Implementation of additive-manufactured hydroforming die for thin metal bellow production – a stride towards additive manufacturing in rapid tooling approach

Abstract

ABSTRACT The hydroforming die was designed based on the required operating conditions. The Fused Deposition Modeling process, Acrylonitrile Butadiene Styrene material, and sparse mode style were used for the fabrication. The first attempt at using the hydroforming die to create SS316 bellow (0.3 mm thickness x 2 ply) failed due to excessive pressure concentration at the convolution region. The die was redesigned to enhance overhanging convolution imprints and reduce their length to 50% of the original design, followed by an ANSYS simulation to identify critical failure regions. The second trial of the hydroforming die for producing SS316 bellow (0.2 mm thickness x 1 ply) was successful in a brief run. However, the formed metal bellow displayed an increased convolution width, attributed to the reduced convolution imprint length in the redesigned die. The stress analysis indicated maximum Von Mises stress at the convolution imprint and minimum stress at the die’s outer boundary. The sparse mode die showed 18.104% lower material consumption and 16.225% shorter build time than the solid mode, with a porosity difference of 30.668%. A 6.66%-dimensional error occurred due to oversizing in the topmost convolute, suggesting a 30% reduction in convolution imprint length to mitigate this error in future designs.