航空复杂产品基于三维产品模型的集成化CAPP系统研究

为了有效解决航空制造企业快速工艺准备的问题,提出了基于三维产品模型的集成化OAPP系统。本文分析了航空行业工艺设计与管理及CAPP技术的应用现状,对航空制造企业基于三维产品模型的CAPP工艺需求和特点进行了分析,提出基于三维产品模型的集成化CAPP系统解决方案,建立了基于三维产品模型的集成化CAPP系统技术体系。以在863“航空行业CAPP解决方案研发与应用”推广课题的研究中基于OAPPFramework和3D-PLM工具平台集成开发的基于三维产品模型的集成化OAPP系统（3D—cAPPFramework）系统为例,对建立支持航空行业的CAPP系统构件库,面向航空行业应用的集成化OAPP系统工具集进行了详细论述,形成具有可定制特性的开放式3D-CAPPFramework产品,以满足航空复杂产品对基于三维产品模型的集成化OAPP系统的需求。     

Flatness and distortion measurements in semiconductor manufacturing

In semiconductor manufacturing processes as currently employed, a 100% error-free mask pattern transfer into the resist layer of a silicon wafer is impossible. It is essentially limited by in-plane and out-of-plane deformations of the mask and wafer substrates. Another limitation is given by the non-error-free transfer system itself, resulting in distortions of the printed wafer pattern.Applied parallel coherent optical interference measurement methods for mask and wafer flatness, as well as for the detection of local distortions of imaging systems of lithographic printers, are presented in this paper.     

云制造的体系结构研究

云计算正迅速改变着信息系统设计构建和服务方式。本文针对现代制造业跨平台、跨区域、跨企业的协同需求,引入云计算思想,给出了云计算平台的总体结构,提出了一种云制造平台的总体结构,讨论了实施云制造所需的关键技术,为中小企业搭建云制造服务平台提供理论支持和技术指导。     

Workload balance and part-transfer minimization in flexible manufacturing systems

Problems related to the flow management of a flexible manufacturing system (FMS) are here formulated in terms of combinatorial optimization. We consider a system consisting of several multitool automated machines, each one equipped with a possibly different tool set and linked to each other by a transportation system for part moving. The system operates with a given production mix.The focused flow-management problem is that of finding the part routings allowing for an optimal machine workload balancing. The problem is formulated in terms of a particular capacity assignment problem.With the proposed approach, a balanced solution can be achieved by routing parts on a limited number of different paths. Such a balancing routing can be found in polynomial time. We also give polynomial-time and-space algorithms for choosing, among all workload-balancing routings, the ones that minimize the global amount of part transfer among all machines.     

Analytical modeling of part distortion in metal additive manufacturing

This work presents an analytical modeling methodology for the prediction of part distortion in powder bed metal additive manufacturing (PBMAM). The present     

A fundamental structure for intelligent manufacturing

In order to realize a high-precision, flexible manufacturing system with easy operation and 24-hour unmanned capability, a completely new concept for “intelligent manufacturing” has been introduced. The fundamental concept and structure of intelligent manufacturing, as implemented in our laboratories, are discussed in this article. The main compnents of the system are knowledge, sensors, and actuators. The physical model provides fundamental knowledge concerning the process. The physical model uses sensor readings of the current system behavior to predict the future system behavior. Then the controller can bring the system into correspondence with the desired state through the use of appropriate actuators. Many different elements, such as force sensors, fail-safe mechanisms, fine-positioning mechanisms, and actively controlled machine structures have been incorporated into the system. Most of these components have been tested in our laboratories. Through the use of intelligent manufacturing systems, manufacturing technology may enter a new stage of development. Moreover, such a system may open new possibilities for manufacturing in alien worlds, such as in space or on the atomic scale.     

航空钛合金结构件的损伤修复技术

钛合金航空结构件的应用越来越广泛,但应用传统制造技术对钛合金结构件的修理则较困难,且存在许多缺陷.综合作者的实验研究成果,本文介绍了钛合金件裂纹的激光焊接、激光熔覆修复技术;对于缺损性损伤,介绍了应用快速成型系统重建损伤结构的技术.     

基于制造资源的复杂箱体零件加工特征识别方法

针对复杂箱体零件的加工特征识别问题,介绍了一种基于制造资源的特征识别方法。在分析加工工艺环境中机床、刀具和夹具的基础上,对制造资源进行了参数化定义,获得了制造资源模型。以STEP/AP203中性文件为数据源,获得了三维零件模型的加工表面,根据加工表面与制造资源的映射关系,获得每个表面的制造资源组合方案,即特征因子,并以提高加工效率和经济性为目标,对特征因子进行优化筛选。将同一装夹下采用同一刀具和机床运动模式的加工表面聚类为一个加工特征,完成零件特征识别。     

Machining process parameters optimization for heavy-duty CNC machine tools in sustainable manufacturing

Machining process parameters (MPP) directly affect the machining quality and efficiency of heavy-duty CNC machine tools (HCMT). The selection of MPP is very important to effectively improve machining performance. Machining performance has been closely related to the HCMT running state. In order to maintain HCMT sustainably manufacturing with high accuracy and low consumption after machining performance degradation for a long time running, MPP should be re-optimized according to the current state of the machine tools. Thus, this paper proposed a MPP optimization method for running HCMT to obtain optimal MPP based on current running state. A multi-objective optimization model was built, considering both the linear factors such as machining time and machining cost and nonlinear factors such as chatter in machining process. The nonlinear factors were reflected by the nonlinear dynamic model of machining process. Furthermore, a grid optimization algorithm was introduced to search the optimal MPP from the multi-objective optimization model. Finally, a case study was implemented to verify the feasibility of the nonlinear dynamic model and the superiority of the multi-objective optimization method compared with single-objective optimization method.     

航空图像的小波去噪

航空图像,除了含有一般数字图像的噪声之外,还有大气扰动产生的噪声,线阵CCD产生的积分条纹噪声等,所以去除噪声对于航空图像来说尤为重要.本文采用二维离散小波sym4阈值降噪的方法对图像进行去噪,实验中将原始航空拍摄图像加入了σ=15的高斯白噪声,对含噪图像进行二维离散小波变换分解成不同分辨率子图像,并对各子图像进行阈值化处理,处理后图像又进行了小波逆变换,从而获得了降噪后的航空图像.含噪图像的PSNR(峰值信噪比)为27.53,去噪后PSNR为29.14.该方法有效降低了噪声,又保持了图像的细节,与传统的滤波降噪相比,降噪效果有较大改善.由实验结果证明了这是一种有效的航空图像降噪手段.     

论焊接件变形的结构和工艺分析

焊接在制造业中的应用正在迅速发展,但焊接变形的不同程度制约着焊接产品的质量.论述在焊接生产中,如何防止和减少焊接变形,并在焊缝长短、焊缝大小、焊接形式、焊接面大小、焊接方法方面加以探索.     

飞机结构件制造信息系统研究

在深入研究我国飞机制造工艺特点的基础上,对飞机结构件的工艺制造过程进行分析研究,打破传统的制造模式,构建了面向车间级的制造信息系统,详细分析系统的体系结构及其实现,最后分析了实现该系统的关键技术.     

Machining scheme of aviation bearing bracket based on additive and subtractive hybrid manufacturing

Journal of Mechanical Science and Technology - Aviation bearing bracket is an important part of aircraft and other aviation products. In this paper, based on additive and subtractive hybrid...     

网络化制造环境下面向定单制造的供应链构建

阐述了在网络化制造环境下，定单驱动型企业构建供应链的步骤。提出考虑能力、时间约束的供应商选择评价方法，从网络化制造平台获取供应商数据信息，将这些信息作为供应链优化模型的输入，以实现交货期最短、成本最低的优化目标。     

硬度与金属组织对超声波加工工具材料磨损的影响

通过对玻璃进行超声波加工,研究了硬度,金属组织对超声波加工工具材料磨损影响的规律。试验表明磨损率是由多因素决定的,硬度与其磨损率呈非线性关系。金相组织也是影响磨损率的因素之一,在试验条件下中碳钢中综合力学性能好的金属组织磨损率较低。     

残余应力作用下的航空整体结构件加工变形仿真

铝合金预拉伸板在成型过程中会产生较大的残余应力,在切削过程中毛坯的初始残余应力的释放对整体结构件的宏观变形有重要的影响。在弹塑性力学的基础上,综合运用Hypermesh和ABAQUS建立残余应力单因素作用下的三维铣削仿真加工变形场的有限元模型,利用生死单元技术模拟了材料的去除,分析了铝合金板材材料去除过程中残余应力释放引起的加工变形规律。并且运用Hypermesh提高了有限元前处理的速度,解决了复杂模型的残余应力加载困难与单元去除困难的问题。     

面向制造全过程的转向架装配制造仿真

为了解决转向架装配制造中的问题,考虑转向架装配制造全过程,利用Delmia各仿真模块及PPR,构建了涵盖虚拟装配线建模、装配工艺规划、装配工艺过程仿真、装配线物流仿真的转向架装配数字化仿真平台,阐述了转向架装配制造数字化仿真平台的框架组成、实施流程、仿真与分析方法,利用仿真平台可以对转向架装配制造全过程进行仿真,实现对转向架装配制造全过程的预规划、验证与优化,能够缩短制造周期,降低制造成本。