Investigation on ultrasonic-assisted embossing process of micro-features with variable curvature as functional surface using ultra-thin sheet of 5052 aluminum alloy

Functional surface with pattern micro-features of sine waves fabricated by ultra-thin metallic sheet is very useful as a shield charactered by variable curvature to diffusely reflect strong light on the severe condition and reduce weight. However, the shape accuracy is difficult to realize using traditional process for the existence of obvious springback. A novel ultrasonic-assisted embossing is developed to precisely fabricate the complex curved surface using its advantages of “Blaha effect.” Some advantages of ultrasonic such as residual softening effect and eliminating residual stress are accepted to reduce the springback micro-features. Effects of embossing parameters were studied by considering the change of strain states. Improvement of shape accuracy by ultrasonic energy and duration time was investigated in the reducing of the springback and increasing of the amplitude of formed sine waves micro-features. Analysis and discussion of the deformation behaviors and springback were carried out in ultrasonic-assisted embossing from the viewpoint of residual acoustic softening effect and eliminating residual stress. Ultrasonic energy and duration time are the main parameters which affect the amplitude of sine waves. Experimental results indicate that the ultrasonic-assisted embossing process is helpful for precisely manufacturing the complex surface with variable curvature using ultra-thin metallic sheet.