in de 100 47 929 a1 this control is used to prevent the pressure in the bottom of the casting frame 2 from becoming too high so that liquid metal can flow out at the downstream side of the casing frame 2 in one embodiment the foil casting device comprises a thickness measuring apparatus 14 which is designed to measure the thickness of the foils 16 produced one example of a thickness measuring apparatus is a proximity sensor 14 which uses a laser beam to measure the distance between a top surface of the foils 16 and the proximity sensor 14 since the distance between the substrate belt 8 and the proximity sensor 14 is known the thickness of the foils 16 can be determined from the measured distance the thickness measuring apparatus 14 is designed to send thickness information to the control module 10 if the metal foils 16 are too thick the control module 10 will lower the pressure in the casting frame by supplying less liquid metal with the aid of the feed device 6 as a result over the course of time the pressure in the bottom of the casting frame 2 will drop thereby reducing a contact surface area between the metal and the substrate belt 8 as a result there will be less heat transfer between the metal and the substrate.