The process steps for powder coating on wood
Process steps for wood powder coating applications follow:
- The substrate is evenly heated in infra red(IR) and/or convection ovens to achieve required conductivity,and release gasses. Typically, the substrate surface temperature is equalized at 200-220° F before entering the spray booth,although some have had success at lower temperatures. Woodmoisture must remain equalized across the surface at about 4 to 6% or higher to maintain conductivity for powder adherance.Since heat evaporates moisture, careful controls on preheating are necessary.
- After preheating, powder is typically applied electrostatically, in a booth. Corona or tribo spray systems are recommended.
- Recovery systems utilize cyclones or filtration to recover 95 to 99.9% of overspray, which can the reused as is.
- Thermosets are cured by IR and/or convection. UV powders are initially melt flowed by IR/convection, then cured with UV light. Time, temperature, and IR or UV settings and wavelength vary with film and substrate thickness, powder, and substrate size and shape.
- After curing, parts cool in open air, or thermosets may cure in a forced air tunnel