高效切削与高完整性加工技术

高效加工是满足日益提高的产品精度和生产效率要求的必要措施.选择合适的高效切削加工工艺和高完整性加工技术,可以在大幅降低生产成本的同时实现加工工件的高尺寸精度和高表面完整性.对高效切削加工工艺及高完整性技术进行综述,介绍和分析包括高速切削技术、复合加工技术、先进加工刀具、高效冷却技术和新型高完整性加工原理及其技术应用.研究表明,切削高速度、刀具高效率、机床高复合、冷却高环保以及新型高完整性加工技术是高效切削及切削后续工艺的重要发展方向.     

面向高速数控机床的刀位文件重构技术

针对高速切削对加工工艺及刀具轨迹的不同要求,从一个全新的角度提出了推广高速切削应用的方式,即对常规数控编程系统所产生的刀位文件作改进与优化,使其满足高速切削技术的要求,从而使得在原常规机床进行加工的零件能够在较短时间内转移到高速机床上加工,减少重复性工作。     

数控切削加工领域的数字化测量技术和量具量仪

作为系统运行质量保证体系中关键信息的获取,分析和评定环节,数字化测量技术和精密量具量仪是数控切削加工技术与装备的"眼睛",装备、服务并推动着先进数字化切削技术和数控切削机床的持续向前发展.     

不锈钢管板小群孔加工技术

分析了不锈钢管板加工的难点,介绍了机床和钻头的选择及优化切削参数,获得较好的技术经济效果.     

发展现代高效刀具提高加工效率和效益

现在我国很多企业制造技术水平不高,对机械行业中通过现代切削技术和高效先进刀具来提高生产效率并降低成本的认识不足,不重视通过提高加工技术水平来提高生产效率。我国的机床生产近年来发展迅速,制造业的机床拥有量已达700万台,在世界遥遥领先,稳居第一,但刀具工业却远远落后于机床的发展。切削技术落后,先进的高效机床没有高效先进的刀具配备,从而使高效机床的加工效率得不到发挥,严重影响了生产效率的提高和加工成本的降低,制约了制造业的进一步发展。     

面向超声波机床加工芳纶纸蜂窝芯的新型固持方法

根据超声波机床加工蜂窝芯的基本原理及切削方式,在双面胶带固持技术的基础上,提出了一种高效、经济的芳纶纸蜂窝固持方法,极大地提高了固持效率,降低了成本。建立了机床功率、真空压力、切削参数以及刀具参数与最小薄膜面积之间的解析表达式,根据机床参数求解可选用新型固持方案的最小薄膜面积。     

集成化工艺设计图象编程智能系统研究

 对系统的智能模型,采用了规划原理和概念模拟方法描述系统的行为和知识;引入了加工特征单元的概念,认为零件是由一组加工特征单元构成的;研究了加工特征单元的表示模式、定义及其识别算法;研究了机床库、刀具库、切削数据库、加工方法的概念模型,详细地分析了加工方法、刀具、切削数据、机床选择的促成因素,并建立了它们的推理模型。     

基于VERICUT超高强度钢零件数控程序的优化

利用VERICUT仿真模块,可以平稳机床的切削载荷,延长刀具和机床的寿命,提高零件的加工质量,实现切削过程无人干预加工,从而减轻工人的劳动强度。     

微小型车铣加工表面粗糙度分析及预测模型建立

随着尖端科学技术和国防工业的不断发展，微小型车铣加工技术作为一种先进的切削加工方法被广泛应用在军民制造领域。为获得微小型正交车铣加工参数引起的零件表面粗糙度的变化规律，以高效车铣复合加工机床正交车铣轴类零件的表面粗糙度为研究对象，采用三水平五因素正交实验分析法和多元线性回归预测法，重点研究了车铣加工参数与表面粗糙度之间的关系、车铣加工参数与表面粗糙度预测模型数值关系。结果表明，采用相同刀具下正交车铣加工轴类零件，其工件尺寸、车削主轴转速、工件进给量、铣削主轴转速和切削深度依次从大到小影响零件表面粗糙度质量，可指导高效车铣复合加工机床的加工工艺参数优化。     

机床切削稳定性研究

自激振动,或称颤振是机床切削加工时,在没有周期性外力作用下,刀具和工件之间产生的振动.它不仅降低了机床的加工质量和切削效率,而且对机床和刀具的使用寿命产生不利的影响.从理论上推导产生自激振动的条件,并且通过实验进行验证,从而找出避免产生自激振动的措施.通过改变主振系统的刚度方向以及改变k1与k2的差值,就可以提高机床抵抗颤振能力.     

三元流闭式叶轮组合电加工技术研究Ⅱ——数控电解预加工

数控电解预加工是组合电加工技术中不可或缺的关键工艺,本文专题论述了三元流闭式叶轮数控电解预加工中阴极及其运动轨迹设计等关键技术。提出了采用多个阴极分区域加工流道的方法,利用先层切再叠加的方法将三维问题简化为二维问题处理而实现阴极加工型面的数值求解。在完成阴极结构优化设计专用工装夹具设计和数控加工程序编制的基础上,以某型三元流闭式叶轮为研究对象进行了加工工艺试验,并加工了符合设计要求的三元流闭式叶轮。试验研究表明,采取数控电解预加工工艺方案能够满足实际生产要求,可提高效率40%,降低电火花加工的电极损耗50%。     

Surface-improvement mechanism of hybrid electrochemical discharge process using variable-amplitude pulses

Superalloys are commonly used in aircraft manufacturing; however, the requirements for high surface quality and machining accuracy make them difficult to machine. In this study, a hybrid electrochemical discharge process using variable-amplitude pulses is proposed to achieve this target. In this method, electrochemical machining (ECM) and electrical discharge machining (EDM) are unified into a single process using a sequence of variable-amplitude pulses such that the machining process realizes both good surface finish and high machining accuracy. Furthermore, the machining mechanism of the hybrid electrochemical discharge process using variable-amplitude pulses is studied. The mechanism is investigated by observations of machining waveforms and machined surface. It is found that, with a high-frequency transformation between high- and low-voltage waveforms within a voltage cycle, the machining mechanism is frequently transformed from EDM to pure ECM. The critical discharge voltage is 40 V. When pulse voltages greater than 40 V are applied, the machining accuracy is good; however, the surface has defects such as numerous discharge craters. High machining accuracy is maintained when high-voltage pulses are replaced by low-voltage pulses to enhance electrochemical dissolution. The results indicate that the proposed hybrid electrochemical discharge process using variable-amplitude pulses can yield high-quality surfaces with high machining accuracy.     

影响电火花成形加工质量的工艺性因素分析

介绍了电火花加工中常见的加工精度和表面质量问题以及产生的原因及相应的改善措施.     

Dual Drive Curve Tool Path Planning Method for 5-axis NC Machining of Sculptured Surfaces

The problem of finished surface being not first-order continuous commonly exists in machining sculptured surfaces with a torus cutter and some other types of cutters. To solve this problem, a dual drive curve tool path planning method is proposed in this article. First, the maximum machining strip width of a whole tool path can be obtained through optimizing each tool position with multi-point machining (MPM) method. Second, two drive curves are then determined according to the obtained maximum machining strip width. Finally, the tool is positioned once more along the dual drive curve under the condition of tool path smoothness. A computer simulation and cutting experiments are carried out to testify the performance of the new method. The machined surface is measured with a coordinate measuring machine (CMM) to examine the machining quality. The results obtained show that this method can effectively eliminate sharp scallops between adjacent tool paths, keep tool paths smooth, and improve the surface machining quality as well as machining efficiency.     

Influence mechanism of machining angles on force induced error and their selection in five axis bullnose end milling

In the machining of complicated surfaces, the cutters with large length/diameter ratios are used widely and the deformation of the machining system is one of the principal error sources. During the process planning stage, the cutting direction angle, the cutter lead and tilt angles are usually optimized to minimize the force induced error. It may lead to a low machining efficiency for bullnose end mills, as the material removal rates are different largely for different machining angles. In this paper, the influence mechanism of the machining angles on the force induced error is studied based on the models of the instantaneous cutting force when the cutter flute traveling through the cutting contact point and the stiffness of the machining system. In order to evaluate the machining angles, the force induced error/efficiency indicator (FEI) is defined as the division of the force induced error and the equal volume sphere of the removed material. FEI is dimensionless, with the lower FEI, the lower force induced error and the higher machining efficiency. For optimal selection of the machining angles, the critical FEI is calculated with the constraint of force induced error and the desired material removal rate, and the critical FEI separate the set of the machining angles into two subsets. After the feed rate scheduling process, the machining angles in the optimal subset would have higher machining accuracy and efficiency, while the machining angles in the other subset have lower machining accuracy and efficiency. Through the machining experiment of five axis machining and freeform surface machining, the effectiveness and superiority of the proposed FEI method is verified with a bullnose end mill, which can improve the machining efficiency with the constraint of force induced error.     

精密复杂曲面零件多轴数控加工技术研究进展

多轴数控（CNC）加工是现代工业中的标志性加工技术,在能源、动力、国防、运载工具、航空航天等制造领域的关键零部件加工中占据着主导地位。随着这些领域中高端装备性能要求越来越高,涌现出一大批加工难度大、性能指标要求苛刻的精密复杂曲面零件,其加工已由以往单纯的形位精度要求,跃升为形位与性能指标并重的高性能加工要求,给传统的复杂曲面零件数控加工技术带来了严峻挑战。针对精密复杂曲面零件形位精度保证、加工效率提升及动态切削过程可控等关键技术问题,从多轴数控加工的高效加工路径设计、进给率规划以及加工动力学分析等方面,详细论述相关加工技术的研究现状、存在的难点和核心问题,指出可行的解决途径、突破方向和未来的发展趋势,为实现复杂曲面零件的高性能数控加工提供参考和依据。     

薄壁叶片叶型多工序加工检验模型建立方法

为了提高叶片的加工质量、降低叶片成品的废品率和加工成本，以航空发动机薄壁叶片数控铣削、抛光、振动光饰、喷丸强化的典型加工工艺为研究对象，提出了一种面向多工序的加工变形误差补偿方法及加工检验模型的建立方法。分析各工序的加工变形规律，将多工序变形误差作为一个整体，利用反变形误差补偿方法建立数控精铣工序的加工模型。图纸要求的理论模型只作为最终检验模型，而工序检验模型根据后续加工误差累加对最终检验模型修改得到。通过实例验证，该方法有效地降低了叶片工序检验结论的误判率，保证了工序检验合格及最终检验合格的要求。     

模具制造的高速加工工艺研究

高速加工不但可以成倍地提高生产效率,还可进一步改善零件的加工精度和表面质量,解决一些常规加工中难以解决的某些特殊材料的高效加工问题,因此,高速加工技术在世界上引起了高度重视。主要从加工工艺方面讲述了高速铣削的技术特点以及在模具加工行业的应用。最后展望了高速加工的发展应用前景。     

复杂曲面FSS加工系统研究

为了解决大型复杂曲面FSS(FrequencySelectiveSurface)加工中的关键技术,研究并开发了5自由度机器人数字化加工系统。与传统的5轴联动加工方法相比,提出的分区加工和浮动电主轴模糊定位相结合的快速加工方法大大提高了系统的加工效率。利用建立的数字化加工系统加工了复杂曲面FSS雷达罩试件和平板FSS试件。对比测试了不同加工工艺条件下平板FSS的频率传输响应特性,验证了该加工系统的有效性。     

基于动态Bayesian网络的叶片加工质量监控与溯源

 针对叶片加工过程中质量精度不高的问题,提出了基于动态Bayesian网络的叶片加工质量监控与溯源方法.利用动态Bayesian网络建立起叶片加工工序间的相互联系,实现对整个加工过程的控制.基于Bayesian网络对影响加工工序的因素集建立因果联系,采用多元统计过程控制中的T²控制图完成对各工序影响因素集的监控.进行误差溯源时,根据Bayesian网络建立的因果关系对失控样本的T²统计量依据原因变量进行误差分解,并构建各分解变量的控制限,将其作为误差源判定的条件.通过对某叶片加工过程的仿真,验证了所提方法的有效性.