Based on the rapid positioning of the standard parts library building method, the library building method combines the program building database technology with the parameterized database building technology. Through the operation of the standard parts sketch, the 3D solid standard parts with spatial information and geometric feature information are obtained. First, the program building logic is used to classify the standard parts according to the spatial geometry of the standard parts and the corresponding planar sketch shapes. Referring again to the parametric database building idea, the standard feature sketch is used as an object to parameterize the feature element size in the standard sketch, and the spatial information of the sketch is parameterized. Finally, the program batch design or human-computer interaction design is used to capture the positioning information of the predetermined position of the standard part, and the positioning information is associated with the spatial information of the sketch, thereby obtaining a sketch of the standard part with the positioning information, and establishing a standard based on the sketch. The 3D solid model of the piece.

Library Construction Method and Scope The core method for establishing a standard parts library suitable for rapid positioning is to operate the sketch and draw a sketch of the assembly directly at the location where the standard part is to be assembled. The sketch information of the part mainly includes two aspects. First, the spatial position information of the sketch, that is, the spatial plane where the sketch is located; secondly, the two-dimensional coordinate system included in the sketch and the geometric feature information in the coordinate system; The geometric feature information in the coordinate system refers to the basic elements of the sketch, such as points, lines, and faces in the sketch. These elements are planarly positioned based on the two-dimensional coordinate system of the sketch, and then combined with the plane where the sketch is located. Three-dimensional positioning. In the CATIA system, the origin of the 2D coordinate system of the sketch is the same as the origin of the 3D coordinate system of the part. If the plane of the sketch is parallel to a 3D basic coordinate plane (XY plane, YZ plane, XZ plane), then the sketch 2 The dimensional coordinate system is consistent with the two-dimensional coordinate system of the corresponding three-dimensional reference plane. Any point A in space is on a plane (P) that is parallel to a certain reference plane (for example, XY plane). There is a fixed distance Z0 between the two planes. The local coordinate of point A on plane P is (X0, Y0). Then, the space coordinate of point A is (X0, Y0, Z0). For specific construction methods, the parts should be classified according to the geometry of the sketch, offset from a basic coordinate plane (for example, the offset XZ plane, the distance is Y2), the offset distance is parameterized, and the offset plane is drawn. A sketch of the standard parts of the type, and parameterize the geometric features in the sketch, and parameterize the sketches of various standard parts to form a parametric grass map. Secondly, through the interactive interface, the user selects the standard part type, the system batch program A accesses the grass map, and obtains the sketch parameter information of the standard part; the system batch program B queries the part structure tree and captures the position coordinates of the point to be assembled (X1) , Y1, Z1). Finally, the sketch plane space transformation, assign the value of Y1 to Y2; obtain the parameter values ​​of each geometric feature according to human-computer interaction, establish a sketch of the standard part at the position to be assembled, call the entity modeling command, and establish a standard part with positioning information. Three-dimensional digital model.

The method mainly realizes the generation of standard parts by parameterizing the sketch. The parameterization of the sketch includes the parameterization of the sketch position and the parameterization of the geometric elements in the sketch. Compared with the parameterization of the 3D entity, it has higher flexibility and flexibility. It can better reflect the advantages of digital design. Therefore, sketch geometry feature parameterization is a higher level of parameterization. The standard parts library established by this method is combined with the tooling database. The coordinate system of the standard parts database and the tooling database should be consistent. It is very suitable for the standard parts of the rotary body, such as various types, pins, etc. The editing of the sketch applies to the in-depth development of CATIA.

Parameter database establishment method under PDM system The data in the standard parts library is managed and called through its internal parameter database. Through the database, it is convenient to query the size parameters of each series of standard parts of a certain type; in order to manage data more conveniently , also put the default geometry values ​​of all parts in the system main program into the database management. Based on the system selection database type to optimize the management and use of data; if the Oracle database under the PDM system is used, data management and update is convenient and fast, but the data access efficiency is lower than the local database; if using a local database (such as Access) ), can improve the access efficiency of data, but the management and update of the database is more troublesome. Since the database is queried several times during the execution of the system program, the local database is combined with the remote database under the PDM. The Access database is installed in the user's computer, and the local database of the Oracle database is updated under the PDM through the corresponding program in the system. In this way, data access efficiency can be improved, and data update and maintenance can be facilitated.

The application example is based on the rapid design of the standard parts library establishment method successfully applied to the rapid design system of rubber capsule forming mold. The rapid design system of rubber bladder forming mold utilizes CAAC++ technology to realize rapid design of mold for secondary development of CAT2IA. The system classifies the sheet metal parts according to the geometric characteristics of the sheet metal parts, and establishes a typical mold structure database by using standardized and parameterized database construction ideas; for the standard parts commonly used in rubber bag forming molds, such as mushroom pins and cylindrical pins, The above method establishes the corresponding standard grass gallery, and shows. Through the human-computer interaction interface, display, select the standard part type, query the parameter database, generate standard parts and tooling digital model, show.

At the end of this paper, the parameterization method and program method of establishing standard parts library are discussed. Based on the analysis and comparison of the two methods, the establishment method of standard parts library based on rapid design is proposed. The standard part library and rubber capsule based on rapid design are formed. The combination of the rapid design system of the mold realizes the fast and accurate positioning of the standard parts in the mold tooling; the standard parts library based on the quick design provides greater convenience to the tooling designer and reduces the mold design compared with the traditional standard parts library. Time has increased the degree of digitization of the mold.

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