薄壁件铣削加工中的铣削力仿真分析

为了研究薄壁件铣削加工过程中的铣削力分布规律,在对铣削加工模型分析基础上,针对材料为45#钢的薄壁零件,采用商业有限元软件ABAQUS建立能够反映实际状态的三维铣削模型,并进行模拟,获得铣削力曲线和应力、应变分布情况。为验证仿真结果的可行性,采用与有限元模型相同的条件进行实验并获得铣削力实验数据,对比表明:铣削力的模拟结果与实验结果能够较好的吻合。分析结果表明:所建立的薄壁零件三维铣削有限元模型是可行的,其对铣削力和薄壁零件加工变形预测具有重要意义。     

7050-T7451铝合金薄壁件铣削仿真建模及试验分析

针对铝合金7050-T7451薄壁零件,建立铝合金薄壁件铣削动力学模型,并进一步通过ABAQUS软件进行有限元分析,获得铝合金薄壁件铣削加工中铣削应力和应变的分布规律;通过铣削加工试验,获取铣削力数值并与仿真铣削力进行对比,验证模型的准确性。     

航空薄壁件三维铣削过程的有限元仿真

铣削加工中铣削力是导致加工变形的直接原因,而航空薄壁件加工中,加工变形是加工误差产生的主要因素。通过有限元法对航空薄壁件的铣削过程进行三维仿真模拟,揭示了切削深度、切削速度以及摩擦因素对切削力的影响。     

钛合金薄壁件相关铣削力模型的试验研究

采用五因素—五水平正交实验法对钛合金薄壁件进行铣削试验,对铣削力进行极差分析,同时分析加工参数对铣削力的影响;建立钛合金薄壁件铣削力模型,同时验证了模型的准确性,为后续的钛合金薄壁件理论和试验研究提供了基础。     

钛合金薄壁件铣削试验及相关铣削力模型的研究

为研究钛合金薄壁件铣削工艺,设计了钛合金薄壁件四因素-四水平正交铣削试验,通过对所得数据(切削力和粗糙度)进行极差分析,获得了各加工参数对铣削力的影响;同时建立了钛合金薄壁件切削力经验公式和粗糙度经验公式,为后续的钛合金薄壁件铣削加工提供了理论研究基础。     

基于变形控制的薄壁结构件高速铣削参数选择

首先对国内外有关研究薄壁件铣削加工变形的文献进行了回顾。然后,对不同切削参数下铣削力变化规律以及因铣削力引起的加工变形进行了理论分析与试验研究,并以此为基础提出了薄壁件高速铣削切削参数选择原则。试验结果表明,采用优化的切削参数不仅使薄壁件加工精度得到了保证,加工效率也大大提高。     

基于加工特征的铣削力预测研究

航空发动机广泛采用钛合金薄壁结构,薄壁件在铣削加工过程中受铣削力的影响易于产生加工变形,影响加工质量。为减少加工变形,提高加工质量,需对铣削加工过程中的铣削力进行预测。为此,以Johnson-Cook本构方程为基础,考虑材料热力学动态性能和断裂准则对铣削力的影响,建立了基于加工特征的钛合金Ti-6Al-4V铣削力预测模型。首先,利用UG/Open工具模块对UG软件进行二次开发,创建了零件加工特征知识库。然后,利用Deform-3D仿真软件对材料本构模型、切屑分离和切屑断裂准则等进行描述,建立钛合金Ti-6Al-4V铣削加工有限元模型,对铣削力进行预测。铣削力实验证明了预测模型的可行性。最后,利用建立的有限元模型研究了工件曲率半径对铣削力的影响。结果表明,圆弧内轮廓铣削过程中的铣削力较大,圆弧外轮廓铣削过程中的铣削力较小。     

薄壁件铣削过程仿真与分析

针对薄壁件加工过程中易产生变形等问题,提出了利用有限元法对铣削过程进行三维仿真的方法,重点研究了LS-DYNA的动态接触算法,建立了薄壁件铣削加工的有限元模型,对工件变形及切削力的变化规律进行了分析.最后,利用分析结果对铣削参数进行调整与优化,可以减小工件变形,保证加工精度.     

薄壁件铣削技术研究

在航空航天工业中,薄壁件数控铣削是一种常见的典型加工。本文以薄壁件铣削加工过程为研究对象,完成了对薄板支架零件的数控加工工艺分析,建立了薄壁件加工变形的力学模型,应用有限元分析软件,建立了薄壁件铣削加工变形的模拟环境,总结了薄壁件铣削加工变形的规律,提出了薄壁件加工变形补偿的方法,并在Pro/E软件中生成了走刀路线。本研究成果为解决薄壁件铣削加工问题提供了一定的参考和依据。     

薄壁零件高速铣削加工变形模型及变形规律研究

针对集中载荷作用下薄壁零件(两邻边固定、两邻边自由的矩形)的变形问题建立静态铣削力模型。利用ANSYS 14.0有限元软件进行仿真加工,研究了铝合金薄壁件在数控铣削过程中切削力不变时,零件在长度和高度方向的变形情况以及不同铣削力对变形的影响。得出薄壁零件在顺铣过程中的变形规律并提出了预防措施。     

An improved dynamic milling force coefficients identification method considering edge force

The identification of the dynamic coefficients is the key to realize accurate simulation of dynamic milling process. To enlarge the scope of dynamic simulation without ignoring edge force, an improved method is presented to calculate milling force coefficients. In this method, linear approximation of average milling force is integrated with multiple linear regressions by supposing that milling force coefficients are time invariant for small variation of feed rate. Therefore, both the shear coefficients and the edge coefficients can be calculated simultaneously. A comparison of simulated milling force with and without the edge force is illustrated and the result shows that the accuracy is higher if the edge force coefficients are considered. This method casts new light on fast and accurate simulation of the dynamic milling force in real industrial environment.     

球头铣刀数控加工表面形貌几何仿真的研究

几何仿真是建立铣削力预测模型的基础,而传统的几何仿真只考虑刀具的平动而忽略其转动。本文在同时考虑刀具平动和转动的基础上,利用工件Z-Map表示模型和刀刃离散表示法,提出了一种球头铣刀三轴数控铣削的微观几何仿真算法。该算法鲁棒性好、适用范围广,不仅能高效而准确地仿真铣削表面形貌,而且能准确提供切屑的轮廓,为建立精确的切削力预测模型提供了重要的几何参数。     

基于LS-DYNA的铣削过程三维仿真研究

金属铣削是一个弹塑性变形和断裂的复杂过程，基于LS-DYNA对铣削加工系统建模，对系统进行动态三维仿真，并对7075铝合金材料进行铣削力动态实验测试，将其与仿真结果进行比较，验证仿真计算可靠性，对铣削温度分布进行了分析，通过调整仿真铣削模型的参数，对铣削过程进行优化，降低铣削力的大小，保证铣削过程的稳定和加工的质量，提高切削效率。     

不同槽型铣刀片铣削过程振动分析

机械加工中工艺系统的振动破坏了零件的加工精度。刀具与工件之间的冲击力是引起振动的主要原因之一。通过对带有三维复杂槽型的波形刃铣刀片与平前刀面铣刀片铣削力和铣削振动的对比试验、铣削力的有限元数值模拟,表明带有三维复杂槽型的波形刃铣刀片铣削力小,铣削过程中引起工艺系统的振动较平稳。可以断言,优化刀具的结构与几何参数可有效地减小铣削过程的振动现象。     

Mechanical behavior and semiempirical force model of aerospace aluminum alloy milling using nano biological lubricant

Aerospace aluminum alloy is the most used structural material for rockets, aircraft, spacecraft, and space stations. The deterioration of surface integrity of dry machining and the insufficient heat transfer capacity of minimal quantity lubrication have become the bottleneck of lubrication and heat dissipation of aerospace aluminum alloy. However, the excellent thermal conductivity and tribological properties of nanofluids are expected to fill this gap. The traditional milling force models are mainly based on empirical models and finite element simulations, which are insufficient to guide industrial manufacturing. In this study, the milling force of the integral end milling cutter is deduced by force analysis of the milling cutter element and numerical simulation. The instantaneous milling force model of the integral end milling cutter is established under the condition of dry and nanofluid minimal quantity lubrication (NMQL) based on the dual mechanism of the shear effect on the rake face of the milling cutter and the plow cutting effect on the flank surface. A single factor experiment is designed to introduce NMQL and the milling feed factor into the instantaneous milling force coefficient. The average absolute errors in the prediction of milling forces for the NMQL are 13.3%, 2.3%, and 7.6% in the x-, y-, and z-direction, respectively. Compared with the milling forces obtained by dry milling, those by NMQL decrease by 21.4%, 17.7%, and 18.5% in the x-, y-, and z-direction, respectively.     

A novel chatter stability criterion for the modelling and simulation of the dynamic milling process in the time domain

The modelling of the dynamic processes in milling and the determination of chatter-free cutting conditions are becoming increasingly important in order to facilitate the effective planning of machining operations. In this study, a new chatter stability criterion is proposed, which can be used for a time domain milling process simulation and a model-based milling process control. A predictive time domain model is presented for the simulation and analysis of the dynamic cutting process and chatter in milling. The instantaneous undeformed chip thickness is modelled to include the dynamic modulations caused by the tool vibrations so that the dynamic regeneration effect is taken into account. The cutting force is determined by using a predictive machining theory. A numerical method is employed to solve the differential equations governing the dynamics of the milling system. The work proposes that the ratio of the predicted maximum dynamic cutting force to the predicted maximum static cutting force can be used as a criterion for the chatter stability. Comparisons between the simulation and experimental results are given to verify the new model.     

Prediction of dynamic cutting force and regenerative chatter stability in inserted cutters milling

Currently, the modeling of cutting process mainly focuses on two aspects: one is the setup of the universal cutting force model that can be adapted to a broader cutting condition; the other is the setup of the exact cutting force model that can accurately reflect a true cutting process. However, there is little research on the prediction of chatter stablity in milling. Based on the generalized mathematical model of inserted cutters introduced by ENGIN, an improved geometrical, mechanical and dynamic model for the vast variety of inserted cutters widely used in engineering applications is presented, in which the average directional cutting force coefficients are obtained by means of a numerical approach, thus leading to an analytical determination of stability lobes diagram (SLD) on the axial depth of cut. A new kind of SLD on the radial depth of cut is also created to satisfy the special requirement of inserted cutter milling. The corresponding algorithms used for predicting cutting forces, vibrations, dimensional surface finish and stability lobes in inserted cutter milling under different cutting conditions are put forward. Thereafter, a dynamic simulation module of inserted cutter milling is implemented by using hybrid program of Matlab with Visual Basic. Verification tests are conducted on a vertical machine center for Aluminum alloy LC4 by using two different types of inserted cutters, and the effectiveness of the model and the algorithm is verified by the good agreement of simulation result with that of cutting tests under different cutting conditions. The proposed model can predict the cutting process accurately under a variety of cutting conditions, and a high efficient and chatter-free milling operation can be achieved by a cutting condition optimization in industry applications.     

基于切削层形状的动态铣削力试验研究及建模

选取轴向切深、每齿进给量、径向切深和主轴转速为试验因素,采用YDX-Ⅲ9702型压电式铣削测力仪,进行了动态铣削力正交实验。针对立铣刀侧铣加工,研究了单刃铣削的临界条件,为设计试验方案提供了理论依据。结合铣削过程,采用角度积分方法求解铣削力模型,避免了轴向积分的繁琐计算。精确地建立了简捷且适应性强的基于切削层形状的动态铣削力预测模型,模型的仿真结果和试验数据相吻合。     

Feedrate optimization for variant milling process based on cutting force prediction

Machining process modeling, simulation and optimization is one of the kernel technologies for virtual manufacturing (VM). Optimization based on physical simulation (in contrast to geometrical simulation) will bring better control of a machining process, especially to a variant cutting process – a cutting process so complex that cutting parameters, such as cutting depth and width, change with cutter positions. In this paper, feedrate optimization based on cutting force prediction for milling process is studied. It is assumed that cutting path segments are divided into micro-segments according to a given computing step. Heuristic methods are developed for feedrate optimization. Various practical constraints of a milling system are considered. Feedrates at several segments or micro-segments are determined together but not individually to make milling force satisfy constraints and approach an optimization objective. After optimization, an optimized cutting location data file is outputted. Some computation examples are given to show the optimization effectiveness. This revised version was published online in October 2004 with a correction to the issue number.     

Multidisciplinary design optimization of a milling cutter for high-speed milling of stainless steel

The milling cutter’s fracture strength is more important than its chemical stability and thermal conductivity in high-speed milling. The multidisciplinary design optimization (MDO) method is employed to optimize the fracture-resistant performance of a milling cutter in this work. An experimental study on high-speed milling of the martensitic stainless steel 0Cr13Ni4Mo is conducted. The cutting forces and cutting temperature in the milling process are measured to provide initial data for the structural optimization of the milling cutter. The mathematical models of cutting force and cutting temperature are studied. Considering that the induced stress in the milling cutter is generated by thermomechanical coupling, the thermoelastic–plastic governing equation in the milling process is introduced in this work. The sensitivity of the structural parameters to the maximum equivalent stress of the milling cutter is calculated, and the structural parameters that have the greatest effects on the maximum equivalent stress are determined as design variables for the cutters’ optimization. The MDO procedure for the cutter’s optimization consists of updating of solid model, finite element analysis of thermomechanical coupling, postprocessing, and optimization algorithm. The MDO results show that the optimized milling cutter has a better fracture-resistant performance than the initial one. The maximum deformation, overall equivalent stress, and deformation are decreased.