Abstract
The application of draw beads in sheet metal stamping ensures controlled drawing-in of
flange parts. Lubrication conditions in draw beads are severe due to sliding under
simultaneous bending. Based on the original draw bead test design by Nine [1]
comprehensive studies of friction in draw beads have been reported in literature.
A major drawback in all these studies is that friction is not directly measured, but
requires repeated measurements of the drawing force with and without relative sliding
between the draw beads and the sheet material. This implies two tests with a fixed draw
bead tool and a freely rotating tool respectively, an approach, which inevitably implies
large uncertainties due to scatter in the experimental conditions.
In order to avoid this problem a new draw bead test is proposed by the authors
measuring the friction force acting on the tool radius directly by a build-in piezoelectric
torque transducer. This technique results in a very sensitive measurement of friction,
which furthermore enables recording of lubricant film breakdown as function of
drawing distance. The proposed test is validated in an experimental investigation of the
influence of lubricant viscosity on the limits of lubrication in drawing of stainless steel
sheet.
| Original language | English |
|---|---|
| Title of host publication | Proceed. ICTP2005 |
| Publication date | 2005 |
| Publication status | Published - 2005 |
| Event | 8th International Conference on Technology of Plasticity - Verona, Italy Duration: 9 Oct 2005 → 13 Oct 2005 Conference number: 8 |
Conference
| Conference | 8th International Conference on Technology of Plasticity |
|---|---|
| Number | 8 |
| Country/Territory | Italy |
| City | Verona |
| Period | 09/10/2005 → 13/10/2005 |