基于特征的CAD／CAPP／CAM集成方法研究

基于特征的ＣＡＤ／ＣＡＰＰ／ＣＡＭ集成是ＣＩＭ实现的核心技术之一。本文从特征在集成环境各子系统中的功能角度，探讨了特征分类，表示和模型转换等关键问题，将面向对象技术应用于特征分类，解决了特征库的可扩充性问题。在特征的表示中提出了大小尺寸、位置尺寸和约束等组成要素，并运用测量实体存储设计者意图。在特征模型转换过程中运用人工智能技术的模糊推理方法实现基于假设的加工特征识别，提高了识别的准确性和自动化程     

CIMS 环境下基于特征的产品模型

ＣＡＤ／ＣＡＭ是ＣＩＭＳ的核心,基于特征的产品模型是实现ＣＡＤ／ＣＡＭ集成的关键。本文通过分析典型ＣＩＭＳ中工程设计分系统功能模型,给出ＣＩＭＳ环境下ＣＡＤ／ＣＡＭ产品特征模型。     

回转类零件 CAD/CAM 并行设计的建模技术

介绍了基于并行设计理论实现ＣＡＤ／ＣＡＭ集成的回转类零件并行设计系统ＤＰＭ－Ｔ的体系结构和零件全局数据模型和系统控制模型的建立。讨论了ＤＭ特征分类，表达方法和零件可制造性评价等问题。     

特征建模技术在汽车制动阀CAD／CAM集成中的应用

简述特征建模技术及基于特征的ＣＡＤ／ＣＡＭ集成方法。以汽车制动阀阀体为例介绍利用特征建模技术对现有的制动阀ＣＡＤ系统进行改造从而实现ＣＡＤ／ＣＡＭ集成的思想，重点介绍利用特征文件作为面向加工的统一的产品定义模型的方法。     

集成CAD／CAM的并行特征技术

特征技术是实现ＣＡＤ／ＣＡＭ集成的关键、本文讨论了特征技术在集成ＣＡＤ／ＣＡＭ中的并行设计方法和途径。     

回转类零件CAD／CAM并行设计的建模技术

介绍了基于并行设计理论实现ＣＡＤ／ＣＡＭ集成的回转类零件并行设计ＤＰＭ－Ｔ的体系结构和零件全局数据模型和系统控制模型的建立，讨论了ＤＭ特征分类，表达 零件可制造性评价等问题。     

回转体零件CAD/CAM集成系统

回转体零件ＣＡＤ／ＣＡＭ集成系统采用特征造型技术建立统一的产品信息模型,实现ＣＡＤ／ＣＡＰＰ／ＣＡＭ的高度集成。ＣＡＤ模块用特征造型方法完成零件的设计,建立零件的特征模型,ＣＡＰＰ模块根据零件的特征模型自动生成零件毛坯,缺点工艺路线。ＣＡＭ模块完成睡线的规划、刀夹具的选择、切削参数的确定。ＡＰＩ模块生成ＮＣ代码。仿真模块模拟毛坯的加工过程,检测干涉和ＮＣ代码的正确性。ＮＣ编辑模块地ＮＣ代码的编辑和     

基于特征的CAD／CAPP集成模型

实现ＣＡＤ／ＣＡＰＰ集成，是实现ＣＩＭＳ信息集成的关键。本文提出了以统一的特征模型为核心，使得ＣＡＤ、ＣＡＰＰ共享此特征模型信息，减少信息的重复输入，省去其间的数据转换，用面向对象技术实现真正意义上的ＣＡＤ／ＣＡＰＰ集成。该研究为实现并行工程环境中ＣＡＤ／ＣＡＰＰ的集成，提供了一种实现模式。     

面向CAD／CAM集成的产品特征模型研究

产品特征建模是ＣＡＤ／ＣＡＭ集成的基础。本文提出了基于特征的产品定义模型。描述了回转体零件的特征类库，讨论了精度信息和其它非形状信息的表达方法以及它们与形状信息之间的关系，使ＣＡＤ／ＣＡＭ集成的实现成为可能。     

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。     

Robustness and generality issues of feature recognition for CNC machining

The problems of multiple interpretations and feature interactions that occur in attributed adjacency (AA)-based feature extraction systems result from a lack of robustness in the recognition algorithm when deviations from the feature definitions occur. This stems from the fact that individual graphs are stored in the feature taxonomy and once multiple graphs interact the interaction issue occurs. In this paper, a new method is presented for defining features based on a type of hint-based taxonomy, which is rare in boundary representation schemes. This new method still uses the traditional AA graph and matrix to define the part but does not extract subgraphs. It is shown that identifying only one face and then proceeding can find a feature. The modified attributed adjacency (MAA) scheme is used to define the part which allows more information to be stored in the part representation (graph or matrix), and this allows multiple interpretations to be solved.     

Extraction of machining features for CAD/CAM integration

Feature-based CAD/CAM integration is a technology used to realise automatic transmission and conversion of component information among CAD, CAPP and CAM applications. A feature is the medium of information transmission in the integration. Since a process planning downstream application has a different viewpoint from the component designer, feature conversion or feature extraction methodology is used to create a machining feature model based on the design feature model. One of the major difficulties in generating machining features is the preservation of feature integrity because of feature interactivity. The most current research, therefore, focuses on the planar-type form feature conversion. This paper discusses the problem of feature interactivity and proposes a feature-based approach to generating hole-series machining features from a design feature model. Hole-series features are important machining features for gearbox components used in machine tools. These kinds of features cannot be obtained directly from a design feature database. A constraint-based method is developed in this paper to define a hole-series feature model based on the geometric and topological information extracted from the design database. In addition, a STEP file is generated to interface the converted machining feature model with the downstream CAPP application. The implemented feature conversion system is verified by considering its application to some component examples and the developed prototype CAPP system. This revised version was published online in October 2004 with a correction to the issue number.     

CAD/CAM集成系统中的特征分类与描述方法研究

特征分类与描述是实现基于特征的ＣＡＤ／ＣＡＭ系统集成的关键技术之一,本文从面向制造系统的角度出发,根据实际需要提出了基于特征族的特征分类方法,并对在特征造及特征识别阶段由于对特征概念理解上的差异所带来的问题进行了探讨,提出了相应的特征描述方法,充分满足了产品生命周期各阶段对特征描述的需要,解决了特征的可扩展性问题。     

回转类零件 CAD/CAM 并行设计中的零件结构设计

主要介绍回转类零件基于ＣＡＤ／ＣＡＭ并行设计的零件结构设计方法，把参数化设计和特征拼合设计结合起来，以实现结构设计和制造信息的集成。文中叙述了基于特征的零件结构设计过程，参数化设计的基本方法，以及参数化结构设计结果向特征模型的转化的有关问题。     

基于CAD/CAM集成的特征系统研究

详细讨论了自行开发的基于CAD/CAM 集成的特征系统,介绍了该系统的体系结构及基于特征的零件信息描述方法,并给出了在Solid Edge 系统基础上开发的特征造型与特征识别系统的功能及其实现过程。     

Extraction/conversion of geometric dimensions and tolerances for machining features

It is important for a feature-based system to preserve feature integrity during feature operation, especially when feature interaction occurs. The paper presents a feature conversion approach to convert design features used in a design model into machining features for the downstream applications. This process includes both form features (geometric information) and non-geometric features conversion. Most researchers have concentrated on geometric information extraction and conversion without tackling the important problem of non-geometric feature information. This paper focuses on the extraction and conversion of feature geometric dimensions and tolerances (GD&T) for downstream machining application.The main barrier to the integration of a feature-based CAD/CAPP/CAM system – feature interaction – is discussed in this paper, which alters design features in their geometries and non-geometric information. How to identify and validate these feature dimensions and tolerances is one of the key issues in feature interaction conversion. The development of robust methodologies for preserving feature integrity for use in process planning application is the main thrust of the work reported in this paper.     

特征识别技术及其在冲压领域的应用

针对冲压零件 ,尤其是带体积成形的冲压件的特点 ,在总结特征识别方法的基础上 ,提出了一种新型的冲压特征识别算法 ,并对特征识别中的难点——特征相交问题提出基于痕迹的冲压件相交特征识别方法。     

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。     

CAD/CAPP集成中的精度信息建模研究

精度信息是CAD／CAPP集成系统产品信息模型中不可缺少的重要组成部分,而精度信息的描述与建模是实现CAD／CAPP／CAM集成的瓶颈问题之一。本文在深入研究产品特征模型中精度信息及其表达的基础上,进一步提出将精度信息作为形状特征的附加属性,并通过引用几何链表将二者集成起来,形成一个能满足集成CAD／CAPP／CAM需要的产品信息模型。进而,详细探讨和实践了特征信息模型的处理方法,采用共享特征数值库存贮特征信息,并利用基于ObjectARX的数据库接口ASI（AutoCAD SQL Interface）技术的数据库的双向操作功能实现了CAD／CAPP各系统间的数据交换与共享,使CAD／CAPP在真正意义上的信息集成成为可能。