发动机缸体制造特征信息获取研究

在CAD／CAPP／CAM系统集成中，面向加工过程的产品制造特征信息的共享是急需解决的问题。在汽车发动机缸体CAPP专家系统开发中，利用Pro／E实现了产品几何特征信息的提取，利用Pro／Toolkit对Pro／E进行了二次开发实现了产品材料与加工特征精度信息的提取，同时利用EXPRESS语言将产品的非几何信息自动写入CAPP系统的底层Oracle数据库。对汽车发动机缸体CAD／CAPP专家系统数据共享问题进行了探求。     

发动机5气门缸盖制造特征信息获取研究

在CAD／CAPP／CAM系统集成中，面向加工过程的产品制造特征信息的共享是急需解决的问题。在汽车发动机缸盖CAPP系统开发中，利用Pro／E实现了产品几何特征信息的提取，利用Pro／Too1klt对Pro／E进行了二次开发实现了产品材料与加工特征精度信息的提取，同时利用EXPRESS语言将产品的非几何信息自动写入CAPP系统的底层Oracle数据库。对汽车发动机缸盖CAD／CAPP系统数据共享问题进行了探求。     

Machine path generation using direct slicing from design-by-feature solid model for rapid prototyping

This paper explains a new machine path generating system that its output is compatible with different rapid prototyping processes. The basis of this system is direct slicing from design-by-feature solid model. Slicing a computer-aided design (CAD) model through intersecting the model with the XY-plane at each Z increment is a well-known method of path generation. Slicing a CAD model is currently conducted through stereolithography (STL) file slicing, direct slicing, and additive direct slicing. A direct slicing approach inside a design-by-feature solid modeler is proposed. Autodesk Inventor solid modeler, as a design-by-feature solid modeler, is used for 3D solid modeling. The proposed system is implemented by Visual Basic codes inside Inventor. In this approach, first protrusion and subtractive features that form a model are extracted. Then, the intersection of each feature and the XY-plane is identified. Then, the internal and external loops are found. Depending on the specific rapid prototyping (RP) process requirements, internal or external hatch are also computed, respectively. Finally, a continuous path in required format is generated. The system reported in this paper has been successfully tested on several complex 3D models created in Inventor. The system offers customized output for different RP processes that need external or internal hatch pattern. The proposed approach for generating RP machine path through feature recognition inside design-by-feature solid modeler overcomes with the problems that are caused by imperfect STL files. Also, this system is capable of generating code compatible with major rapid prototyping processes.     

Automatic recognition of machining features from a solid model using the 2D feature pattern

Feature recognition systems are now widely identified as a cornerstone for conceiving an automated process planning system. Various techniques have been reported in the literature, but a few of them acquired a status of generic methodology. A flexible and robust approach is demanded for recognising a wide variety of features, e.g., non-interacting, interacting circular and slanting features. This research aims to exploit the concept of the ray - firing technique, in which a 2D surface pattern for each feature is generated and information is extracted from these patterns to correlate it with the corresponding machining features. The system first defines a virtual surface and then probing rays are dropped from each point of this surface to the 2.5D features of the B-rep solid model. According to the length of rays between the bottom face of the 2.5D machining features and the virtual surface, 2D feature patterns are formed for each machining feature. Finally, features are recognised using an algorithm described in this article. Different types of examples have been considered to demonstrate the effectiveness of the proposed approach.     

发动机曲轴箱制造中复杂特征识别实现

本文阐述了数字化工厂工艺规划系统中的特征识别原理和种类,着重研究了加工过程中的复杂特征及其识别方法.以发动机曲轴箱制造过程为例,说明该方法能有效解决数字化加工中CAD/CAM沟通难以及现有特征识别中存在的鲁棒性较差、复杂特征不易识别的问题.     

发动机凸轮轴的制造特征信息分析和建模

在对CAD／CAM技术及机械制造技术进行研究的基础上，针对发动机凸轮轴的结构和加工制造的特点，对其产品的制造特征信息进行了研究，重点分析了其凸轮外形轮廓，并应用Pro／Ensineer作为基础软件环境，实现了产品特征信息模型的建立，为凸轮轴的计算机辅助工艺过程设计(CAPP)提供所需的特征信息和加工数据。     

Protrusion recognition from solid model using orthogonal bounding factor

Feature recognition is important for describing shapes in many applications taking advantage of solid modeling. Graph-based feature recognition methods search from solid models the unique patterns of features that are represented as a graph. A typical example of such patterns is a loop of concave edges. When the loop is an inner loop on a single face, it is a strong hint of the existence of protrusion feature and recognition of protrusion faces is straightforward. However, when a protrusion feature lies on multiple faces, it is bounded by a loop of concave edges that are not on a single face. Consequently, the rule of inner loop is no more available and recognition of protrusion faces becomes unclear. To address this problem, a new quantitative measure, orthogonal bounding factor (OBF), is introduced. OBF is defined as the sum of cross products of two consecutive vectors normal to a set of faces, and it physically represents the possibility of being a protrusion in a solid model. The formal definition of orthogonal bounding factor is established and a method to recognize protrusion features using OBF is presented. Examples are also shown to demonstrate the effectiveness of the method for feature recognition.     

面向工业互联网平台的制造服务可信特征识别方法

制造服务是否可信是产品服务系统(PSS)应用的关键问题,工业互联网平台(IIP)的快速应用及部署为制造服务的可信接入提供了平台支撑.分析了传统的网络化制造平台与工业互联网平台下制造服务可信特征的区别和联系,围绕制造服务映射保真、服务信誉、协作状态3个方面,给出了制造服务综合可信特征指标体系,提出了工业互联网平台下的制造服务可信特征识别框架及其关键技术,设计了基于去噪自编码器的制造服务可信特征分类方法.最后以智慧物流的案例仿真验证了所提方法的有效性和优越性.     

制造信息系统仿真模型规划

制造信息系统是一个复杂系统,基于复杂性思维对系统演化模型的运行和评价过程进行了研究,建立了制造信息系统的仿真及评价模型体系,该模型体系包含仿真运行子系统、评价与预测子系统和IT规划子系统.模型的建立有利于系统的优化、设计和实施,具有协助制造企业对生产运作流程优化、实现生产过程的信息管理和监控一体化、辅助制造业信息系统的建设规划等功能,以使相应的制造企业能在市场竞争中取得发展.     

基于特征的零件信息模型

特征建模技术是CAD/CAPP/CAM集成的关键技术之一,特征模型使CAD、CAPP、CAM等系统共享统一的产品模型成为可能。文章介绍特征的概念和分类以及基于特征的零件信息模型的结构和构造方法。     

基于几何与公差信息的加工特征识别方法

为实现计算机辅助设计与计算机辅助工艺规划系统的有效集成,提出了一种同时利用几何信息和公差信息的加工特征识别新方法。建立了加工资源、加工表面和加工方法三类信息模型。提出了切削模式的概念及以之为基础的表面加工方法生成原理和过程。建立了表面加工方法优化选择模型。采用多目标模糊优化结合蚁群算法求解该模型,为每个加工表面选择最优加工方法,并将在同次装夹中采用同一刀具类型和加工条件进行加工的表面聚为加工特征。最后,通过实例测试,验证了该方法的正确性和有效性。     

制造信息系统概念模型的研究

制造信息系统是制造系统的抽象,制造信息系统中的制造信息在企业内部分为垂直的四个层次,每个层次的水平方向上又都有相应的制造信息相互作用,而不同的垂直层次之间的制造信息也相互作用,每一个层次又都与外界环境交互共同完成生产制造活动,形成一个立体多维的信息系统的体系结构。     

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。     

Automatic feature recognition from engineering drawings

Recognising features from 2D engineering drawings is one of the most important issues facing advanced integrated design and manufacturing. Although the problem of recognising features from a solid model has been extensively studied, most existing product models are expressed as engineering drawings. Moreover, the solid model can only provide complete 3D topological and geometrical data. Some essential machining information cannot be retrieved. In this study, an automatic transfer system is proposed with the capability of recognising linear swept features from engineering drawings. The swept profiles are first extracted from drawing views, then features can be identified from the swept profiles using a set of recognition rules. In addition to the feature types and their geometry, some annotations of drawings, e.g. dimensions and geometric tolerances, can also be recognised and attached to the recognised features by this approach.     

基于UG实体模型的特征信息提取技术研究

CAPP系统用“制造特征”来产生与零件加工探作相关的信息。然而,这些制造特征信息在传统的CAD系统中并没有明确的包含。本文尝试着集成特征识别技术和基于特征的设计技术实现从设计特征模型中提取出制造特征。而且,随着“全息模型”技术的发展,产品的三维设计模型中逐步包含了一些CAPP系统所必需的零件信息,如零件表面粗糙度、几何公差和基准等。本文也提出一种方法将它们从零件模型的工程数据库中提取出来。     

轴类工程图的零件特征识别技术的研究

提出轴类回转体的分层识别方法,该方法首先提出工程图的基本图元几何关系的描述;其次先识别出轴类图形如通孔、键槽之类的细节特征和折断线省略画法,然后去除它们;最后识别回转圆柱体.     

制造企业能源信息模型的设计与应用

为了支持制造企业精细化的能源管理,满足多维度的能源监控与分析需求,采用面向对象设计模式,建立了一套可复用的制造企业能源信息模型,包括支持分层组合的设备资源模型,表达能源流程关系的能源网络模型,描述能源运行状态的能源计量模型。基于本模型开发了能源管理系统并经案例验证,表明本模型实现了设备资源、能源流程、能源计量的抽象和解耦,能通过配置满足制造企业从设备资源、时间、量纲等维度分层能源监控与分析的需求。     

制造特征到夹具特征的映射研究

介绍了夹具规划研究中各种特征模型的应用，分析了进行特征转换的必要性，并着重探讨了零件制造特征与夹具特征间的映射问题。给出了该范畴中的特征映射的基本思路和算法，从而实现了不同特征模型之间的转换。     

异构三维CAD模型制造特征重构技术研究

针对异构CAD/CAPP/CAM系统的特征集成,提出一种异构三维CAD模型制造特征重构过程:确定基本形状特征分类,在此基础上构造设计特征库和制造特征库;通过基于产品数据交换标准(STEP)的特征识别技术实现异构三维CAD模型设计特征提取,并采用基于参数化二维图素多态耦合的特征识别方法,提高特征识别系统的代码重用性;运用成组技术建立制造特征族后,通过特征映射实现制造特征重构。