Mechanical Components Feasibility Study Based On AutoCAD

AutoCAD is now one of most popular CAD softwares, this software has the formidable two-dimensional project cartography function and the part three dimensional mapping function, in engineering designs and so on machinery and building obtained the extremely widespread application. At the same time, AutoCAD provides a complete, high performance object-oriented CAD program development environment, from the menus and toolbars until every one graphic object, can be precisely customized for users and develpers to provide a variety of options, so that specialization and customization. AutoCAD is an open mapping system, which provides users with two kinds of continued development of the method.1. AutoCAD supports multiple file formats, such as the program parameter file, linear files, design files, script files and menu files. Users can modify or create these files to meet individual needs.2. AutoCAD application programming interface(API) with a variety of windows systems under the integrated development environment combination. Type of interface tools: AutoCAD Mechanical,AutoLISP,Visual LISP,ADS,VBA,ObjectARX. Users can use these languages to create a new AutoCAD commands to meet their application needs.Mechanical components are widely used in people's daily life. A mechanical product is generally composed of more than two components at least, and expressed by an assembly body. Assembly design plays an important role in mechanical product design.The assembly of mechanical comonents means the parts will constitute the machine together to form a complete process of mechanical products. In the traditional mechanical components designe and development process, part of the assembly design need people to complete the drawing by hand, the assemply of positioning difficultes, and thus the high cost of product design and development, product design and development cycle long, weak product market competition.Mechnical product's features and designers intent is reflected in the specific geometry of part and assembly structures, especially the assembly relation among components and the relative location and direction of particular importance. Therefore, development of product assembly information to part-level modeling, but also should pay attention to assembly-level modeling. Assembly information model is a set of parts, after a group of assembly operations generated after the assembly has to determine the relationship between the product model, which reflects and describes the product assembly process all relevant factors and relationships.With the computer technology in mechanical product widely used in the field of modeling, mechanical prodect information modeling has become a kind of computer hardware and software systems supporting the people of mechanical product design methods and technology.Mechanical product assembly information modeling process is generally divided into the following steps:1. Orders made through the analysis of user requirements, the establishment of a conceptual model to meet demand. Conceptual model used by designers with experites and knowledge based on these definitions the relationship between the design and constratints. Conceptual model of visual information, including the initial calculation of decuments and information on a number of visible icons.2. Conceptual model of the icons will convert the information into the assembly information model. Assembly information modeling, on one hand to choos the appropriate part structure, on the other hand the position to define the relationship between components and the comstraint relationship. Assemply information model is a visual expression of assembly drawing, assembly drawings reflect the product works, functins and overall structure.3. In the assembly information model based on the description of parts to further establish the relationship between geometry and topology of the part model. Part model can be inherited form the assemply information model of the structure,size,precision and material information, the adoption of appropriate expression of the full expression of the structural components. Part model contains the details of the product design, visusal expression is a part drawing.Assembly information model and assembly information modeling in the whole process of product assembly information modeling plays an important role. Assembly information model must both inherit the conceptual model of information, to effectively carry out assembly design, but also the design of information passed to the part models. In a sense, the assembly of information modeling is the core content of product information modeling, which connect the conceptual model and parts model of complete product information model is generated to meet the product life cycle, the information needs of various sectors has a very important effect.The assembly design research of mechanical components focus on two-dimensional and three-dimensional design. With the rapid development of computer technology, many kinds of three-dimensional design softwares have appeared on the market one after another, so users'requests of mechanical production design have changed from two-dimensional design to three-dimensional design. But until now, two-dimensional engineering drawing also plays an important role in the actual design and the production. In the assembly design of two-dimensional domain, the part drawing and the assembly drawing are used to express composition structures by the multi-views of orthogonal projection, that is to say, each side of components (or assembly body) and their internal structures are drawn in the same two-dimensional space.Because the two-dimensional design is still the main expression way in engineering design at present, also it is the main technical document in component manufacture domain, it occupies the main status. This article studies the assembly feasibility of mechanical components in the two-dimensional domain and the positioning of components. The main idea is, according to the assembly constraint conditions of two components, to determine assembly feasibility and solve positions of components.This paper mainly studied the following contents:1. In the mechanical production assembly design, the standard components are frequently used (such as bolt, nut and rivet). Standard component library of the mechanical products has been built, which contains several series, more than 50 kinds of commonly used components.2. According to the actual needs in the mechanical engineering design, 7 kinds of assembly constraint conditions are put forward, and the assembly information modeling based on the assembly constraint relations is built. At last, taking the oil pump and bolt for the example, the detailed explanation is given.3. It studies the assembly feasibility of mechanical components and the positioning of component based on the two assembly constraints. Three areas are divided: the assembly feasible areas, the assembly possible areas as well as the assembly unfeasible areas. Conditions which the areas need to satisfy are determined. The position solving algorithm of components is used to solve the space position and the direction of components.4. Assembly design system based on the assembly feasibility determination and the positioning of components are designed and realized. After given the assembly constraint conditions of two components, the system determines the assembly feasibility, and solves positions of components automatically.