US Patent 7197839 Microwave drying method of honeycomb formed bodies

A method for drying a honeycomb formed body using microwaves is provided. The method can reduce the difference in the drying speed inside the honeycomb formed bodies during the drying process and can dry the honeycomb formed bodies without cell deformation. The method comprises placing the honeycomb formed body in a drying furnace with the cell axis in the vertical direction and irradiating the honeycomb with microwaves at a frequency of 300–30,000 MHz. The difference of the water content in the vertical direction of the honeycomb formed body 1 is maintained at 0.3% per mm or less during microwave irradiation.