Researchers have used the Spraytec laser diffraction particle size analyser from Malvern Instrument to optimise the application of water-based furniture coatings using airless spraying.
Spraytec is a laser diffraction particle size analyser designed for use in a diverse range of spray applications, and is used across different industries.
With data acquisition rates up to 10kHz, broad dynamic range (0.1 to 2,000 microns) and patented multiple-scattering algorithm for measurement at high concentrations, it provides real-time characterisation for product optimisation and quality control.
As a result of work with the Spraytec, the researchers from Becker Acroma - a manufacturer of high-quality solutions and customised systems for the wood finishing industry - have been able to tailor the droplet size of the paint to different applications, ensuring the best possible surface finish.
Mikael Beving, research and development project leader at Becker Acroma, said: 'Within an individual paint, we could very clearly see the application parameters that resulted in smaller droplets produced a smoother surface.
'The Spraytec proved to be a good optimisation tool for coating application,' he added.
Waterborne coatings are used increasingly in wood finishing, producing results similar to those of solvent-based paints but with less environmental impact.
In terms of their application, the use of airless spraying reduces overspray, and at the same time increases transfer efficiency and production rate.
However, droplet size of the applied product is critical and must be optimised and maintained in order to assure the application of a uniform coating.
Spraytec is said to be proving well suited to characterising paints and coatings, where it is important to be able to measure high-concentration sprays of different geometries and having wide spray fans.
Its ability to measure in real time has allowed the Becker Acroma teams to track the changes in droplet size, which can occur during coating operations.
Using the Spraytec, the researchers have been able to investigate a number of parameters, beginning with the variation in droplet size across the spray fan, to assess how the range of sizes within the distribution affects the finish.
Since sprays are often used at an angle, which introduces a variation in the distance between nozzle and target, the effect of distance on droplet size has also been examined, as has the effect of liquid pressure on droplet size.
As a result, they have been able to tailor the droplet size to different applications by varying the paint pressure.
