Low-temperature continuous furnaces for annealing headlights in the automotive industry
For the annealing process to remove stress after welding in automotive headlights or rear group lamps, we have manufactured a whole range of low-temperature furnaces with a vertical paternoster conveyor and several furnaces with a horizontal chain conveyor. The forced air circulation divided into several zones in these furnaces ensures perfect temperature distribution directly on the charge. The paternoster conveyor in furnaces with a vertical conveyor (e.g. furnace SV 30500/15) also minimizes the demands on the built-up area.
For headlamp manufacturers, it is essential that there is minimal dust inside the furnace. The lamps are painted after the heat process, there must be no dust on them and the inlet and outlet of the furnace are connected to a super clean room to maintain the given conditions. The interior of the furnace is also designed to keep dust to a minimum. We therefore had to ensure that no insulation was exposed anywhere in these continuous furnaces. All mechanical parts and insulating surfaces inside the furnace chamber are covered with sheet metal and sealed with a special silicone-free gasket.
Another requirement is to maintain the exact temperature distribution in the furnace, which we had to check directly on the parts. Since these are continuous furnaces with a conveyor, we measured the temperature distribution using non-contact sensors. Thanks to the powerful air circulation, we managed to achieve the required value of +/-3 °C.