FLIR thermal imaging helps ensure plastic weld integrity

FLIR thermal imaging has complemented Yanfeng Automotive Interiors’ IR welding thanks to its ability to measure the efficiency of the welding process.

The technology is responsible for ensuring consistent welding quality, high product throughput, and reduce wastage.

Yanfeng uses IR welding on the defroster grille for the Ford Escape vehicle, and during the process two halves of the product are held rigidly in position near the infrared platen to melt the joining surfaces.

The platen is then removed and the two parts are driven together to re-solidify under pressure.

Shortly after installing this new technology, management realised that there was no real way of telling if the weld had succeeded, except by conducting a visual check after the heat cycle had been completed, which essentially stopped production.

Also, as two pieces per hour were taken for sample inspection, the method could not ensure 100 per cent product quality.

The use of thermal imagery to ensure the integrity of the weld made clear sense, and Yanfeng chose continuous monitoring of thermal performance with FLIR A315 fixed mounted thermal imaging cameras.

Not only did this allow quality to be controlled automatically, but also without incurring production downtown.

The FLIR A-Series is widely used in the automotive industry for checking the functionality of a variety of systems such as heated car seats, windscreens demisters, and exhaust systems.

The compact nature of these cameras allows them to be installed discreetly in any production system and integrated into the control network so that all thermal anomalies are detected automatically.

Following successful trials, four FLIR A315 cameras were installed on the Yanfeng IR welding machine responsible for joining the defroster grille.

Together they monitor 40 regions of interest on the plastic parts after the heat cycle, and in combination with dedicated analysis software they recognise when a registered temperature is within the upper and lower control limits that determine a good weld.