Research On Shape Simulation Of Billet With Twin Nozzles In Multi-spray Forming

In recent years, twin nozzles and multi-scanning are commonly used to spray large size billets. The emergence of high-tech scanning twin-nozzles is one of major breakthroughs to promote spray forming technology in the large-scale production.However, spray forming with twin nozzles is a complex process with many influencing factors. At present, there is little fundamental research work dealing with this in domestic and foreign countries. The numerical simulation of billet's shape can make us learn the evolution of billet and analyze effects of some processing parameters. Lots of cost can be saved if computer simulation is adopted instead of experimentation, which provides technical guidance for industrialization of spray forming technology.In this paper, a pair of multi-spray forming equipment structure is studied and the geometric layout of twin nozzles is also analyzed. Integrating the actual forming process of deposition, a spray forming model is established to predict the shape evolution. Through tracing surface coordinates of the billet, the model can be used to calculate the shape and size at the different time and the result is very reliable. The model proposes a discrete method of calculation for billet's shape, which is simple and feasible. The influence of key process parameters on shape evolution is researched, including the initial eccentricity of nozzle, the initial tilt angle and the largest scanning angle, withdrawal speed of the substrate, rotation speed of the substrate, the atomization coefficient, the scanning frequency and the distance of substrate. Thus the geometric shape and size of product under different conditions can be predicted.A generic flow chart for the optimization of the spray forming parameters for production of billets is proposed. The blindness of process design would be reduced by this method. Optimized process parameters are obtained and on the basis of these parameters, the spray forming experiment is carried on. The experimental result indicates that the simulation result is in good agreement with the actual result. So the model has better forecast function and instruction function to the process design.