微小几何特征微铣削试验研究

微小型零件几何特征的加工质量直接影响微小型零件的使用性能,本文对50μm厚的微小几何特征尺寸精度及表面质量开展试验研究。正交试验结果显示:微铣削黄铜材料时,铣削参数对铣削力的影响主次为每齿进给量f_z、轴向切深a_p、径向切深a_e;铣削参数对尺寸误差的影响主次为a_p> a_e> f_z;铣削参数对表面粗糙度的影响主次为a_p> f_z> a_e。试验获得优化参数组合为a_p=15μm、a_e=30μm、f_z=0. 7μm,表明微铣削过程中轴向切深对加工质量的影响大于其他参数。因此,实际生产中应选择合适的轴向切深,较大的进给量和径向切深,以保证微型几何特征的加工质量,获得较高的加工效率。     

薄壁零件高速铣削振动试验与分析

切削速会加强振动随针对薄壁零件在高速铣削加工过程中存在的振动问题,为有效抑制加工振动,采用单因素试验,对每齿进给量、度、工彳车径向轴向切深、径向切深等加工参数进行了研究。试验结果显示：每齿进给量并不是越小越好;转速过高过低都振动：切深增随轴向切深增大振动增强;随径向切深增大振动逐渐减弱,较大轴向切深下,径向切深小于1mm时,大而增强。综合数据优选：薄壁零件高速铣削时,每齿进给量在0．1～0．15mm之间;转速在11000—14000r／min之间;较小的轴向切深和较大径向切深会有效抑制加工振动。     

不锈钢微结构铣削仿真与试验研究

针对不锈钢微结构微铣削过程中铣削力以及加工质量,进行了微铣削参数仿真及试验研究。通过单因素有限元仿真,揭示了微铣削关键工艺参数每齿进给量、轴向切深和径向切深对铣削力影响规律。结果显示,尺寸误差以及表面粗糙度随着径向切深的增加波动变化,总体数值变化不大,径向切深对不锈钢微结构微铣削过程中的加工质量影响不大。因此,实际生产中,可以采用大径向切深小进给,提高生产率并保证加工质量。     

曲面薄壁特征微细铣削试验研究

曲面薄壁零件在微电极及微型涡轮等领域有着极其重要的应用,为了保证其加工质量,针对曲面薄壁特征进行了微细铣削试验研究,探究关键铣削参数每齿进给量f_z、轴向切深a_p、径向切深a_e及主轴转速n对表面粗糙度Ra、尺寸误差Δ_w及毛刺宽度h的影响规律,基于综合平衡法,优化获得最优铣削参数。研究结果表明,对Ra、Δ_w及h影响最大的因素分别为n、f_z、a_p;变轴向切深加工工艺能够抑制毛刺的形成,获得较好的加工质量。在保证质量的同时,为提高加工效率,可以在加工过程中适当采用较大的a_e值及f_z值。     

不同走刀方式高速铣球墨铸铁的刀具磨损研究

新型铸铁在汽车、机电、航空等行业的零部件制造中有较多应用,研究其高速切削时的刀具磨损问题具有实际的意义。研究单向行切、双向行切、环切这三种走刀方式及不同轴向切深对新型球墨铸铁进行高速切削时的刀具磨损影响。设计双因素重复实验方案并进行高速铣削实验,建立后刀面磨损情况的切削长度曲线;通过方差及贡献率方法,分析不同走刀方式及轴向切情况对有效切削时间、材料去除量及刀具磨损的影响程度。结果表明:走刀方式对刀具磨损、材料切除量等影响非常显著,实际加工中应该优选双向行切走刀方式,并适当增大轴向切深及降低切削速度以获得较优材料切除率并提高刀具耐用度。     

铝合金薄壁件高速铣削尺寸精度的试验研究

通过铝合金薄壁件高速铣削的正交试验,对加工尺寸精度的测量结果进行了分析,总结了铣削参数对工件尺寸精度的影响规律,并确定了铣削参数的选用原则.     

拐角高速铣削切削力正交试验研究

对DMU60T高速加工中心加工P20模具钢时的15°、45°和75°拐角高速铣削切削力进行正交试验研究.绘制了单因素趋势图,运用单因素极差分析法分析了拐角切削力与切削参数(轴向切深ap、径向切深ae、进给速度f、主轴转速n)的关系,优化了拐角高速铣削参数.试验表明:轴向切深和进给速度是影响拐角切削力的主要因素,主轴转速和径向切深是次要因素.     

基于有限元分析的走刀策略对铝合金薄壁筋铣削仿真工艺研究

铝合金薄壁筋具有弹载计算机结构件的典型特征,其结构简单但整体刚性差,在加工过程中极易产生加工变形,影响工件的加工精度。为合理选择走刀策略,使用ABAQUS软件对铝合金薄壁筋铣削过程进行有限元仿真建模,分析了不同走刀策略下铣削过程中的铣削力及工件铣削后的变形情况。同时设计对照试验组进行试切验证,通过三坐标测量仪分别测量了薄壁筋在不同走刀策略下的形变,验证了仿真分析结果的正确性。     

硬质合金平头铣刀铣削力系数的试验研究

为分析硬质合金平头铣刀的铣削力系数与各工艺参数的关系,选取不同每齿进给量、轴向切深、径向切深等工艺参数组合进行正交试验。采用二次回归方程方法拟合出切向铣削力系数函数和径向铣削力系数函数,并验证了铣削力系数函数的可靠性。通过试验研究,确认轴向切深和每齿进给量对硬质合金平头铣刀铣削力系数影响较大。     

薄壁腹板加工变形规律及其变形控制方案的研究

针对薄壁结构框体零件切削加工中腹板变形问题进行了分析研究。通过建立薄壁腹板铣削加工受力模型、有限元变形分析模型，结合切削试验，得到了薄壁腹板加工变形的基本规律，并据此提出了相应的变形控制工艺措施。结果表明，薄壁腹板加工变形模式与腹板结构尺寸、走刀路径、切削用量等因素的组合有关；大切深法以及分步环切法可以充分利用薄壁零件自身刚性，减小加工变形，提高加工精度，是两种控制薄壁腹板加工变形的有效工艺措施。     

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。     

Design optimization of cutting parameters for side milling operations with multiple performance characteristics

In this paper, a grey relational analysis is applied to a set of two-stage experiments designed to determine the cutting parameters for optimizing the side milling process with multiple performance characteristics. The cutting parameters to be considered are cutting speed, feed per tooth, axial depth of cut, radial depth of cut, overhang length and flank wear of peripheral cutting edge. L₃₆ and L₉ orthogonal arrays are used in the experiments and lower-the-better is used as a qualitative characteristic to evaluate the results. It is found that using the grey relational analysis coupled with a deliberate design of the two-stage experiments is simple and efficient in determining an optimal combination of the cutting parameters. The results of the confirmation test also show that this new approach can greatly improve the cutting performance of side milling process.     

Effects of Cutting Parameters on Tool Insert Wear in End Milling of Titanium Alloy Ti6A14V

Titanium alloy is a kind of typical hard-to-cut material due to its low thermal conductivity and high strength at elevated temperatures, this contributes to the fast tool wear in the milling of titanium alloys. The influence of cutting conditions on tool wear has been focused on the turning process, and their influence on tool wear in milling process as well as the influence of tool wear on cutting force coefficients has not been investigated comprehensively. To fully understand the tool wear behavior in milling process with inserts, the influence of cutting parameters on tool wear in the milling of titanium alloys Ti6Al4 V by using indexable cutters is investigated. The tool wear rate and trends under different feed per tooth, cutting speed, axial depth of cut and radial depth of cut are analyzed. The results show that the feed rate per tooth and the radial depth of cut have a large influence on tool wear in milling Ti6Al4 V with coated insert. To reduce tool wear, cutting parameters for coated inserts under experimental cutting conditions are set as: feed rate per tooth less than 0.07 mm, radial depth of cut less than 1.0 mm, and cutting speed sets between 60 and 150 m/min. Investigation on the relationship between tool wear and cutting force coefficients shows that tangential edge constant increases with tool wear and cutter edge chipping can lead to a great variety of tangential cutting force coefficient. The proposed research provides the basic data for evaluating the machinability of milling Ti6Al4 V alloy with coated inserts, and the recommend cutting parameters can be immediately applied in practical production.     

Effects of cutting parameters on tool insert wear in end milling of titanium alloy Ti6Al4V

Titanium alloy is a kind of typical hard-to-cut material due to its low thermal conductivity and high strength at elevated temperatures, this contributes to the fast tool wear in the milling of titanium alloys. The influence of cutting conditions on tool wear has been focused on the turning process, and their influence on tool wear in milling process as well as the influence of tool wear on cutting force coefficients has not been investigated comprehensively. To fully understand the tool wear behavior in milling process with inserts, the influence of cutting parameters on tool wear in the milling of titanium alloys Ti6Al4V by using indexable cutters is investigated. The tool wear rate and trends under different feed per tooth, cutting speed, axial depth of cut and radial depth of cut are analyzed. The results show that the feed rate per tooth and the radial depth of cut have a large influence on tool wear in milling Ti6Al4V with coated insert. To reduce tool wear, cutting parameters for coated inserts under experimental cutting conditions are set as: feed rate per tooth less than 0.07 mm, radial depth of cut less than 1.0 mm, and cutting speed sets between 60 and 150 m/min. Investigation on the relationship between tool wear and cutting force coefficients shows that tangential edge constant increases with tool wear and cutter edge chipping can lead to a great variety of tangential cutting force coefficient. The proposed research provides the basic data for evaluating the machinability of milling Ti6Al4V alloy with coated inserts, and the recommend cutting parameters can be immediately applied in practical production.     

The optimal cutting-parameter selection of heavy cutting process in side milling for SUS304 stainless steel

This paper presents an optimal cutting-parameter design of heavy cutting in side milling for SUS304 stainless steel. The orthogonal array with grey-fuzzy logics isapplied to optimize the side milling process with multiple performance characteristics. A grey-fuzzy reasoning grade obtained from the grey-fuzzylogics analysis is used as a performance index to determine the optimal cutting parameters. The selected cutting parameters are spindle speed, feed per tooth,axial depth of cut and radial depth of cut, while the considered performance characteristics are tool life and metal removal rate. The results ofconfirmation experiments reveal that grey-fuzzy logics can effectively acquire an optimal combination of the cutting parameters. Hence, performance in theside milling process for heavy cutting can be significantly improved through this approach.     

螺旋铣孔工艺的切削稳定性及工艺参数规划

以螺旋铣孔工艺时域解析切削力建模、时域与频域切削过程动力学建模、切削颤振及切削稳定性建模为基础,研究了螺旋铣孔的切削参数工艺规划模型和方法。切削力模型同时考虑了刀具周向进给和轴向进给,沿刀具螺旋进给方向综合了侧刃和底刃的瞬时受力特性;动力学模型中同时包含了主轴自转和螺旋进给两种周期对系统动力学特性的影响,并分别建立了轴向切削稳定域和径向切削稳定域的预测模型,求解了相关工艺条件下的切削稳定域叶瓣图。在切削力和动力学模型基础之上,研究了包括轴向切削深度、径向切削深度、主轴转速、周向进给率、轴向进给率等切削工艺参数的多目标工艺参数规划方法。最后通过试验对所规划的工艺参数进行了验证,试验过程中未出现颤振现象,表面粗糙度、圆度、圆柱度可以达到镗孔工艺的加工精度。     

切削用量对立铣加工钛合金Ti6Al4V切削力和切削温度影响规律的有限元仿真研究

利用软件AdvantEdge建立硬质合金涂层立铣刀三维铣削Ti6Al4V钛合金的有限元分析模型,模拟分析切削参数(切削速度、每齿进给量、轴向切削深度及径向切削深度)对刀具切削温度、切削力的影响规律。研究发现:切削力及切削温度随每齿进给量、轴向切削深度及径向切削深度的增加而增加:切削温度对切削深度的变化较敏感,随轴向切削深度和径向切削深度的增加显著增加;随着切削速度的增加,切削力先增大后减小,临界切削速度为120m/min。     

高速铣削1Cr18Ni9不锈钢切削力建模及实验分析

采用多因素正交实验法,在五轴高速加工中心上,进行了高速铣削1Cr18Ni9不锈钢的实验。基于概率统计和回归分析原理,对回归方程进行了显著性检验,并建立了1Cr18Ni9不锈钢的切削力经验模型。通过分析正交实验直观图,研究了切削参数对切削力的影响。     

Milling of Ti alloy honeycomb treated by ice fixation in cryogenic

ABSTRACT

This article presents the first comprehensive investigation on ice fixation milling method for titanium (Ti) alloy honeycomb with cryogenic cooling. Milling simulation model of ice fixation was established, the material was treated by ice fixation process, and a series of cryogenic experiments was conducted by CNC milling machine. The honeycomb properties and reasons of machining defects were analyzed in details, whilst cryogenic milling mechanism with ice fixation was deduced. The analysis indicated that compared to the conventional processing way, the ice fixation milling surfaces have great improvement, and the processing defects such as burr, collapse edge are effectively suppressed, as well as ice fixation cryogenic method can improve the strength of honeycomb. Meanwhile, the cutting depth has greater influence on surface quality. Furthermore, the influence order of cutting parameters on the milling force: cut deep is the largest and more than three times can be improved, followed by feed speed, and the spindle speed has minimal impact. Conclusion: for efficient processing of Ti alloy honeycomb material with small in-plane radial equivalent strength and low rigidity thin-wall, the ice fixation provides a new processing method with cryogenic cooling.