【作者】 牟涛；

【导师】 李剑峰；

【作者基本信息】 山东大学 ， 机械制造及其自动化， 2009， 硕士

【摘要】 钛合金Ti6Al4V具有比强度高、耐热性和耐蚀性好等优良性能,被广泛应用于航空航天工业,然而由于其导热系数低、化学活性高、弹性模量小等特点使其成为典型的难加工材料,引起加工过程中刀具磨损破损严重、生产效率低、加工表面质量差、生产成本高等制造工艺难题。本文以高速铣削钛合金Ti6Al4V为研究对象,通过研究高速铣削Ti6Al4V过程中切削力、切削温度、表面完整性为基础,综合分析研究了硬质合金刀具高速铣削Ti6Al4V过程中刀具的磨损、破损机理及刀具使用寿命,并研究了刀具磨损后对加工过程的影响。1.高速铣削Ti6Al4V切削力的试验研究。分别利用可转位铣刀和整体硬质合金刀具进行了高速铣削Ti6Al4V的正交试验和单因素试验,对实验结果进行了极差分析,分析了不同切削因素对切削力的影响,利用线性回归方法建立了铣削力的经验公式,并研究了随着刀具磨损对切削力大小的影响。2.高速铣削Ti6Al4V刀具磨损机理及刀具寿命研究。利用可转位铣刀在不同的冷却条件下进行了刀具磨损试验,建立了刀具寿命经验公式,采用扫描电镜和能谱分析对刀具的磨损形态进行了分析,并探讨了高速铣削钛合金时的刀具磨损机理;分析了不同冷却环境对刀具磨损的影响,发现涂层可以有效提高刀具使用寿命,不同冷却环境对刀具寿命影响较大。3.高速铣削Ti6Al4V刀具磨损对表面完整性与切屑形貌的影响。在刀具寿命试验的基础上研究了随刀具磨损对表面完整性和切屑形貌的影响规律,对不同切削速度下可转位铣刀和整体刀具对表面粗糙度的影响做了分析。研究表明,当刀具磨损后刀具结构和性能发生明显变化,对切削力和切削温度有影响,从而导致了对表面质量和切屑形貌的变化。4.高速铣削Ti6Al4V切削稳定性分析。通过理论方法分析了切削过程中刀具和工件产生形状误差的原因,建立铣削颤振模型;通过试验分析了不同结构立铣刀加工过程中颤振的强弱,进行了切削性能比较;分析了切削参数对切削颤振的影响。更多还原

【Abstract】 Ti6A14V are extensively used in aerospace industry because of their excellent properties of high specific strength (strength-to-weight ratio), fracture resistant characteristics, and their exceptional resistance to corrosion. However, Ti6A14V are considered as typical difficult-to-cut materials due to their high temperature strength, high chemical reactivity and its low modulus of elasticity which will lead to rapid tool wear, low machining efficiency, low machining surface quality and high cost. In this paper, some researches were carried out on the fundamental aspects of high speed milling of titanium alloys Ti6A14V, such as the cutting force, cutting temperature, surface integrity. Based on the fundamental study, the comprehensive analysis and study were carried out on tool wear, tool breakage and tool life.1) Cutting force in high speed milling of titanium alloy. The multi-factors orthogonal and single factor experiments were carried out with indexable milling cutter and solid carbide tools. The empirical formula for evaluating the milling force were concluded by means of regression analysis. Range analysis is studied. The variation trend of cutting force along the tool wear was studied.2) Tool life and tool wear mechanism. Multi-factors orthogonal and single factor experiments indexable milling cutter and solid carbide tools were carried out to investigate the tool life. The effects of tool and workpiece material on tool life were also studied, and the empirical equations of tool life were established. Tool wear mechanism and characteristic in high speed milling of titanium alloy were analyzed by scanning electron microscope (SEM) and energy disperse spectroscopy (EDS).3) Variation of surface integrity and chip morphology along tool wear. Based on tool life experiments, variation of surface integrity and chip morphology along tool wear was studied.4) Machining stability in high speed milling of titanium alloy. Based on the dynamic cutting force and dynamics model established, the form error and machining stability of cutting tool and workpieces are analysis were studied. High speed machining stability experiments were conducted with different structure solid carbide tools. Cutting performances were compared of different cutting tools. The influence of cutting parameters to cutting chatter is analyzed.更多还原