Development and application of CAPP system in Kunm

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Kunming Machinery Factory is a large state-owned enterprise subordinate to the Ministry of railways. It mainly produces all kinds of railway maintenance machinery, including full section ballast cleaning machine, tamping machine, stabilizing car, two-way ballast distribution and shaping car, etc. Since 1995, the enterprise has introduced CAD technology and popularized it in the whole plant. The design cycle of products has been significantly shortened. Compared with the past, the design efficiency has been improved by nearly five times, and the design quality has also been greatly improved

however, in the process design, it still depends on the knowledge and experience of technologists. Due to the complex product structure and many kinds of processes involved, on the one hand, manual process design can not effectively use the mature process of the enterprise, and the rich process knowledge and experience accumulated by old technologists for many years, so it is not very convenient to coordinate different processes of the same part. In particular, for various process documents for management, manual statistics become very troublesome and inefficient due to changes in process design. Therefore, as early as 1996, the factory had done a lot of data collection and collation work, put forward specific process needs, and also cooperated with some colleges and universities to carry out joint development, but the results were not ideal for various reasons and could not be implemented in the factory. In recent two years, with the deepening of the application of CAD technology, in order to make full use of the part design information generated by CAD system and improve the process design and process management level of the whole enterprise, it is very urgent to introduce CAPP technology and develop process design management system. Summarizing the past experience of failure, in order to make the system development successful and implement smoothly in the whole plant, we have formulated the following implementation guidelines:

1. Conduct a full and detailed investigation on the domestic commercialized CAPP system, based on these commodity software, select a more mature and practical CAPP system that is more in line with the needs of our factory, and on this basis, carry out secondary development according to the process design and management characteristics of our factory, To shorten the development cycle and improve the success rate

2. Carry out enterprise standardization and standardization of the existing process design of our factory, and lay a solid foundation for the comprehensive deployment of CAPP system in the future

3. Fully consider the characteristics of the enterprise and formulate detailed process design requirements

second, the guiding ideology and functional requirements of system development

based on the comprehensive analysis of the process design and process management requirements of the factory, the overall requirements of the process design management integrated system to be developed are put forward

1. Practicality

it does not overemphasize the automation of process design, but focuses on practicality. It can make full use of the experience of process designers and existing mature processes, provide process knowledge, and assist technologists in process calculation and process decision-making, with the goal of quickly and efficiently generating all kinds of required process procedures

2. Product oriented

considering that the product is the basic object of the enterprise's product design, production preparation, production management and cost accounting, the system is required to be able to carry out process design and process management for products, cover all process types of products, and realize integrated process design and process management

3. Integration

from the perspective of products and their entire life cycle, it realizes the integration of process design and process management, and meets the information integration requirements in CIMS environment

4. Networking

according to the characteristics of product process design, it supports the sharing of product process data in the network environment, and supports the collaborative design from technologist - process team - chief technologist in the network environment

5. Standardization

in the case of manual design, the process consistency and standardization of the design are poor. The system must ensure the standardization and standardization of design process

according to the overall requirements of the system, we put forward specific functional requirements:

1 Product data management

the system can provide product data management functions, including product creation and deletion, adding and deleting parts in the product, browsing and modifying parts to realize software speed regulation information and other functions. It can directly read product data from CAD system to avoid inefficiency and inconsistency caused by repeated input

2. Process card design

using the system, we can easily design our existing processes, including 12 kinds of machining process cards, forging process cards, welding process cards, heat treatment process cards, casting process cards, assembly process cards, electroplating process cards, etc

3. For a variety of process design methods

the system can provide a variety of process design methods, including interactive and different types of retrieval methods, to adapt to different products and different types of process design requirements. For the interactive design process, tools can be provided according to machining, forging, welding, heat treatment, casting and assembly processes to help process designers calculate the process and quickly select the required resources, such as the determination of machining allowance, the determination of blanking size, the generation of forging blank drawing and the automatic calculation of blank weight, the determination of runner section shape and specification, riser design, etc

4. At present, there are many kinds of CAD systems used in our factory. Two dimensional CAD includes kaitu CAD and accelerating the update of plastic granulator technology, AutoCAD; 3D includes UG, SolidEdge, Cimatron, etc., which requires the system to make full use of part graphics from CAD system to quickly generate process drawings. At the same time, the product design information can be obtained from the CAD system

5. Automatic generation of various summary tables

the system can provide the function of process files for automatic statistical management to completely solve the problems of manual statistics. According to the actual situation of our factory, these management documents should include drawing catalogue, product process catalogue, parts processing route list, parts production and processing catalogue; List of purchased parts, list of outsourced parts, list of standard parts, and list of various parts; List of special process equipment and list of standard tools purchased by the enterprise; List of material consumption process quota, summary of unit product material consumption process quota, list of auxiliary material process quota, list of casting material consumption quota

6. For basic process data

the system can provide material library, profile specification library, equipment library, standard tool library, standard measuring tool library, industrial art language library (including process name library, process content library, etc.) and auxiliary material library. The required data can be transferred to the corresponding position of the process card at any time when designing the process

7. Process card format drawing and management

the system can provide more than 30 process cards and management documents that meet the requirements of our factory and take machining process cards as the main cards. Considering that with the development of enterprises, new process cards may be added or existing process cards may be modified, the system is required to provide process card format drawing and definition tools, which can be used to easily expand the process file system

III. selection of CAPP system

since 1997, we have conducted a comprehensive investigation on domestic CAPP software providers, mainly making a careful and detailed comparison on the strength, software development ability, software functions, and the company's technical support and services to enterprises. After nearly two years of market research, we finally selected the GS-CAPP system of Zhejiang Datian company in early 1999

In addition to meeting the specific requirements put forward by our factory, Datian CAPP system also has several features that are very helpful to our factory's process design:

1. The system integrates process design and process management. It can design different types of processes, provide process knowledge, assist technologists in process decision-making and process calculation, and automatically generate process documents for management, It can control and manage the whole process design process and provide a complete safety mechanism. Therefore, it is convenient to carry out secondary development based on the relatively perfect process design management function provided by Datian CAPP to meet the actual needs of our factory

2. The system introduces the product tree, which not only clearly describes the assembly relationship between product parts, but also takes the product tree as the main line for process design and process management, which can easily obtain the process information related to the product, so it is easy to realize the information integration with other systems

3. the system gives different process design methods according to the process design characteristics of different products and different types of processes. For example, based on the typical process retrieval, the process of the existing product parts of the enterprise can be summarized and sorted out, and the optimized and standard typical process can be obtained. On this basis, the system provides the typical process management function, which can continuously accumulate the typical process of the enterprise in the process of using the system. In this way, when designing a new process, the new process can be quickly generated by retrieving the typical process and making a few modifications

when using interactive design new process, the system provides a variety of means to help users quickly carry out process design, such as automatically reading the design information of parts; Automatically obtain the related information of the process card and maintain the consistency of the modification of the related information; Automatic calculation of process card column is realized by establishing association relationship

in addition, it also provides whether to choose ball screw or trapezoidal screw based on production? The design methods such as product tree retrieval and parts name retrieval before making a decision, so that the system has a wide range of adaptability and better flexibility

4. In addition to providing a wealth of common process resources, the system also provides a complete set of management methods, which can maintain these process resources according to user needs, and fuzzy query can be carried out according to the characteristics of process resources. In addition, the system can also establish new process resources at any time according to the needs of actual production, including defining the structure of resource library and adding library records

5. The system provides process submission, process audit, process standardization, process countersignature and process change functions, tracks and records the status of process cards, and can control and manage the design process of each process card

IV. system development and application

after nearly half a year of cooperative development, the system was installed and commissioned in Kunming Machinery Factory in August 1999. It was first applied in the technical service department. The designed process involves all types of process cards of nine products, including machining, forging, casting, welding, heat treatment, electroplating, coating, assembly and electrical assembly, There are several reasons why Dong Mingzhu can support lithium titanate automatically: the management documents with long service life or automatic statistics cover all types of current management documents of the enterprise, including drawing catalogue, product process catalogue, various parts list, special process equipment list, process quota list of parts and materials consumption per unit product, summary table of materials consumption per unit product, etc. From the operation of more than half a year, the efficiency, quality and standardization of the system design process have been significantly improved. Taking the S500 new product newly developed and trial produced by our factory this year as an example, 5886 process and technical documents of 3186 drawings of the product originally took three months to complete the design, but now it is completed in one month, and the comprehensive work efficiency has been improved by more than three times. High efficiency is especially manifested in the calculation and statistics work. Once the machining process card is designed, the material process quota, cutting tool budget summary and various related management process documents can be automatically counted. Originally, it took about one and a half months to complete these calculation and statistics work of a product by one person, but now it takes only half a day to complete it, which improves the work efficiency by 60-80 times, such as

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