The drying oven is made of thin steel plates, and a glass fiber insulation layer is used between the working chamber and the outer shell of the box. There is a glass door between the box doors for observing the situation inside the studio. Opening the exhaust valve on the top of the box can facilitate the exchange of hot and cold air in the working room. The temperature control is automatically controlled by a thermal expansion controller or digital display instrument, and all electrical operating equipment is installed in the control layer on the side of the box. The control layer has a side door that can be removed for inspection or repair of the circuit. The electric heater is installed under the working chamber of the box and is indicated by an indicator light for heating operation. When the light is on, it indicates that the electric heater is working, and when the light is off, it indicates that the heating has stopped.