机械类外文文献重要的CAD/CAPP/CAM设计工作

重要的CAD/CAPP/CAM设计工作

在机械制造行业,随着产品的持续改进和升级,大量的技术规则需要完成设计工作。

面向对象的轴类零件特征模型的建立和特征信息模型箱部件数据结构,使用适当的CAD/CAPP/CAM系统是关键。零件模型的特点要求CIMS的体系具有高水平的部分描述几何学信息和相应的表达加工、测试、装配、分析和其他有关信息的功能,语言的过程中所描述的部分特征的几何语义信息的载体和桥梁作用的重要性已被越来越多的研究人员认识到。为达此目的,它被认为是CAD/CAPP/CAM集成范围的基于特征的零件信息模型,根据该模型在研发新一代基于特征的计算机辅助设计(CAD)系统是一种基本的办法来解决CAD/CAPP/CAM一体化的有效途径。

传统的工艺设计是由工艺师手边的各部分零部件一块一块的,设计过程具有多样性,并重复这个笨重的设计工作,设计周期长,难以适应市场的竞争机制。为了缩短生产准备周期、提高产品的生产质量，工艺分析、工艺设计及大部份的工作人员从繁琐的、重复的工作中解放，研究和开发推广使用计算机辅助工艺设计(CAPP)系统是一个基本的方法。CAPP系统能够极大地提高新产品开发、市场竞争力和适应力，有重要的社会和经济意义。CAD/CAPP/CAM集成技术,以满足我们的现代制造工程的发展。CIMS也是一个重要的组成部分,为此,我们在分析国内外现状的基础上,利用CAD/CAPP/CAM专家系统、数据库技术已成功地开发了一种基于特征的盒零件CAD / CAPP集成系统。该系统可以CAD/CAPP集成机器零件,拥有齐全的决策过程,并自动生成技术文件。

一个整体的系统计划：

很长一段时间以来,先进的CAD/CAPP/CAM是一个独立的国家的发展,无法实现自动之间通过系统和资讯的交流。计算机辅助设计(CAD)系统输出的设计结果是二维的工程图纸及相关技术文件,在机械加工工艺设计原则,通过手工CAD图纸到经常需要重新CAPP然后计算机数据不仅影响整个系统的设计开发效率,而且在数据转换和传递过程中,会减少可能导致错误的可靠性设计。

CAPP的部分信息输入系统,最佳的方式是实现CAPP计算机辅助设计(CAD)系统和直接传输的信息系统之间。然而,所需的信息和传统CAD系统的CAPP系统输出的信息是不完全相同的,不仅包含了零件几何信息,而且也包括部分的制造过程信息。解决这一问题的研究现状进行了详细的CAPP广泛的研究和深入的分析,在此基础上,我们建议发展基于CAD/CAPP集成系统的程序。

特征建模系统包括一个完整的CAD/CAPP子系统组成的两部分。几个核心功能模块及其子功能之间的工作关系如下:

(1)CAD特征建模模块的核心系统模块子系统是实现CAD/CAPP一体化的重要组成部分,主要完成部分的设计和信息的输入。在三维实体造型系统模块的基础上,构造特征与零件,并完成了一项特征交互技术通过资产分配。建成后,部分设计的数学模型,通过产生的特征信息数据库的CAPP系统联系在了一起。

(2)规则的推理过程决策模块,模块是另一个核心模块CAPP子系统。它的特点是信息数据库从最初的开始,所运用的策略是一个确定的流程规则知识库的工艺路线和工艺中推断出整芯的内容的系统。

(3)过程控制程序规则的知识库模块和数据库组成。控制程序和推理规则数据库模块之间的关系是数据库程序知识和技术规则等。这个模块是高度互动与用户交互模块,以允许用户修改或添加模块的过程的规则的相关知识。

(4)交互模块的用户界面，模块也可以与应用数据、修改数据库内容来交换,这是平台设计体现思维的旗帜。

(5)模块是手动建造过程的核心系统的CAPP子系统。它是基于规则推理模块的工艺路线,并对齐模块结构的三维实体模型特征建模部分产生二维过程图和过程的总结,内容和过程的自动填写标准或自定义过程卡,建立过程手册。

关键技术和解决方案：

虽然一些研究已经建立CAPP,但是有几个关键技术问题还没有令人满意地解决。这包括零件信息的描述与输入,使实现过程、流程图表和工艺文件自动。我们的CAPP系统和部件在设计过程中,提出并采取了一系列的技术策略,来完成三个核心模块的设计系统,以克服这些技术问题,使尽可能的设计开发的CAPP系统的功能是完美无缺的。

零件信息的描述和1输入：

进入部分信息有各种各样的方法,使CAPP系统直接从CAD模型提取零件信息的最好方法是,能去除大量数据的烦琐和低效率的手动输入。这一定是在CAD零件建模,除了通常的几何形状信息,但也加入过程信息。我们用来描述方法和输入特征建模的传达的信息的一部分,使用现有商品化CAD软件作为一种图形支持,根据预期的功能齐全的零件形状特征能处理,然后再加上配件制造信息,形成独具特色的信息。通过定义一个统一的特点的描述方法和特性的数据存储结构,一个统一管理的特点,并在此基础上设计建模部分的特征,初步将设计制造信息带入，形成部分的设计特点、后续的CAPP模块只要经过一定的决策过程,就可以很容易地读直接从特点、系统介绍了数据库的特征信息。

特征建模是计算机辅助设计(CAD)的部分子系统的功能设计、部分三维CAD模型几何过程设计和工艺信息的CAPP系统所必需的部分提供所需信息。如何提取的CAPP系统的零件信息技术，直接从计算机辅助设计系统的CAPP和技术上的难题的关键技术之一。该系统采用了CAD/CAPP集成的特征模型来解决这个问题。零件特征,包括几何形状信息和制造过程信息,数据在该系统通过以下的优化设计提供了依据。CAD设计的各部分不成功制造出了第一个三维CAD软件作为图形辅助软件,CAD设计的部分。在计算机辅助设计（CAD）过程中,函数部分所能加工的一系列的形态特征,在增加生产过程的信息。当零件CAD设计,完成的部分可以得到的几何描述的信息和处理信息的特点,这些几何特征的统一模型过程的记录和统一的数据库管理系统技术作为一种CAPP的信息来源为决策模块,使零件CAPP系统能存取信息。直接从计算机辅助设计(CAD)和实现中和的过程中得到。在已经以三维CAD设计的原零件、模块可以在原模型的基础上,建立几何特征模型。此外也能通过进入部分地人机交互信息,建立特征模型。

实施决策过程：

CAPP系统的核心技术是决策。CAPP状况的研究、分析和比较各种CAPP系统的实施过程中,发现的决策方法在过度追求的CAPP系统的自动化控制决策的过程并不是最好的。很长一段时间以来,CAPP目标系统已经取代技术人员开发自动化系统的指导,开发“自动”这一目标的CAPP系统的整合,虽然有专家的知识和经验,但公司经常需要使用一个较长的时间为数据的准备和系统调试,但也有很多训练,它会挫伤积极性的用户。此外,“自动”于其内部推理的CAPP系统和算法不是为用户经常提供未知变量的答案,当系统的实际情况和经验与用户系统的推理和决策不一致时，方法不是用户修改,用户将会对系统结构丧失信心。另外一点是，追求程序设计自动化将大大增加工作量，大量的数据和结构会更复杂,这些误差可能会导致软件增加对的潜在软件运用的可靠性。另一方面,工艺设计和动态的多样性。据统计,中国生产工厂现场,大约30%的工艺设计的实际生产能力和需求和修改现有的制造资源,才能得以实施。特别是在今天的更丰富,更大趋势的大批量生产,生产地有点小扰动(如设备故障,缺乏工具、生产计划变化等)往往带来不可预知的预处理方法的处理秩序和改变。

而现有的工艺设计过程,通常是一个产生了一个独一无二的路线为目标,改变工艺的规格要求繁琐的程序较长的和时间。这使得生产过程的顺序对生产现场的不可预测的变化在缺少足够的适应性和灵活性。使CAPP系统设计过程中的劳动强度减少，都具有良好的灵活性和适应性。在广泛研究，测试和技术专家与工厂再三讨论的基础上,提出了一种结构框架CAPP子系统。在这个系统中,实现决策过程的基础上,利用生产实际的非线性过程采用有向无环图的设计方法。非线性特征,主要体现在对结果系统提供的多选择:为每个部分提供了若干优化的工艺路线。第一个要考虑的优先级最高的过程秩序,不申请的情况下,如果进程的订单情况的生产现场被遗弃的,然后第二个优先级别的技术规定将会被考虑,所以重复这个过程持续下去,直到一个满意的点上的描述指令。技术和建模的决策过程,能使生产过程计划,以满足动态变化。依照本决策过程指导设计模块自动生成工艺路线,用户可以根据实际生产生活的资源(如机床设备、加载速率、目前在保修期间等),该过程用于植物分类与选择中涉及的工艺路线,以达到一个平衡的系统的自动化和适应性。除了自动生成过程,该系统可以提取规则,在这个过程中产生有用的信息,不断增添工艺数据库。

用户也可以输入过程存在的秩序数据库。在设计过程中,根据零件的相似性的原理产生的工艺规则已经被召唤,稍微修改,或直接使用,这样就避免了重新设计,以节省时间。

地图和处理自动生成的过程文件

过程和文件地图是一个重要的组成部分。如果在CAPP系统,利用计算机自动生成和绘画图,将大大提高过程效率的工艺设计。作为过程从空白成品的形状、大小、变化过程、过程地图将必须反映这个动态过程后,在一个特定的瞬间(每道工序)的一部分,这部分的形式是多种多样的,每个过程的一部分,可以有不同的秩序,所以很难生成一个固定的方式来处理的地图。这使得CAPP系统开发过程中,发展成集绘图软件困难的工作。为了解决这个问题,我们开发了一种技术档案代子系统和子系统特征建模与CAD/CAPP子系统集成决策过程作为一个整体。子系统包括：

(1)过程中产生的决策子系统的数据文件输入过程数据；(2)根据进口的过程数据和特征从CAD三维建模系统子系统部分数据,通过分析和处理,生成二维过程图象；(3)生成一个完整的工艺文件；(4)后处理,如修改的观点,在这个过程中文件,加上特殊的内容。程序自动生成的地图CAPP技术是其中的关键。经过大量的研究,决定利用三维CAD软件的二次开发接口,采用观察矩阵系统开发方法,建立智能化管理过程的面向对象的图形渲染子系统。该系统可以根据工艺决策过程产生的部分模块的线条,参数设置智能地生成过程图,显示结构框架。该系统能从CAD模型的特点、工艺设计方面的资料和标准图形库,以得到必要的数据和信息,自动生成过程的计划和相应的工艺卡。你也可以从人机交互设计师所产生的过程和工艺过程卡片编辑修改计划。CAD/CAPP/CAM集成制造是一个热门的领域，这是很重要的CIMS工程的关键。在本文中,CAD/CAPP集成系统,通过数据集成,使CAD/CAPP的信息交流和反馈,并在CAPP系统设计采用非线性工艺设计的方法,以观察矩阵智能图形生成过程的技术策略,使系统具有更尽善尽美的为CAD/CAPP集成系统提供了一种切实可行的方法,同时也为先进的CAD/CAPP和CAM提供进一步整合的实践经验。

The Important CAD/CAPP/CAM Design Work

In the machinery manufacturing industry, as the product of continuous improvement and upgrading, a large number of technical rules need to complete the design work.

Object-oriented feature model of the shaft parts and the establishment of box parts feature information model data structure, use of appropriate CAD / CAPP / CAM system is the key. Requirements of part modeling features of CIMS system with a high level description of the part geometry, topology information and the corresponding expression processing, testing, assembly, analysis and other information about the function of the process of language features as described in part geometric topology of semantic information the carrier of its role as a bridge to the importance of researchers has been increasingly recognized. To this end, it is recognized as a CAD / CAPP / CAM integrated range of feature-based part information model, based on this model in developing the next generation of feature-based CAD system is a fundamental solution to CAD / CAPP / CAM integration effective way.

The traditional process was designed by the technologist on the parts by hand carried piece by piece, the design process out of the diversity, and repeat the cumbersome design work, design cycle is long, difficult to adapt to the market competition mechanism. In order to shorten production preparation cycle, improve the quality of process design, process design and make the majority of staff from the tedious repetition of the work of liberation, research and development and promote the use of computer assisted process planning (CAPP) system is a fundamental way. CAPP System can greatly enhance new product development, market competitiveness and resilience; have important social and economic significance. CAD / CAPP / CAM integrated technology to meet our modern manufacturing engineering development. CIMS It is also an important component of the project to this end, our analysis of the situation at home and abroad on the basis of CAPP, the use of CAD, CAPP, expert system, database technology has successfully developed a feature-based box parts CAD / CAPP integrated system. The system can machine parts CAD CAPP integration with the complete decision-making process and automatically generate technical documents.

An overall system plan

For a long time, CAD, CAPP, CAM is an independent state of development, can not be achieved automatically passed between systems and exchange of information. CAD system output of the design results is two-dimensional engineering drawings and related technical documentation, during the machining process design rules, often through manual drawings into CAD CAPP then required to re-enter the computer data, not only affects the efficiency of design, but also in data conversion and transfer process may result in error and reduce the reliability of the design.

CAPP will be part of the information input system; the best way is to realize CAPP CAD system and direct transmission of information between systems. However, the information needed to CAPP system and traditional CAD system output of the information is not exactly the same, which not only contains the parts geometry information, but also includes parts of the manufacturing process information. To solve this problem, the study status of the CA PP extensive research and in-depth analysis on the basis, we propose the development of feature-based CAD / CAPP integrated system of programs.

Feature modeling system consists of an integrated CAD and CAPP subsystem composed of two parts. Several of the core functional modules and their relationship works as follows:

(1) CAD feature modeling module is the core module of feature modeling subsystem is to achieve integration of CAD and CAPP important part, mainly to complete part design and information input. Modules in three-dimensional solid modeling system, based on the feature set constructed with parts, and completed a feature interactive technology through the property assignment. Part design model is completed, by generating the characteristic information database system linked with the CAPP.

(2) Rules of inference modules that process decision-making module, is another core module CAPP subsystem. It features information database from the original start, the strategies used by a certain process rules knowledge base to infer process route and process the contents of the whole core of the system.

(3) Process control procedures by the rules of knowledge base module and database composition. Control procedures and inference rules database module is the link between the database process knowledge and technology by the rules and so on. This module is highly interactive with the user module that allows users to interactively modify or add modules process rules knowledge.

(4) Interaction module user interface module can interact with the application data, modify database contents, which is platform design reflects the thinking of a flag.

(5) Manual build process module is the core module of CAPP subsystem. It is based on rules of inference modules aligned process routes, and the module structure of the part feature modeling three-dimensional solid model to generate two-dimensional process diagram and process content and Process summary, the auto-fill to the standard or custom process card, the build process manual.

Key Technologies and Solution

Although some research has been based CAPP, but several key technical issues has not been satisfactorily resolved. This includes a description of part information and input, making the implementation process, process diagrams and process files automatically. We CAPP system box part in the design process, the proposed and adopted a series of technical strategy, to complete three core modules of the design of the system in order to overcome these technical problems as far as possible, make the design of the function of CAPP system as perfect.

Description of part information and input

Enter the parts information in a variety of methods, so that CAPP system directly from the CA D model to extract part information is the best method, which can remove large amounts of data cumbersome and inefficient manual input. This must be modeled in the CAD parts, in addition to the usual geometric shape information, but also adding process information. we used to describe the methods of feature modeling and the input part of the message that the use of existing commercial CAD software as a graphics support, according to the function of parts intended shape good range of shape features that can be processed, then add parts manufacturing information, the formation of characteristic information. By defining the characteristics of a unified description of methods and characteristics of the data storage structure, a unified management features, and on this basis part design modeling, the characteristics of the manufacturing information into the initial design information into. is designed to form parts with features, follow-up of the CA PP module as long as the decision-making process passing through certain can easily be read directly from the characteristics of the database characteristic information.

CAD feature modeling sub-system function is the part of the three-dimensional design, the part CAD model geometry process design and process information necessary to the CAPP system to provide the required part information. CAPP system how to extract the parts directly from CAD systems information technology is the CAPP and the technical difficulties one of the key. The system uses CAD / CAPP integrated feature model to solve this problem. Part features, including geometric shape information and manufacturing process information, the information in this system by the following obtained. CAD design for the parts not made the first three-dimensional CAD software as graphics support software, CAD design of parts. In the CAD design process, the shape functions by parts can be processed booked a series of shape features, while adding manufacturing process information. When the parts to complete CAD design, the part can get a geometric description of information and process information the characteristics of a unified model. these geometric features with the process of recording and unified by the database management system technology as a CAPP source of information for decision-making module, so that the CAPP system can access parts information directly from the CAD to achieve the integration of CAD and the CA PP. has been made to the original three-dimensional CAD design of parts, the module can be in the original model based on the geometric feature models directly established. In addition also enter part by human-computer interaction information, the establishment of feature model.

Implementation of decision-making process

CAPP system technology is the core of decision-making. By the status of CAPP research, analysis and comparison of various CAPP system implementation process in the decision-making methods, found that excessive pursuit of CAPP system in the automation of decision-making process is not the best. For a long time, CAPP The target has been replaced by technology staff to develop the automation system, developed under the guidance of this goal of "automatic" CAPP system, although the integration of expert knowledge and experience, but companies often need to use a longer time for data preparation and system debugging, but also a lot of training, which will dampen the enthusiasm of the user. In addition, "automatic" in its internal reasoning CAPP system and algorithms not for the user is often unknown variable, when the system answers to the actual situation and experience with the user The system inconsistent methods of reasoning and decision-making not be user modified, the user will lose confidence in this system. Another point is that over the pursuit of program design automation will greatly increase the workload of large amounts of data and the structure complex, and these errors will cause the software to increase the potential impact software reliability. On the other hand, process design and dynamic diversity. According to statistics, the production at the plant site, about 30% of the process design needs the actual production capacity and existing manufacturing resources, and amendments, to be implemented. Especially in today's more variety, less the trend of mass production, the production sites a little small perturbation (such as equipment failure, lack of tools, production planning changes etc.) often lead to unpredictable pre-processing method of processing the order and change. While the existing process design is generally a process to generate a unique route for the target, change process specification requires cumbersome procedures and longer time. This makes the process of order on the production site of unpredictable changes in the lack of sufficient adaptability and flexibility. To make the CAPP system design process design process to minimize both labor intensity, have good flexibility and adaptability In extensive research, testing and technology experts with the factory on the basis of repeated discussions, we propose a structural framework CAPP subsystem. In this system, the realization of decision-making process using actual production based on directed acyclic graph non-linear process design methods. Nonlinear characteristic is mainly reflected in the results provided by the system on multiple choices: for each part to provide a number of optimized process routes. the first to consider the highest priority process of order, does not apply if the process of order conditions at the production site was abandoned, then the second priority level of technical rules to be considered, so repeat the process continue until a satisfactory point of order. as described on the technology and modeling decision-making process can make the production process planning to meet the dynamic change. in accordance with this decision-making process guiding the design module automatically generates process route, and users are able to live according to the actual production of resources (such as machine tool equipment, loading rate, currently at the maintenance period, etc.) and the process used to plant involved in sorting and selection of processing routes, in order to achieve a balanced system automation and adaptability. In addition to automatic generation of process, this system can extract the rules in the process has generated useful information, constantly added to the process database. Users can also pre-existing process of order input process database. During the design process, according to the principle of similarity of parts from which technical rules have been called, slightly modified, or used directly, thus avoiding the re-designed to save time.

Process map and process the file automatically generated

Process documents; process map is an essential component. In the CAPP system, if generated automatically by a computer and draws

Process diagram, will greatly improve the efficiency of process design. As is the process from blank to finished part shape, size, changing the process, process map will have to reflect this dynamic process in a particular instant (after each procedure) part of the form, and the part is very diverse, each part of the process and can have a different order, so it is difficult to generate a fixed way to process map. This makes the CAPP system development process mapping software, developed as a difficult work.

To solve this problem, we developed a technology file generation subsystem and subsystem feature modeling with CAD, CAPP subsystem integration decision-making process as a whole. Subsystems include: (1) generated from the process decision-making subsystem process the data file to import process data; (2) According to the import process data and features from the CAD three-dimensional modeling subsystems are part of data, through analysis, processing, generating two-dimensional process map; (3) to generate a complete process documents; (4) post-processing, such as modifying the view, in the process file, add special content. Procedure automatically generated map CAPP technology is one of the key. After much research, decided to use three-dimensional CAD software, the secondary development interface using the view matrix method for system development, the establishment of smart process object-oriented graphics rendering subsystem. The system can follow the process decision-making process module generates the part line, parameter-driven intelligence to generate process maps, the structural framework shown in Figure 4. The system can features from the CAD model, process design information and standard graphics library to obtain the necessary data and information, automatically generate process plans and the corresponding processes card. You can also human-computer interaction generated by the process designer of the process to modify plans and processes cards editing.

CAD / CAPP / CAM integrated manufacturing is one of the hot areas is extremely important in the CIMS project key. In this paper, Box Parts CAD / CAPP integrated system, through data integration, enabling a CAD and CAPP exchange of information and feedback, and in the CAPP system design using non-linear process planning method, using the view matrix intelligent graphics generation process technology strategy, makes the system more perfect for CAD / CAPP integrated system provides a practical feasible way, but also for CAD, CAPP and CAM provide the further integration of practical experience.

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