旋转超声磨削钛合金的磨削力与工具磨损研究

发布时间：2018-04-04 21:37

本文选题：旋转超声磨削　切入点：磨削力　出处：《西南交通大学》2017年硕士论文

【摘要】：钛合金因耐高温、比强度高、密度小、耐腐蚀等一系列优点被广泛应用于航空制造业中。由于钛合金高温化学活性大、导热系数小,所以钛合金在实际加工中易出现刀具磨损严重、加工表面质量差等问题。旋转超声磨削加工是集金刚石刀具磨削加工与普通超声振动加工为一体的复合加工,具有磨削力较小、加工表面质量较好的优点。磨削力是表征磨削过程的重要参量之一,不仅影响磨削钛合金加工表面质量,对工具寿命亦有较大影响。旋转超声磨削过程中,若工具磨损量较小,将导致工具迅速钝化,磨削过程产生的高温将导致加工表面烧伤等问题,若工具磨损量较大,又会因频繁更换工具而导致加工成本升高。为了提升钛合金零件表面质量和降低加工成本,开展旋转超声磨削钛合金磨削力与工具磨损的研究显示出重要的工程意义。本文将对钛合金旋转超声磨削加工中磨削力与工具磨损展开研究,主要工作包含以下三个方面:(1)建立磨粒分布随机、形状随机的多颗磨粒工具三维模型,使用该三维模型进行旋转超声磨削钛合金有限元仿真。对主轴转速、进给速度、超声振幅和超声频率等加工参数对钛合金旋转超声磨削力的影响规律进行预测,并通过设计相同参数条件下的正交试验验证了有限元仿真模型的正确性。(2)基于量纲分析和正交试验相结合的方法建立了旋转超声磨削钛合金工具磨损数学模型。使用该模型定量求解了旋转超声磨削钛合金中工具磨损量与加工工艺参数和工具结构参数之间的非线性关系,并研究了加工参数与工具结构参数对工具磨损量的影响规律,最后采用方差分析检验了所建立的数学模型的有效性和显著性。(3)使用Fortran语言对DEFORM-3D进行二次开发,将不同磨损机理对应的磨损计算模型编入DEFORM-3D子程序中,使用该磨损子程序对不同磨料粒度下旋转超声磨削钛合金工具磨损量的影响规律进行预测,磨料粒径较大的工具磨损量较大,与已建立的工具磨损数学模型所揭示的磨料粒度对工具磨损量的影响规律一致,说明新建立的工具磨损有限元模型具有较高的磨损预测精度。
[Abstract]:Titanium alloy is widely used in aviation manufacturing industry because of its advantages of high temperature resistance, high specific strength, low density and corrosion resistance.Due to its high chemical activity at high temperature and low thermal conductivity, titanium alloy is prone to serious tool wear and poor surface quality in practical machining.Rotary ultrasonic grinding is a combination of diamond tool grinding and ordinary ultrasonic vibration machining, which has the advantages of less grinding force and better surface quality.Grinding force is one of the important parameters to characterize the grinding process, which not only affects the surface quality of grinding titanium alloy, but also has a great effect on tool life.In the process of rotary ultrasonic grinding, if the tool wear is small, it will lead to the rapid passivation of the tool, and the high temperature produced in the grinding process will lead to the burn of the machined surface.Because of the frequent replacement of tools and lead to higher processing costs.In order to improve the surface quality of titanium alloy parts and reduce the machining cost, the research on grinding force and tool wear of titanium alloy by rotary ultrasonic grinding is of great engineering significance.In this paper, the grinding force and tool wear in rotary ultrasonic grinding of titanium alloy are studied. The main work includes the following three aspects: 1) establish a three-dimensional model of multi-particle tool with random distribution and random shape of abrasive particles.The three-dimensional model is used to simulate the rotary ultrasonic grinding of titanium alloy by finite element method.The influence of machining parameters such as spindle speed, feed speed, ultrasonic amplitude and ultrasonic frequency on the rotary ultrasonic grinding force of titanium alloy is predicted.The correctness of the finite element simulation model is verified by orthogonal test under the same parameters. (2) based on the method of dimension analysis and orthogonal test, a mathematical model of rotary ultrasonic grinding of titanium alloy tool wear is established.The nonlinear relationship between tool wear, machining process parameters and tool structure parameters in rotary ultrasonic grinding of titanium alloy is quantitatively solved by using this model, and the influence of machining parameters and tool structure parameters on tool wear is studied.The wear subroutine is used to predict the effect of rotary ultrasonic grinding on the wear of titanium alloy tools with different abrasive particle size.The effect of abrasive particle size on tool wear is consistent with the established mathematical model of tool wear, which shows that the new finite element model has high precision of tool wear prediction.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG663;TG580.6

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