Research Of Surface Quality In Single Point Incremental Forming Part Of Sheet Metal

Single point incremental forming (SPIF) of sheet metal technology is a new plastic forming technology. Compared with traditional processes which don't need special mould forming process, saves the traditional mould manufacturing and maintenance cost and short processing cycle. It's suitable for processing small quantities and many varieties and complex sheet metal the workpiece, and forming equipment required for low energy consumption, small local sheet forming force. It belongs to the modern green processing category,which has broad application prospects in the industry of aerospace, automotive industry and medical field etc.The poor surface quality of forming parts is the main aspect of restricting the popularization of this technology. It is important to study the influence factors and rules of the surface quality of forming parts to improve the surface quality of the parts.According to the principle of single point incremental forming, the geometric model of the residual wave height on the surface of the straight and free surface is established. The influence of the forming parameters of the straight wall and the free surface on the residual wave height of the surface is analyzed. Based on the analysis of the characteristics of single point incremental fotming friction, the characteristic model of the residual wave height on the surface of the forming parts is established.The influence of material properties on surface waviness is analyzed.Based on HASS-VF Vertical NC machining center, a single point incremental forming experimental platform has been established. Research on feed step, tool radius, straight wall forming angle, curvature radius and freeform surface normal angle of forming parameters on the straight wall, "concave and convex" free surface, "concave" free surface and "convex" free surface four types of parts surface waviness and surface roughness effect. The maximum surface waviness height is compared with the theoretical model analysis, and the reasons for the difference between the two are analyzed. The effects of material properties on the surface waviness are analyzed by experiments, and the validity of the model is verified. The influences of forming parameters such as feed step, tool head radius, feed speed and spindle speed on the lateral surface roughness are analyzed.Grey relational analysis and response surface analysis are used to optimize the surface roughness of single point incremental forming parts. Taking the typical straight wall square cone as an example, the significance of the tool head diameter, the feed step, the feed speed and the spindle speed on the longitudinal and transverse surface roughness of the forming parts is obtained. As well as the overall effect of the longitudinal and transverse surface roughness. The prediction model of the longitudinal and transverse surface roughness is obtained. Based on the longitudinal and lateral surface roughness prediction model, the best forming parameters of the longitudinal and transverse surface roughness of the formed parts are obtained.