Research on CAPP system development tool for heavy

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Research on CAPP system development tools for heavy machine parts

1 preface

capp (Computer Aided Process Planning) can improve the quality of process design and promote the optimization and standardization of process. The development and application of CAPP system can fundamentally change the backward situation of traditional process design, and make many process personnel free from tedious and repeated calculation and compilation, and engage in the research of new processes and technologies. CAPP is also a bridge connecting CAD and cam. It is a key link to realize computer integrated manufacturing system (CIMS). Therefore, the research of CAPP system has been widely valued at home and abroad, and a variety of CAPP systems have been developed

The CAPP development tool is the generation environment of CAPP system. Through developing tools, we can quickly and conveniently establish a practical CAPP system, so as to provide efficient and convenient automation means and support for the universal application of CAPP system. The development of CAPP system involves many factors, and the amount of data and information used is very large. Heavy machinery is mainly produced in single piece and small batch, with complex structure and many types of parts. There are many manufacturers of heavy machinery, and the product types, production batches, production equipment, technical force, process methods and process habits of each factory are different. Through the analysis, it is found that the CAPP system for heavy machinery parts has a common implementation foundation in many aspects (for example, the basic contents of the engineering database required by the CAPP system, the decision logic in each stage of CAPP, system input and output, etc.), so it is necessary to develop an intelligent CAPP system development tool for comac-c (9) 19 mechanical parts that are being accelerated

The intelligent development tool for CAPP system of heavy machinery parts - zjcappdt system adopts the methods of system engineering and software engineering to design the standard components of CAPP system for heavy machinery parts, and adopts component assembly technology to automatically generate a practical CAPP system for heavy machinery parts. Users can realize the function reconfiguration of CAPP system for heavy machinery parts by selecting components and combinations, and quickly generate a CAPP system for heavy machinery parts that meets the needs of users and faces the actual production. Users do not need to program or only do a small amount of programming themselves. The basic strategies for designing standard components are:

(1) component independence principle. The functions of components should be cohesive and the data between components should be coupled as much as possible, so as to improve the reliability of component composition

(2) information hiding principle. The local information contained in the component is "private". For other components that do not need this information, their internal data and processes are invisible

(3) component reusability principle. The classification, composition and structure of components shall meet the needs of flexible construction of CAPP practical system. That is to say, through the combination of components, a CAPP system that meets the needs of users and faces the actual production can be quickly generated

the CAPP development tool using component synthesis technology has the following advantages:

(1) it is easy to realize the reconstruction of CAPP practical system for heavy machinery parts. Using the component composition technology of standard components, the structure of the practical system corresponds to the database structure for solving problems. The development of the system focuses on the structure design, not the control flow design. The system structure is clear and easy to implement. When the number of components is large, it is easy to ensure the correctness of component synthesis CAPP system

(2) components are easy to construct and maintain. Because components are independent and information is hidden, each component has a single function. The composition of component is based on some operation of database, which greatly simplifies the complexity of component and facilitates the construction and maintenance of component

(3) friendly user interface. Because of the component assembly technology, users can be involved in the design, use and maintenance of CAPP system for heavy machinery parts at every stage of the software life cycle, and can give full play to their own advantages

3 structure analysis of CAPP system

due to the complex structure and production process of heavy machinery parts, the CAPP system of heavy machinery parts is also different from other CAPP systems in parts description, process generation and process file output. Ignoring the differences between CAPP systems for heavy machinery parts and extracting their commonalities, the structure of typical CAPP systems for heavy machinery parts can be obtained, as shown in Figure 1

4 division of standard components of CAPP system

abstract the structure of the above CAPP system for heavy machinery parts, and we can get zjcappdt system, a CAPP system development tool for heavy machinery parts based on standard components. The main components of the system are shown in Figure 2

(1) knowledge base development and management component. This component is used to help users determine the knowledge expression mode, select knowledge, establish knowledge base, test the consistency and redundancy of knowledge, and manage the knowledge base. It puts forward process decision-making knowledge, manufacturing resource selection knowledge, part description information, process parameter optimization operation, etc. suitable for development and description, so as to form CAPP system knowledge base of different types and levels

(2) part description and information input component. Its sub components include human-computer interaction input component, part information standard database retrieval component and component integrated with CAD system to input part information. Considering the characteristics of heavy machinery parts, a part information standard database is designed to store the relevant national standards of heavy machinery parts information. The part information that conforms to the national standard can be retrieved directly from the part information standard database, and the human-computer interaction input component is used for users to input various part information that is not in the part standard database. With the CAD system set, it is strictly forbidden to start moving the measured components during force application and force release, so that the CAPP system of heavy machinery parts can directly obtain the part description information from the CAD system

(3) process generated components. This component is the core component of zjcappdt, and its function is to generate the process of heavy machinery parts. Considering the characteristics of heavy machinery parts and development tools, the process generation component is composed of derived generation process, hybrid generation process and intelligent generation process, i.e. inference machine sub component. For different types of heavy machinery parts with different characteristics, users can choose to use retrieval and hybrid methods for process design, or select inference engine for intelligent design, or synthesize several methods to generate the process of heavy machinery parts. When using this tool to combine the practical CAPP system for heavy machinery parts, users can select one, several or all sub components to assemble according to the specific situation and production characteristics of the enterprise, forming the process generation module of the CAPP system for heavy machinery parts of the enterprise

(4) manufacturing resource management component. The component provides various equipment, tools, fixtures and measuring tool databases and their management systems. With the help of this component, users can easily establish their own manufacturing resource database for process decision-making and production scheduling

(5) intelligent interpretation module component. When the inference engine is started for intelligent design of technological process, the intelligent interpretation module generated by the component can clearly explain the reasoning decision at each stage of technological design, explain the reasoning process in the form of user understanding, the reasons for the conclusion and answer the questions raised by the user; Help users find out the causes of wrong conclusions; Help users to establish and debug the system, and provide users with relevant knowledge

(6) part information standard database generates components. The national standard information of various heavy machinery parts is stored in the part information standard database. The database is open. Users can add part information or delete existing information in the database when assembling the system

(7) process output components. Its sub components include: operation diagram output component; Process document output component; NC machining instruction output component, etc. The user can use this component to output the generated operation diagram, process file and NC machining instruction to the computer screen or through the printer

(8) NC machining instruction generator component. This component is designed for the process of NC machining. Its main functions are: ① automatically generate NC machining control instructions according to the work step decision. ② It provides necessary data for dynamic simulation of machining process. ③ Check the semantics and syntax of the existing NC machining control instructions, and dynamically simulate the machining process to check the correctness of the machining instructions

(9) dynamic simulation component of machining process. Dynamic simulation of machining process is a very important work. Through simulation, we can check the possible unreasonable phenomena, interference and collision phenomena in the part processing process, and visually simulate the part processing process through the display of graphics and process parameters

5 conclusion

the research of CAPP development tool for heavy machinery parts based on standard components is a pioneering work. Because the process design itself is a complex multi-level and multi task decision-making process, the workload of developing a CAPP system development tool for heavy machinery parts is considerable. Using the methods of system engineering and software engineering, we fully analyzed the structural and production characteristics of heavy machinery parts, combined with the CAPP system developed by the actual heavy machinery parts enterprises, determined the standard components and their relationship models of the CAPP system for heavy machinery parts, and established the information standard database for heavy machinery parts by regularly coating a thin layer of molybdenum disulfide grease. This greatly reduces the workload of users in generating a practical CAPP system for heavy machinery parts, shortens the development cycle of the system, and improves the efficiency of process design. It provides a general development platform for the research and development of CAPP system for heavy machinery parts. (end)

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