In-Process Monitoring of Springback in Industrial Bending Using a Laser Sensor-Based Method

Abstract

Bent tubes and profiles are widely used in many industries such as automotive, aerospace and shipbuilding. In bending of tubes and profiles, springback is normally regarded as a challenge, affecting the dimensional accuracy of products. Springback control significantly determines the production route of products, including logistics. At present, effective in-situ measurement methods are lacking. This makes it difficult to realize in-process, closed-loop control of springback for improving product quality and productivity, while putting improved flexibility on the production route. In this research, an in-process measurement technique for monitoring springback in rotary draw bending was developed. A device with a laser transmitter and receiver was installed on a bending machine to detect displacement changes of the part after being released from the tool. The displacement information was collected by a controller that shows the measured displacement. A series of tube bending experiments together with the developed in-line laser sensor measurement and conventional off-line manual measurements were carried out. The result shows that the in-line laser sensor method provides a good capability for springback measurement. Since the laser measurement method is done with no need to remove the workpiece from the tooling system, it facilitates developing an in-process compensation strategy to control springback.