高速铣削加工的数学模型建立和实验研究

在高速铣削机理研究中,铣削参数的应用实验研究是至关重要的.通过单因素和多因素实验,研究高速铣削参数对已加工工件表面粗糙度和表层残余应力的影响规律.实验表明,高速铣削能够获得较好的工件表面质量.     

机械加工零件表面的质量控制措施

为了确保进行机械加工时更好地控制工件表面质量,通过实例分析法,结合硬铝合金工件在实际铣削加工过程中不同参数情况下工件表面质量情况,进行分析与研究。结果表明:铣削加工硬铝合金工件的作业过程中,随着切削深度值逐步增大,加工工件的粗糙度也有所增加;设定的径向进给量参数值越小,加工工件的表面粗糙度也会进一步的减小;进给速率参数逐步增加,工件粗糙度相应也会随之增。通过实验得出了不同因素对于工件表面质量影响的规律,为工件加工中具体参数确定提供了参考与依据。     

CVD金刚石刀具的微细铣削仿真及试验研究

为研究切削参数对CVD金刚石微铣刀切削性能的影响,运用扩展有限元法对CVD金刚石微刀具的铣削加工和刀具损伤应力进行仿真模拟,研究了铣削加工后工件的表面粗糙度随切削参数的变化规律,分析了切削参数对微铣刀失效的影响,并通过试验验证了仿真结果的正确性。研究结果表明:在CVD金刚石微铣刀加工TC4钛合金时,铣削深度和每齿进给量的增加不利于工件加工质量的改善;铣削速度增加对工件加工表面粗糙度影响较小;铣削深度是影响刀具失效的主要因素,铣削速度和每齿进给量是影响刀具失效的次要因素。     

高速铣削加工表面质量实验研究

应用高速铣削加工的工件表面质量,是必须关注的问题。本文通过高速铣削加工参数的实验研究,对工件表面粗糙度影响规律进行了分析研究、得出了初步结论。     

镍基高温合金短电弧铣削加工性能与电极损耗规律研究

简述了短电弧切削加工技术中的新型铣削方法和短电弧数控铣削加工机床的加工原理。采用短电弧铣削加工方法加工镍基高温合金(GH4169),在不同电源放电参数下观察加工后工件的宏观组织、工件加工表面粗糙度、电极的损耗情况,测量工件显微硬度、观察加工波形图,初步得出在不同加工电源参数对加工工件表面质量的影响规律。实验表明:通过对加工后的工件宏观观察发现,工件表面粗糙度与放电占空比有关,结合采集到的放电波形可以总结出,占空比越大,表面粗糙度值越大;电压在小范围变化时电压对加工工件表面质量影响不大;离加工表面越近,显微硬度越高;电压越大,相对电极损耗比较小;通过调整电源参数可以得到满意的镍基高温合金(GH4169)的表面质量与较小的电极损耗。     

TC4钛合金铣削力及表面粗糙度分析

铣削力和表面粗糙度是评价工件加工工艺质量的重要指标,特别是对于薄壁件的加工,过大切削力会使零件产生弹塑性变形,造成零件过切或欠切,从而严重影响工艺质量.本文通过多因素正交实验,研究了各铣削参数对铣削力及表面粗糙度的影响程度,并建立了铣削力及表面粗糙度的经验预测模型.结果 表明,在铣削力方面,铣削深度和每齿进给量的影响高...     

铣削加工粗糙度的智能预测方法

提出了一种基于最小二乘支持向量机的铣削加工表面粗糙度智能预测方法.首先进行了铣削工艺参数对工件表面粗糙度影响的正交实验,再通过对主轴转速、进给速率和切削深度三因素,以及各因素之间交互三水平实验的数据分析,找出了铣削工艺参数对工件表面粗糙度影响的一些规律.利用最小二乘支持向量机算法建立了铣削预测模型,通过该模型能在有限实验基础上利用工艺参数方便地得到粗糙度预测值.实际预测表明,在相同情况下,该模型构造速度比反向传播神经网络建模预测方法高2个～3个数量级,预测精度高10倍左右.     

超声铣削铝合金表面微观形貌实验分析

使用超声振动辅助铣削和普通铣削两种方式对7075铝合金进行加工,分别以转速、振幅、每齿进给量为变量设计单因素实验,使用超景深测试仪、白光衍射仪观测加工表面的形貌,对比不同加工方式和不同参数下工件表面的粗糙度值和微观形貌,对产生该形貌的原因以及该形貌的特征进行分析。实验表明:在相同转速和进给量条件下,使用较小超声振幅加工的工件,其表面粗糙度值低于普通铣削方式;超声振动辅助铣削方式会使工件表面产生均匀、整齐的鳞状网格结构;加工参数不同,造成表面形貌产生明显的差异。     

基于LS-SVM的汽轮机叶片高速铣削表面质量预测建模

针对汽轮机叶片高速铣削加工中存在的表面质量不易控制问题,借助最小二乘支持向量机原理,建立了被加工不锈钢叶片表面的粗糙度预测模型。实验结果表明,该模型能方便地预测切削速度、主轴转速、进给量、铣削宽度等铣削参数对铣削加工工件表面粗糙度的影响,并能利用有限的实验数据得出整个工作范围内的表面粗糙度预测值,模型适合于表面粗糙度预测,回归预测精度高。     

微细铣削工艺参数优化实验研究

以被加工工件表面粗糙度为指标,对微细铣削工艺参数进行了实验研究,采用所研发的基于pmac运动控制器的开放式三轴桌面微细铣削机床,选取轴向切深,径向切深和进给量三个因素安排正交实验,对黄铜H59进行了微细铣削加工。运用白光干涉仪对微细铣削宽槽底部的表面粗糙度进行了测量,通过对测量数据的极差分析和方差分析,确定了各因素对表面粗糙度的影响规律及三个因素对表面粗糙度影响的主次顺序,实验表明径向切深对表面粗糙度值影响最大。     

Investigation of the effect of machining parameters on the surface quality of machined brass (60/40) in CNC end milling—ANFIS modeling

Brass and brass alloys are widely employed industrial materials because of their excellent characteristics such as high corrosion resistance, non-magnetism, and good machinability. Surface quality plays a very important role in the performance of milled products, as good surface quality can significantly improve fatigue strength, corrosion resistance, or creep life. Surface roughness (Ra) is one of the most important factors for evaluating surface quality during the finishing process. The quality of surface affects the functional characteristics of the workpiece, including fatigue, corrosion, fracture resistance, and surface friction. Furthermore, surface roughness is among the most critical constraints in cutting parameter selection in manufacturing process planning. In this paper, the adaptive neuro-fuzzy inference system (ANFIS) was used to predict the surface roughness in computer numerical control (CNC) end milling. Spindle speed, feed rate, and depth of cut were the predictor variables. Experimental validation runs were conducted to validate the ANFIS model. The predicted surface roughness was compared with measured data, and the maximum prediction error for surface roughness was 6.25 %, while the average prediction error was 2.75 %.     

Influence of dielectric and machining parameters on the process performance for electric discharge milling of SiC ceramic

Silicon carbide (SiC) ceramic has been widely used in modern industry because of its superior mechanical properties, wear, and corrosion resistance even at elevated temperature. However, the manufacture of SiC ceramic is not an efficient process by conventional machining methods. This paper employs a steel-toothed wheel as the tool electrode to machine SiC ceramic using electric discharge milling. The process is able to effectively machine a large surface area on SiC ceramic. To further improve the process performance, three kinds of emulsion are proposed as the dielectric in this paper. The effects of dielectric, tool polarity, pulse duration, pulse interval, peak voltage, and peak current on the process performance such as the material removal rate (MRR) and surface roughness (SR) have been investigated. Furthermore, the microstructure of the machined surface is examined with a scanning electron microscope (SEM), an energy-dispersive spectrometer (EDS), and X-ray diffraction (XRD).     

Investigation on the effect of cutting fluid pressure on surface quality measurement in high speed thread milling of brass alloy (C3600) and aluminium alloy (5083)

The quality of a machined finish plays a major role in the performance of milling operations, good surface quality can significantly improve fatigue strength, corrosion resistance, or creep behaviour as well as surface friction. In this study, the effect of cutting parameters and cutting fluid pressure on the quality measurement of the surface of the crest for threads milled during high speed milling operations has been scrutinised. Cutting fluid pressure, feed rate and spindle speed were the input parameters whilst minimising surface roughness on the crest of the thread was the target. The experimental study was designed using the Taguchi L32 array. Analysing and modelling the effective parameters were carried out using both a multi-layer perceptron (MLP) and radial basis function (RBF) artificial neural networks (ANNs). These were shown to be highly adept for such tasks. In this paper, the analysis of surface roughness at the crest of the thread in high speed thread milling using a high accuracy optical profile-meter is an original contribution to the literature. The experimental results demonstrated that the surface quality in the crest of the thread was improved by increasing cutting speed, feed rate ranging 0.41–0.45 m/min and cutting fluid pressure ranging 2–3.5 bars. These outcomes characterised the ANN as a promising application for surface profile modelling in precision machining.     

微细精密铣削表面粗糙度DRSM研究

DRSM方法具有序贯性、可旋转性、模型的稳健性以及试验次数少等优点,近年来逐渐运用在微细精密车铣加工运用中,笔者着重对微细精密铣削表面粗糙度进行DRSM分析,得出了微细精密铣削条件下工艺参数对表面粗糙度的影响规律,并进行了表面粗糙度的预测,有较强的理论实践和现实意义。     

Selection of optimum tool geometry and cutting conditions using a surface roughness prediction model for end milling

Influence of tool geometry on the quality of surface produced is well known and hence any attempt to assess the performance of end milling should include the tool geometry. In the present work, experimental studies have been conducted to see the effect of tool geometry (radial rake angle and nose radius) and cutting conditions (cutting speed and feed rate) on the machining performance during end milling of medium carbon steel. The first and second order mathematical models, in terms of machining parameters, were developed for surface roughness prediction using response surface methodology (RSM) on the basis of experimental results. The model selected for optimization has been validated with the Chi square test. The significance of these parameters on surface roughness has been established with analysis of variance. An attempt has also been made to optimize the surface roughness prediction model using genetic algorithms (GA). The GA program gives minimum values of surface roughness and their respective optimal conditions.     

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。     

表面粗糙度对304不锈钢空蚀腐蚀联合作用的影响

为探究不同表面粗糙度对腐蚀空蚀破坏的影响机制,利用超声空蚀实验装置,对不同表面粗糙度的304不锈钢试样在质量分数3.5%NaCl溶液中进行空蚀腐蚀联合作用实验。通过分析试样的质量损失、表面形貌、显微硬度和电化学性能变化,探究不同表面粗糙度对空蚀腐蚀表面形貌和性能的影响规律。结果表明：空蚀腐蚀后的304不锈钢试样表面出现蚀坑,且蚀坑主要发生在磨痕边缘,并呈现腐蚀和空蚀双重特征;随着表面粗糙度的增大,蚀坑的密度增加,试样质量损失更加严重,但粗糙度达到一定程度时,空蚀会降低表面粗糙度数值,起到平整作用;经过空蚀腐蚀作用后,试样表面均出现硬化现象,但随着表面粗糙度的增大,试样表面硬化现象变弱;空蚀腐蚀后,试样的腐蚀电流增大,腐蚀电位负移,且随着粗糙度增大,试样的腐蚀电位和腐蚀电流变化也增大,呈现耐腐蚀性能不断下降趋势。     

Tribological compatibility and improvement of machining productivity and surface integrity

Machining process productivity and machined part quality improvement is a considerable challenge for modern manufacturing. One way to accomplish this is through the application of PVD coatings on cutting tools. In this study the wear rate and wear behavior of end milling cutters with mono-layered TiAlCrN and nano-multilayered self-adaptive TiAlCrN/WN PVD coatings have been studied under high performance dry ball-nose end-milling conditions. The material being machined in this case is hardened H13 tool steel. The morphology of the worn surface of the cutting tool has been studied using SEM/EDX. The microstructure of the cross-section of the chips formed during cutting was analyzed as well. The surface integrity of the workpiece material was also evaluated. Surface roughness and microhardness distribution near the surface of the workpiece material was also investigated. The data presented shows that achieving a high degree of tribological compatibility within the cutting tool/workpiece system can have a big impact on tool life and surface integrity improvement during end milling of hardened tool steel.     

正交车铣TC4钛合金表面粗糙度分析

车铣加工技术是近年发展起来的先进切削加工技术之一。本文采用多因素正交试验法,进行了一系列的正交车铣TC4钛合金切削试验,研究了车铣切削用量与表面粗糙度之间的变化规律。通过方差分析确定了各因素对表面粗糙度的影响大小的主次顺序,每齿进给量和偏心量对表面粗糙度的影响较大。采用回归分析原理,建立了表面粗糙度的预测模型,根据统计检验结果表明,已加工表面粗糙度预测模型呈高度显著检验状态,具有很高的可信度。     

Interface roughness effect on friction map under fretting contact conditions

In many industrial applications where fretting damage is observed in the contact (e.g. rotor/blade, electrical contacts, assembly joint, axe/wheel, clutch) the external loadings or geometry design cannot be changed. Therefore, the surface preparation and finishing process become essential to control and reduce the damage caused by fretting. In this paper, the authors present the experimental study of the initial surface roughness and machining process influence on fretting conditions in both partial and full sliding regimes. Surfaces prepared by milling and smooth abrasive polishing processes have been analysed. The influence of roughness on sliding behaviour and analysis of friction have been reported. Also, the contact pressure influence and qualitative analysis of fretting wear scar have been presented.