基于过程阻尼效应的五轴车铣加工钛合金叶轮颤振稳定性研究

Five-axis turn-milling is an advanced processing technology, which has a strong ability of producing complicated curved surface or special-shaped parts,wherein both cutting tool and workpiece are given a rotary motion simultaneously. In the field of aviation manufacturing, it has an extensive application prospect when producing difficult-to-cut thin-walled workpieces. This project is developed based on research findings in orthogonal turn-milling machining mechanism. The flow of this project strictly follows comprehensive research procedures, which is establishing theoretical model, conducting simulation analysis and doing verification experiments based on the chip formation theory and the machining dynamics theory in turn-milling.The chatter stability and the process parameters optimization when machining integral Titanium alloy impellers are studied based on the process damping effects. Established on the vibration coupling properties of the machining system, the dynamics model of turn-milling, which is determined by the relative dynamic characteristics between milling cutter subsystem and compeller subsystem, and a nonlinear machining process damping model are developed. The critical conditions of the chatter stability are also defined. The aim of this study is to bring an insight on the influence of the process damping effect during titanium alloy compeller production, precisely extract chatter information properties and better predict chatter stable, analyse the inter-relationship between process parameters, cutting force, chatter stability and machined surface quality, establish a multi-objectives function using chatter stability as constraint condition, surface quality and production effectiveness as objectives and finally, explore and form a novel turn-milling technology when producing titanium alloy compellers.

五轴车铣加工是通过铣刀和工件同时旋转的合成运动来实现复杂曲面或异型零件的先进加工方法，在航空难加工材料的复杂薄壁零件方面具有代替磨削的应用前景。本项目基于申请者对正交车铣加工机理的研究成果，融合切屑成形理论和加工动力学理论，采用理论建模、仿真分析和加工实验的综合方法对基于过程阻尼效应的五轴车铣加工钛合金叶轮的颤振稳定性及工艺参数优化展开研究。基于加工系统产生的振动耦合特性，建立由"铣刀"子系统和"叶轮"子系统之间的相对动态特性决定的加工动力学模型及非线性过程阻尼模型并确定颤振稳定域的临界条件。本研究揭示过程阻尼效应对加工钛合金叶轮颤振稳定性的影响及作用程度，从而准确提取颤振信息特征并较好预测稳定区域；分析加工工艺参数对切削力、颤振稳定性、表面质量之间相互影响规律；以加工颤振稳定性为约束条件，以表面质量、加工效率等为多目标函数并合理优化工艺参数；探求并形成钛合金叶轮的五轴车铣加工新技术理论。

五轴车铣加工是通过铣刀和工件同时旋转的合成运动来实现复杂曲面或异型零件的先进加工方法，在航空难加工材料的复杂薄壁零件方面具有非常广阔的应用前景。本项目融合切屑成形理论和加工动力学理论，采用理论建模、仿真分析和加工实验相结合的研究方法，建立了考虑压痕效应的球头铣刀五轴铣削叶轮的过程阻尼切削力模型，并验证理论模型准确性。针对薄壁零件铣削颤振问题，建立由“铣刀”子系统和“叶轮”子系统之间的相对动态特性决定的加工动力学模型，引入等效过程阻尼系数，得到考虑过程阻尼效应的叶轮五轴铣削加工稳定性边界，并实验验证稳定性模型的准确性。针对过程阻尼效应引起的低速切削稳定性边界提升的现象，分析了过程阻尼效应的机理，并应用过程阻尼的相关理论提高叶轮的加工效率。本项目还针对加工效率和加工质量问题，对加工工艺参数和叶轮表面粗糙度进行了研究，分别建立铣削工艺参数优化模型和表面粗糙度模型，仿真与实验结果表明，采用优化过的工艺参数能够提高加工效率和叶轮的加工质量。本研究揭示过程阻尼效应对加工钛合金叶轮颤振稳定性的影响及作用程度，从而准确提取颤振信息特征并较好预测稳定区域；分析加工工艺参数对切削力、颤振稳定性、表面质量之间相互影响规律；以加工颤振稳定性为约束条件，以表面质量、加工效率等为多目标函数并合理优化工艺参数；探求并形成钛合金叶轮的五轴车铣加工新技术理论。