The baking plates and the baking process are the core piece of industrial wafer production. Haas wafer baking ovens contain up to 176 baking plate pairs. Besides the recipe of the batter, the most decisive parameters for a high-quality baking process are the baking temperature and the baking pressure, which builds up between the closed baking plates during baking. The closer in time to the process these parameters are measured and controlled, the better are the baking results. Up to now, however, this was impossible during baking due to the difficult conditions of the measuring environment.

Franz Haas has solved this problem. The new “intelligent baking plates” contain a sensor, which transmits data about baking temperature and baking pressure by radio signal in real time. Furthermore, this data also allow distinguishing information from each individual baking plate in the oven. All data are either sent to the control panel where a human operator can take immediate corrective action or they are automatically compared with preset values by the oven control system which regulates accordingly. The difference between actual and target temperature is immediately recognized enabling to identify and correct inaccurate heating settings without delay and to optimize energy consumption.

What´s behind this? The concept of the "intelligent baking plate“ was introduced for the first time at the Interpack 2011, where visitors were guided through the whole wafer baking process: at the beginning, the baking plate pair is open and batter is applied by a depositor onto the lower baking plate. The upper plate is then lowered to close the baking plate pair before it enters the baking chamber of the oven, where the batter is baked to wafer sheets at a temperature of 160 to 180°C. After one full cycle through the oven, the baking plate pairs re-open and the baked wafer sheets are released from the baking plates and transferred to the downstream line.

Up to now, however, it was impossible during baking to transmit signal data because of the baking plates being in direct contact with the flames of the burners which would have destroyed conventional electronic sensors. It was possible to solve this problem by using SAW (surface acoustic wave) technology which allows data to be transmitted wirelessly.