Research On Key Technology Of 3D Assembly Process System Based On Lightweight Model

In recent years, with the continuous development of computer technology, computer-aided design(CAD), computer-aided manufacturing(CAM), and computer-aided process planning(CAPP) technologies have achieved a great progress and wide application. But, compared with CAD and CAM that have become an indispensable technology in enterprises, CAPP as a bridge connecting the design and manufacture is lagging behind a lot. Especially the traditional two-dimensional assemly CAPP can not meet the growing demand for the development of enterprises' informatization strategy. Therefore, the 3D and visualization of assembly CAPP have gradually become a hot spot of the research on CAPP technology. In this paper, a detailed background analysis of the development of 3D assembly process system and an in-depth analysis of the key technologies of 3D assembly process are presented, including assembly process information model, assembly process are presented, assembly process planning implementtation and assembly process documentation. According to the realistic needs in the industrial projects, some feasible solutions for the 3D visualization of assembly process are put forward.This paper has analyzed the impact of assembly process information model on the assembly process creation and documentation. Based on the observation on their relations, a lightweight data conversion method is developed for transforming the design models to the assembly models. The transformed model can meet the data and information requirements of the subsequent assembly process construction. At the same time, redundant information in the design model, which is not needed in process planning, is removed. This speeds up the display of the models later on.The paper also presents our work on information extraction from the assembly models. Here, we mainly focus on the extraction of assembly structure information, part geometric information and other process-relevant information. Based on the API provided by the HOOPS/3dAF Graphical development tools, a program for fast display of the assembly model is developed in the Visual Studio integrated development environment.Then, according to the enterprise demand for assembly process documents, some software functions for creating the process steps are developed. To explain the process steps, the explosion display for assembly models is implemented, which can provide the exploded view in the automatic and manual way. Combined with the explosion display, some assembly process view is also generated, including the generation of different assembly state sequence, the save of key assembly steps, and continuous playback and simulation of the assembly process.Finally, an example is given to validate the system, in which an assembly process is created and its technical documentation is made for the production of the rear axle differential gear.