Deep Drawing with Hydrodynamic Lubrication
A modified Deep Drawing process is proposed which eliminates dry friction by hydrodynamic flow. In principal, this process enables an increase in the Limit Drawing Ratio (LDR) by virtue of relaxing interfacial constrains. The fluid is enforced to lift up the blank from the die and to stream radially beneath it in a narrow gap. The coupling between the hydrodynamic flow parameters and the process variables (speed of operation, geometry of the tools, etc.) is presented. The analytical study of the process is idealized for non hardening and isotropic material but with accounting for various frictional conditions not considered hitherto. Implicit equations which relate the LDR to the governing parameters of the process are derived for two cases for comparison (a) dry friction (b) hydrodynamic lubrication. A supplementary approach based on an upper bound formulation leads to a similar behavior. An experimental apparatus is used to investigate the feasibility of the proposed process by testing cylindrical-cup forming in various conditions. Positive results are shown.
Unable to display preview. Download preview PDF.
- 10.B. LARSEN (1977) Hydromechanics Forming of Sheet Metals, Sheet Metal Ind. 162–166.Google Scholar