Development of cadcam integrated system for the ho

Development of cad/cam integrated system for rolling bearings

1 introduction

rolling bearings are commonly used standard parts, and their design and manufacturing have unique characteristics: ① bearing product design and process design are complex, the calculation workload is huge, and it is easy to make mistakes, but its mathematical model is relatively unified, and the design process is highly standardized, which is especially suitable for the application of computer-aided design. ② Bearing manufacturing is a mass flow production. Tens of thousands or hundreds of thousands of products of the same model are put into production at one time. There are many repeated links in production, which is easy to realize computer-aided management; ③ In the process of bearing manufacturing, because there are many production processes, complex technological processes, strict regulations and inspection records for each process, and a large amount of information exchange, computer-aided management is particularly needed. The development of cad/cam integrated system for rolling bearings plays a positive role in improving the production technology and management level of enterprises and shortening the product development cycle

based on the actual process of bearing product development in an enterprise, this paper carries out the development and research of bearing cad/cam integrated system by means of computer assistance. Firstly, the system structure is discussed; Secondly, the product development process of the system is introduced; Finally, the key technologies in the specific software development of the system are discussed

2 system function and structure

2.1 system function requirements

according to the actual development of bearing products, the rolling bearing cad/cam integrated system should meet the following product development function requirements:

(1) it can complete the design of standard or non-standard rolling bearing products. Automatically complete the structural design calculation of new products, and automatically query the data of dimensional tolerance, surface roughness and geometric tolerance of each part according to relevant technical standards; According to the calculation and query results, the product assembly and part design drawings are automatically generated, and the designed drawings can be manually modified when necessary, and the drawings and data in the database are kept unified

(2) according to the processing technology standards of various parts, automatically query the process data and design the bearing processing technology; Automatically generate the processing drawing files of all parts, and the designed drawings can be manually modified when necessary, and maintain the uniqueness of the data

(3) it should have a fully functional product data management function. Establish a database system according to the needs of product design and process design; It also has a fully functional database management system, which is convenient for data query, modification, addition and deletion

(4) the system should have a good man-machine interface, which can facilitate the integrated design of rolling bearing products

2.2 system structure

according to the above requirements, the rolling bearing cad/cam integrated system adopts the structure shown in Figure 1. The system is mainly composed of control module, design function module, database management module and database system

2.2.1 system control module

through the human-machine interface of the system, according to the enterprise product development process, coordinate the operation of each module, and uniformly manage the data flow of each module, so as to complete the product cad/cam process

2.2.2 design function module

design function module is composed of three sub modules: initialization, CAD and cam. Among them, CAD module and cam module complete bearing product design and processing technology design respectively, which is the core of product development system

2.2.3 function module

function module is to provide integrated product design and process environment. When the CAD design and processing technology design of the product are completed, if some data needs to be modified, the data can be modified through the user interface based on the design drawing template provided by the module, and the modified data can be directly stored in the database

2.2.4 database management module and database system bearing

cad/cam integrated system includes: actual product database, bearing design standard database, bearing process standard database. The database management module is used for data query, addition, deletion, modification and other functions of each database

3 product development process

based on the above system structure design, and considering the connection with the existing product design and process design mode of the enterprise, the system adopts the product development process shown in Figure 2 and figure 3. After receiving a product development task, the engineering and technical personnel of the enterprise can start the cad/cam integrated system. First, the product structure design is completed according to the process in Figure 2 through the CAD module of the system, and then the process design is carried out according to the process in Figure 3 by using the cam module of the system. All product development work is completed in the integrated system, which realizes the process integration and information integration of bearing product development, and improves the efficiency of product development and the level of organization and management. The system product development process is detailed as follows

3.1 CAD module workflow

first of all, designers should query whether the product to be designed has been designed by the enterprise. If it has been designed, they need to judge whether the original design product meets the requirements of the product to be designed, so as to decide whether to redesign. To complete this function, the system provides the corresponding input interface and product database. The input interface can input the model and accuracy grade of the product to be designed. The system combines the input bearing model and accuracy grade to form a product ID number and query the product database. If there is no relevant record of the product in the product database, it will be transferred to the design parameter interface to start a new product design; If there are relevant records of the product in the product database, the existing information of the product will be fed back, and the main parameters of the product will be listed for the product designer to check and decide whether to modify. If the product designer is sure not to modify, the product design will be transferred to the product parameter output, otherwise the product modification design will be carried out in the parameter input interface of the transfer. At this stage, the system automatically calculates other parameters required according to the input parameters, structural design calculation model, and the data of the relevant product standard database (standard structural parameters, dimensional tolerances, geometric tolerances, surface roughness, etc.). After the calculation, it turns to the checking calculation stage. The system checks the calculated results according to the constraint conditions entered by the product designer, and returns the checking calculation results, If it is unqualified, return to the parameter input interface and modify some parameters of the product. After the checking calculation is qualified, the task of product design calculation is completed, all relevant parameters of the product can be stored in the product database, and the design results (design specification output, product drawing) can be output. After checking by the product designer, if the product needs to be partially modified, it can be modified in the module of the system to meet the requirements of special customers. So far, the product designer has completed the CAD task of rolling bearing products, and can transfer to the cam task of rolling bearing products

3.2 cam module workflow

process designers carry out process design according to the product data designed by CAD module and enterprise process standards. After receiving the design task, the process designer can input the bearing model and grade in the input interface of the system. The system queries the product database according to this data. If the product does not exist, it will be transferred to the CAD module to start the product structure design; Otherwise, check whether the product has process design data, so a tensile machine with a large stroke is required to detect the tensile properties of flexible packaging materials. If so, output the process design results of the product; If there is no design, the process design of the inner and outer rings, cages and other parts of the product will be carried out separately. After the design, all the process parameters of the product will be saved in the product database, and the process (drawing of process drawings) will be output. After the process designer checks, if the product needs to be partially modified, it can be modified in the module of the system to meet the particularity of process requirements of some products

4 software implementation of the system

4.1 development tools

the system uses the object-oriented visual programming tool software basic as the development tool++ It provides a large number of controls, which can be used to design interfaces and realize various functions, and can easily use the ADO object 1 it provides. Using ADO to create the data binding function and data source connection of data source class plays an important supporting role in developing the product design module, graphics generation module and data management module of this system

since the system was initially designed for a single user, acess20o3 database system was adopted to establish product design standard database B, process design standard database B and product database B respectively, and the database was built into a relational database system, in which the corresponding product design standards, process design standards and various data related to products were stored, and these data were accessed through ADO object and control programming, It can retrieve data directly from the data source. AutoCAD has powerful first: what needs to be done day by day; With the function of drawing and automatic generation of graphics, AutoCAD objects can be programmed from the outside by using the secondary development technology of VB Based on activexautomation

4.2 key technology

at present, there are four main implementation methods of bearing product development CAD, namely interactive, variant, modular and parametric, which have their own advantages 121. Because the production of rolling bearings has the practical characteristics of standardization and serialization, the system will adopt the relatively mature parametric bearing design method 1510

because the processing technology scheme of rolling bearings has been standardized, the system adopts the automatic process design method 14]. The main contents of bearing product development cam include process parameter calculation, process scheme formulation, equipment selection, tooling selection and process card drawing. The process parameters can be obtained through the process standard database and combined with relevant calculation models. The processing scheme adopted for a specific product is based on the structure and overall dimensions of the product. Therefore, the standard processing scheme and application rules can be stored in the process standard database for process scheme design. The selection of equipment is similar to the selection of processing scheme. It is necessary to establish processing equipment and selection rule base. The selection of tooling and inspection tools is determined according to the processing scheme and overall dimensions, so the selection relationship database of tooling can be established to store the selection rules of tooling. To sum up, the process design process of rolling bearing can be informationized by establishing formula base, rule base and template base. With appropriate formula calculation and rule analysis modules, the automation of rolling bearing process design can be realized

based on the above system implementation strategy, its software development mainly involves the following key technologies

4.2.1 implementation of communication between development application and database

the system uses ADO to realize the communication between application and acces database. ADO is the most effective and simplest method to operate data resources supported by Microsoft at present. Due to the object-oriented characteristics of ADO, ADO is more flexible than Dao or RDO, and provides a standard COM interface. ADO provides access to various resources from text files to EXCEL documents, sqlserver, acess and so on. It is the best way to access external data sources through programming, and provides a new interface for effectively accessing local and remote data sources. This system references microsoftactivex data objects 2.6 library and uses edb 4.0 data engine, for example, can establish a connection with product database B through the following code. The connection of other databases is similar

4.2.2 generation of product drawing and process drawing

this module is implemented by using VisualBasic to develop AutoCAD based on ActiveX Automation. AutoCAD Activex Autom