abrasive is proved to be efficient by protecting adhesion on the surface which results in 0924-0136/$ see front matter . 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jmatprotec.2006.11.183 S.L. Ko et al. / Journal of Materials Processing Technology 187188 (2007) 1925 Fig. 1. Overall view of inductor EMI-2 (a) and the scheme of its application (b). improved surface roughness. And continuous supply of coolant improves the surface roughness. The influence of flow rate is also investigated. 2. Experiment equipment The electromagnetic inductor EMI-2 was designed and manufactured specially for burrs removal on surfaces of small parts made from ferromagnetic or non-magnetic materials. The view of the inductor and the scheme of the experiments are shown in Fig. 1. Three kinds of movements are involved in this case: inductor rotation； feed of the sample (workpiece)； oscillation of the top plate with a sample in the direction normal to the feed direction. The sample moves inside the working gap filled by magnetic abrasive powder. The powder flows over the sample and performs finishing and deburring for both sides at the same time. The smaller working gap height is, the larger magnetic intensity B and cutting forces are (Fig. 2). These data were obtained from the working gap without powder. Magnetic intensity increases to 10% when the gap is filled by magnetic abrasive Fig. 2. Magnetizing curves for magnetic inductor EMI-2 at the different height of the working gap. powder. The positive peculiarities of magnetic inductor EMI-2 are the homogeneity of the process of the surface process through the working gap and the continuous contact between a workpiece and magnetic abrasive powder during process. Mag-Fig. 3. The sample from alloy Fe (60%) + Ni (40%) (a) and geometry of micro burrs and edges cross-section (b and c). S.L. Ko et al. / Journal of Materials Processing Technology 187188 (2007) 1925 netization curves for EMI-2 with different working gaps are shown in Fig. 2. The vibrating table was used to activate abrasive cutting and to improve the quality of worked surfaces. It is claimed that the extra oscillation movement at MAF guarantees self-sharpening of the powder and higher productivity and better quality of a worked surface as a result 2. The used vibrating table creates longitudinal or transverse oscillation of its top plate to the feed movement direction. The top plate is exchangeable and can be made from ferromagnetic or non-magnetic material. 3. Characterization of inductor EMI-2 The main differences of the electromagnetic inductor EMI-2 to EMI-1, which was developed for the burr on plane 4 are following: a sample is continuously at contact with magnetic abrasive powder during process； both sides of the sample are Fig. 4. Influence of MAF parameters to process productivity using the inductor EMI-2: volume of the powder (a), height of the work gap (b), inductor rotation frequency (c) and feed (d). Fig. 5. Influence of coolant to MAF productivity and the work surface rough-ness: at different methods of cooling (a and c) and at different discharge of coolant flow (b). S.L. Ko et al. / Journal of Materials Processing Technology 187188 (2007) 1925 processed at the same time. But this inductor can be used only for small parts, which can be placed inside gap. 3.1. Determination of deburring conditions Parts of electric guns from FeNi alloy were used as samples to determine MAF conditions for removal of micro burrs by inductor EMI-2 (Fig. 3a). There are three holes with diameter 0.1 mm made by piercing. It is necessary to remove micro burrs to improve edge quality of holes and surface quality. The geometry of initial burrs and edge cross-section are shown in Fig. 3b and c. The experiments were carried out using the scheme shown in Fig. 1b. Workpieces were fastened to aluminum top plate. The specific removed allowance is defined as the removed volume per unit area, which is used for comparison of deburring conditions 6. MAF conditions are: working gap height 4 mm； magnetic intensity in the gap 0.48 T； coil current I = 11.5 A； inductor rotation frequency n = 95280 min.1； feed f = 127 mm/min； oscillation frequency of vibration table nosc = 500 min.1； amplitude of oscillation Aosc = 2.5 mm； MAF duration corresponds to number of the table strokes in feed N = 1, 2, 4, 8 (it corresponds to 0.5, 0.9, 1.9, 3.8 min)； magnetic abrasive powder Fe(CH2)； volume of the powder portion Vp = 1127 cm3. Influence of parameters Vp, n, f, nosc, were investigated. Fig. 6. View of a hole edge after punching: (a) 200and (b) 1000. 3.1.1. Amount of the powder for process The powder is packed inside the working gap by magnetic forces, and the amount of powder is important for productivity and cost of MAF operation. The volume of the working gap (the gap height = 4 mm) at inductor EMI-2 equals to Vg =19cm3. This volume was calculated as 100% of the powder for one-time process Vp. Other conditions are: n = 95 rpm； f = 127 mm/min； I =1.0A (B = 0.45 T)； N = 2； coolant (cutting Fig. 7. Rounding of edges by MAF (100). S.L. Ko et al. / Journal of Materials Processing Technology 187188 (2007) 1925 oil) flow rate 0.96 l/mm. The experimental result is shown in Fig. 4a. Increase of the amount of powder is accompanied by larger magnetic forces and leads to increase of the productivity but not very much, because there is free space where the extra powder may be located in the gap near the poles. 3.1.2. Height of the work gap The design of inductor EMI-2 allows to change the height of the work gap from 2 up to 10 mm according to the height of a workpiece. Influence of the wok gap was examined over the range = 410 mm at Vp = 130% Vg. Other conditions were the same as at previous experiment. Increase of the work gap induces the decrease of productivity by the decrease of magnetic intensity inside the gap. The coil current was constant during this experiment. It can be observed from Fig. 4b that magnetic intensity becomes smaller as work gap increases. 3.1.3. Inductor rotational frequency and feed When the volume of powder equals to 100% V and the height of the gap = 4 mm at this experiment, the influence of the rotation frequency of inductor is shown in Fig. 4c. The duration of the contacts of powder grains with the work surface increases proportionally to the rotation frequency n, which increases the productivity either. But rate of the increase of productivity becomes slow at the frequency larger than 180 rpm as shown in Fig. 4c. This might be caused by the increase of centrifugal forces as the rotational speed increases, by which most part of the grains is thrown out of the gap. The experiment of feed optimization was carried out at following conditions: n = 95 rpm； f = 127507 mm/min； nosc = 500 min.1； Aosc = 2.5 mm； = 4 mm； B = 0.48 T； MAF durationtwo work strokes (415 s of processing correspondingly to the feed value)； with coolant. The result is shown in Fig. 4d. The influence of the feed over range of 127342 mm/min is not very large. But best surface roughness was obtained at f = 342 mm/min. 3.1.4. Role of a coolant The use of chemical active and surface-active coolants is very important for MAF process 2. Induced currents are generated inside a workpiece material and especially inside of its blanket during MAF. The electric charged surface of the workpiece activates chemical processes and an action of surface-active matters. This fact was verified at the research of deburring by MAF 6. The research on the role of coolant was continued at these experiments. The experiment was carried out with n = 95 rpm； Vp = 100% Vg； = 4 mm. Others conditions were same as the previous ones. The specific removed allowance increases when the coolant is periodically injected ins ide the work gap, and it increases more when the coolant is used like the constant flow as shown in Fig. 5a. The flow of the coolant guarantees the supply of the coolant to all sections of the work surface inside the work gap and increases the productivity. Increase of the coolant flow rate increases the productivity. But too big discharge of the coolant reduces the productivity, since the strong stream of the coolant washes out the powder from the work gap (Fig. 5b). The presence of the surface-active coolant is very important for good surface roughness. The dependences of the surface roughness Ra to the coolant supply method during MAF process are shown in Fig. 5c. MAF process without coolant and with cooling by periodical injections worsen the roughness. The case without coolant, which is shown as . in Fig. 5c generates worst surface roughness. It may be explained by phenomena of an adhesion of the powder component on the work surface due to the heat generated during MAF. The process without coolant reveals more severe deterioration of surface than the periodic supply of coolant (. in Fig. 5c). The adhesion is activated with the electrically charged work surface. Cooling by periodically injection of the coolant decreases adhesion but does not avert it fully. Cooling by the continuous coolant flow (. in Fig. 5c) prevents the adhesion and improves the roughness. So the proper conditions for removal of micro burrs at parts obtained from the experiment can be summarized as: EMI2 inductor rotation frequency n = 180 rpm； f = 342 mm/min； nosc = 500 min.1； Aosc = 2.5 mm； = 4 mm； Vp = 1.3Vg； method of coolingthe continuous flow of coolant with the discharge rate 1 l/min. The iron powder without abrasive particles was used here as magnetic abrasive powder. The test of MAF deburring using the determined conditions showed that burrs with initial height 1.52.5 m are removed for 15 s. 4. Analysis of edges and surface quality after MAF The samples shown in Fig. 3 were used. The edges after piercing had several kinds of defects: burrs, scratches and rough surface roughness (Fig. 6). Magnetic abrasive finishing deletes all these defects. And it takes longer to remove all the defects than to remove burrs. For example burrs were completely removed after one stroke of feed and the rounding of edges was Fig. 8. Edge quality before (a) and after MAF (b) (1000). S.L. Ko et al. / Journal of Materials Processing Technology 187188 (2007) 1925 Fig. 9. The top worked surface after MAF using (8500) mixture powder CH2 +Al2O3 (a) and CH2 (b). performed after two and more strokes. The rounding of edge of 4.1. Worked surface quality hole after one, two, and four strokes is shown in Fig. 7ac. One can see, that it is possible to control the radius of the edge: the The top surface is polished during deburring or rounding on longer MAF duration is, larger the radius is. The quality of the edge of holes by MAF. Influence of MAF conditions to surface edge before and after MAF is shown in Fig. 8. The iron powder roughness was described above. MAF process has the characterCH2 was used for deburring and edge rounding in this case. istic that work surface becomes to be electrically charged at the Fig. 10. Views at 1500 and the EDS diagrams of the attached particle after MAF using mixture powder (a), the same after MAF using iron powder (b) and grain of iron powder (c). S.L. Ko et al. / Journal of Materials Processing Technology 187188 (2007) 1925 25 Table 1 Chemical composition of the worked surface, powder grain and the attached particles Chemical element Amount of an element (%) Work surface Work surface after Work surface after A grain of the An attached particle An attached particle before MAF MAF with powder MAF with powder CH2 after MAF with after MAF with CH2 mixture powder mixture powder powder CH2 C 2.47 0 1.46 23.11 5.84 Si 0.40 0.30 0.71 1.99 Mn 0.51 0.44 0.64 1.09 0.36 0.35 Fe 55.94 58.70 58.07 96.42 39.90 50.34 Ni 38.88 40.34 40.73 25.96 34.17 Cu 0.18 0.23 0.07 Er 1.61 0 1.09 Al 0.56 0.37 Others Co (0.32) O (6.78)； Ca (0.72)； O (4.79)； Ca (3.35)； Cl (0.61)； K (0.20) Cl (0.20) Total 100 100 100 100 100 100 process, and this promotes adhesion of the component of powder to the work surface. We showed above that a surface-active coolant hinders from adhesion. The experiments were carried out at conditions: n = 180 rpm； f = 127 mm/min； nosc = 500 min.1； Aosc = 2.5 mm； B = 048 T； MAF duration for two strokes. The coolant (cutting oil) was periodically injected into the gap. Two sorts of powders were used: mechanical mixture of powders of iron CH2 (50% vol.) and Al2O3 (50% vol.)； iron powder CH2 4. The top surface of sample has tracks of abrasive cutting when deburring was performed by the mixture powder (Fig. 9a). There were no tracks on the surface when iron powder was used (Fig. 9b). The tracks may be made by the hard particles, Al2O3, in the mixture powder, which deteriorates the surface roughness. However the specific removed allowance is almost same in both cases. It was also found that there are some particles attached on the worked surface even after cleaning by alcohol, and chemical composition of the surface was changed. The pictures of attached particles are shown in Fig. 10, and their chemical composition is described in Table 1. The chemical composition of worked surface was changed after MAF. Carbon and erbium vanished, and silicon was decreased or deleted. Small amount of aluminum appears when MAF was made using mixture powder containing Al2O3. That is why the iron powder is recommended for micro deburring of precision parts with soft material. The attached particles consist of the workpiece material (chips) and chemical elements of the coolant. Ultrasonic cleaning of workpieces after MAF is necessary to keep initial chemical composition of worked surfaces. The extra experiment showed that ultrasonic cleaning in a tank with distilled water guarantees removing of coolant films and the attached particles fully. 5. Conclusions (1) Electromagnetic inductor for deburring and surface finishing of the part of electric gun is developed before. More detail characteristics of deburring are investigated by changing the main parameters. (2) As deburring conditions, volume of powder, height of gap, inductor rotational frequency, feed velocity and the method of coolant supply are analyzed by experiment more detail. (3) In addition to the performance of deburring, the influence to surface roughness is also analyzed. To improve the surface roughness, several systems of coolant supply are applied. The continuous coolant flow improves the surface quality. (4) The remained particle on surface after MAF consists of the component of the coolant and abrasive. Ultrasonic cleaning can remove the particles completely. And the iron powder is recommended to prevent adhesion and the particles on surface. Acknowledgement This work was supported by the Ministry of Science and Technology of Korea through the 2001 National Research Laboratory (NRL) program. References 1 Y.M. Baron, Technology of Abrasive Finishing in Magnetic Field, Mashinostroenie, Leningrad, 1975. 2 Y.M. Baron, Magnetic Abrasive and Magnetic Finishing of Products and Cutting Tools, Mashinostroenie, Leningrad Rus, 1986. 3 H. Yamaguchi, T. Shinmura, Study of an internal magnetic abrasive finishing using a pole rotation system. Discussion of the characteristic abrasive behavior, Precis. Eng. J. Int. Soc. (2000) 237244. 4 S.L. Ko, Y.M. Baron, J.W. Chae, V.S. Polishuk, Development of deburring technology for drilling burrs using magnetic abrasive finishing method, in: LEM21, November, Niigata, Japan, 2003. 5 J.L. Park, S.L. Ko, Y.H. Hanh, Y.M. Baron, Effective deburring of micro burr using magnetic abrasive finishing method, key engineering materials, Trans Tech Eng. 291292 (2005) 259264 (ISSN 1013-9826). 6 Y.M. Baron, S.L. Ko, J.I. Park, Technique of comparison and optimization of conditions for magnetic abrasive finishing, key engineering materials, Trans Tech Eng. 291292 (2005) 297302 (ISSN 1013-9826). 使用磁性粉末去除精密部件上毛刺的加工方法 S.L. Ko a, Yu M. Baron b, J.I. Park a 摘要 使用改进后的电磁感应器去除微小毛刺，分析加工中的更多细节特征。根据实验来检验不同条件对去毛刺的影响：粉末的体积，间隙的宽度，感应器的转动频率和进给速度。找出去毛刺最佳的工作条件来满足生产率和精确度的要求。除了对去毛刺效率的研究之外，还要研究加工对表面粗糙度的影响。为了改善表面粗糙度和去除杂质，需要研究冷却液供给方法和粉末的配料。连续流动的冷却液和未经研磨的铁粉对于去除毛刺和改善表面质量是非常有效的。 关键词：磁性研磨粉末加工法（ MAF）；微小毛刺；电磁感应器；去毛刺 1.导言 从表面和边缘的质量能评估出精密部件的质量。边缘的几何形状由去毛刺加工和圆周加工决定 ,这对于零件的好坏有巨大作用。工件表面质量取决于表面粗糙度和表面受应力的情况。作为精加工方法的一种，磁性粉末法 (MAF)已经用了很长时间了。 MAF 的原理是：磁铁的具有的磁化的性质以及能够研磨加工的性质，它是由二氧化三铁和碳化硅组成的。随着磁性感应器所形成的磁场的运动，那些磁粉将被排列成像刷子一样，这些磁性刷子的浓度和硬度可以被电流供应所控制。 最初应用 MAF 技术去除毛刺是尝试去除钻孔后在平面上形成的毛刺。为了能够进行更有效的 去除毛刺的分析研究，我们制造了一个去除钻孔形成的毛刺的感应器。用一个精密的部件作为这项研究的样本，它的毛刺的平均厚度有 5-10微米。进行加工后，表面的毛刺厚度变成了 0.3-0.4 微米。在实验前期的准备工作中，我们设计并且制造了去除毛刺的电磁感应器，在不用的条件下进行感应器的性能评估。之前一些合适的粉末通过某种评测方法从各种性质的粉末中被挑选出来。从稍稍改进的实验方法中能够得出特征方程式，它能够预先推算出生产力和粉末工具的寿命。在这个研究里，得出合适的工作条件将被推荐为精密部件去除毛刺。粉末的体积，感应器的转 动频率，间隙的宽度和工作台的进给速度是根据这些实验得出的需要进行详细研究的主要条件。实验结果是为提高生产效率和最优化生产环境。使用震动台工作能改善去毛刺的性能，在实验之前已经被验证了，如图一所示。去除毛刺的效果以及表面粗糙度能够通过使用震动工作台来改进。 在需要去除微小的毛刺的情况下，去除毛刺过程中如何改进表面粗糙度成了首要任务之一。影响粗糙度大部分因素是粉末的组成和冷却液的提供方法。未经研磨的铁粉在防止表面粘附力被证实更有效果，这些粘附力能直接影响表面的粗糙程度。并且连续不断的冷却液供应也能改善表面的粗糙 度。而这个流速的影响也需要进行研究。 2.实验设备 电磁感应器 EMI-2 为了去除精密部件上的毛刺被特别设计并且制造出来的，它是由铁磁体和无磁性材料做成的。感应器的外观和实验的方案都在图片一上显示。这里涉及到三种运动方式：感应器的转动，样品（工件）的进给，样品从正常方向到进给方向的顶盘的震动。样品在填满电磁粉末的加工间隙里运动，这些粉末淹过了样本，同时进行修整和两边去除毛刺的加工。图二中是加工间隙高度较小，电感强度 B 较大和切削力。这些数据从没有填粉末的加工间隙推算出。当间隙里面填满磁性粉末时，磁感强度增加了 10%。在加工过程中，通过加工间隙和工件与磁性研磨粉末之间持续不断的接触，磁感应器 EMI-2 的表面加工工序和磁粉具有相同的特性。 EMI-2 对不同加工间隙的磁化曲线在图二中显示。 震动台被用来辅助砂轮切割和改善工件表面质量。它要求 MAF 额外的震动运动来保证粉末的自我锐化，来取得更高的生产力和更好的工件表面质量。这个震动工作台产生了顶盘在进给运动的方向上的纵向的和横向的震动。这个顶盘是可以替换的，它由铁磁体和无磁性的材料做成。 3感应器 EMI-2 的描述 电磁感应器 EMI-2 和 EMI-1 之间最大的区别就是：在加工 过程中，样本与磁性粉末持续不断地相接触。样本的两面同时进行加工。但是感应器仅仅检测到能够放到内部间隙的较小的一部分。 一部分的铁镍合金的电枪作为样本通过感应器 EMI-2 来确定 MAF 去除微小毛刺的工作环境 (图 3a)。上面有三个直径 0.1mm 的通孔。为了提高孔的边缘的质量和表面的质量有必要进行微小的毛刺的去除。最初的毛刺的几何形状和边缘横截面如图 3b 和 c。 实验按照图 1b 的计划执行完成。工件被固定在铝制的顶盘上。特定的加工余量被定义为每个单位区域内的体积。这些区域是被用来做去毛刺环境的比较。MAF 加工环境：加工 间隙宽度 4mm；磁感强度 0.48T；线圈电流 I=1-1.5A；感应器转动频率 n=95-280min-1；进给速度 f=127mm/min；振动台的震动频率 nosc = 500 min1；震动的幅度 Aosc = 2.5 mm； MAF 的周期与工作台进给的节奏相一致N= 1, 2, 4, 8（它相对应的时间是 0.3， 0.9， 1.9， 3.8 分钟）；磁性研磨粉末铁粉；粉末的体积 Vp = 1127 cm3；需要研究的参数： Vp, n, f, nosc。 磁力使铁粉充满了加工间隙，对于生产力和 MAF运转的消耗，知道粉末 的总数是非常重要的。感应器 EMI-2上加工间隙（间隙厚度 = 4 mm）的体积等于 19cm3，这个体积能计算出 100%的粉末在一次加工动作中的体积。其他条件： n = 95 rpm；f = 127 mm/min； I = 1.0A (B = 0.45 T)； N= 2；冷却液（切削液）流动率 0.96l/mm。实验结果在图 4a中显示。粉末的数量的增加能伴随着更大的磁力，而能使生产力得到提高。但不是很明显，因为这里有一些空余的间隙，多余的粉末有可能进入主轴附近的这些间隙里。 感应器 EMI-