Page 21 - CFCM Sept-Oct-2020_Neat

industrial finishing: POWDER COATING QUICK COLOR CHANGE

Speeding up the Powder

Color Change Process

BY HARSHIT NIGAM

COLOR CHANGE is a precarious issue in a powder coating
system compared to a liquid coating system. The downtime
required for a color change in the powder coatings system
could extend to more than two hours, and hence presents
large obstacles for coating manufacturers in adopting the
coating method. The process hinges on improving first-
pass transfer efficiency (FPTE) and integration of advanced
technology to achieve a quick color change.
Transfer efficiency is defined as the ratio of the amount
of powder deposited on the substrate to the amount of
powder directed to the substrate. In the coating process,
powder materials are attracted to the surface of the
grounded component through the electrostatic charge
caused by the gun generator. A higher charge on the pow-
der particle improves the transfer efficiency. A high first-
pass transfer efficiency can be attained through numerous
processes such as maintaining high gun voltage, maintaining Left: MG 400 EH systems from SAMES KREMLIN are fitted with a fluidized powder
gun target distance between six to 12 inches, optimum tank. The powder pump is built into the gun and removable for cleaning.
powder output velocity, and proper part orientation. Right: Gema’s MagicCylinder design ensures low powder
accumulations and quick cleaning without entering the booth.
The variables impacting the time required for color
change are associated with a reclaim system that includes
booth type (manual or automatic), number of booths, spray- four times in comparison to the conventional pumping
to-waste, recovery system (cyclone separator, or cartridge system, and further improves coating capabilities for large
booth), booth canopy type, powder gun type, and number and complex parts. The low air output over the front portion
of powder guns. These variables affect the time utilized in of the guns avoids powder from gusting away from Faraday
color coating change. Modifications in the aforementioned areas. This technology offers uniformity and consistency in
variables could enhance system capability, providing quick powder application, in turn reducing the overspread of
turnaround and facilitating the fast delivery of products, powder. Further, its repeatability feature without the require-
resulting in wider adoption of the technology. ment of adjustment for wear of a pump is contributing to
The powder coating reclaim system utilizes cartridge the adoption of the technology. These factors increases
collector technology and cyclone technology. The cartridge material utilization and aid to quick color change.
systems employ cartridge collectors to reclaim powder Rapid technological development led by the industry
formulations or individual colors. It reclaims overspread players is driving incremental advances in gun design,
powder by a self-cleaning cartridge, which contains a powder pump design, remote feedback loops, and improved
detachable color module. In the color-changing process, the electrostatic control in real-time, in turn improving the
guns, pumps, booth canopies, and hoses are cleaned, capabilities of powder coating technology. For instance,
followed by replacement with the next color module, facili- powder coating equipment suppliers are offering efficient
tating quick color change in comparison to other methods. gun charging mechanisms to enhance efficiency through
With cyclone technology, multiple cyclones are utilized improved technology, such as advanced corona charging.
to recollect all the powder or color formulations that are It allows users to use a gun at high voltage, and low gun
sprayed in a booth although the complex orientation of current to increase transfer efficiency. In addition, the system
the system and multiple components extends the time for manufacturers’ focus on automation and smart technology
cleaning and the color-changing process. integrated systems in response to consumer demand for
quick color change is expected to further proliferate in the
OTHER IMPROVEMEnTS business landscape in the coming years. n
Dense phase pumping systems possess the ability to provide
efficient flow rate outputs, increasing transfer efficiency by Harshit Nigam, Analyst, Adroit Market Research.

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