Friction Conditions on Deep-Drawing Tool Radii When Using Volatile Media as Lubrication Substitute

Abstract

Sustainability in production and avoidance of harmful substances are widespread drivers for further developments of production processes. In conventional deep drawing, for example, mineral lubricants are usually used to reduce friction or wear and to avoid surface damage to components. These lubricants often contain harmful additives such as chlorinated paraffins. Furthermore, the lubricants must be applied to the sheet metal before the forming process and removed again, as they have a negative influence on subsequent processes such as bonding, welding and painting. In order to counter these disadvantages a new tribological system for deep drawing processes was developed using volatile media (nitrogen or carbon dioxide) as lubricant. The advantages are avoidance of harmful substances and reduction of necessary process steps, since these media are introduced directly into the tools during forming and evaporate without residue after the process. In this context, the present work deals with experimental investigations on the tribological friction conditions at tool radii using volatile lubricants, such as CO2. In order to keep the multitude of possible influences on the tribological system as low as possible, the investigations were carried out on a strip drawing testing rig with simple deflection. The aim of the investigations was the characterization of the tribological system and the friction conditions at tool radii under varying boundary conditions such as retention force and injection angle of the lubricant.