Abstract
In-situ stamping process monitoring plays a critical role in enhancing productivity and ensuring part quality in sheet metal stamping. This paper investigates the realization of two sensing methods to create a tooling-integrated sensing system: mutual inductance-based displacement measurement for sheet draw-in, and distributed contact pressure measurement at the tool-workpiece interface. The two sensing systems are complementary in nature, and together, they significantly enhance the on-line observability of the stamping process. The performance of the draw-in sensor was evaluated using numerical simulations and experiments in a small-scale and a large-scale lab setup, and its effectiveness has been confirmed under the presence of wrinkled sheet. To study the spatial and temporal variations of the tool-workpiece contact pressure in a stamping operation, experiments were conducted on a customized panel stamping test-bed with an array of thin-film force sensors embedded below the die flange and die cavity. The force sensor data were then numerically interpolated to form the contact pressure distribution across the tool-workpiece interface, based on the thin plate spline (TPS) method. Comparison between the interpolated pressure obtained from the surface generation techniques and direct measurement using redundant sensors and a press mounted load cell confirms the validity of the new contact pressure sensing method. The integrated sensing technique provides insight into the stamping process by quantifying process variations and providing a reference base for process control to reduce product disparities. Additionally, new product and process designs can be created based on the quantified and referenced variations.
Original language | English (US) |
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Pages (from-to) | 634-644 |
Number of pages | 11 |
Journal | International Journal of Machine Tools and Manufacture |
Volume | 49 |
Issue number | 7-8 |
DOIs | |
State | Published - Jun 2009 |
Funding
The authors gratefully acknowledge funding provided by the National Science Foundation under CMMI-0620957 and CMMI-0620972.
Keywords
- Draw-in sensing
- Embedded pressure sensing
- Stamping process monitoring
- TPS surfaces
ASJC Scopus subject areas
- Mechanical Engineering
- Industrial and Manufacturing Engineering