钣金零件的特征设计

在分析了钣金零件的特点和要求的基础上,利用特征技术来组织和描述产品模型,并且以ＡｕｔｏＣＡＤ为平台,实现钣金件的设计。     

基于特征的钣金零件信息模型的研究

特征建模是ＣＡＤ／ＣＡＭ系统集成的基础,本文针对钣金类零件,描述了特征的分类及其联系,提出了一个基于特征的钣金零件信息模型,并采用面向对象的建模技术来表达及组织特征,使ＣＡＤ／ＣＡＭ集成的实现成为可能。     

ARX开发环境下基于MDT API开发CAD／CAPP／CAM集成系统

本文研究了在ＭＤＴ软件平台上开发ＣＡＤ／ＣＡＰＰ／ＣＡＭ集成系统的方法,基于ＡｕｔｏＣＡＤ ＡＲＸｔ ＭＤＴ ＡＰＩ二次开发环境建立了特征建模系统七发工具,在此基础上实现了箱体类零件ＣＡＤ／ＣＡＰＰ／ＣＡＭ的集成系统。     

钣金零件 CAD/CAPP 集成化信息模型的研究

特征建模技术已被认为是实施ＣＡＤ／ＣＡＰＰ／ＣＡＭ集成最有效的手段之一。针对钣金零件的特点，提出了基于特征的钣金零件集成化信息模型的建模方法及其结构。     

钣金零件CAD／CAPP集成化信息模型的研究

特征建模技术已被认为是实施ＣＡＤ／ＣＡＰＰ／ＣＡＭ集成最有效的手段之一。针对钣金零件的特点，提出了基于特征的钣金零件集成化信息模型的建模方法及其结构．     

基于特征的轴类零件信息生成系统

针对轴类零件,分析了创成式ＣＡＰＰ系统中工艺决策所需的基础数据———零件信息,研究了零件设计特征与制造特征的区别及制造特征所包含的内容。对轴类零件的特征进行了合理的分类,并介绍了特征之间的关系,由此阐述了特征建模的方法。介绍了在ＡｕｔｏＣＡＤ 二维图形环境下开发的基于特征的轴类零件信息生成系统及其数据结构和系统信息流程,设计了零件信息的输出格式。该系统实现了二维图形环境下的ＣＡＤ／ＣＡＰＰ的集成。     

基于特征的轴类零件信息生成系统

针对轴类零件，分析了创成式ＣＡＰＰ系统对工艺决策所需的基础数据－零件信息，了零件设计特征与制造特征的区别及制造特征所包含的内容。对轴类零件的特征进行了合理的分类，并介绍了特征之间的关系，由此阐述了特征建模的方法。介绍了在ＡｕｔｏＣＡＤ二维二维图形环境下开发的基于特征的轴类零件的信息生成系统及其数据结构和系统信息流程，设计了零件信息的输出格式。该系统实现了二轴图形环境下的ＣＡＤ／ＣＡＰＰ的集成。     

冲模CAD系统零件图形信息的自动获取

介绍以ＡｕｔｏＣＡＤ为图形输入器的冲模ＣＡＤ系统图形信息自动获取的原理，叙述了从无序的ＡｕｔｏＣＡＤ图形中生成模具设计所需的零件组环数据信息的方法。     

基于特征的钻模板 CAD/CAM 系统的开发

分析机体零件、钻模板零件的特点,以并行工程为指导,利用ＩＤＥＦ０方法和面向对象的特征信息建模方法分别建立起系统的功能模型和全局的单一的数据模型,定义相应的基本特征、阵列特征、数控加工特征、特征数控段,使所建立的数据模型将设计特征和制造特征统一在同一特征定义中,从而为本ＣＡＤ／ＣＡＭ系统内部数据的无缝集成打下基础。最后,在ＡｕｔｏＣＡＤ１４上,用Ｃ＋＋语言实现了本系统。     

基于B－rep表示的机械零件工作图尺寸标注的智能化

基于实体造型和特征造型技术，对机械零件工作图尺寸标注智能化进行了系统的研究．建立了尺寸标注综合模型，论述了尺寸标注冗余性判断基本原理，将神经网络、特征识别和尺寸键技术相结合，确定零件的尺寸标注方案；采用了基于范例推理（ＣＢＲ）的方法完成了零件标注尺寸的自动市置，最后通过ＡｕｔｏＣＡＤ输出零件工作图．     

[成形质量的闭环与自适应控制技术]具有开放几何特征钣金件渐进成形的回弹控制与补偿

实现了具有开放几何特征钣金件的渐进成形。提出采用工艺参数优化、多道次渐进成形和轨迹补偿等方法提高钣金件的几何精度。设计了多道次渐进成形方法的中间构型,目的在于增大材料塑性变形并减小几何偏差。采用层切法轮廓轨迹形成两道次成形中第一道次的构型,为了防止第一道次成形时出现破裂,将非固定方向的成形角度设定为75°,第二道次将非固定方向的板料完全成形。采用基于几何补偿的两道次渐进成形方法可以将开放几何特征钣金件的几何偏差控制在0.5 mm左右。     

钣金件的工艺过程自动生成系统

介绍了钣金件的工艺过程自动生成系统。该系统直接从ＣＡＤ系统获取零件的有关信息，采用零件特征自动识别的方法来实现ＣＡＤ／ＣＡＰＰ的信息集成，自动生成零件的特征编码，利用工艺知识库，通过分级推理，自动完成零件的工艺过程设计。     

基于制造约束的钣金零件结构工艺性评价

在基于特征的零件模型基础上,建立了制造约束与钣金零件特征之间的关系,对钣金零件的制造约束类型进行了归纳,并给出了相应的钣金零件结构工艺性评价方法。     

并行工程环境下钣金零件面向制造的设计

提出了并行工程环境下面知制造的设计方法（ＤＦＭ）,以钣金零件为实例,建立了原型设计系统,并采用了特征技术和人工智能技术以及面向对象的方法。其中主要解决了钣金件基于特征的产品建模和面向对象的知识表达以及零件早期设计的ＤＦＭ 评价。     

Generating Alternative Interpretations of Machining Features

One of the major difficulties in extracting machining features is the lack of a systematic methodology to generate alternative ways of manufacturing a machined part. Most of the early research in feature extraction and process planning has not considered this aspect, and has focused on the generation of a single interpretation. In this paper, we propose a feature-based approach to generating alternative interpretations of machining features from a feature-based design model. The proposed approach simplifies the generation of alternative machining feature models by using information on feature which is captured and maintained during feature-based model-ling and machining feature extraction. A set of machining features is incrementally extracted during the feature-based design process of a machined part. A feature conversion process converts each design feature into a machining feature or a set of machining features by using information on the geometry and the feature. Using reorientation, reduction, and/or splitting operations, alternative models are generated from the sets of extracted machining features. During the execution of each operation, unpromising models are pruned by using criteria such as minimising the number of accessibility directions. The machining features and their precedence relationships are represented in a STEP-based machining feature graph for the purpose of data exchange.     

Indexing and retrieval in case-based process planning for multi-stage non-axisymmetric deep drawing

This paper presents a case-based reasoning (CBR) methodology for computer-aided process planning (CAPP) for multi-stage, non-axisymmetric sheet metal deep drawing. The methodology addresses the indexing and retrieval of process planning cases. Planning cases are indexed via a feature-based representation of deep drawn parts. Efficient case retrieval is achieved by a feature-based similarity analysis between a new deep drawn part and existing parts in the case library. An illustrative example is included to demonstrate the operation of the proposed approach and show its effectiveness in speeding up CAPP for multi-stage non-axisymmetric deep drawing. This revised version was published online in April 2005 with a correction to the corresponding author’s address.     

Challenges of manufacturability and product data management in bending

Effective production in a networking environment of sheet metal products needs accurate and relevant PDM (product data management) data, appropriate modeling of components supported by local and global network solutions, and utilization of advantages of feature-based modeling. To enable these aspects of effective production in sheet metal production, it is necessary to evaluate the integration of DFMA (design for manufacturing and assembly) and PDM. This paper aims at identifying the challenges of DFMA and PDM integration through recognizing possible malfunctioning parts of their integration. The observations are based on sheet metal specimens in which the DFMA and PDM aspects are visible in punching and bending. This study will focus on five issues that are included either in DFMA or PDM, or both: the effects of different calculation methods for the flattened length, utilization viewpoints of global or local manufacturability guidelines, assembly conditions, options to tune the manufacturing process instead of changing the product geometry, and possible additional requirements given by the customers. Based on practical design and manufacturing tests, it has become evident that one option to improve the quality of analyzed sheet metal parts is to further develop the integration of DFMA features with the workshop’s cutting and punching parameters. As one possible improvement to these kinds of integration tasks of DFMA and PDM, it is suggested that the responsibilities for developing DMFA and PDM applications with proper design parameters could be analyzed more deeply between persons working with information exchange, product design, software design, or production machine design.     

焊枪头与钣金件空间间隙的自动检查

针对车身三维模型中焊枪头与焊点附近的钣金件之间空间间隙检查过程复杂、检查结果不准确等问题,提出了焊枪头与钣金件空间间隙的自动检查方法。在特征识别算法和包围盒技术的基础上获得焊点特征、钣金件特征和螺母特征等分析要素;基于三维模型的投影算法和距离测量算法计算钣金件的拓扑面与虚拟焊枪之间的距离,与安全阈值比较,筛选出与焊枪发生干涉的危险平面、孔和螺母;对焊接空间不足的焊点进行标注并截图。利用二次开发环境所提供的函数库编程实现了上述算法,通过运行实例以及企业的实际使用,验证了自动检查系统的可行性。