1.The surface resistance of MDF is between 10 to the 5th power Ω to 10 to the 9th power Ω, and it is easy to complete electrostatic spraying;

2. The moisture content of MDF sheet is maintained at 4-8%；if the moisture content is too low, the conductivity is not good, and it is not easy to spray.

If the moisture content is lower than 4%, the electrostatic adsorption is too weak. If the moisture content reaches 7%, it has a good electrostatic adsorption capacity at room temperature;

If the water content is too high, pinhole bubbles and cracks are easily generated when applying, and the moisture content of the wood should not exceed 10%.

3. Before spraying, use far-infrared radiation to make the temperature of the plate reach 60-70 degrees (1-2 minutes). At this time, the moisture inside the plate gathers to the surface, and the surface conductivity is improved, which is conducive to spraying;

(There are also literatures that use a preheating drying tunnel of 90-125 degrees, heating for 5-10 minutes, the effect is the same, and the temperature of MDF is slower)

4. When electrostatic spraying, the electrostatic voltage is about 30-50KV, and the electrostatic voltage is too high (rebound effect), which is easy to not -powdering and cause smearing problems;

5. The curing process after spraying, using UV powder, or using low temperature and short time curing powder, the process is different;

UV curing powder: The first stage uses strong infrared radiation and weak convection heating to melt the powder as soon as possible, and the second stage uses weak radiation and strong convection heating. The temperature of the heated gas in these two stages is constant, and the convection plays an auxiliary role in the radiation; the temperature of the convective gas flow is kept at 100 °C, which can reduce the temperature of the part (the surface close to the radiation source or the thinner part) that exceeds 100 °C due to the infrared radiation. After cooling, the UV-cured powder is heated by far-infrared radiation to melt and level to form a smooth film, and finally the coating is cured by ultraviolet rays. The UV lamp should be matched with the powder and distributed evenly.

The whole process of melting and solidification takes about 3 minutes. After the solidification is completed, it is forced to cool down to 35°C with cold air to protect the board.

Strong infrared radiation should be set at the entrance of the drying tunnel to make the powder melt quickly, and the temperature of MDF is still very low at this time;

Low-temperature heat-curing powder: The curing tunnel adopts far-infrared radiation + hot air circulation, strong infrared radiation is set at the entrance of the drying tunnel, and radiation and convection are used in the interior. This drying tunnel is generally longer than that of UV powder, depending on the characteristics of powder coating.