Feasibility analysis of lubrication through magneto-rheological fluids in sheet metal forming processes

Magneto-rheological fluids represent one of the most recent technologies introduced in many industrial applications to design fast and reliable electro-mechanical devices. Such fluids, which consist of a dispersion of metallic particles in a fluid carrier, may drastically change their rheological properties when subjected to external magnetic fields with short response times and low power consumption. Up to date, the most common applications of MR fluids regard the integration in mechatronics applications mainly in civil and mechanical fields, where they are often used as active lubricants in rotary components such as bearings. However, no investigations can be found in literature on their tribological performances when applied in metal forming processes. The paper aims at investigating the tribological behaviour of magneto-rheological fluids when applied as lubricants in sheet metal forming processes. To this aim, a new experimental apparatus has been developed to test the friction coefficient at the interface between the tools and the metal sheet when different magnetic fields are applied. The stamping of AA alloys was taken as reference case to select the process parameters in terms of contact pressure, magnetic field and sliding speed.