AZ31b镁合金微铣削力及加工机理的研究

发布时间：2018-04-17 12:56

本文选题：J-C本构模型 + 尺寸效应　；参考：《太原理工大学》2017年硕士论文

【摘要】：随着工业4.0创新概念的提出,制造业不断朝着智能化、自动化、高精密方向发展,新兴技术手段层出不穷,而其中将传统铣削与微细加工相结合的精密加工技术更是成为当今科研界非常活跃的研究热点。微铣削具有加工精度高、灵活性大、已加工表面质量较高、能够实现3D加工等优点,因而被广泛应用于航空航天、生物医疗、国防电子等领域。镁合金材料作为工业领域最轻的实用结构金属,具有良好的热传导性、减震性、尺寸稳定性和优良的机加工性能,特别是相对比强度和比刚度高,使其完全适用于汽车及航空航天等精密加工领域,然而由于低屈服点和弹性系数、易燃性也降低了镁合金材料在机加工过程中的实际使用价值,此时相关机械加工性能的研究显得十分必要。本文在现有微细加工研究的基础上采用理论分析和有限元仿真模拟的方法对AZ31b镁合金微铣削力及加工机理进行了探究,并搭建HAAS机床试验平台对模型的准确度进行验证,同时分析了不同切削参数对于微铣削力和加工表面质量的影响规律。依据现有切削理论并对其进行了改进,建立考虑切削刃钝圆半径、最小切削厚度、尺度效应、刀具有效前角和刀具偏摆等因素在内更符合微切削加工特性的AZ31b镁合金微铣削力数学解析模型。利用大型商用软件Abaqus/Explicit显式动力分析模块对微铣削过程进行二维旋转模型有限元仿真,将塑性应变梯度引入其中建立材料微铣削本构模型,得到了一种全新的实际有效前角计算方法,并对切屑的形成及其发生条件进行了分析,同时探究了切削层厚度和刀具参数对于切削力的影响以及加工过程中材料的动态力学性能变化;创建基于任意拉格朗日-欧拉法(ALE)三维有限元仿真模型并编写子程序使其基本设置参数化、可视化,获得了不同切削参数对微铣削加工过程中切削力的影响规律。搭建试验平台利用?0.1mm日进铣刀对AZ31b镁合金材料进行单因素及正交两种方法的微铣削试验,得到了实际加工条件下不同切削参数的铣削力和已加工表面,同时试验结果显示与有限元仿真结果有较好的一致性,验证了理论分析的准确性,最终建立了?0.1mm日进铣刀微槽铣时的切削力经验公式,可以实现一定状态下的微铣削力预测。
[Abstract]:With the development of the concept of industry 4.0 innovation, manufacturing industry continues to develop in the direction of intelligence, automation and high precision.Among them, the precision machining technology which combines traditional milling and micro machining has become a very active research hotspot in the field of scientific research.Micro-milling has many advantages, such as high machining precision, high flexibility, high quality of machined surface and the ability to realize 3D machining, so it has been widely used in aerospace, biomedical, national defense electronics and other fields.As the lightest practical structural metal in the industrial field, magnesium alloy materials have good thermal conductivity, shock absorption, dimensional stability and excellent machining performance, especially, the comparative strength and specific stiffness are high.It is suitable for precision machining fields such as automobile, aerospace and so on. However, because of low yield point and elastic coefficient, flammability also reduces the practical value of magnesium alloy material in the process of machining.At this time, it is necessary to study the machining performance.In this paper, based on the existing micro machining research, theoretical analysis and finite element simulation method are used to explore the micro milling force and machining mechanism of AZ31b magnesium alloy, and the accuracy of the model is verified by setting up the HAAS machine tool test platform.At the same time, the influence of different cutting parameters on micro-milling force and surface quality is analyzed.Based on the existing cutting theory and its improvement, the cutting edge radius, minimum cutting thickness and scale effect are considered.The mathematical analytical model of AZ31b magnesium alloy micro-milling force is more suitable for the factors such as the effective front angle of the cutting tool and the tool deflection and so on.The finite element simulation of two-dimensional rotation model is carried out by using the Abaqus/Explicit explicit dynamic analysis module, and the plastic strain gradient is introduced into it to establish the constitutive model of micro-milling material.In this paper, a new method for calculating the actual effective antecedent angle is obtained, and the formation of chip and its occurrence conditions are analyzed.At the same time, the influence of cutting layer thickness and cutting tool parameters on cutting force and the change of dynamic mechanical properties of materials during machining are discussed.The 3D finite element simulation model based on arbitrary Lagrangian Euler method (Ale) was established and subprogram was written to make it parameterized and visualized. The influence of different cutting parameters on the cutting force in micro-milling process was obtained.A test platform was built for micro-milling of AZ31b magnesium alloy materials by using 0.1 mm daily advance milling cutter. The milling force and the machined surface of different cutting parameters were obtained under the actual machining conditions.At the same time, the experimental results show that there is good agreement with the finite element simulation results, and the accuracy of theoretical analysis is verified. Finally, the empirical formula of cutting force in micro-slot milling of 0.1 mm daily advance milling cutter is established, which can realize the prediction of micro-milling force in a certain state.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG54

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