Research and Development on Web-Based Digital Pre-assembly System

摘要

The purpose of the research on digital pre-assembly technology is to offer an environment and some related tools to evaluate product assemblability, reduce modification or rework caused by design error and enhance competition ability of enterprise. In the 21st century, manufacturing enterprises face with increasingly intense competition of global market. With the development of computer network technology, it has become a trend for enterprises to research new manufacturing modes, such as web-based distributed collaborative design and manufacture, concurrent engineering, agile manufacturing etc. Based on the analysis of scientific research, an architecture of web-based digital pre-assembly system is given, which is open, reconfigurable, reusable and extendible. This system is divided into five layers: interface layer, control layer, application layer, database layer and network layer. Application layer is the core to realize the system, and it is made up of system environment and application function sets. In this paper, both WRML file and feature information file are used as the carrier of product model, feature information file is developed from CAD software, it can supply the information that VRML model has lost; a new assembly model combining product hierarchical relation model with product connectivity relation model is studied based on analysis of assembly model. A database of feature template is built, a method with which different three-dimensional CAD models can be inputted into WebDPAS(web-based digital pre-assembly system) is put forward, and then the system case is given by using UG. Two key assembly simulation tools are studied to assist user to research in this environment. Movement simulation tool is to define various movements. Another key tool - collision detecting combined Bounding Box with Octree method is Used to analyze the components along their movement direction during assembly simulation.A Web-based Digital Pre-assembly System (WebDPAS) is developed in our lab. A case study is also introduced to illustrate it.