汽车覆盖件自由曲面特征识别算法研究

特征技术应用于汽车覆盖件冲压工艺CAPP系统被认为是提高汽车覆盖件制造水平,并逐步实现CIMS的关键.应用特征识别技术,从CAD系统中识别出CAPP系统所需要的信息,将为工艺设计提供丰富的信息.通过汽车覆盖件自由曲面特征识别技术研究,提出了一种新的基于规则的特征识别算法,实现了从自由曲面模型识别出两种最基本的特征,孔类和翻边类特征.以UGII软件为平台,开发了汽车覆盖件零件模型自动特征识别功能,基本上解决了基于特征的覆盖件冲压工艺CAPP系统信息输入问题.     

基于分级规划的工艺决策策略与模型

论述了基于分级规划的工艺决策策略,并将其与黑板推理策略结合在一起,构造了基于分级规划与黑板推理的工艺决策模型。该策略将工艺决策这个复杂问题分解成一定数量和易于求角的不同性质的子任务,分别用不同的推理机进行求解,从而简化了推理机的结构。     

CAD/CAPP/CAM集成系统的研究与开发

文章介绍了可实用的CAD/CAPP/CAM集成系统。该系统是由机械产品设计人员,工艺人员和数控机床NC编程人员共同努力,在商品CAD/CAM软件Pro/ENGINEER平台上开发的。系统由三个子系统组成：零件信息识别子系统,CAPP子系统和自动CAM子系统。零件信息识别子系统从三维零件中提取零件信息,CAPP子系统分析零件信息,自动生成零件加工工序和工步,从刀具数据库中查询刀具及切削用量,并完成各工序的工步排序。自动CAM子系统根据CAPP的结果,自动生成Pro/ENGINEER的NC工步,经过NC仿真后     

轴瓦类零件的CAPP系统开发

本文介绍了一套适用于轴瓦行业的CAPP系统。叙述了基于工序代码优先数和工艺决策自动生成轴瓦类零件的加工工艺以及基于GT代码和工序图特征图形要素库自动生成轴瓦零件加工工序图的方法。     

汽车覆盖件冲压工艺CAPP系统特征建模技术

特征技术应用于汽车覆盖件冲压工艺CAPP系统被认为是提高汽车覆盖件制造水平,并逐步实现CIMS的关键.为此,本文对汽车覆盖件进行了特征分类,建立了面向CAPP系统的覆盖件特征表达模式.以UGII软件为开发平台,提出自动识别孔类特征算法,采用交互式特征识别方式识别其他特征,建立了覆盖件特征模型,解决基于特征的覆盖件冲压工艺CAPP系统信息输入问题.     

LGTIM—CAPP：集成化工艺设计及管理系统

分析了当前机械制造企业在工艺设计及管理中存在的一些典型问题,提出了相应的解决措施,研制了一种集成化工艺设计及管理系统ＬＧＴＩＭ－ＣＡＰＰ。该系统能与编码系统、产品数据管理（ＰＤＭ）系统相结合,实现设计、工艺与制造信息的集成与共享。     

基于本体论的工艺信息描述方法研究

依据本体论的概念论述了零件信息和制造资源信息的描述方法,给出了它们本体的定义方式。描述了零件本体和特征本体的属性,分析了各本体间和本体属性间的关系。以开发的CAPP系统为例,阐述了此描述方法在实际应用中体现出的特点。     

Automated generation of NC part programs for turned parts based on 2-D drawing image files

This paper describes a novel method for automated generation of process plans and numerical control (NC) part programs from 2D drawing image files. Four algorithms are introduced in this paper. First algorithm deals with extraction of geometrical data, second algorithm used to recognise turned features from the extracted geometrical data base. Recognised features are then passed to third and fourth algorithms for generation of process plans and NC part programs respectively. Using proposed system, it is possible to achieve fully automation of recognition of turned features, generation of process plans and NC part programs. Thus, it becomes possible to go from scanned image to finished product in a fully automated fashion. These algorithms have been implemented on mini-computer to process image data, and display recognised turned features, process plans and creates output files containing NC part programs. These NC part programs are verified through CNC train simulation package. The results are satisfactory.     

A combinatorial optimisation approach for recognising interacting machining features in mill-turn parts

Feature interactions may result in many process alternatives in part machining. Traditional process planning methods only identify one of the options, which is usually not optimal in the sense of engineering. This paper presents an optimisation approach to handle the interacting feature recognition problem in mill-turn parts. The approach subdivides the material removal volume into cells first and then it combines the cells into features. Here, a two-level cell combination method is developed. On the lower level, individual features are formed by searching the combinations of cells near a given part face; on the upper level, the feature distributions are explored by rearranging the order of part faces for feature formation. In order to optimise the feature distribution, a novel optimisation model is proposed, which quantitatively distinguishes its options by considering the factors of feature numbers, tool approaching directions, cutting directions and surface roughness. The combinatorial optimisation problem is solved with the simulated annealing algorithm. Instead of searching cell combinations directly, the proposed method explores different part face sequences, which drastically reduces the search space. The case studies show that the proposed approach can effectively handle the traditional difficulty in recognising the interacting features for mill-turn parts.     

多层并行分布式CAPP和PPC集成方法

针对多品种小批量车间作业型企业的工艺计划和生产计划的整体优化，提出了支持功能集成的多级并行分布式ＣＡＰＰ和ＰＰＣ集成的体系结构，给出了一种基于集成平台的系统实现方法和产品层原型系统的具体实现。     

基于TAD聚类的零件装夹规划方法研究

为实现零件加工时的自动装夹分组及定位面、装夹面的自动选择,从定义特征、加工面、装夹方案及它们之间的关系出发,采用聚类的思想求解装夹规划问题.在划分加工阶段的基础上,提出用"找相同元素法"获得刀具进入方向(TAD)相同的特征组合.对特征——TAD矩阵做变换,得到TAD可行解,进一步对TAD可行解寻找装夹面、定位面,并生成装夹可行解,即可形成装夹方案.以CATIA平台为基础,用CAA开发软件验证了该方法的可行性.该方法对实现零件的装夹分组有重要作用.     

基于NX平台的级进模工艺自动化设计中的关键技术与软件系统研发

目的 开发一套基于NX平台的自动化级进模工艺设计系统,提升工艺设计的自动化水平.方法 基于工艺结构一体化的思想,采用自动化特征识别、工具体记忆特征和折弯中性层展开等技术,实现自动化的工艺设计.结果 在NX7.5平台上,以格力空调外机右侧板为例进行测试,完成工艺设计大约耗时10 min左右,生成的工艺信息可以用于后续的模板模架生成、冲头调用和标准件排配等模块,实现了自动化的结构设计.结论 基于特征识别等技术研发的自动化工艺设计系统,显著提高了设计效率,缩短了模具设计周期.     

基于成形过程的钣金特征识别与工序排配

目的在工序排配中引入特征识别技术,提高工序排配的自动化水平。方法提出了一种基于成形过程的钣金特征识别与工序排配的方法,先在最终的产品零件上进行钣金特征识别,然后按照工序步骤反向逐步进行中间工序设计,形成最终工序排配方案。结果在NX11平台上,以微波炉门体为例进行测试,该方法完成工序排配大约耗时5min,每序设计结果能用于辅助该序数字化模具的生成。结论基于成形过程的钣金特征识别与工序排配,显著提高了工序排配的效率,降低了钣金模具设计的周期。     

基于特征的机械产品分类编码系统设计

介绍了一种基于特征的机械产品分类编码系统,阐述了分类编码的内容和原则,描述了编码的结构,给出了各码位所代表的零件特征信息,并以某一气门产品为例介绍了这种编码系统在实际中的应用.     

Automated extraction of dimensional inspection features from part computer-aided design models

Metrological inspection planning is among the least explored computer-aided process planning (CAPP) domains. This paper examines the basic issues involved in automated dimensional inspection planning that works within an environment of a generic CAPP support system. A new algorithmic approach based on multi-attributed spatial graphs is developed for extracting inspection features. The features of specific interest to the planner are selected by applying a sequential filtering method. The method is capable of extracting many common types of inspection features (polyhedral, cylindrical and free-form) found in industrial practice.     

基于AutoCAD平台下装配图明细表生成系统的开发

提出了在AutoCAD平台下装配图的明细表系统的算法及开发过程,从而实现了装配图明细表管理过程的自动化和智能化,提高了设计效率,保证了图纸信息与明细表的汇总信息高度一致,因而更有利于实现计算机辅助工艺设计(CAPP).     

基于工序能力指标的工序公差优化设计研究

在分析了现有的工序公差优化设计模型基础上,提出了一种基于工序能力指标最大化的工序公差优化设计模型,并采用功效系数法将多目标规划转换成单目标规划,对于实现工序公差的稳健设计、提高CAPP 的质量,有重要意义。     

基于网络与数据库的多任务并行CAPP集成平台

分析了传统ＣＡＰＰ系统存在的不足和原因,提出了基于网络与数据库的多任务并行ＣＡＰＰ集成平台的解决方案,介绍了该集成平台的网络结构、模块框图、基本功能和主要特点。     

Feature-based geometric reasoning for process planning

We present a framework based on Domain Independent Form (DIF) features for automatic evaluation of manufacturability and process planning for machining. The framework enables interpretation of a common product model with respect to each task in the transition from design to manufacture. A key idea here is to generate the interpretation suitable for each task in two steps. In the first step, DIF features that are defined through feature enumeration are automatically extracted from the geometric model. The extracted DIF features are then mapped into features meaningful for individual tasks through geometric reasoning based on domain dependent knowledge. The formal approach to feature definitions and separation of the domain specific reasoning from the general geometric reasoning enable us to overcome the bottlenecks reported in features technology. Work reported in this paper has been funded in part by grants from Aeronautical Development Agency and the Department of Science and Technology.