The use of dry film lubricants in aluminum sheet metal forming

In the process of aluminum sheet metal forming, the tribological system is mainly influenced by the surface texture, the surface of the draw die and process parameters such as deformation rate and lubrication. Because of their high deep drawing performance today’s production process is mainly based on liquid lubricants. Due to the very sensitive surface of aluminum blanks dry film lubricants were developed in order to protect the blank surface during transportation and handling. Now dry film lubricants show advantages over conventional oil lubricants because of their higher deep drawing performance, especially on complex shaped body panels. Beyond that a cleaner process within the press shop can be established. In this paper the effect of dry film lubricants on the deep drawing process of aluminum alloys is shown. This is proven by fundamental experiments on the tribological properties in a stretch forming test and drawing investigations on complex shaped automotive body panels. The characterization of the blank surface is based on 3D surface parameters which are more appropriate for the classification of tribological properties of a surface texture than conventional 2D parameters. To show the great step forward in formability, some series applications in the press shop are presented.