Influence of blank thickness fluctuation on flange state and final thickness distribution in the power spinning of thin-walled head

The initial blank exists unavoidable thickness fluctuation. In the spinning process of head parts, this fluctuation affects the flange state and final wall thickness distribution of the parts, which seriously deteriorates the forming quality. To research the blank thickness fluctuation on flange and spun head thickness distribution, three-dimensional (3D) finite element (FE) models considering blank fluctuation for the spinning process of 2219 aluminum head parts were established. The blank fluctuation was characterized using the Latin hypercube sampling method (LHS), and three fluctuation ranges and three fluctuation types were adopted (type 1, the average blank wall thickness is approximately equal to 1.0 mm, 1.0 mm is defined as the ideal standard blank thickness (ST); type 2, the average blank wall thickness is bigger than ST; type 3, the average blank wall thickness is smaller than ST). Then, flange fluctuations and the variations of wall thickness deviation were analyzed. The results showed that the maximum flange fluctuation appears within the 20% spinning process; the maximum flange fluctuation of type 1 is larger than those of type 2 and type 3. In the top zone of the spun head, the maximum wall thickness deviation of type 3 is the largest. While in the middle and edge zones, the maximum wall thickness deviation of type 2 is the largest. Simultaneously, a greater initial blank fluctuation leads to the bigger thickness frequency deviation. The research provides an in-depth understanding of the effects of blank wall thickness fluctuation on the forming quality in the head spinning process, and thus lays a basis for choosing the blank.