砂轮约束磨粒喷射精密光整加工表面互相关性分析

磨粒喷射精密光整加工是重要零件在磨削后进行去除表面缺陷层、降低粗糙度和波纹度为目的光整加工新工艺.试验在M7120磨床上完成,加工试样为Ra0.4～0.6 μm的45#钢.加工表面形貌和微观几何参数用SEM和TR200表面轮廓仪测量.本文应用随机过程的互相关性对磨削加工表面和光整加工表面进行了研究.试验结果表明,试样表面从连续的方向一致的沟槽被随机不连续的微坑所代替,表面粗糙度明显得到改善.随着加工循环的增加,Ra值由0.4～0.6 μm下降到0.2 μm左右.此外,光整加工可以获得各向同性网纹交错的表面,表面轮廓的支撑长度率提高,对工件的耐磨性有利.     

砂轮约束磨粒喷射精密光整加工工艺特性研究

研究了砂轮约束磨粒喷射精密光整加工工艺特性，分析了磨粒尺寸、磨料流体浓度、加工循环、砂轮速度、携带流体对加工表面质量的影响。利用平面磨床M7120对Q235A进行喷射加工实验，用TALYSURF轮廓仪测量加工后的微观几何参数值，用扫描电镜和金相显微镜观察表面微观形貌。实验结果表明，选用质量分数10％W7Al2O3微粉与防锈润滑液进行喷射加工20～30循环，不仅保持或获得高的表面肜状精度，而且又可高效的获得具有粗糙度Ra0．15～1．6μm的无缺陷加工表面，明显去除磨削加工过度塑性变形，减少表面层污染和磨削烧伤，实现高效、高精度、低粗糙度，并且磨削和抛光可以集成的表面精密光整加工新方法。     

预应力条件下系统颤振对磨削工件表面形貌的影响研究

目的基于应力刚化效应,通过施加预应力来调节颤振强度,进而研究预应力条件下系统颤振对磨削工件表面形貌的影响规律。方法选用45钢作为研究对象,首先建立两自由度磨削系统动力学模型,采用时域与频域相结合的方式来获得磨削系统的动力学特性。然后运用Johnson变换获得砂轮表面磨粒的非高斯分布,基于磨粒的运动轨迹和磨削系统的动态特性,建立多因素耦合型工件表面形貌的数学模型,进而获得考虑颤振因素的工件表面几何形貌。结果预应力条件下,磨削工件表面轮廓高度在1.1～1.7μm范围内波动,工件表面的平均轮廓高度沿着砂轮的进给方向呈增大趋势。考虑颤振因素的轮廓高度计算结果更接近测得的工件表面平均轮廓高度,随着砂轮转速的增大和进给速度的减小,工件表面的平均轮廓度降低。结论通过对比实验与仿真条件下工件表面轮廓的高度值,发现预应力条件下系统颤振导致工件表面轮廓高度分布呈现一定的不均匀性,工件表面平均轮廓高度沿着砂轮进给方向逐渐增加。同时,颤振很大程度上降低了加工工件表面微观几何精度。在实际生产中,可采用提高砂轮转速与降低砂轮进给速度的方式来减小颤振对预应力磨削工件微观表面轮廓高度的影响。     

关联系统动静态特征端面磨削表面创成机理

目的 关联主轴系统动静态特征,研究端面磨削表面创成机理.方法 以粉末冶金不锈钢316L为研究对象,首先构建关联主轴系统动静态特征的有限元模型,分析主轴系统动静态特征对砂轮端面各位置位移大小的影响.然后基于端面砂轮表面磨粒的位置和尺寸信息,建立端面砂轮磨粒三维空间轨迹方程,推导相邻磨粒运动关系式,采用轮廓搜索法确定端面磨削表面的动静态创成过程.最后,结合端面磨削加工实验,分析端面磨削系统动态、静态特征对加工表面粗糙度与轮廓度的影响规律,阐释加工表面材料去除不均匀的本质,并提出创成表面质量的参数化修正方法.结果 靠近砂轮边缘的磨粒静态退让量大于靠近砂轮中心部分的磨粒静态退让量,但不同位置的磨粒动态振动量差异不大.静态退让量随切深的增加而增大,动态振动量随砂轮转速的增加而增大.结论 砂轮表面磨粒的静态退让性是造成加工表面轮廓度误差的重要因素,同时主轴系统动态振动特征会影响加工表面粗糙度.分析可得,砂轮转速在400 r/min左右,与之匹配无理数转速比的工件转速和较小的法向切深,可提高端面磨削表面质量表征.     

电化学光整加工过程中电流场分布特性

为改善电化学光整加工整平效果,根据电化学光整加工前后表面微观轮廓的变化,在提出的圆锥体和半球体表面微观几何形貌的基础上,建立了极间电流场的数学模型,并分析了电化学光整加工过程中电流场分布特性的变化。研究结果表明,尖峰状表面微观几何轮廓有利于强化电化学的选择性溶解,有利于提高整平效果,验证了电化学光整加工过程中,机械作用具有使表面微观几何轮廓尖峰化的作用。     

飞秒激光加工单晶金刚石制备正前角磨削工具

目的制造一种磨粒有序排布、具有正前角的无结合剂端面金刚石磨削工具。方法采用波长为1030 nm、脉宽为250 fs的钛蓝宝石飞秒激光对单晶金刚石(SCD)进行烧蚀加工,首先研究加工工艺参数(特别是烧蚀轨迹间距)对金刚石加工效率及表面质量的影响。采用预先设计的激光扫描路径,基于优化后的工艺参数在SCD表面加工出微磨粒阵列结构,各磨粒呈方锥台形结构,其顶部倾斜角约为100°。在此基础上,对微磨粒阵列进行烧蚀加工,将所有微磨粒顶部的倾斜角减小至小于90°。结果当激光烧蚀轨迹间距为10.0μm时,烧蚀加工表面RMS粗糙度最小。确定了一种微磨粒边缘倾斜角小于90°且磨粒有序排布的新型无结合剂金刚石端面磨削工具的激光制备方法和工艺,采用该工艺加工的磨削工具表面质量好,轮廓精度高,磨粒平均正前角约为9.80°。结论采用飞秒激光可以高质量、高效率地制备出磨粒有序排布的新型正前角无结合剂金刚石端面磨削工具,该工具有望在硬脆材料磨削中减小磨削力,提高材料表面完整性。     

几种因素对快速点磨削表面粗糙度的影响

分析了点磨削加工表面形貌及其精度的几种影响因素.研究发现:砂轮速度和磨削深度对表面粗糙度的影响都可归结为未变形切屑厚度的改变.减小点磨削倾斜角,可以减小未变形切屑厚度,从而得到理想的表面粗糙度.加大磨削深度和轴向进给量可提高材料去除率,但会造成粗糙度增大.这可归结为砂轮有效磨粒数的减少导致工件的表面粗糙度降低.点磨削通过改变倾斜角大小来增加参与磨削的有效磨粒数,保证高材料去除率的同时获得良好表面质量.增加光磨次数和应用倾斜型砂轮都增加了磨粒和工件表面轮廓突峰的接触次数,对于改善表面粗糙度十分有益.     

脉冲电化学光整加工中表面形貌变化试验*

探究脉冲电化学光整（PECF）加工过程中表面形貌变化特性及其工艺能力。在能实现表面良好加工效果的参数范围内, 对 304 不锈钢车削与磨削表面进行脉冲电化学光整加工,通过对加工前后表面微观形貌变化规律的对比分析,研究脉冲电化学光整加工工艺对不同表面的整平能力。试验结果表明：脉冲电化学光整加工车削和磨削表面所能获得的最终表面粗糙度大体相当,加工后两种表面粗糙度 Ra、R_z 和 R_sm值处于同一量级,分别达到 0.09、0.7、50 μm 左右。表面微观形貌趋于一致, 表面完整性良好,表面特征指标不具有显著差异性。脉冲电化学光整加工车削和磨削表面的形貌变化过程有所差别,车削表面存在由原始表面形貌向脉冲电化学光整加工表面形貌转变的一段中间过程,磨削表面形貌则在短时间内迅速转变为脉冲电化学光整加工表面形貌。对原始表面较为粗糙的零件或者难以采用磨削加工的薄壁件,PECF 加工是一种具有实际应用价值的加工方式,且对于一些具有特殊要求的功能性表面形貌,车削后进行 PECF 加工可能成为一种新的加工方法。     

铝合金研磨加工表面自相关性分析

研磨加工是重要零件在磨削后进行去除表面缺陷层、降低粗糙度和波纹度为目的的光整加工工艺。试验在UNIPOL-802型精密研磨抛光机上完成,加工试样为磨削加工后粗糙度为0.6μm的2A12铝合金,加工表面形貌和微观几何参数用M ICROMESURE2和TR200表面轮廓仪测量。应用随机过程中的自相关性对磨削表面和研磨加工表面进行研究。分析结果表明,该加工方法明显提高了工件的表面质量,降低了工件的表面粗糙度并均化了波纹度。     

电泳技术在脆性材料磨削中的应用

利用超微磨粒的电泳特性,在加工过程中使超微磨粒的向工具泳动并沉积在工具表面,形成一动态的超微磨粒层,对脆性材料表面进行精密加工,本文介绍超微磨粒层的形成机理的特性,并通过对硅片进行电泳磨削的实验数据,着重讨论该技术的工艺特性及其对脆性材料加工质量的影响。研究结果表明,该技术能量明显地降低被加工表面的粗糙度。     

Influence of grinding parameters on the corrosion behavior of austenitic stainless steel

Samples of the austenitic stainless steel grade X5CrNi18‐10 (1.4301, AISI 304) were ground industrially with various grinding parameters to study their influence on corrosion resistance. The ability of the mechanically ground surfaces to form a stable passive layer was evaluated by KorroPad test and a modified electrochemical potentiodynamic reactivation test based on a single loop (EPR‐SL). Furthermore, the surfaces were characterized by surface analytical methods. The main influence was determined regarding abrasive belt type. Surfaces mechanically ground with granulate abrasive belts constantly had a lower corrosion resistance than surfaces ground with single‐coated grain. The granulate abrasive belts generated more sensitized surface areas and left formations of welded sample material on the mechanically ground surfaces. A post‐treatment with a nonwoven abrasive proved to be an effective finishing process by which the surface defects and sensitized material got removed and the surfaces regained the expected corrosion resistance.     

磨粒有序化砂轮磨削微沟槽减阻表面的研究

为研究砂轮磨粒排布样式对磨削结构化沟槽表面的影响，使用叶序、错位和阵列3种磨粒有序化排布的砂轮磨削工件平面。首先，建立3种有序化排布的数学模型；其次，根据结构化沟槽表面减阻的特性参数，设计砂轮磨削参数，并使用MATLAB软件进行磨削运动仿真，将仿真结果与理论计算值进行比较；最后，使用磨削试验验证数学模型与仿真结果的可靠性。结果表明:3种磨粒排布有序化的砂轮均能磨削出微沟槽表面，此时相邻两行磨粒的轴向间距分别为0.04 mm（叶序排布）、0.40 mm（错位排布）和0.80 mm（阵列排布），对应的磨削深度均为0.050 0 mm；磨粒阵列和错位排布的砂轮磨削出的沟槽表面更加稳定，但沟槽的参数比未能达到0.200～1.000的要求；磨粒叶序排布的砂轮加工出的沟槽，能满足表面减阻特性的要求。      

Progress in fluidized bed assisted abrasive jet machining (FB-AJM): Internal polishing of aluminium tubes

This paper deals with the internal finishing of tubular components made from a high strength aluminium alloy (AA 6082 T6) using a fluidized bed assisted abrasive jet machining (FB-AJM) system.Firstly, a Taguchi's experimental plan was used to investigate the influence of abrasive jet speed, machining cycle, and abrasive mesh size on surface roughness and material removal trends. Secondly, the leading finishing mechanisms were studied using combined 3d profilometer-SEM analysis to monitor the evolution of the surface morphology of machined workpieces. Finally, the circumferential uniformity and precision machining of the inner surface of workpieces were tested by evaluating the values of the more significant roughness parameters in different circumferential locations.Consistent trends of surface roughness vs. operational parameters were measured, and significant material removal was found to affect the workpieces during machining. As a result, FB-AJM was found to preferentially machine the asperities and irregularities of the surface, thereby altering the overall surface morphology producing more regular and smoother finishing. Moreover, the good circumferential uniformity and machining accuracy FB-AJM guarantees even on ductile aluminium alloy workpieces ensure that this technology can be applied to a diverse set of industrial components.     

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。      

Influence of finishing by burnishing on surface characteristics

The aim of this study was to analyze the evolution of residual stresses, microhardness, and roughness in relation to the finishing process. The x-ray diffraction (XRD) technique was used to determine the residual stresses, which were measured from the surface to the bottom of the machined workpiece. Processes that were studied included turning, grinding, and burnishing. Burnishing was done on a surface that was initially turned, or turned and then ground. A duplex stainless steel was used in this study. This material belongs to a high-strength stainless steel family with high corrosion resistance properties. We noted that the burnishing process produces the best quality of the surface when compared with turning or grinding.     

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.     

氮化铝陶瓷基片的集群磁流变效应研磨加工

采用集群磁流变效应研磨加工方法对氮化铝(AlN)陶瓷基片进行研磨加工,系统地分析了主要工艺参数的影响和最终经过精密研磨后的加工表面形貌特征。结果表明,集群磁流变效应研磨加工方法可以实现对氮化铝(AlN)陶瓷基片的高效率高精度研磨加工,原始表面Ra1.730μm经过粗研10 min和精研30 min后可以达到0.029μm,下降两个数量级。在粗研阶段,选用二氧化硅磨料#4000、磨料体积分数12%、研磨盘转速150 r/min、研磨压力3.5 kPa,可以获得较高的材料去除率和较光滑的加工表面。     

Abrasive enhanced electrochemical slurry jet micro-machining: Comparative experiments and synergistic effects

Abrasive enhanced electrochemical slurry-jet machining (ESJM) is presented as a new approach to the micro-machining of metals using a combination of abrasive slurry-jet machining (ASJM) and electrochemical jet machining (ECJM). A novel ESJM prototype was developed to generate a charged slurry jet consisting of a mixture of Al₂O₃ abrasive particles and an electrolytic solution of NaCl and NaNO₃. A DC potential of 30 V was applied between the nozzle and specimen. A series of micro-channels were machined in Stellite 12 using ASJM, ECJM and ESJM processes to investigate the relative effects of erosion and anodic dissolution on the material removal rate and surface finish in the combined process of ESJM. The results illustrated that the ESJM process results in significantly greater target mass loss rate than the separate erosion and corrosion processes. The magnitude of the synergistic effect on the rate of mass loss was found to vary from positive to negative as the erosion component increased with increasing particle kinetic energy (jet pressure) and particle concentration. The roughness of the channels machined using ESJM was between that obtained with ASJM and ECJM. The roughness decreased as the erosion component of the total mass loss increased.     

永磁场磁力研磨TC11钛合金的实验研究

目的解决钛合金机械加工后表面质量差的难题。方法采用磁力研磨工艺对TC11钛合金进行了表面光整加工。以表面粗糙度为主要评价指标,研究了磁力研磨工艺参数对钛合金表面质量的影响,并对工艺参数进行了优化。采用优化后的工艺参数对钛合金进行了表面光整加工,研究了磁力研磨工艺对钛合金金相组织的影响。结果当加工间隙为3 mm时,研磨压力适宜,加工后工件表面粗糙度值最小。采用粒径为100目的磨粒使工件表面研磨加工后纹理更细,表面粗糙度值最低。提高主轴转速,工件表面材料去除率增加,当主轴转速为1500 r/min时,加工后工件表面粗糙度值最小。对比工件加工前后的金相组织,加工后试样表面组织晶粒变细,晶界增多,工件表面应力状态由张应力转变为压应力。结论实验确定了较优的工艺参数组合,即:加工间隙为3 mm,磨粒粒径为100目,主轴转速为1500 r/min。采用永磁场磁力研磨工艺,能够大幅降低TC11钛合金表面粗糙度,并使钛合金表面组织得到改善。     

增韧莫来石陶瓷加工表面的耐磨性分析

本文应用表面粗糙度参数和磨损率，研究增韧莫来石材料磨削，珩磨及平顶珩磨表面的耐磨性能，通过Ra，表面轮廓，支承长度率曲线，轮廓高度幅度分布图，轮廓峰谷比等粗糙度参数评定其加工表面的耐磨性。试验结果表明，增韧莫来石加工表面的磨损率高于原始烧结表面。材料的表面粗糙度影响其耐磨性，材料的磨损率随其表面粗糙度参数Ra值增大而增大，陶瓷表面的耐磨性与加工方式有关，平顶珩磨表面的耐磨性较好。