A study on the cutting force and chip shrinkage coefficient in high-speed milling of A6061 aluminum alloy

In this paper, finite element (FE) simulation for high-speed milling of aluminum alloy was performed using a ductile fracture model with Mohr–Coulomb criterion proposed by Bai and Wierzbicki (BW). To verify the model, predicted cutting forces were compared to experimental results in the same cutting conditions. Then, further simulations were performed to estimate the cutting forces and chip shrinkage coefficients subjected to different cutting parameters such as cutting speeds, cutting depths, and clearance angles of a cutting tool. The obtained results were also used to determine optimal cutting parameters using the Taguchi method. The analysis of variance (ANOVA) was employed to investigate the influence percentage of each cutting parameter on cutting force and chip shrinkage coefficient. The simulation results showed that inclusion of strain rate in numerical model significantly improved the accuracy of estimated cutting force in comparison to experiment. The optimum values obtained for high-milling process were cutting speed 1000 m/min, cutting depth 1 mm, clearance angle 15°, and rake angle 4°.     

Experimental investigation of weld characteristics on submerged friction stir welded 6061-T6 aluminum alloy

Journal of Mechanical Science and Technology - Mechanical properties such as fatigue life, corrosion resistance, brittle fracture, hardness and dimensional stability mainly depend on the residual...     

不同切削参数的镍基合金直角切削有限元模拟

利用非线性有限元方法研究镍基合金高速切削过程。在平面应变状态下,通过对材料本构模型、边界条件与接触摩擦模型,以及网格划分环节进行处理,建立有限元直角正交二维切削模型。采用不同刀具前角、切削深度条件对镍基合金直角切削过程进行模拟和试验,分析得出直角切削过程中不同刀具前角和切削深度时切削力、剪切角变化情况,为选择合适的切削参数、提高切削质量提供理论依据。     

Wear and friction of 6061-T6 aluminum alloy treated by laser shock processing

Laser shock processing (LSP) is becoming an important surface treatment to induce a compressive residual stress field, which improves fatigue and fracture properties of components. In this work, we examine the effect of laser shock processing on the wear and friction behavior of 6061-T6 aluminum alloy. Wear rate and friction coefficient evolution are investigated for different process parameters of LSP. Roll-on-flat tribometer is used with different loading conditions. Hardness and residual stresses are assessed as well. It is observed that wear rate decreases as pulse density increases; this is explained in light of residual stress distribution.     

基于正交试验钛合金激光切割工艺参数优化

激光切割质量受各种因素的影响,为了得到高质量的激光切割件,需要根据不同的切割板材进行优化。利用厚度1.5mm的TC1薄板作为研究对象,研究激光功率、切割速度、焦点位置和辅助气体压力主要因素对激光切割质量的影响,采用正交试验方法安排激光切割试验,使用L16(45)正交表,完成十六组激光切割试验。利用测量点轮廓精度的算术平均值作为结果进行分析,采用直观分析法,因素效应曲线图,方差分析对切割参数进行分析研究。结果表明:切割速度和辅助气体压力是主要因素,对切割质量和精度有较大影响,而激光功率对切割后试件的轮廓度影响较之上两个因素小,但是激光功率改变对切割件的表面质量影响显著。     

铝合金高速切削表面粗糙度影响因素研究

为有效降低高速切削中铝合金的表面粗糙度值,通过多因素正交试验和单因素试验对各铣削参数进行研究,结果显示:各参数对铝合金表面粗糙度影响程度从大到小的顺序是:切削深度、主轴转速、每齿进给量、行距,且转速为18000r/min,每齿进给量为0.075mm,行距和每齿进给量一致,选择较小的切削深度时,在铝合金表面可获得较好的加工质量。     

Fundamental study on electron beam weld sections and strengths using AA6061-T6 aluminum alloy plate

This study was carried out to establish an electron beam welding process for a nuclear fuel plate assembly fabrication. A preliminary investigation for plate fuel fabrication was conducted with a consideration of weld performance using AA6061-T6 aluminum alloy made by the electron beam welding process. The optimum welding parameters for the fuel plate assembly were obtained in terms of the accelerating voltage, beam current and welding time. The soundness of the weld region between the side plate and the end fitting for the fuel plate assembly was proven by the intact of the weld metal on the fractured surfaces. The integrity of the welds by the electron beam welding process was also confirmed by the results of the tensile test, an examination of the cross sections and the fracture surfaces of the welded specimens.     

基于DEFORM的刀具涂层对6061铝合金铣削性能影响研究

针对生产加工中常使用的6061铝合金,运用DEFORM有限元软件对6061铝合金的铣削过程进行了仿真,得出了涂层对于切削力,切削温度和刀具磨损的影响,并且对原因机理进行了探讨和涂层优选。为生产加工提供了有力的依据。     

MEMS based acoustic thermomechanical characterization of aluminum 6061-T651 beams

Temperature-based testing is an important tool in determining the mechanical characteristics of structures. Metallic structures, such as aluminum beams, respond to temperature variations. Similarly, Young’s modulus of elasticity of the material has a temperature dependence that contributes significantly to the overall mechanical qualities of the material. In this work, a method based on flexural frequency response is described in which the variation in the experimental 5th natural frequency under thermal loading is employed to extract the coefficient of thermal dependence of Young’s modulus. This coefficient is then employed in the theoretical model to validate the experimental 2nd, 3rd, 4th and 5th natural frequencies of the aluminum beam. A micro-electro-mechanical-systems based microphone is used to monitor the frequency response of the beam. Constant geometry and constant elasticity models are presented and compared. The proposed method is applied to an aluminum 6061-T651 beam. Experimental results are in good agreement with the theory.     

An investigation of optimum SiO2 nanolubrication parameters in end milling of aerospace Al6061-T6 alloy

Aluminium AL6061-T6 is a common alloy which is used for many purposes since it has the superior mechanical properties such as hardness and weldability. It is commonly used in aircraft, automotive and packaging food industries. Milling of Al6061-T6 would be a good process especially in producing varieties shape of products to adapt with different applications. The capability of the CNC milling machine to make batch production would be a noteworthy advantage. However, the demand for high quality focuses attention on product quality, especially the roughness of the machined surface, because of its effect on product appearance, function and reliability. Introducing correct lubrication in the machining zone could improve the tribological characteristic of Al6061-T6 leading to higher product quality. In this research work, the optimum SiO₂ nanolubrication parameters in milling of Al6061-T6 are investigated to achieve correct lubrication conditions for the lowest cutting force, cutting temperature and surface roughness. These parameters include nanolubricant concentration, nozzle angle and air carrier pressure. Taguchi optimization method is used with standard orthogonal array L₁₆(4)³. Furthermore, analyses on surface roughness and cutting force are conducted using signal-to-noise (S/N) response analysis and the analysis of variance (Pareto ANOVA) to determine which process parameters are statistically significant. Finally, confirmation tests were carried out to investigate the optimization improvements.     

基于改进遗传算法的铝合金型材下料方法研究

铝合金型材的下料问题属于一维下料问题.主要针对多规格铝合金型材下料问题,在铝合金原材料长度大于零件长度的情况下,采用了蚁群算法和遗传混合模拟退火算法两种不同的求解方法求解多规格铝合金型材下料问题,并进行分析对比.根据某门窗有限公司在铝合金门窗方面实际下料情况,建立一维下料优化模型并设计算法,通过MATLAB进行编程,并...     

基于田口法的高速切削参数优化研究与应用

应用田口法对切削速度、背吃刀量以及每齿进给量三个主要影响表面粗糙度的因素进行分析,求出各个因素不同水平的平均表面粗糙度和信噪比(S/N),得到最优切削参数。预测经最优切削参数加工得到的表面粗糙度值,最后通过确认实验验证了其正确性。     

The Merchant's model of orthogonal cutting revisited: A new insight into the modeling of chip formation

The Merchant's model, as the most famous approach of orthogonal cutting, is widely used in introductive courses on machining. However, the shear angle predicted by the Merchant's model from the criterion of minimization of the cutting energy, does not generally agree with experimental data and numerical simulations. The aim of this paper is to elucidate the theoretical reason for which the Merchant's model fails to predict the correct orientation of the primary shear zone. It is shown that the principle of minimum of the cutting energy must be supplemented by a stability criterion of the chip morphology. A modified Merchant's formula is then obtained for the value of the shear angle.     

Influence of micro-textured parameters on cutting performance and chip formation of milling Ti6Al4V

Journal of Mechanical Science and Technology - In view of the lack of researches on the influence of micro textures on the cutting performance of milling cutters, this paper studies the cutting...     

Erosion of aluminum 6061-T6 under cavitation attack in mineral oil and water

Studies of the erosion of aluminum 6061-T6 under cavitation attack in distilled water, ordinary tap water and a viscous mineral oil are presented. The mean depth of penetration for the mineral oil was about 40% of that for water at the end of a 40 min test. The mean depth of penetration and its rate did not differ significantly for distilled and tap water. The mean depth of penetration rate for both distilled and tap water increased to a maximum and then decreased with test duration, while that for mineral oil had a maximum during the initial period. The ratio $\text{h}\text{2a}$ of the pit depth h to the pit diameter 2a varied from 0.04 to 0.13 in water and from 0.06 to 0.20 in mineral oil. Scanning electron microscopy indicates that the pits are initially formed over the grain boundaries and precipitates while the surface grains are deformed under cavitation attack.     

Study on mechanism of chip formation during high-speed milling of alloy cast iron

By adopting an equivalent geometry model of chip, a finite element model was developed to study the mechanism of chip formation during high-speed milling of alloy cast iron. Several key technologies such as material constitutive model, friction model, chip separation criteria, chip damage criteria, heat dissipation, and transfer were implemented to improve the accuracy of finite element simulation. Saw-tooth chip of alloy cast iron was observed. The chip shape and cutting force agreed well with experimental results. The simulation results show that the maximum cutting temperature produced with appearance of saw-tooth chip crack, and it is located on the chip-tool contact surface. The saw-tooth chip is caused by double actions of thermoplastic instability and plastic instability. The chip saw-tooth degree decreases when increasing the rotating speed, while it increases when increasing the feed speed. This work provides a useful understanding for chip formation process and helps to optimize machining parameters and process of high-speed milling of alloy cast iron.