Novel Approaches for In-line Draw-in Measurement Using Cost Effective Tactile Sensors

The application of Industry 4.0 and advanced controllers is advancing rapidly in deep drawing and stamping companies. The main goals of process monitoring, sensor data analysis, and the design of new controllers are process optimization and increased process robustness. These approaches directly result in reduced scrap and the development of more environmentally friendly processes. During process monitoring, measuring draw-in is crucial for both the try-out of new tools and production monitoring of stamping operations. This measurement allows for adjustments in lubrication and blank-holder forces, leading to a more robust process. This paper presents a novel method for the in-line draw-in measurement using cost-effective and robust tactile sensors based on pneumatic cylinders. The new sensor can track draw-in when curved blank-holders are used, allowing the monitoring of the full draw-in temporal curve. This paper first presents the design of the new sensor along with its accuracy measurements. Next, the sensor is tested using curved blank holders, and the buckling behaviour of the contacting finger is analysed. Finally, the sensor’s performance in a real-world environment is evaluated.