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。     

航空不锈钢30CrMnSiA大去除率条件下的铣削力分析

针对航空不锈钢30CrMnSiA加工效率和加工质量的问题,从粗加工角度出发,研究大去除率条件下切削参数对切削力的影响规律。以主轴转速、每齿进给量、轴向切深与径向切深为影响因素,采用多因素正交试验与极差分析法对铣削力进行研究。分析结果表明:在大去除率铣削参数条件下,径向切深、每齿进给量、主轴转速分别为X、Y、Z三个方向切削力的最主要影响因素。     

高速铣削铝合金时切削力和表面质量影响因素的试验研究

对高速铣削典型铝合金框架结构工件时的切削力和加工表面质量进行了试验研究。在高速进给铣削时 ,当进给方向发生改变 ,机床的加减速特性将导致在拐角处进给量减小、铣刀切入角增大 ,从而引起切削力增大和加工振动。在恒切削效率条件下高速铣削铝合金的试验结果表明 ,高速铣削时宜采用较小的轴向切深和较大的径向切深 ,以减小铣削力、提高加工表面质量 ;刀具动平衡偏心量是高速铣削时引起轴向振纹的主要原因     

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。     

高速铣削加工钛合金Ti6Al4V的切削力和表面粗糙度试验

利用单因素实验法对高速铣削Ti6Al4V过程中各切削要素对切削力的影响进行分析,切削力随着切削速度的增加先增大后减小,随着每齿进给量和切削深度的增加而增大;利用正交试验法对高速铣削Ti6Al4V进行粗糙度分析,得出每齿进给量对工件表面粗糙度的影响最大,其次分别是切削速度、径向切深和轴向切深。     

基于正交试验的淬硬模具钢球头铣削加工表面粗糙度研究

采用正交试验法研究整体硬质合金球头铣刀铣削加工淬硬模具钢Cr12Mo V时切削参数对零件加工表面粗糙度的影响。设计了以主轴转速、每齿进给量、径向切深、侧偏角和前倾角为主要因素的5水平5因素正交试验,通过极差分析和方差分析方法研究了切削参数对表面粗糙度的影响规律,明确了主要影响因素。结果表明:表面粗糙度随每齿进给量和径向切深的增大而增大,随主轴转速的增大而减小,随侧偏角和前倾角的增大呈现出先减小后增大的趋势,各因素的影响程度从大到小依次为每齿进给量、径向切深、主轴转速、侧偏角、前倾角。     

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。     

微细铣削力对毛刺尺寸的影响规律研究

毛刺是影响微细铣削质量和效率的关键因素之一,本文运用有限元仿真与微细铣削试验相结合的方法研究了微细铣削中轴向力与径向力对毛刺宽度的影响,并以毛刺宽度为试验指标获得轴向力与径向力对毛刺宽度的影响规律。结果表明:当微细铣削参数大于临界未变形切屑厚度时,毛刺宽度随轴向切深、每齿进给量的增大而增大;当微细铣削参数小于临界未变形切屑厚度时,毛刺宽度随轴向切深、每齿进给量的增大先增大后减小,轴向力、径向力随轴向切深、每齿进给量的增大先增大后减小。总的来讲,毛刺宽度总体趋势随着轴向力、径向力的增大而增大,在后续的微细铣削参数优化中可以将切削力作为优化指标,间接地降低毛刺尺寸。     

切削用量对TC4薄壁件铣削力的影响

TC4薄壁零件刚性较低,切削力容易使工件变形。为了提高加工质量,研究了切削用量对铣削力的的影响规律,并建立了和铣削力相关的经验公式。结果表明:切削力Fx和Fy与切削速度呈负相关,而切削力Fz与切削速度呈正相关;切削力Fx、Fy随每齿进给量、轴向以及径向切削深度的增大而增大,其中对切削力影响最大的因素为径向切深。     

钛合金TC21铣削切削力预测实验研究

基于正交试验,针对钛合金TC21难加工性,研究了铣削工艺参数切削速度、每齿进给、轴向切深和径向切深对切削力的影响规律;借助数理统计和回归分析实验理论和方法,建立了钛合金TC21切削力的预测模型,并对该模型及回归系数进行显著性检验。研究表明,在高速铣削TC21钛合金过程中,切削力随切削速度的增大而减小,随每齿进给、轴向切深、径向切深的增大而增大;切削深度、每齿进给量对切削力的影响较大,切削速度和径向切深对切削力的影响不显著;经切削验证,建立的切削力预测模型是高度显著的。     

薄壁铸铝合金高速铣削加工试验研究

以铸铝合金薄壁件为加工对象,分别研究不同的切削速度、每齿进给量、径向切深对表面质量和切削力的影响规律,并优化切削参数的选择,力求为合理选择高速切削加工参数提供可靠依据。     

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.     

响应曲面法优化超高强度钢铣削加工切削参数的研究

通过试验对30CrMnSiNi2A钢高速干铣的表面粗糙度进行研究。在因子试验研究的基础上利用响应曲面法考察了切削速度、进给量、切深和切宽四个因素对表面粗糙度的影响规律并寻求最优工艺参数。结果表明切削速度对表面粗糙度值影响最大,响应曲面法用于超高强度钢的高速铣削参数优化可行有效。     

Optimization of end mill tool geometry parameters for Al7075-T6 machining operations based on vibration amplitude by response surface methodology

This paper aims at developing a statistical model to envisage vibration amplitude in terms of geometrical parameters such as radial rake angle, nose radius of cutting tool and machining parameters such as cutting speed, cutting feed and axial depth of cut. Experiments were conducted through response surface methodology experimental design. The material chosen is Aluminum (Al 7075-T6) and the tool used was high speed steel end mill cutter with different tool geometry. Two channels piezoelectric accelerometers were used to measure the vibration amplitude. The second order mathematical model in terms of machining parameters was built up to predict the vibration amplitude and ANOVA was used to verify the competency of the model. Further investigation on the direct and interactive effect of the process parameter with vibration amplitude was carried out for the selection of process parameter so that the vibration amplitude was maintained at the minimum which ensures the stability of end milling process. The optimum values obtained from end milling process are Radial rake angle-12°, Nose radius-0.8 mm, Cutting speed-115 m/min, Cutting feed rate-0.04 mm/tooth, axial depth of cut-2.5 mm. The vibration amplitude exhibited negative relationship with radial rake angle and nose radius. The dominant factors on the vibration amplitude are feed rate and depth of cut. Thus it is envisaged that the predictive models in this study could produce values of the vibration amplitude close to the experimental readings with a 95% confidence interval.     

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。     

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.     

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.     

HIGH SPEED MILLING OF GRAPHITE ELECTRODE WITH ENDMILL OF SMALL DIAMETER

Graphite becomes the prevailing electrode material in electrical discharging machining (EDM)currently.Orthogonal cutting experiments are carried out to study the characteristics of graph- ite chip formation process.High speed milling experiments are conducted to study tool wear and cutting forces.The results show that depth of cut has great influence on graphite chip formation.The removal process of graphite in high speed milling is the mutual result of cutting and grinding process. Graphite is prone to cause severe abrasion wear to coated carbide endmills due to its high abrasive- ness nature.The major patterns of tool wear are flank wear,rake wear,micro-chipping and breakage. Cutting forces can be reduced by adoption of higher cutting speed,moderate feed per tooth,smaller radial and axial depths of cut,and up cutting.