In coating industries like paint and automobile, spray systems are widely used to apply both powder and liquid coatings. Years ago, the spray system was not in the picture. The entire coating industry worked manually and the result was not as expected. But today, the spray system has made the work easy and effective.
Though the spray system has reduced the burden of work and improved quality, there are lots of things that you need to be worried about. You need to accurately describe and classify specific spray characteristics of the nozzles used in the spray industry to get the quality finished coating. Not only this, you need to know about spray velocity measurements.
In this post, we have discussed the importance of particle sizing, which is one of the major spray characteristics. You cannot also refer to it as droplet size.
The spray nozzles do not deliver uniform droplets. They atomize into a wide range of individual droplet sizes, which directly affects the output. The coating does not come out accurate and leaves behind a poor impression. Particle sizing is critical in the development of optimized transfer systems.
In liquid coating, determining droplet size is an important part of assessing atomization efficiency. With the change in the properties of the spray plume by manipulating variables like nozzle geometry and atomization pressure, a maximum amount is transferred onto the surface.
In case the spray system is loaded with high solids, it allows good transfer efficiencies and avoids the relatively high cost associated with any waste. High solid systems reduce solvent handling problems and deliver improved coverage.
In powder coatings, optimization of particle size is more complex. It’s because fine powders are less likely to flow freely and are prone to agglomeration. At the time of handling, the cohesive forces between particles increase exponentially with decreasing particle diameter.
Other than flow and dispersion characteristics, the particle size of powder painting correlates with its behavior during the application process. Due to so much complexity in powder spray, the method widely used for coating is an electrostatic spray. In this method, fine particles are important to wrap around an object and coat both sides. But larger particles are easier to charge and control. They have a high degree of straight-line inertia which makes it easy for them to penetrate more successfully into the corners of an object.
What happens during the curing process?
If the particles are small, the pack well on the surface and melt easily in any condition. But unfortunately, they produce a poor surface finish as a result of melting too rapidly. On the other hand, large particles are associated with severe curing conditions. They take time to melt and leave imperfection on the surface if melted completely.
According to the post, determining particle size is important for spray systems in the coating industry and it should neither be too large nor too small. You should have control of both maximum and minimum particle size to ensure that the finish achieved is acceptable.