Process monitoring of the wire drawing process using a web camera based vision system

Abstract

Wire drawing is a cold metal forming process where a wire is drawn through a series of dies, reducing the wire dimension, and enhancing the material properties. The wire drawing process requires lubrication to function, as discrepancies in the lubrication can cause failure of the entire process. Such incidents can be costly and there is a need to monitor the process so that changes in the lubrication can be detected, and addressed, before failures occur. The aim of this work was to determine whether a CCD-camera could be used to monitor the wire drawing process. The purpose of the monitoring was to detect if the process was about to fail. In this work the failure of the process was initiated by removal of the lubricant, causing galling between the wire and the die. The signal from the CCD-camera was compared to the signal from a drawing force measurement that clearly indicates when the friction in the die increases, which in turn indicates imminent failure of the process. It was found that the CCD-camera signal clearly indicated the removal of lubricant, and thus failure. In this work, the CCD-camera was tested on two different wire materials and two different lubricant, both with positive results. All tests were performed in an industrial wire drawing setup.