Studies on wrinkling and control method in rubber forming using aluminium sheet shrink flanging process

• Wrinkling was analyzed by shrink flanging in rubber forming process with orthogonal experimental design.
• Different factors had large effect on the extent of wrinkling.
• The best range of the forming pressure is under 300 bar for 2024-O and 7075-O.
• Three steps forming is a good method to control wrinkling of shrink flange in rubber forming process.

Thin aluminium sheets have great usage in aircraft manufacturing due to their light weight and high strength. Wrinkling is one of the major defects in the rubber forming of aluminium sheets and may be an obstacle to assembling the parts. In this study, wrinkling was analyzed by shrink flanging in rubber forming process with orthogonal experimental design. Four effect factors (die radius, the flange length, die fillet radius and forming pressure) were analyzed. Three alloy materials (2024-O, 7075-O, 2024-T3) were used as material. The area of wrinkles was introduced to analyze the difference of the effect factors. It was found that different factors had large effect on the wrinkling. The extent of wrinkling of different materials agrees well with their strengths. The best range of the forming pressure is under 300 bar for 2024-O and 7075-O. Wrinkling can be predict using numerical simulation. Three steps forming is a good method to control wrinkling of shrink flange in rubber forming process.