微细铣削硬铝时切削用量对表面粗糙度的影响

利用自研的三轴微小型立式数控铣床和微径立铣刀(直径小于1mm),通过双因素及中心复合实验设计的方法,分析微细铣削硬铝LY12过程中的铣削参数(包括每齿进给量、轴向切深、主轴转速、刀具直径以及刀具悬伸量)对工件表面粗糙度的影响,重点探讨了每齿进给量和轴向切深对表面粗糙度的交互影响,并建立了数学模型,为微细铣削工艺参数的选择和表面质量的控制提供了基本依据。     

金刚石飞切加工微结构表面的工艺参数优化

为了获得具有纳米级表面质量的微结构表面,利用‘Nanosys-300'超精密复合加工系统实现了微结构表面的三维金刚石飞切加工,研究了主轴转速、进给量以及背吃刀量对微结构表面粗糙度的影响.理论分析表明,金刚石飞切加工微结构时理论表面粗糙度沿法线方向并没有变化,而沿进给方向存在着周期变化.减小进给量和金刚石飞刀前端角或增大切削半径可以降低理论粗糙度值.实验分析表明,表面粗糙度值Ra随进给量的增加而增加,主轴转速对Ra影响不大.切削聚碳酸酯(PC)时,在5～40 μm Ra随背吃刀量的增加而增加;而切削铝合金(LY12)时,在2～10 μm Ra随背吃刀量的增加而减小.实验中Ra最好可达38 nm(LY12)和43 nm(PC).最后,利用优化工艺参数加工出了微沟槽阵列和微金字塔矩阵微结构.     

贮箱壁板材料高速铣削加工表面质量试验分析

对火箭箭体壁板材料在高速铣削条件下的加工表面质量进行试验分析,测量了不同转速下刀具最大径向位移跳动量,分析对比了干式切削和微量润滑切削条件下的加工表面粗糙度变化规律。结果显示,主轴转速16000r/min,每齿进给量0.20mm/z,轴向切深4mm时能够获得综合性能较好的加工表面质量和加工效率;在供液距离为50mm时,选用微量润滑高速铣削能够获得更加良好的加工表面粗糙度。     

金刚石飞切加工微结构表面的表面粗糙度研究

为了获得具有纳米级表面质量的微结构表面,利用‘Nanosys-300’超精密复合加工系统实现了微结构表面的三维金刚石飞切加工,研究了主轴转速、进给量以及背吃刀量对微结构表面粗糙度的影响。通过对理论表面粗糙度分析可知：金刚石飞切加工微结构时理论表面粗糙度沿法线方向并没有变化,而沿进给方向存在着周期变化。减小进给量f和金刚石飞刀前端角ε或增大切削半径可以降低理论粗糙度值。实验分析结果表明：表面粗糙度值Ra随进给量的增加而增加,主轴转速对Ra影响不大。切削PC时,在5μm-40μm范围内,Ra随背吃刀量的增加而增加;而切削LY12时,在2μm-10μm范围内,Ra随背吃刀量的增加而减小。实验中Ra最好可达38nm（LY12）和43nm（PC）。最后利用优化工艺参数加工出了微沟槽阵列和微金字塔矩阵微结构。     

微铣金属表面微沟槽结构的粗糙度及形貌分析

为了提高和改善微沟槽表面质量,设计了高速微铣削实验,研究了微沟槽底面表面粗糙度和侧壁残留毛刺的变化规律。从理论角度引入了已加工表面的形成机理,建立了微观表面粗糙度理论模型,提出了刀具跳动对侧壁形貌变化影响的规律。利用三轴联动精密微细铣削机床加工微细直沟槽,并选取主轴转速、轴向切深、进给速度、刀具跳动量和材料组织结构为研究因素。采用多因素正交实验和极差分析法,对表面粗糙度值进行数值分析。铝合金,钢和钛合金三类微沟槽底面对应的最佳表面粗糙度值变化范围分别为1.073~1.481 μm,0.485~0.883 μm,0.235~0.267 μm;无刀具跳动钛合金微沟槽壁毛刺的最大高度为7.637 μm,而当刀具存在0.3 μm的径向综合跳动量时对应的微槽壁毛刺的最大高度为21.79 μm。铣削参数对表面粗糙度值的影响按从大到小依次为进给速度、主轴转速、轴向切深,且随着进给速度和轴向切深的增大,表面粗糙度值增大;随着主轴转速的增大,表面粗糙度值先减小后增大;在相同加工条件下,若微圆弧刀刃无磨损,微刀具的跳动量对微直沟槽侧壁表面质量有较大影响。同时,不同金属材料特性也是影响微沟槽表面质量的潜在因素。     

基于主成分分析和灰色关联度的铝合金铣削参数优化

在飞机耳片槽的加工中经常出现耳片变形、切削振动引发表面质量变差等质量问题,为确保耳片加工表面质量,以7050-T7451铝合金为试验对象,把径向切削深度作为试验定量,主轴转速、每齿进给量和轴向切深为试验变量,设计三因素三水平的正交铣削试验,以表面粗糙度和材料去除率为输出特性指标,采用灰色关联理论主成分分析法对试验数据进行分析,确定灰色关联分析中的权重系数,对铣削加工进行多目标优化。研究表明,3个因素对试验表面粗糙度和材料去除率的影响程度的显著性排序为:每齿进给量轴向切削深度主轴转速;最优铣削加工参数为:主轴转速为5000 r/min,每齿进给量为0.25 mm,轴向切削深度为4 mm,径向切削深度为0. 5 mm。     

Vit1块体金属玻璃微铣削表面粗糙度试验研究

为研究金属玻璃的微铣削表面粗糙度,采用直径为0.5 mm的双刃硬质合金微铣刀,在Vit1块体金属玻璃表面加工微尺度沟槽结构;以试件表面粗糙度Ra值为衡量指标,利用三因素五水平正交试验方法分析主轴转速、进给速度和铣削深度对微铣削表面质量的影响。试验结果表明:主轴转速对表面质量影响最为显著,而进给速度影响较小。对影响表面质量及形貌的原因进行了深入分析,其结果对研究Vit1块体金属玻璃的微铣削加工机理具有一定的借鉴意义。     

单齿飞刀铣削航天薄壁件加工工艺优化研究

针对航天薄壁件加工过程中的变形问题,基于正交试验方法优化航天薄壁件飞刀铣削参数组合,采用极差分析法并绘制试验指标与各试验因素间的关系曲线图得出了各因素对加工质量的影响程度,并以此为基础优化参数,进行航天薄壁件铣削加工工艺优化研究。试验表明:主轴转速n和刀具圆弧半径r对工件表面质量影响较大,且各因素对表面粗糙度的影响程度大小顺序为:主轴转速、刀具圆弧半径、刀具后角、进给量、背吃刀量。采用优化后的工艺参数加工试验,当r=1.1mm、a0=8mm、f=8μm/r、ap=1μm和n=950r/min时,得到了表面粗糙度Ra为72nm的质量表面。     

钛合金表面多磁极耦合旋转磁场光整加工特性

面向激光增材制造钛合金表面的光整加工需求,设计出一种多磁极耦合旋转磁场光整加工装置来研究光整加工特性。基于ANSYS Maxwell仿真软件分析了光整加工装置的磁场强度分布。搭建了实验光整平台,分析了主轴转速、C轴转速和加工间隙对表面质量的影响。结果表明,在主轴转速500 r/min、C轴转速160 r/min和加工间隙0.7 mm的加工条件下,表面粗糙度Ra由5.991 μm下降至0793 μm。扫描电子显微镜(SEM)观测表明,光整后的钛合金表面沉积层消失,表面质量得到显著改善。     

基于振动信号控制的水室封头铣削加工工艺的优化

水室封头部件是蒸汽发生器的关键部件,关系到核电发电效率及安全性。水室封头铣削加工的工况为大悬深量、大进给量、轴向切削深度大,产生较大的切削力,导致主轴-刀具系统产生非常大的振动,进而造成工件表面质量和刀具寿命降低。针对上述问题,对铣削水室封头的工艺进行优化,减少了铣削过程的振动,从而提高型面加工精度。采用正交实验分析切削参数对X方向切削振动的影响,分析得出轴向切削深度是影响铣削振动的主要因素,每齿进给量次之,主轴转速影响最小的结论。优化后的切削参数是轴向切深为1.5mm,每齿进给量为0.8mm/z,主轴转速为500r/min。     

An association rule mining and maintaining approach in dynamic database for aiding product–service system conceptual design

Many previous researches on high-speed machining have been conducted to pursue high machining efficiency and accuracy. In the present study, the characteristics of cutting forces, surface roughness, and chip formation obtained in high and ultra high-speed face milling of AISI H13 steel (46–47 HRC) are experimentally investigated. It is found that the ultra high cutting speed of 1,400?m/min can be considered as a critical value, at which relatively low mechanical load, good surface finish, and high machining efficiency are expected to arise at the same time. When the cutting speed adopted is below 1,400?m/min, the contribution order of the cutting parameters for surface roughness Ra is axial depth of cut, cutting speed, and feed rate. As the cutting speed surpasses 1,400?m/min, the order is cutting speed, feed rate, and axial depth of cut. The developing trend of the surface roughness obtained at different cutting speeds can be estimated by means of observing the variation of the chip shape and chip color. It is concluded that when low feed rate, low axial depth of cut, and cutting speed below 1,400?m/min are adopted, surface roughness Ra of the whole machined surface remains below 0.3?μm, while cutting speed above 1,400?m/min should be avoided even if the feed rate and axial depth of cut are low.     

加装气浮飞刀铣削装置的车床改造及应用

为了实现细轴上微小平面的精密加工,研制了一套飞刀铣削装置,该装置的主轴采用空气静压轴承,回转精度为0 1 μm.将其加装在精密数控车床的工作台上,配合成组车削刀具,使工件能在一次装夹过程中,按照数控指令实现车削轮廓及飞刀铣削出微小平面,从而提高微小平面的加工精度.研究了气浮飞刀切削速度、背吃刀量和进给量等主要切削参数对微小平面表面粗糙度的影响规律.在0 4 mm×0 4 mm范围内的平面,其尺寸和位置精度±2 μm,平面度小于1 μm,表面粗糙度值达Ra0 03 μm.     

Determining the effect of cutting parameters on surface roughness in hard turning using the Taguchi method

This study focuses on optimizing turning parameters based on the Taguchi method to minimize surface roughness (Ra and Rz). Experiments have been conducted using the L9 orthogonal array in a CNC turning machine. Dry turning tests are carried out on hardened AISI 4140 (51 HRC) with coated carbide cutting tools. Each experiment is repeated three times and each test uses a new cutting insert to ensure accurate readings of the surface roughness. The statistical methods of signal to noise ratio (SNR) and the analysis of variance (ANOVA) are applied to investigate effects of cutting speed, feed rate and depth of cut on surface roughness. Results of this study indicate that the feed rate has the most significant effect on Ra and Rz. In addition, the effects of two factor interactions of the feed rate-cutting speed and depth of cut-cutting speed appear to be important. The developed model can be used in the metal machining industries in order to determine the optimum cutting parameters for minimum surface roughness.     

Optimization of cutting conditions for minimum residual stress,cutting force and surface roughness in end milling of S50C medium carbon steel

Residual stresses are usually imposed on a machined component due to thermal and mechanical loading. Tensile residual stresses are detrimental as it could shorten the fatigue life of the component; meanwhile, compressive residual stresses are beneficial as it could prolong the fatigue life. Thermal and mechanical loading significantly affect the behavior of residual stress. Therefore, this research focused on the effects of lubricant and milling mode during end milling of S50C medium carbon steel. Numerical factors, namely, spindle speed, feed rate and depth of cut and categorical factors, namely, lubrication and milling mode is optimized using D-optimal experimentation. Mathematical model is developed for the prediction of residual stress, cutting force and surface roughness based on response surface methodology (RSM). Results show that minimum residual stress and cutting force can be achieved during up milling, by adopting the MQL-SiO₂ nanolubrication system. Meanwhile, during down milling minimum residual stress and cutting force can be achieved with flood cutting. Moreover, minimum surface roughness can be attained during flood cutting in both up and down milling. The response surface plots indicate that the effect of spindle speed and feed rate is less significant at low depth of cut but this effect significantly increases the residual stress, cutting force and surface roughness as the depth of cut increases.     

An experimental study of micromilling parameters to manufacture microchannels on a PMMA substrate

Rapidly prototyping a polymer microfluidic device is a growing interest in the application fields of the disease detection, drug synthesis, and the environmental monitoring because of the benefits of the miniaturized platforms. Micromilling is one of the micromachining methods and it has been commonly used to manufacture polymer microfluidic devices. The advantages of using micromilling for polymer microfluidic devices include faster fabrication process, lower cost, easier user interface, and being capable of fabricating complicated structures, which make micromilling a perfect candidate in rapid prototyping polymer microfluidic devices for research idea testing and validation. This aim of this study is to understand the influence of each micromilling parameter to the surface quality, followed by the factor analysis to determine the optimal cutting conditions. The parameters included spindle speed, feed rate, depth of cut, and the selection of coolant (compressed air/oil coolant), and the milled surface quality was measured by a stylus profilemeter. Polymethyl methacrylate (PMMA) is the mainstream substrate material in the microfluidics due to its excellent optical property and popularity and is used as the target substrate. The experiment results showed that using the compressed air as a coolant can deliver a better surface quality than the oil coolant, and the smallest roughness achieved was 0.13 μm with the spindle speed of 20,000 rpm, feed rate of 300 mm/min, and the depth of cut of 10 μm. Factor analysis revealed that the depth of cut has the largest impact while the spindle speed has the minimized impact to the surface quality of a micromilled PMMA substrate. To further confirm the optimal cutting conditions, another 12 reservoirs were micromilled with the optimal cutting conditions and the average roughness is 0.17 μm with a stand deviation of 0.08 μm.     

金刚石磨头刀具磨铣加工对高体份SiCp/Al复合材料加工表面质量的影响

针对高体份SiCp／Al复合材料,采用佥刚石磨头刀具磨铣切削的加工方法,研究了高速磨铣加工中机床主轴转速、工件进给速度及背吃刀量对材料加工表面形貌损伤以及表面粗糙度的影响规律。研究表明,机床主轴转速的提高、工件进给速度的减小都能够减小材料表面形貌的损伤情况,改善加工表面粗糙度质量：背吃刀量的改变对材料表面形貌损伤以及表面粗糙度的影响不大。     

Empirical models and optimal cutting parameters for cutting forces and surface roughness in hard milling of AISI H13 steel

In the present research, an attempt has been made to experimentally investigate the effects of cutting parameters on cutting forces and surface roughness in hard milling of AISI H13 steel with coated carbide tools. Based on Taguchi’s method, four-factor (cutting speed, feed, radial depth of cut, and axial depth of cut) four-level orthogonal experiments were employed. Three cutting force components and roughness of machined surface were measured, and then range analysis and analysis of variance (ANOVA) are performed. It is found that the axial depth of cut and the feed are the two dominant factors affecting the cutting forces. The optimal cutting parameters for minimal cutting forces and surface roughness in the range of this experiment under these experimental conditions are searched. Two empirical models for cutting forces and surface roughness are established, and ANOVA indicates that a linear model best fits the variation of cutting forces while a quadratic model best describes the variation of surface roughness. Surface roughness under some cutting parameters is less than 0.25 μm, which shows that finish hard milling is an alternative to grinding process in die and mold industry.     

涂层刀具高速铣削模具钢SKD11的表面粗糙度模型预测

为有效控制和预测高硬度模具钢加工的表面质量和加工效率,通过设计正交切削试验,研究了在不同切削参数组合(主轴转速、进给速度、轴向切削深度和径向切削深度)及冷却润滑方式条件下、Ti Si N涂层刀具对模具钢SKD11(62HRC)的高速铣削。应用BP神经网络原理建立表面粗糙度预测模型,并进行试验验证其准确性。研究表明,在不同加工条件下,基于BP神经网络模型建立的涂层刀具铣削模具钢SKD11表面粗糙度模型有较好的预测精度,其预测误差在3.45%-6.25%之间,对于模具制造企业选择加工工艺参数、控制加工质量和降低加工成本有重要意义。