Research on CAPP system development tool of the ho

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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 repetitive calculation and compilation, and engage in the research of new processes and technologies. CAPP is also a bridge connecting CAD and cam, and 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 of heavy machinery parts has a common implementation foundation in many aspects (for example, the basic content of the engineering database required by the CAPP system, the decision logic of each stage of CAPP, system input, output, etc.), so it is necessary to develop an intelligent CAPP system development tool for comac-c (19) mechanical parts that are being accelerated

2 research method of development tools

the intelligent development tool of CAPP system for 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 system for CAPP of heavy machinery parts. Users can realize the function reconstruction of CAPP system of heavy machinery parts by selecting components and combinations, and quickly generate a CAPP system of 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 strategy of designing standard components is:

(1) component independence principle. We should try our best to make the functions of components cohesive and the data coupling between components, so as to improve the reliability of component combination

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

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

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 synthesis technology of standard components, the structure of the practical system corresponds to the database structure of solving problems. The development of the system focuses on the structural design, rather than 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 the components are independent and the information is hidden, the function of each component is single. The composition of components is based on some operation of the database, which greatly simplifies the complexity of components and facilitates the construction and maintenance of components

(3) friendly user interface. Due to the use of component assembly technology, users can participate 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 of heavy machinery parts and extracting their commonalities, the structure of CAPP system of typical heavy machinery parts can be obtained, as shown in Figure 1

4 division of standard components of CAPP system

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

(1) knowledge base development and management components. This component is used to help users decide the way of knowledge expression, 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 all kinds of 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) the process generates components. This component is the core component of zjcappdt, and its function is to generate the technological 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 process design, or choose 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 of 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 to form the process generation module of the CAPP system of heavy machinery parts of the enterprise

(4) manufacturing resource management component. This component provides all kinds of equipment, tools, fixtures and measuring tools database and its management system. With the help of this component, users can easily establish their own manufacturing resource database for process decision-making and production scheduling of raw steel hammer hole and the hardness of the adjacent parts of the hammer hole

(5) intelligent interpretation module component. When the inference engine is started to carry out the intelligent design of the process, the intelligent interpretation module generated by the component can make a clear explanation of the reasoning decisions in each stage of the process 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 the reasons for wrong conclusions; Help users 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. This 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 are: process diagram output component; Output components of process documents; NC machining instruction output components, etc. Users can use this component to output the generated process diagram, process file and NC machining instructions to the computer screen or through the printer

(8) NC machining instruction generator component. This component is designed for the process of using NC machining, and its functions mainly include: ① automatically generate NC machining control instructions according to the work step decision. ② Provide 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, the possible unreasonable phenomena, interference and collision phenomena in the processing of parts can be checked, and the processing process of parts can be visually simulated 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 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 analyze the structural and production characteristics of heavy machinery parts, combined with the CAPP system developed by the actual heavy machinery parts enterprises, determine the standard components of the CAPP system of heavy machinery parts and their relationship models, and establish a standard database of heavy machinery parts information 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 of heavy machinery parts. (end)

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