Research Of Key Technologies Of 3D Virtual Simulation Platform Of Sheet Metal Forming

With deepening development of sheet metal forming and virtual reality technology, the original simulation system of sheet metal forming process software has been unable to meet with the acquirements of practical application scenarios. Therefore, in this article the stereo 3D simulation of sheet metal forming has been investigated thoroughly. And the virtual simulation system has been developed for dieless NC process and CNC bending.This paper introduced the architecture of the three-dimensional graphics engine OpenSceneGraph, and its characteristics were summarized. Through analysis of the concept of scene graph, an effective way had been investigated to set up the scene as well as control and manage it.For sheet metal forming equipment and technological features, this paper presents a way to realize the abstract modeling for most modeling geometric entities by the information of two-dimensional contour, using modeling techniques which is based on the stretched body; then calculated the data by use of the reverse polish notation to achieve parametric data, and it enabled same geometric topology model to generate a series of physical models with different sizes and specifications; At last, a method of two views extrude modeling based on simple extrude model technique and two-dimensional contour information is proposed to build simple engineering models fast.For the requirements of the simulation of dieless NC, the path simulation has been realized through transfer G codes with the technology of key frames and the control of timeline. The discrete method based on image space has been used to build rough model with cylinder voxels to achieve a high performance algorithm for the detection of collision. This simulation system has been applied in the AFS2 software of dieless NC process planning.During the development of CNC sheet metal bending simulation system for Huazhong CNC, firstly, simulation capabilities of flexible sheet metal is solved by using morph target animation, and its display performance has been optimized by the way of vertex buffer objects.The motion animation manager was designed by hardware abstraction layer of the CNC system to achieve the connection between virtual simulation system and CNC system. By the research of bending process the synchronization between the flexible simulation and the motion of bending machine has been achieved and the system can simulate a continuous bending process. Additionally, the simulation of expansion length, spring back, thinning and other features in bending process can be supported in this simulation platform.