微铣削力建模研究进展

微铣削加工是实现具有三维复杂结构和材料多样性特征的微型零部件制造的有效技术手段,具有日益广阔的应用前景。然而由于刀具尺寸及加工参数的急剧缩减,微铣削表现出显著不同于传统铣削的加工机理。作为理解微铣削加工机理的最重要基础之一,至今已有大量关于微铣削力建模的研究,但是它们主要针对单一现象或者某几个现象进行研究,尚少有系统完善的理论来解释微铣削加工的力学过程,因此对微铣削加工切削力的全面总结是非常必要的。结合国内外微铣削技术的最新研究进展,从微铣削与传统铣削的不同加工机理出发,对微铣削力建模进行全面的论述和总结,并重点介绍刀刃钝圆半径、刀具跳动、挠性变形和刀具磨损对微铣削力建模的影响。探讨了目前微铣削力建模方法中的热点与难点,并指出了现有微铣削力建模有待研究的内容。     

圆周铣削加工动态和静态铣削力MATLAB仿真分析研究

基于圆周立铣刀在铣削加工中静态和动态切削力分布对工件尺寸精度有较大影响的现状,对静态和动态铣削力模型进行建模研究,建立有效铣削力分布预测仿真,并对静态和动态铣削力仿真结果进行对比分析,研究结果表明在铣削过程中动态铣削力分布对工件已加工部分的尺寸精度预测较静态铣削力预测有较大优势,通过改变刀具齿数、进给速度、径向切深3个加工参数,对铣削力分布进行对比仿真研究,选择出更加合理的铣削参数,研究表明对比分析较单纯依靠单一模型更加具有参照性.     

确定铣削力模型中刀具偏心参数的一种算法

对数控加工中球头铣刀铣削力建模时刀具偏心参数的确定进行了研究。在铣削力模型的建立中考虑了刀具偏心的影响,推导出刀具偏心参数的表达式,考虑到刀具单刃切削条件,提出了刀具偏心参数的确定算法。在通过铣削力试验数据计算铣削力系数的过程中,采用上述算法确定了刀具的偏心参数,用于铣削力的仿真预测中,仿真结果和铣削力试验的结果表明,算法效果良好。     

基于曲率的圆周铣削铣削力建模

在对具有自由曲线外形的零件进行铣削加工的过程中,由于诸多影响铣削力大小的参数相对于定曲率外形零件铣削加工时发生了很大变化,导致传统的铣削力建模方法在应用于自由曲线外形零件的圆周铣削加工过程时产生了很大的误差,使得误差预测和补偿变得非常困难.针对此问题建立了基于零件轮廓曲率的圆周铣削铣削力模型,分析了曲率对铣削力的影响.     

一种新的螺旋刃球头铣刀铣削力模型

为提高铣削加工的安全性和生产效率，有必要在加工实际进行之前准确地预测切削过程的物理信息，如铣削力、刀具振动等。给出了球头铣刀丸线几何模型，采用理论削力分析与实验--系数识别相结合的方法建立了新的螺旋刃球头铣刀的铣削力模型。对不同切削条件下的铣削力进行了仿真，与实验测量数据吻合良好，证明离线仿真可以对铣削力做出较准确的预测。     

芳纶纤维复合材料铣削加工研究进展

芳纶纤维复合材料因其特有的超高强度、高模量、高硬度和优良的冲击性能,在航空、航天和军工等领域应用日益广泛。综述了芳纶纤维复合材料的铣削加工研究进展,重点介绍了高速铣削过程中铣削力、铣削温度的变化规律,阐述了铣削加工缺陷的成因、影响表面质量的因素和铣削工艺优化措施,展望了芳纶纤维复合材料铣削加工的发展方向。     

基于改进粒子群算法的刀具瞬时铣削力预测研究

针对刀具微元铣削力模型预测精度低的问题,建立了基于刀具径向跳动的瞬时铣削力模型,采用改进惯性权重的粒子群算法(IWPSO)对模型进行系数求解。通过改进粒子群算法,避免算法过早收敛而陷入局部最优,提高了算法的速度和精度,降低了模型系数的求解难度,从而减小模型预测铣削力的误差。通过与线性拟合方法求解的铣削力系数对比,在0～0.1s内铣削力预测波形图的波谷与实际铣削力波形图误差较小(5%以内),验证了此模型的精度更高。采用不同铣削参数进行实验,验证了铣削力预测模型预测铣削力的准确性,对实际的铣削加工有着重要意义。     

基于BP神经网络的球头铣刀铣削力建模与仿真

将BP神经网络的理论和算法应用于球头刀具铣削力建模的研究中.采用LM算法建立了铣削力预测的神经网络模型,模型中考虑了影响铣削力的加工参数,选取铣削力试验数据对神经网络模型进行训练,用训练好的神经网络模型对铣削力进行仿真.仿真结果表明,用BP神经网络方法建立的铣削力模型能够对铣削力进行准确的预测.     

薄壁件不一致刀齿铣削时铣削力系数构造与预测

针对薄壁件铣削过程中刀齿半径不一致现象引起的铣削力系数计算失真问题,提出构造刀齿半径不一致时的实际铣削力系数,并采用核偏最小二乘法对不同铣削用量时的实际铣削力系数进行预测。针对两齿螺旋铣刀铣削过程推导理论铣削力系数,根据刀齿半径不一致铣削过程引入名义铣削力,推导刀齿半径误差,构造实际铣削力系数;基于核分析方法突出的非线性分析及预测能力,提出采用核偏最小二乘法在高维空间建立实际铣削力系数关于铣削用量及其组合量的预测模型,分析该方法中核主元个数、高斯核函数核参数对预测模型精度的影响并确定其取值范围。最后分析考虑刀齿半径误差与不考虑时的铣削力系数,并比较核偏最小二乘预测方法与偏最小二乘预测方法,结果表明所提铣削力系数构造过程及预测方法具有较高的计算精度和预测能力。     

基于傅立叶级数的球头刀铣削力模型

球头刀铣削广泛应用于复杂曲面零件的加工,精确的铣削力模型是加工过程控制优化的基础。本文分析了球头刀的铣削过程,将剪切系数拟为微元刀刃轴向高度的多项式,对考虑剪切与犁切双重效应的周期性铣削力进行傅立叶变换,建立了铣削力的傅立叶级数形式。加工实验表明,应用本文方法的预测结果与测量得到的铣削力吻合良好,铣削力模型的有效性得到了验证。     

基于数字化加工的铣削力预测系统的开发

切削用量的实时获取是切削力预测的关键技术之一。基于数字化加工技术,通过在加工仿真过程中对三维实体图形进行分析,获得实时的切削参数,实现了切削力的实时预测;开发了一个针对铣削加工的切削力预测软件系统,通过铣削试验验证了该系统的正确性。     

基于主轴电流的铣削力间接监测方法

实时准确地监测铣削状态对于提高加工质量与加工效率具有重要意义,切削力作为重要的加工状态监测对象,因其监测设备昂贵且安装不便而受到限制,为此提出一种考虑刀具磨损的基于主轴电流的铣削力监测方法.首先基于切削微元理论建立了考虑后刀面磨损的铣削力模型,并通过铣削实验进行铣削力模型系数标定;然后对主轴电流与铣削力的关系进行理论建...     

硬孔攻丝用高性能先端丝锥的设计及应用

热后硬孔攻丝螺纹变形量小、尺寸稳定、强度高。该工艺方法对刀具强度要求较高,使用普通高速钢丝锥和螺纹铣刀加工时,普通高速钢丝锥无法承受热后硬孔攻丝所产生的大扭矩而频繁折断,报废率较高,同时螺纹铣刀成本高,不适合大批量生产。针对热后硬孔攻丝工艺复杂、成本高的问题,专门设计了硬孔攻丝用高性能先端丝锥,解决硬孔攻丝难题,并与其他种类丝锥进行了切削力对比。     

钛合金型腔圆角高速铣削特征研究

钛合金型腔圆角加工容易发生切削负载增大和颤振等现象,导致圆角表面质量较差,难以实现钛合金高效加工。通过钛合金型腔圆角铣削试验,基于铣削力和圆角表面质量检测,分析内圆角铣削特征和原理,并优化铣削参数。试验表明:采用小切削宽度的高速加工,可实现钛合金内圆角的高效加工;在Vc=90m/min,ft=0.06mm/t,ap=20mm,ae=1mm切削参数组合下,切削力相对较小,加工效率高,切削表面质量高。     

Milling Force Model for Aviation Aluminum Alloy:Academic Insight and Perspective Analysis

Aluminum alloy is the main structural material of aircraft,launch vehicle,spaceship,and space station and is pro-cessed by milling.However,tool wear and vibration are the bottlenecks in the milling process of aviation aluminum alloy.The machining accuracy and surface quality of aluminum alloy milling depend on the cutting parameters,material mechanical properties,machine tools,and other parameters.In particular,milling force is the crucial factor to determine material removal and workpiece surface integrity.However,establishing the prediction model of milling force is important and difficult because milling force is the result of multiparameter coupling of process system.The research progress of cutting force model is reviewed from three modeling methods:empirical model,finite element simulation,and instantaneous milling force model.The problems of cutting force modeling are also determined.In view of these problems,the future work direction is proposed in the following four aspects:(1)high-speed milling is adopted for the thin-walled structure of large aviation with large cutting depth,which easily produces high residual stress.The residual stress should be analyzed under this particular condition.(2)Multiple factors(e.g.,eccentric swing milling parameters,lubrication conditions,tools,tool and workpiece deformation,and size effect)should be consid-ered comprehensively when modeling instantaneous milling forces,especially for micro milling and complex surface machining.(3)The database of milling force model,including the corresponding workpiece materials,working condi-tion,cutting tools(geometric figures and coatings),and other parameters,should be established.(4)The effect of chatter on the prediction accuracy of milling force cannot be ignored in thin-walled workpiece milling.(5)The cutting force of aviation aluminum alloy milling under the condition of minimum quantity lubrication(mql)and nanofluid mql should be predicted.     

铣削力预测研究进展

从切削几何条件不变的平直面加工和切削几何条件可变的曲面加工两个方面综述了当前铣削力预测方面的研究成果。指出研究复杂曲面加工的铣削力预测,尤其是非球头铣刀复杂曲面五轴加工的铣削力预测是本领域的重要发展方向。     

Development of in situ system to monitor the machining process using a piezo load cell

The measurement of cutting force is one of the most frequently used techniques for monitoring machining processes. Its widespread application ranges from tool condition identification, feedback control and cutting system design to process optimization.This paper suggests another system for measuring cutting force in milling processes. Generally, tool dynamometers are taken into account for the most appropriate cutting force measuring tool in the analysis of a cutting mechanism. However, high prices and limited working space make in situ systems difficult for a controllable milling process. Although an alternative suggestion is to use an AC current from a servomotor, it is unsuitable for cutting force monitoring because of a small upper frequency limit and noise.The suggested cutting force measuring system is composed of two piezo load cells placed between the moving table bracket and the nut flange of the ball screw. It has many advantages, such as lower cost and a wider measurement range than the tool dynamometer, over using the built-in feeding system and the low-cost piezo load cell for applying a conventional machining center.This paper focuses on the performance test of a newly developed measuring system. By comparing the cutting force between the tool dynamometer and the system developed from a series of end milling experiments, the accuracy of the cutting force measurement system was verified. Linearity, transverse sensitivity and the upper frequency limit of the system were verified by experiment.     

Prediction of cutting force, tool wear and surface roughness of Al6061/SiC composite for end milling operations using RSM

The results of mathematical modeling and the experimental investigation on the machinability of aluminium (Al6061) silicon carbide particulate (SiCp) metal matrix composite (MMC) during end milling process is analyzed. The machining was difficult to cut the material because of its hardness and wear resistance due to its abrasive nature of reinforcement element. The influence of machining parameters such as spindle speed, feed rate, depth of cut and nose radius on the cutting force has been investigated. The influence of the length of machining on the tool wear and the machining parameters on the surface finish criteria have been determined through the response surface methodology (RSM) prediction model. The prediction model is also used to determine the combined effect of machining parameters on the cutting force, tool wear and surface roughness. The results of the model were compared with the experimental results and found to be good agreement with them. The results of prediction model help in the selection of process parameters to reduce the cutting force, tool wear and surface roughness, which ensures quality of milling processes.     

An experimental investigation on the process parameters influencing machining forces during milling of carbon and glass fiber laminates

Milling is the most feasible machining operation for producing slots and keyways with a well defined and high quality surface. Milling of composite materials is a complex task owing to its heterogeneity and the associated problems such as surface delamination, fiber pullout, burning, fuzzing and surface roughness. The machining process is dependent on the material characteristics and the cutting parameters. An attempt is made in this work to investigate the influencing cutting parameters affecting milling of composite laminates. Carbon and glass fibers were used to fabricate laminates for experimentations. The milling operation was performed with different feed rates, cutting velocity and speed. Numerically controlled vertical machining canter was used to mill slots on the laminates with different cutting speed and feed combinations. A milling tool dynamo meter was used to record the three orthogonal components of the machining force. From the experimental investigations, it was noticed that the machining force increases with increase in speed. For the same feed rate the machining force of GFRP laminates was observed to be very minimal, when compared to machining force of CFRP laminates. It is proposed to perform milling operation with lower feed rate at higher speeds for optimal milling operation.