A spring roll is a traditional food product in Viet Nam, which has a high market share in the world. A circular net-wrapper with grids inside is used to make a spring roll, and approximately 20 tons of net-wrappers are made daily in the Vietnamese food industry. Because net-wrappers are still done manually, not only its productivity is very low, but also the quality is not sufficient from the viewpoint of food hygiene and shape uniformity. This study deals with the design of an automatic production machine for net-wrappers. First, the mechanical design of the automatic machine that employs a slider-crank mechanism and a rotating disk is presented. Next, kinematic equations are derived to describe combined motions of the slider-crank and the rotating disk. The developed simulation system based on the kinematic equations allows the designer to select geometric parameters to achieve the desired shape of net-wrappers. The experiment’s result showed good coincidence with the simulation and gave a set of reliable geometric parameters for future use by machine designers.