共查询到20条相似文献,搜索用时 140 毫秒
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为满足动态多变的产品需求,研究了知识化制造产品工艺路线自重构问题.以最小化平均在制品水平和最小化重构后各工序在机器上的分配变动数目为目标,在满足生产率、工序优先顺序、工件加工完整性、机器加工可行性约束的前提下,对产品工艺路线重构问题进行数学建模.提出了改进的混沌非支配排序遗传算法,利用带随机参数的Skew Tent映射对种群个体进行扰动,避免搜索陷入局部最优.设计了基于工序优先约束矩阵和候选机器集的解码方法,可获得产品可行的加工工序序列及加工机器序列.通过实例研究验证了模型和算法的有效性,为决策者提供了多种可选工艺路线重构方案. 相似文献
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可重构制造系统工艺路线与系统布局设计研究 总被引:4,自引:0,他引:4
为使可重构制造系统的重构过程更加快速有效,提出了一种工艺路线和系统布局设计的方法.首先,基于图论构建了可重构制造系统工艺路线的有向网络模型,并采用Dijkstra算法和双向扫视算法,进行最优工艺路线和备选工艺路线的选择;然后,以工艺路线为基础,依据排队论中的相关理论,对制造系统的布局进行优化设计,以获得可重构制造系统布局方案.实例表明,该设计能够适应可重构制造系统快速多变的特征,提高对制造系统已有资源的利用率. 相似文献
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异形拉深件的曲面复杂,用传统的测绘方法很难达到其精度要求.采用逆向工程技术理论对异形拉深件进行研究和分析,利用三维激光扫描仪对零件的几何特征进行数据扫描,并在Geomagic软件中进行数据处理后导入UG软件实现模型重构,生成了零件三维数学模型.同时对所生成的异形拉深件模型运用Dynaform软件进行CAE模拟分析,模拟了发生形变的过程,在材料成型RE/CAD/CAE/CAM集成上做了一定的探索. 相似文献
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结合人工神经网络所表现出来的良好特性,利用正交试验获得的数据作为神经网络的训练样本,建立输入为弯曲工艺参数、输出为回弹量的神经网络模型,并通过样本检验了ANN模型的准确性,从而缩短设定工艺参数的时间,在工艺参数取值范围内,采用ANN模型代替CAE软件模拟试验,结合正交试验法,对工艺参数进一步优化.结果表明:将神经网络与正交试验、数值模拟三者结合用于板料弯曲成形参数优化,可以缩短优化工艺参数的时间.提高工艺设计效率,并能获得比单纯使用正交试验和数值模拟方法更为优化的结果. 相似文献
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利用CAXA软件对战斗机工艺品模型的上模、下模、支撑架、滚轮进行三维造型设计,同时设定相关设计参数及制定加工工艺路线,并进行了仿真模拟加工和数控编程后置处理;运用数控加工中心机床进行战斗机模型实体曲面加工,采用普通车床对战斗机支撑架、战斗机滚轮进行实体加工,最后运用钳工工艺进行整体装配,最终完成战斗机模型的设计及制作过程. 相似文献
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Mujin Kang 《Journal of Mechanical Science and Technology》2000,14(12):1337-1347
The focus of CIM is on information as it is the crucial element for integrating all the manufacturing activities. CAPP, as one of the key elements in CIM, needs to extract the manufacturing information such as machining features and precision specifications like surface roughness and tolerances from a geometric model in order to link CAD and CAM. However, these data are not real attributes of the geometric model in most of the current CAD systems. Therefore, human interpretation is inevitable for further processing of CAD model for downstream application like process planning or inspection. This paper proposes a scheme to represent the manufacturing information in a neutral format using STEP technology in order to enable downstream users such as process planner and inspection planner to make correct decisions on process selection, processing conditions, etc. It is shown that by using STEP AP224 manufacturing information encompassing machining features, surface roughness, dimensional and geometric tolerances can be completely represented together with part geometry, which certainly contributes to successful implementation of CIM. 相似文献
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针对当前连续体结构优化所面临的有限元模型与CAD模型转换困难,产品设计意图和结构工艺在优化过程中难以保持等问题,研究了面向CAD系统的连续体结构形状与拓扑优化方法。通过分析CAD几何表达和CAE网格划分特点,采用欧拉网格和扩展有限元法,建立面向结构优化的CAD/CAE模型融合机制;而后基于连续体物质导数,推导了CAD直接建模操作敏度,驱动CAD实体模型进行结构形状与拓扑优化。在此基础上,针对操作敏度量纲不一致问题,采用速度场均匀化方法,修正操作敏度,以提高优化收敛效率。通过三维CAD实体模型结构优化实例,验证了上述方法的可行性和求解效率。 相似文献
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The purpose of this study is to establish a CAD (Computer Aided Design) system for research and development (R&D) of a new product. In the R&D process of a new product, the design objects are frequently redesigned based on the experimental results obtained with prototypes. The CAD/CAE systems (which is based on computer simulation of physical phenomena) are effective in reducing the number of useless prototypes of a new product. These kinds of conventional CAD/CAE systems do not provide a function to reflect the experimental results to the redesign process, however. This paper proposes a methodology to establish the CAD system, which possesses the engineering model of a designed object in the model database, and refines the model on the basis of experimental results of prototype. The blackboard inference model has been applied to infer model refinement and redesign counterplan by using insufficient knowledge of R&D process of new products. 相似文献
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装配顺序规划是研究和开发计算机辅助装配工艺设计系统,实现产品装配设计过程和装配工艺设计过程有效集成的关键技术。研究了CAD模型中装配设计信息提取、子装配体识别法和拆卸法综合应用的装配顺序规划、基于装配结构树的装配设计与工艺集成数据接口的定义等相关技术。在这些研究的基础上,借助国产三维CAD平台CAXA的二次开发平台和XML技术,对以上技术进行了实现。最后,以电机产品为研究对象,给出了相关实例。 相似文献
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面向对象的CAD/CAM集成技术的研究 总被引:1,自引:0,他引:1
将面向对象方法应用于CAD/CAM集成的研究,提出面向对象的CAD/CAM集成的思想和方法;利用面向对象方法建立够集成产品设计和制造信息的产品定义模型-面向对象的产品定义模型,集成表达零件的设计,工艺规划,数控编程等活动所需信息,在此基础上开发CAD/CAM集成系统。介绍利用该思想方法所开发的回转类零件CAD/CAM集成系统。 相似文献
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通过对数控加工中自动编程和手工编程各自的优势及使用条件进行对比,指出了CAD/CAM技术已经广泛应用于各行各业,是加速产品更新、提高产品质量和增强市场竞争力的强大工具.以工件星轮的CAD建模过程和CAM加工过程作为例证进行分析,给出了如何运用CAD/CAM软件生成产品三维模型,刀路轨迹,加工程序及进行产品加工的整个过程,指出了计算机辅助造型及辅助制造的关键技术及操作过程,表明现代企业进行产品加工中使用CAD/CAM技术的必要性,并给出了建模、仿真、加工各个过程的细节问题及注意事项,为数控加工爱好者使用为CAD/CAM过程提供了一种研究方法. 相似文献
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Hong Lu Zhi Liu Shaojun Wang 《The International Journal of Advanced Manufacturing Technology》2014,73(1-4):209-227
Nowadays, the demand for high-quality enveloping surface parts is increasing in machinery, aviation, military, and many other fields. Given the complexity of the surfaces, the enveloping surfaces parts are usually processed by grinding method. This grinding process is low in precision and poor in efficiency for lack of accurate digital CAD model of these parts. In this paper, a new modeling method for the complicated enveloping parts has been developed. The digital CAD model is constructed by using vector representation, transformation matrix, and spatial meshing theory. Next, a better computerized numerical control (CNC) machining code is generated based on the accurate digital CAD model, and a high-quality envelope surface could be machined on the basis of the code in CNC machining center. The normal vector algorithm is adopted to detect and avoid collision and interference during the processing. Finally, the digital CAD models of a planar double-enveloping worm and worm wheel famous at difficulty in modeling and CNC machining have been conducted as an instance. The machining experiment results show that the machining precision of the enveloping surface parts have been increased because the part’s digital CAD model is extraordinarily accurate. 相似文献
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R. T. Lee W. S. Cheng 《The International Journal of Advanced Manufacturing Technology》2002,19(5):313-317
When working with a computer-aided design system (CAD), it is often necessary to rescale a geometrical model. CurrentCAD software
packages can provide only one scale factor for all three axes or one scale factor for each of the three axes. Therefore, difficulties
arise when more than one scale factor is required in any of the three axis directions.
In the shoe industry, a sample shoe sole is first designed for each shoe style. This sample sole is used as a standard for
grading (scaling) for every size of shoe soles. This grading process must scale the sample sole by different factors in different
zones. Thus current CAD systems cannot be applied.
A multizone scaling method is presented to satisfy this need. Engineers create a set of 3D B-spline curves for the sample
shoe sole using a CAD system. This method then divides the CAD geometrical model into several zones in each of the X-, Y-,
Z-axes and each zone is given a scaling dimension (value) to generate a new CAD geometrical model. A CAD geometrical model
for every size of shoe soles can be produced by this multizone scaling method. 相似文献