Research Article

Lubricant-free deep drawing using CO₂ and N₂ as volatile media injected through laser-drilled microholes

¹ Institut für Strahlwerkzeuge, University of Stuttgart, Pfaffenwaldring 43, 70569 Stuttgart, Germany
² Institute for Metal Forming Technology, University of Stuttgart, Holzgartenstrasse 17, 70174 Stuttgart, Germany
³ Fraunhofer Institute for Interfacial Engineering and Biotechnology, Fraunhofer IGB, Nobelstraße 12, 70569 Stuttgart, Germany

^* e-mail: gerd.reichardt@ifu.uni-stuttgart.de

Received: 14 December 2018
Accepted: 24 April 2019

Abstract

Most metal forming processes use lubricants based on mineral oils as an intermediate medium to reduce friction and wear. To avoid the well-known drawbacks of oil lubrication, a novel and environment friendly lubrication system for deep-drawing processes was demonstrated at the University of Stuttgart. Liquid carbon dioxide and gaseous nitrogen are being used as volatile lubrication during the deep-drawing process, locally injected at high pressure through laser-drilled microholes. This new tribological system provides a significantly enlarged working range and at least 15% larger drawing depths compared to conventional oil lubrication.