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Electrostatic powder spraying is the process of applying powder coating onto a coated object through electrostatic action, and baking it at a certain time and temperature to form a coating. The factors involved in this process include the coating object, powder coating, spray gun, baking equipment, etc. Analyzing these factors helps to understand the entire process. Confirmation of the coated object: From an economic perspective, the coated object is a commodity. In addition to metal, wood and plastic should be among the options, among which plastic cannot be considered temporarily due to temperature resistance issues at this stage. For wood, MDF (medium density fiberboard) has become the preferred choice. The reason is that electrostatic powder coating requires materials to have conductivity, while wood is a hygroscopic material that exchanges moisture with the surrounding environment. After a certain period of time, it will absorb moisture from a specific environment at a certain temperature, thus achieving equilibrium. Therefore, under normal circumstances, the moisture content of Kimura products will maintain an appropriate balance with the local climate. It can be considered that by adjusting the moisture content of the wood substrate, the wood can be placed in a state close to or equivalent to a conductor. Medium density fiberboard is a type of wooden product that also possesses the aforementioned characteristics. In addition, medium density fiberboard, as an environmentally friendly green building material, has a huge application volume and is growing rapidly in artificial boards. Moreover, medium density fiberboard is a large-scale industrial product, and its quality stability and product process adjustability are also important factors. It is these factors that make medium density fiberboard the preferred choice for electrostatic powder coating. Technological progress in powder coatings: For a long time, the application range of thermosetting powder coatings has been limited by the curing temperature. In recent years, an increasing number of low-temperature curing powder coatings have emerged. According to relevant reports, powders that can be cured at 120 ℃ x 20 minutes can be prepared, but there are still problems with poor storage stability of low-temperature cured powders, which to some extent limits their application range. It is believed that there will be some improvement in the near future. In the spraying of medium fiber board, the powders used include ultraviolet curing type and ultra-low temperature curing type. It is reported that relevant companies have announced the material of maleic acid/vinyl ether UV curable powder coating, which is applied to MDF. At present, the epoxy/polyester blend powder we use in MDF (medium density fiberboard) is controlled within the high curing temperature range of general coatings. A new breakthrough in electrostatic powder spraying equipment: The corona charging spray gun has gone through several stages such as voltage charging, current charging, and total energy control charging. The first two charging methods limit the sprayed workpiece to metal parts, while the "TEC total energy control charging" technology breaks through the above limitations. This technology mainly lies in the ability to automatically adjust the current and voltage simultaneously when the distance between the spray gun and the workpiece changes, in order to maintain the total charging energy, effectively control the amount of powder charging, and ensure powder feeding efficiency. |