Temperature control during the manufacture of automobile headlights. Checking for proper baking.


Purpose: The manufacturer in this case was already using a sticker to identify each headlight manufactured during the production chain.

This label contains a set of identification data: batch, date, several codes, ...

It was build on this support role to include a thermosensitive witness who enabled this thermosensitive label to verify the temperature reached during baking of the headlights that took place at a particular point in the chain of production. Specifically, it is needed to check that exceeded 80 ° C during the baking of the piece.


Thermosensitive Product Used: Irreversible Ink 90. If you want to access to the online website sales, click onto the left upper "shopping basket button ".


Work done: the client chose an area of the ID label so that it was printed with ink irreversible 90. This ink, at room temperature, is white. The final design was implemented in rectangular stickers, supplied on rolls for more effective handling.

At the start of the manufacture process, the operator sticked a label on each carrier / batch; at this time, the label showedcompletely white and only the printed data was visualized in the conventional black ink for identification of each headlight. At the end of the production chain, the headlights had passed through an oven at 80°C and thus the label had to show a black coloured vertical band. Although the temperature to certify was 80°C, the ink was calibrated at 90ºC due to the typical hysteresis of these inks.


This system allowed temperature control with a completely unassisted mode and it was possible to obtain directly the actual temperature at the surface of the headlight. Furthermore, as the indicator passed all the headlight manufacture chain, the reading obtained was totally reliable and accurate.