镍基高温合金微小结构/零件微铣削加工关键技术研究

To meet the urgent demands of micro structure/parts which have high strength in high temperature environment in the fields such as aerospace, energy, power, bio-medical etc., aimed at the problem of tool easy wearing, the complicated cutting force variation rule and the low processing efficiency when micro-milling nickel-based superalloy due to its complex micro structure, high strength and high hardness, key technologies of micro-milling micro structure/parts on nickel-based superalloy are studied. Building instantaneous cutting thickness model is adopted as the entry point of the research. Theoretical modeling method is used to build the nickel-based superalloy micro-milling cutting force model, and then achieves the aim of forecasting the cutting force. SEM and Spectrum analysis technologies are used to observe and analyze the wear and damage condition of the tool during the micro-milling process, revealing the micro-tool's failure mechanism systematically. Additionally,the cutting force threshold when tool gets worn or damaged is analyzed and a monitor model by neural network algorithm is built, achieving the goal of monitoring the tool's condition by means of the cutting force. Finally, According to the restriction of the tool life and the surface roughness taking tool life into account, nickel-based superalloy micro-milling process optimization model is given for the objective of the highest machining efficiency, and the processing experiments are done. Eventually, the machined nickel-based superalloy microchannel is 100μm in height, 30μm in width, width and height deviations of microchannel are less than 5%.The goal of high machining efficiency and quality is achieved.

面向航空航天、能源、动力、生物医学等领域对高温环境下具有高强度的微小结构/零件的迫切需求，针对镍基高温合金材料微观结构复杂、强度高、硬度高等特点导致的微铣削加工时刀具易于磨损、微铣削力波动规律复杂以及加工效率低等问题，研究镍基高温合金微小结构/零件微铣加工关键技术。以建立瞬时切削厚度模型为切入点，建立镍基高温合金微铣削力模型，实现微铣削力的预测；通过扫描电子显微镜和能谱分析技术对微刀具在切削过程中的磨、破损形貌进行观察分析，系统地揭示微铣削镍基高温合金时微刀具的失效机理；对刀具磨损和破损的切削力阈值进行分析，采用神经网络算法建立监控模型，通过微铣削力对刀具状态进行监控；以加工效率为目标，以考虑刀具寿命的铣削力和表面粗糙度为主要约束，建立镍基高温合金微铣削工艺优化模型并开展工艺试验，最终实现宽度100μm，高度30μm，宽度和高度尺寸偏差在5%以内的镍基高温合金微通道的微铣高效加工。

面向航空航天、能源、动力、生物医学等领域对高温环境下具有高强度的微小结构/零件的迫切需求，针对镍基高温合金材料微观结构复杂、强度高、硬度高等特点导致的微铣削力波动规律复杂、微铣刀易磨损及破损、表面完整性预测困难以及加工效率低等问题，研究了镍基高温合金微小结构/零件微铣加工关键技术。.首先，考虑刀齿齿尖次摆线运动轨迹及刀齿齿尖径向跳动影响，建立名义微切削厚度计算模型和实际切削过程累计切削厚度模型。然后，以最小切削厚度值为分界点，将微细切削过程划分为以剪切效应为主导和以耕犁效应为主导的两个不同切削过程。依据切削力与切削层面积成比例，并考虑耕犁效应影响，建立以剪切效应为主导的镍基高温合金微细铣削过程三维动态切削力预测模型；依据耕犁力与切削刃与工件间的过盈体积成比例，建立以耕犁效应为主导的镍基高温合金微细铣削过程三维动态切削力预测模型。开展镍基高温合金微细铣削试验，研究各切削参数对切削力的影响规律,依据正交试验结果，建立三维微切削力经验模型。.基于DEFORM 11.0软件对镍基高温合金Inconel 718微铣削过程进行有限元三维仿真，并通过实验验证了模型的准确性。在此基础上，研究了每齿进给量对刀具磨损的影响规律。基于微铣削试验，研究了微铣削Inconel718过程中，刀具前后刀面的磨、破损情况及磨损机理，并分析了微铣削刀具磨、破损的特点及其与镍基高温合金传统铣削的区别。研究结果表明：微铣削镍基高温合金时刀具的主要失效形式为刀尖磨损、前后刀面的涂层剥落及切削刃微崩刃；主要磨损原因为黏结磨损、扩散磨损和氧化磨损的综合作用，磨粒磨损不明显。提出一种基于理论模型预测微铣刀早期破损的新方法。.以镍基高温合金微铣削表面残余应力和加工硬化为研究对象，建立基于ABAQUS的镍基高温合金微铣削三维有限元仿真模型，实现了微铣削表面残余应力的预测，并结合应变与硬度之间的关系，实现了微铣削表面显微硬度的预测。基于单因素试验研究主轴转速、每齿进给量和轴向切深对表面残余应力和显微硬度的影响规律；基于响应曲面法研究主轴转速、每齿进给量和轴向切深对表面显微硬度的交互影响作用。.最后，进行了以能耗、材料去除率和表面粗糙度为优化目标的镍基高温合金微铣削切削参数优化研究。最终实现了宽度为100μm，高度为650μm，宽度和高度尺寸偏差在5%以内的镍基高温合金微微流控芯片热压模具的加工。