Review of Rubber Based Sheet Hydro-forming Processes

Rubber based forming process is a versatile metal fabrication process used in commercial aerospace, automotive and defence applications. It is well suited for prototyping and production of small quantities of sheet metal parts. Rubber based forming employs a rubber pad contained in the rigid chamber or flexible diaphragm as one tool half, requiring only one solid half to form a part to final shape. The solid tool half is similar to the punch as in conventional process. The rubber exerts nearly equal pressure on all workpiece surfaces due to its incompressibility. The multidirectional nature of the force from the rubber pad produces variable radius during forming and thus enhances uniform elongation of the workpiece. The process exploits the benefits of flexible rubber punch and produces the complex shaped sheet metal components with minimal spring back and profile deviation. Parts with excellent surface finish can be formed with no tool marks and severe variations in the metal thickness, as occurs in conventional forming processes, is reduced considerably. Some of the very popular processes under Rubber-pad forming are Guerin process, Marform deep drawing process, Verson Hydroforming process, SAAB rubber diaphragm process and Maslennikov’s process. The paper discusses in brief about these processes and presents literature review of various developments occurred in this field.