On the potential of stereo digital image correlation in thermoforming

Process insight in thermoforming is a critical factor to secure the production of high quality parts. In thin gauge thermoforming, different tools exist to monitor this complex process and to gain insight. In heavy gauge thermoforming, this is not yet the case. The current paper demonstrates by means of three applications how in situ digital image correlation (DIC) can be used as a tool to acquire in depth knowledge of the ongoing process. In the first application, it is used as a 3D reconstruction tool. The second describes how full fields wall thickness distribution can be retrieved. The third application combines the previous two and demonstrates how the effects of asymmetric heating can be quantified. The technique makes it possible to visualize in a simple and straightforward way the amount of thinning of the sheet in every step of the process. In all three cases, the main goal is to provide more process insight, making it easier for the thermoformer to master his process, reduce the setup time for new products and control the process parameters.status: publishe