Investigation of the Friction Conditions Occurring During Dry Deep Drawing Using Volatile Media as Lubrication Substitution
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 sheet metal 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 lubricants. 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 paper gives an overview on gained results concerning basic friction investigations using a flat strip drawing testing rig and very first results of a new strip drawing testing rig with a simple deflection. With this testing rig friction conditions and friction coefficients at tool radii can be investigated using volatile lubricants. Also the results of first real deep drawn parts, using this new tribological system is presented, including tool and process set up and the investigations on the remarkably increased process window of this new dry forming process.
KeywordsDeep drawing Friction Dry forming
The scientific investigations of this paper are funded by the German Research Foundation (DFG) within the priority program SPP 1676 Dry Metal Forming - Sustainable Production by Dry Processing in Metal Forming and are carried out by the Institutes IFU, IGVP and IFSW of the University of Stuttgart.
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