Powder coating line has been proven to be the most important factor to obtain high-quality MDF powder coating.
Powder coating line has been proven to be the most important factor to obtain high-quality MDF powder coating. Unfortunately, the small metal surface powder coating company, if you want the old metal powder coating production lines to obtain high-quality MDF powder coating is impossible.
The most important part of the spraying production line oven technology oven paint melting. If the thermal curing powder chemical curing. To remember is that the low thermal conductivity of the MDF. Therefore, the design of the oven need to make their temperature can be evenly distributed; Otherwise, the heat does not like aluminum distribution in the entire substrate surface. However, the heating on the MDF, you must ensure that the surface temperature of the uniform distribution
Due to the low thermal conductivity of the MDF, we just take advantage of this. As previously discussed, the powder in an appropriate temperature melting and solidification. This temperature more often than the MDF can bear. However, when the powder is infrared heating, the powder and the surface of the board quickly reach the temperature of melting and solidification. Slow due to the thermal conductivity of the board, the center of the plate temperature is still relatively low, much lower than the temperature in the melting and solidification of the entire powder completion of the process. Therefore, the thermal stress in the MDF board is minimized, resulting in no damage.
We can see two kinds of oven described above melting and solidification of the thermal curing and UV curing, and is not suitable for MDF powder coating. Conventional thermal curing of the entire powder and MDF heating, due to the low thermal conductivity of MDF to reach 150-160 degrees requires a long time. The results of powder has not fully cured, MDF has been damaged. Other UV curing, so far in order to achieve uniform distribution of UV intensity and dose, while the different colors, different powder coating thickness curing degree. Thus the UV curing has not yet successfully used the example of MDF powder coating. However, UV curing for MDF powder coating transparent powder according to the optical layer (in this case without a detailed description).
Melting and solidification can be successfully used for MDF powder coating is the infrared oven. The challenge is to provide the MDF surface (including edges) uniform irradiation of infra-red. Fortunately, modern infrared ovens have a high level of uniform irradiation. Figure 6 is a temperature distribution diagram showing the surface temperature measured by the temperature sensor in the infrared oven MDF top, middle and bottom. Very small changes in the MDF surface distribution of temperature, temperature range is less than 15 ° F
A well-designed infrared curing oven shows the MDF substrate at the top in the end the Ministry of below 15 ° F temperature change.
In order to get a good powder coating, before the start powder coating must be the temperature distribution within the oven were measured. Measurement and monitoring not only in a surface location, but also around the MDF surface, including its edge. The oven temperature should be adjusted to avoid the different positions of the temperature difference between the temperature exceeds the limit value, for example, less than 15 ° F. Figure 7 is a two temperature distribution in Figure a and Figure b. Figure 7a is an adjustment well infrared oven; sensor is fixed to the MDF surface of a variety of positions, including the edge. We can see the MDF surface temperature distribution is very uniform.
Obviously, the surface of the MDF oven temperature setting change is greater than 75 ° F can not be uniform powder coating performance. In some cases, due to technical defects of the oven, even the uniform distribution of temperature can not be realized. In other cases, a well-designed ovens in a suitable temperature settings. These cases will lead to the production should not be used in powder coating, in many cases will lead to the failure of MDF powder coating.
On a given substrate size (including the edge), melt – maximum temperature of the curing oven before making any decision with the manufacturer, a good discussion, as well as strict rules. Once the oven is installed, the production line must be set up through the production process in the temperature distribution measurement and continuous temperature distribution monitoring to optimize. This will ensure that the quality of the powder coating to meet the specification.