Camera control means better welds
1 min read
Surface welding, instead of penetration welding, allows a laser to produce a weld that is only visible on one side. But can the laser's power be controlled to prevent it burning a hole through the metal? A new camera system from Fraunhofer is said to ensure a perfect weld by analysing thermal images in real time.
The process, developed by the Fraunhofer Institute for Physical Measurement Techniques IPM, is called 'controlled partial penetration welding'. The weld seam is controlled to penetrate the lower sheet without damaging the bottom surface. Until now, say the researchers, it was not possible to control this type of welding precisely and to produce a seam that meets strength requirements.
"As we do not weld through the sheet, we cannot see what we are doing," states Andreas Blug, project manager at Fraunhofer IPM. Using an innovative camera that generates thermal images enables the system to recognise how deep the laser has penetrated into the sheets. A software program then adapts the laser's output accordingly. "The process is closed loop controlled in real time," Blug explains, adding "the system can analyse up to 14,000 images per second."
The process is thought to be particularly applicable in automotive applications – in the welding of door panels, for example.
