Manufacturers face many problems with powder coating quality, we always suggest performing certain tests to ensure at the powder coating products they provide to applicators are of the highest quality and conform to industry standards, especially when adding new types of powder coating additives in your manufacturing materials. For these tests, we suggest examining various qualities of your final product of powder coating. The powder coating properties being tested for include:
DISTRIBUTION OF PARTICLE SIZE
POWDER DRY FLOW
MOISTURE CONTENT
SPECIFIC GRAVITY
BAKING TIME
DISTRIBUTION OF PARTICLE SIZE
Having the right powder particle size and distribution for the application method is one of the main physical requirements that powder coating quality needs to meet. The particle size affects the powder’s ability to take on the electrostatic charge, the electrostatic charge needs to be sufficient for the powder to attach to the surface, and then the powder needs to encourage film build-up without becoming insulating. in case your products still have this problem you can use the Charge Regulator Collection (KC3020, KC3060, KC3090) of our Dongyuan powder coating additives products. The tests for particle size and distribution include sieve analysis(the simplest technique where the powder is passed through a series of sieves), sedimentation techniques(such as the Andreaseanpipette, Backman, and Shimadzu sedimentation balance and photo sediment to the meter), the Coulter counter(a process where the powder is dispersed in an electrolyte), and laser light diffraction.
POWDER DRY FLOW
The dry flow of a powder coating can clearly affect powder handling, and transport, and sprays the amount through feed lines during application and recovery. A powder needs to have reasonable flow characteristics, and the wider the particle size distribution the worse the flow of the powder. In case your products still have this problem it is suitable to use the Accelerator Collection (KC5210, KC5230, KC5280) of our Dongyuan powder coating additives products. Tests for this include the angle of repose (analyzing the angle formed as the powder gathers in the apilesona collecting plate), and the SAMES flow meter(measuring powder behavior in a ‘fluidized’ clear plastic tube).
MOISTURE CONTENT
Moisture level content is one factor that can directly affect the powder coating quality of texture, distribution, and flow. The most common method of determining moisture content is using the oven at 150°C to heat a quantity of powder in an oven. A more accurate method is to heat weighed amount for 15 minutes in a 200°C oven before allowing it to cool in a desiccator.
SPECIFIC GRAVITY
The specific gravity of a powder coating is its density relative to water. Water has a specific density of 1. This is an important measure because it helps calculate the coverage of the powder and so the cost as a function of coverage. It is measured through either displacement Oragaspycno meter. In the displacement method, much like Archimedes in his meter, the amount of fluid displaced by a known powder weight is used to determine its specific gravity. Agaspycnometer measures the volume of air displaced by a known weight of powder and is the more accurate method.
BAKING TIME
The gel time of a powder coating is the length of time it takes for a thermosetting powder to gel on a polished metal surface at a specified temperature. It is a useful indication of curing agent speed and the consistency of powder quality. In case your products still have this problem it is suitable to use the Accelerator Collection of our Dongyuan powder coating additives products.