Research On Multi-stage Single Point Incremental Forming

Multi-stage single point incremental forming is a novel technology proposed for sheet metalparts with large forming angle. To understand and master multi-stage single point incrementalforming is very important for the development of incremental forming technology. Therefore, thisarticle studied multi-stage incremental forming in three aspects that is deformation law, processoptimization and accuracy based on multi-stage. Main research contents and results are shown asfollows:1．Study on the deformation law. Flowage property and strain distribution was studied based onthe deformation trend of the part gained by multi-stage single point incremental forming.Experimental results show that a significant second major strain, increasing with increase in formingdepth, exists and thickness decreases with increase in forming depth for the part. According to theanalysis of the experiments, a limitation in forming depth in multi stage single point incrementalforming was proposed. Further more, increasing the quantity of stage can avoid the stepped featureand improve the forming quality.2．Study on the optimization of process. Conducted an experimental research on the process ofmulti-stage single point incremental forming for hyper-hemispherical shell to discuss the processoptimization principle of the first stage and the succeeding stages, and found the influence of the toolmoving direction on wall thickness, managed to get uniform wall thickness of hyper-hemisphericalshell. Experimental results show that the principle to get uniform wall thickness is to adjust the firstplastic deformation region for wall thickness of large fluctuation range and change subsequent toolmoving direction for wall thickness of small fluctuation range.3．Study on the shape accuracy based on multi-stage single point incremental forming. A bulge ofside wall existed on pyramidal parts in single point incremental forming. Experimental results showthat the multi-stage strategy can improve the shape accuracy significantly, and the multi-stage strategywith an increase radius in corner can make the bulge nearly disappear, the more stages used, thehigher accuracy gained.