数控加工中效率提升的有效措施

如何利用和发展数控加工,实现高效数控加工（High Efficiency NC Machining）已成为企业普遍关心的大事。许多企业中数控加工效率低下．数控制造能力不足已成为较突出的共性问题。如何通过高效数控加工技术的研究提高数控制造技术水平,提高数控加工的能力,是摆在我们面前的严峻课题。实现高效数控加工对增强企业的综合竞争力,提高可持续发展能力都具有现实意义。     

陶瓷刀片高效加工技术在航空盘类零件应用

航空发动机高压压气机盘、涡轮盘等零件,属于发动机中高速旋转的关键部件,零件的结构、形状较为复杂,尺寸精度与技术条件要求较严,材料多为强度高、硬度高的切削性能较差的高温合金材料,加工过程中零件的余量较大,按传统工艺进行加工,效率较低,影响零件的周转与交付进度。选取陶瓷刀具,采用数控加工工艺进行零件的粗加工、半精车加工工作,能够达到提高零件加工效率与加工质量的目的。通过梳理盘类零件的工艺规程,筛选、确定以某型号发动机九级轮盘作为典型零件,开展陶瓷刀具高效加工研究、攻关,从而带动盘类零件整体制造技术的提升。该零件特点是,形状较为复杂,零件的加工精度较高,材料为镍基高温合金,在发动机盘类零件中具有代表性。通过采用高性能陶瓷刀具实施高效数控加工,对于批量生产的零件,能够大大减少加工时间并提高质量,解决制约生产的难题。本文主要阐述了应用数控车设备,选择适用的陶瓷刀具,进行数控加工程序的编制,以及切削加工参数的摸索、验证,成功实现九级轮盘零件采用陶瓷刀具高效数控加工的工艺过程。     

高精度大型整体薄壁零件高效加工制造技术研究

本文对大型整体薄壁零件加工制造技术进行了详细的论述。通过应用法国数控立车,应用高效数控加工程序及新式控制变形工装,探索出了解决大型薄壁零件高效数控加工方法,解决了零件加工变形问题,大大提升了行业高精度大型整体薄壁零件高效加工制造技术水平。     

基于影响数控机床加工效率的因素及对策研究

我国数控机床技术应用过程中普遍存在数控加工效率较低的现象,如何通过高效数控加工技术的研究提高数控制造技术水平。提高数控加工能力,是企业最关心的课题。本文简要介绍数控机床的含义,重点分析影响数控机床加工效率的因素,并提出了相应的对策。     

基于Mastercam典型零件的加工工艺改进

通过MasterCAM软件对典型零件进行数控加工编程,提出如何改进加工工艺、提高加工效率的问题,同时保证零件的加工精度,实现高效优质的数控加工。     

机匣类零件数字化制造技术研究

通过对"在机匣零件中实现MBD的应用","机匣典型零件基于设计模型的工序高效建模及模块化编程应用"、"机匣数控加工仿真环境数据库建设","基于PDM系统的机匣高效切削数据库建设","机匣零件数控加工防错方法技术"等五个方面的研究,来提升机匣加工的数字化制造水平。     

薄壁件数控车加工工艺浅析

本文介绍了法国SNECMA公司CFM56型号薄壁件四级密封环的数控车加工工艺，着重论述了采用数控机床车加工四级密封环的优势，以及如何选用合理的切削参数、专用机夹刀具及优化的数控程序来精车加工密封环斜篦齿和U型槽等关键型面。     

航空薄壁件数控车加工工艺研究

薄壁零件刚性羞、强度弱,在加工中极容易变形,使零件的形位误差增大,不易保证零件的加工质量,薄壁零件的加工是传统机械加工中比较棘手的问题。通过探索法国SNECMA公司CFM56型号薄壁件四级密封环的数控车加工工艺,选用合理的切削参数、专用机夹刀具及优化的数控程序来进行精车加工密封环斜篦齿和U型槽等关键型面,可以验证采用数控机床车加工航空薄壁件的优势。     

某薄型叶片高效精密数控加工工艺研究

本文通过攻关试验解决了某薄型叶片难加工材料数控铣叶身型面弹性变形大,加工精度低、效率低的问题,实现了薄型叶片的高效精密数控加工。本文涉及到薄型工件的刚性优化技术;高效铣加工技术;难切削材料的刀具选择等几个问题。     

高效数控加工技术应用探析

随着我国经济发展以及科技创新的当下,我国的很多行业都在多个方面有了非常大的提升,在这一过程中,我国的机械加工行业也得了非常大的进步和发展,在我国机械行业的发展过程中,数控加工技术的发展代表着我国工业实力的提升,应当积极做好数控加工技术的发展创新。我国数控加工技术的创新在很大程度上提升了我国机械加工行业的加工效率以及加工质量,因此在我国机械加工的过程中,数控加工技术的应用非常广泛,同时也取得了非常好的发展效果。本文主要针对高效数控加工技术的相关内容进行详细的论述以及分析,希望通过本文的阐述以及分析能够有效地提升我国数控加工技术的发展,同时也为我国加工行业的创新以及发展贡献力量。     

Intelligent tool path correction for improving profile accuracy in CNC turning

This paper presents the development of an intelligent predictive tool for improving the accuracy of parts produced on CNC turning centers. Actual dimensions and shape (form) produced on components during machining differ from the nominal dimensions commanded in the CNC program. These dimensional and form errors on parts depend on a variety of factors such as tool/work deflections, machine tool accuracy, machining conditions etc. These errors, if predicted, can be used to correct the ideal CNC code and thus improve the part accuracy in CNC machining. In the present work artificial neural networks are used to capture the complex relationship between the errors on the component and the input process conditions. Significant improvement in part accuracy has been obtained using the corrected CNC code during machining.     

Computer-aided optimization of multi-pass turning operations for continuous forms on CNC lathes

The Computer Numerical Control (CNC) machine is one of the most effective production facilities used in manufacturing industry. Determining the optimal machining parameters is essential in the machining process planning since the machining parameters significantly affect production cost and quality of machined parts. Previous studies involving machining optimization of turning operations concentrated primarily on developing machining models for bar components. Machined parts on the CNC lathes, however, typically have continuous forms. In this study, we formulate an optimization model for turned parts with continuous forms. Also, a stochastic optimization method based on the simulated annealing algorithm and the pattern search is applied to solve this machining optimization problem. Finally, the applications of the developed machining model and the proposed optimization algorithm are established through the numerical examples.     

Optimal cutter size determination for 2½-axis finish machining of NURBS profile parts

A curve model of non-uniform rational B-spline (NURBS) has been widely adopted in mainstream CAD/CAM software systems to design complicated geometries of mechanical parts, for example, the curved profiles of pockets, sides, and islands. NURBS profile parts (the profiles include NURBS curves for pockets and islands) are produced in 2½-axis rough and finish machining. In rough machining of the parts, several end-mills with different sizes are employed for high cutting efficiency, and in finish machining, a single end-mill is usually used to cut along the profiles for high surface quality. To accurately produce the geometries with NURBS curves in finish machining, the cutter size should be optimised in order to eliminate gouging and save machining time. Although this topic has been a research focus for a decade, optimal cutter size determination still remains as a technical challenge. To rise to this challenge, our work proposes a new approach to determining the largest allowable size for the cutter to move along all the profiles (including NURBS curves) in 2½-axis finish machining without global and local gouging. The salient feature of this approach is that an original model of the cutter size is formulated and an effective solver–the particle swarm optimisation method–is employed to compute the largest allowable cutter size. This intelligent approach is more efficient and accurate than the conventional computational method based on the test examples in this work. It can also be applied to global and local gouging detection for NURBS profile machining. Our research work has great potential to advance CNC machining techniques.     

基于有限元分析的薄壁圆环零件加工工艺研究

目的 针对薄壁圆环零件刚性差、强度弱、加工过程中易发生受力变形的难题,基于薄壁圆环零件加工成形工艺,优化零件的加工工艺和装夹方式。方法 考虑到工艺对零件加工质量的影响,对零件的加工方法和装夹方式进行研究,提出一种新的加工工装,运用ANSYS软件对零件装夹受力情况和振动变形进行有限元模拟仿真分析。结果 该工装不仅能够防止零件发生应力集中,还提升了零件加工精度和表面质量,工装设计为一夹一顶方式,只需调整顶尖压紧力便可确保圆环件在加工中不会发生变形,同时拆装方便,提高了生产效率。结论 对于薄壁圆环件的数控加工,可通过科学设计零件加工工艺流程和装夹工装,解决零件受力变形问题,保证薄壁圆环零件的尺寸、形位公差和表面粗糙度符合要求,提高了生产加工效率,满足产品批量生产使用要求,为类似薄壁件的加工提供了参考。     

自由曲面的CNC直接插补加工技术

在ＣＮＣ系统上直接根据曲面几何定义与加工工艺参数对多轴贡面加工的连续运动轨迹进行实时插补控制，在ＣＮＣ上直接在ＡＰＴ高级语言编程，极大地科化了零件程序，并可在线修改与补偿机床运动结构、刀具形状尺寸及加工作量等工艺参数，使曲在线曲面精加工经济而高效。在单ＣＰＵ硬件环境下实现了从一般二次曲线到复杂的参数组合曲面，从两轴加工到复杂的五轴联动功能，可采用多种加工刀具与加工方式，可实时检测与处理刀具干涉，并     

Design of Vibration Monitoring System of CNC Machine

CNC machine have a fast development and is widely used in China. Generally, CNC machine tool, includs CNC lathes and CNC milling machine. CNC machine tool is a necessary tool for machining. It plays an important role in the mechanical design and machining fields. CNC machine tool is mainly composed of two parts of the machine body and the computer control system. Mechanical equipment failures usually related information such as vibration, sound, pressure, temperature performance. CNC machine tool vibration monitoring system with piezoelectric accelerometer, the eddy current displacement sensor, signal amplifier, signal conditioning modules. We can take an advantage of the CNC machine tool vibration monitoring system for vibration monitoring and fault diagnosis of CNC machine tools.     

Load spectra of CNC machine tools

Load spectra of CNC machine tools are described in this paper; 112 CNC machine tools have been traced for 3 years. Data including machining parameters and conditions, drawings and NC programs of parts, process cards and specifications of each individual CNC machine tool are gathered. A database containing this information is designed. The loads of CNC machine tools are calculated and the distribution parameters of loads are estimated. A fuzzy multicriteria comprehensive evaluation method is applied to evaluate the fitness of the distribution model. This methodology lays a foundation for the reliability designs of CNC machine tools. Copyright © 2000 John Wiley & Sons, Ltd.     

New algorithm to minimise kinematic tool path errors around 5-axis machining singular points

The singular points of a given 5-axis CNC machine could be found in the domain of the joint variables of the machine. In the neighbourhood of a singular point, even for a small change of the tooltip position, an enormous change of axis displacements of the machine is often required. This causes a large deviation between the real cutting path and the desired tool path, and the machining surface could be destroyed. This paper provides with an analytical scheme for identifying singular configuration of 5-axis CNC machines. In particular, an efficient and robust algorithm is proposed to compute the cutter path across the neighbourhood of the singular points identified such that the computed cutter path tracks the desired tool path within a controllable error. Numerical examples and real cutting parts are carried out and discussed to show the effectiveness and the efficiency of the presented method.     

Automatic identification of aspect vectors and geometrical validation of 2.5D parts

A part can be viewed from infinite viewpoints, but it may look 2.5D from some specific viewpoints only. Its solid model may be arbitrarily oriented in space as per the designer's convenience in positioning it in an overall assembly. However, this orientation may not be suitable for proper and economic manufacturing. A manufacturing engineer has to reorient the part in such a way that it looks a 2.5D part, if possible. Manufacturing of 2.5D parts is economic and efficient since standard machine tools, cutters and clamping devices are used. An algorithm is presented to automatically determine the machining coordinate system that is convenient for machining. The selected coordinate system specifies the approach directions (aspect vectors) for machining the part. The underlying principle of the algorithm is the generation of machined faces on a three-axis CNC vertical milling machine with a set of flat-bottomed end-milling cutters and standard clamping devices. The part can have only planar and cylindrical faces under such machining conditions. Another algorithm is presented to validate whether or not a part falls under the 2.5D domain. Both algorithms are required since the present state of feature-recognition technology is limited to 2.5D parts. There is a need for a pre-processing system that automatically determines the aspect vectors for a 2.5D part and checks whether or not the design fed to the feature-recognition system is valid.     

The Research of CNC Machining Cutter Choice Based on CAXA

The article introduces the unique characteristics of CNC machining center cutter compared to traditional cutters,analyzes the choice of CNC machining cutter and factors of choice.Meanwhile,proved by the examples with manufacture software CAXA2004,the correct choice of CNC machining center cutter can give full play to the advantages of CNC machining and improve the economic efficiency and production levels of enterprises.