With the development of computer technology and sheet metal digital technology, sheet metal forming technology has been rapid development, sheet metal forming information has been a certain development. The quality and economy of sheet metal forming mainly depends on the forming process method and the quality of mold design. Choosing the appropriate sheet metal forming method and designing the reasonable mold structure requires a lot of material information, equipment information, process information, product geometric characteristic information , Typical mold structure information. At present, these sheet metal information is stored in different forms in different carriers, and the information integrity is poor, which directly affects the overall technical level of sheet metal forming. Especially, the complex aviation sheet metal parts which are currently processed by pressure forming method, Quality and manufacturing efficiency and so there are many problems, which is forming sheet metal forming technology is not inseparable. Sheet metal forming information technology is still difficult to express information, information quantitative difficult, difficult to extract information, information is not standardized form, there are many problems such as information island.
1. The connotation of sheet metal forming information
Sheet metal forming information is mainly divided into sheet metal geometric characteristics of information, material information, process information, simulation results information, forming mold information, equipment information, see Figure 1. These sheet metal forming information is the basis for the development of forming plan, the preparation of forming process, the determination of process parameters, the design of forming molds, the part of knowledge engineering, the improvement of sheet metal forming knowledge reuse rate and the overall sheet metal forming technology level.
2. Sheet metal forming information classification and existence
Sheet metal forming information, including material information, sheet metal forming process information two categories. Material information includes material descriptive information, material mechanical properties and forming properties. Material description information includes material name, grade, status, batch, manufacturer and other information; material mechanical performance information including density, Young's modulus, tensile strength, Poisson's ratio, tensile curve, etc .; forming performance including the minimum bending Radius, drawing coefficient, forming limit diagram, material constitutive model, thick anisotropy index, heterosexual parameters, cup convex test value and so on. Material descriptive information using phrases or sentences that sheet metal forming information, can be directly obtained; material mechanical performance information is mainly quantitative
Information, calculated by the single pull test, in addition, the single pull curve information can also be graphically expressed, are graphic information; metal plate forming performance generally through a specific process test to obtain forming performance parameters, forming limit diagram using two-way tensile test And the calculated anisotropy index is obtained by the single pull test, while the other anisotropy parameters are related to the material model.
3. Sheet metal forming information related technology
At present, sheet metal forming information exists island, the relevance of information is not fully reflected. Sheet metal forming information carrier for the paper, the information is not convenient, not easy to associate with other information, not suitable for automatic retrieval. Therefore, the sheet metal forming information first need to be related information
Sub-chemical, stored in the computer, to avoid the use of paper carrier. As the sheet metal forming information involved in the large amount of information, information types are complex, need to use different ways to save sheet metal forming information, material information is mainly quantitative information and descriptive information, can be used to save the form of database, sheet metal process information, including the number Model information, descriptive information, etc., save the form of database and digital form. For the material information and sheet metal parts in the process of quantitative information and descriptive information, the use of relational database to store the information, and the establishment of information between the relationship.
4. Specification of sheet metal forming information
Sheet metal forming a wide range of information, both explicit information, but also hidden information, information carrier is very different. In order to obtain the necessary sheet metal forming information efficiently and accurately, it is necessary to standardize the sheet metal forming information, and establish a unified specification sheet metal forming information expression and storage principle. (1) consider the relationship between the information, in the same carrier to store sheet metal forming information as much as possible when the associated feature information related to the association, such as material parameters must be associated with the material (1) to consider the relationship between the information, (2) The description of the class information is defined by the method of knowledge definition, and the coding is quantified. (2) The information of the class information is defined by the method of knowledge definition, and the coding information is used to quantify the information such as the name, the geometric characteristic, the geometric dimension and so on. (3) the use of a unified CAD software data format, to avoid data heterogeneous problems, digital and analog to meet the standard MBD specification, with PDM technology to manage , Standardize its naming and characteristics; (4) standardize the various types of sheet metal forming information storage carrier, storage, storage format.