Surface purification: during the manufacturing process of the workpiece, some iron filings, oil stains and dirt will inevitably be added. A blower and other methods are needed to remove various mechanical impurities and possibly conductive particles.

Pre drying: pre drying shall be carried out before impregnation. The purpose of pre drying is to drive out the moisture and volatiles inside the workpiece, and make the workpiece have proper temperature, so that the insulating paint is easy to penetrate. During pre drying, the temperature shall be increased gradually, and the heating speed shall not be greater than 30 ℃ / hour. If the temperature is raised too fast, the moisture on the surface of the workpiece will evaporate quickly, and the moisture will diffuse from the surface to the inside of the workpiece, so that it is not easy to discharge. The pre drying temperature is 120 ± 5 ℃. Pay attention to exhaust during pre drying, so that the water vapor in the drying room can be discharged in time, but the temperature shall be maintained.  

First dip: the product is generally immersed. Lift the workpiece into the paint tank, and the paint surface shall not exceed 20 mm of the workpiece, so as to have enough pressure to make the paint liquid penetrate into all the gaps of the workpiece. Before impregnation, the temperature of the workpiece is 50-60 ℃, and if the temperature is too high, the insulating paint solvent is volatile; if the temperature is too low, the fluidity and permeability of the insulating paint are poor. The soaking time is about 15 minutes (adjust according to the volume of the workpiece until there is no bubble).

First paint dropping: take out the workpiece soaked with paint and drop the remaining paint to avoid a large amount of volatile gas after entering the drying room. The dripping time shall be more than 30 minutes.

First baking: the baking process is divided into two stages, the first stage is low temperature stage, the temperature is controlled at 60-80 ℃, about 3 hours. At this time, if the temperature is too high, the surface of the workpiece will dry too fast, which will affect the inner layer drying; the second stage is the high temperature stage, when the temperature is controlled at 120 ℃ for about 8-12 hours, or 150 ℃ for about 5-8 hours, and the insulation resistance value of the workpiece to the ground is more than 6 megohm, and the baking will end when it is stable at the same value for 3 hours. The drying room shall be equipped with a forced exhaust air exchange system to prevent combustion and explosion during baking. The door of the drying room shall be able to be opened automatically in case of sudden increase of internal pressure, so as to ensure safety. The exhaust gas is led out of the room through the pipeline, so as to avoid the explosion hazard caused by too much combustible gas in the room.

Scond impregnation: after drying, the workpiece is cooled to 50-60 ℃ for the second impregnation. The purpose of the second impregnation is to increase the film thickness and improve the performance of the workpiece. If the soaking time is 3-5 minutes and the time is too long, the formed paint film will be damaged.

Second paint dropping; the time of paint dropping shall be more than 30 minutes.

The second baking: the baking process is divided into two stages, the first stage is low temperature stage, the temperature is controlled at 60-80 ℃, about 3 hours; the second stage is high temperature stage, the temperature is controlled at 120-150 ℃, and the baking ends when the insulation resistance of workpiece to ground is greater than 10 megohm and stable at the same value for 3 hours.

The viscosity of the paint in the paint tank will be increased due to the use of several times or the volatilization of the solvent which is not tightly sealed. Et1000 diluent can be used to adjust the viscosity according to the required viscosity (coating - 4 cups, 23 ℃, 20-35 seconds).