Experimental and numerical investigation on thin sheet metal roll forming process of micro channels with high aspect ratio

Traditional punch and die stamping process are not capable of fabricating micro channels with high aspect ratio due to stress concentration and large thickness reduction. A thin sheet metal roll forming process using involute gears as rollers was proposed as a method to fabricate micro channels with high aspect ratio in this paper. Corresponding relations of gear-rollers and formed channel's geometrical morphology were firstly established as designing guidelines. Then, process characteristics, material deformation behavior, and process mechanism were studied by experiments and simulation. Micro channels with aspect ratios up to 1.0 was formed with thickness reduction lower than 18.7% using 0.1-mm SS316L metal sheets. And both experiments and simulation reveal that thickness reduction can be further lowered down by reducing friction. The forming process of a micro channel consists of two chronological states-forming stage and quitting stage which, respectively, determines the formability and dimension accuracy. Furthermore, process parameters and assembly errors were demonstrated to have great influences on the process' formability. This paper provides designing guidelines and process mechanism for thin sheet metal roll forming process as a promising method to fabricate micro channels with high aspect ratio.