For the electrostatic powder coatings industry to grow, it is imperative that powder coating users have the option to rapidly change colors on-line, using either manual or automatic application equipment. With powder coating, a key advantage is the ability to collect the oversprayed, unused powder and reuse it to make the system pollution-free as well as energy efficient. Speedy color change both is a major strong point and a key problem for manufacturers.
In today’s Modean newsletter, we would like to concentrate on new powder coating innovations that allow automatic systems to change colors within six minutes or less. This new capability opens up the potential for many industries to begin using powder coating — industries that up until now were not able to consider it, due to the numerous colors required in the production of their products. Now automatic powder coating color change can be almost as easy as automatic liquid coating color change. The videos shown at the end of this post may be especially helpful in giving you a sense of how the system works.
How the Quick Color Change Innovation Happened
To explain how this works, let us offer a quick refresher on the similarities and differences between powder and liquid systems: Both require a conveyor, a cleaning system and a form of drying after cleaning. Both also necessitate a curing system and a cool-down time before unloading. In using either one, the parts must be allowed to cool down, but with liquid, a flash-off time is required, while with powder no flash-off time is needed.
However, the heart of the difference lies in the application area, which differs considerably with each system. In liquid, the material can be applied either electrostatically or else simply be air sprayed. Powder, on the other hand, can be applied only electrostatically. The electrostatic application charges the powder particle with a negative charge and the grounded part is normally positively charged which creates a molecular adhesion between the powder and the substrate. The powder adheres to the part until melted by heat and cured on the surface in the cure oven. (There are also powders now that use lower temperatures and UV curing.)
The amount of powder that sticks to the part depends upon: the charging efficiency of the gun, a good ground for the part and the shape and composition of the part. Efficiency can vary between 30% and 85%, or even higher when spraying a flat surface. In powder, the overspray can be reused, giving powder a tremendous advantage in the finishing industry. Well known are the “4E’s” of powder coating: 1. Economy, 2. Ecology, 3. Excellence of finish, 4. Energy Efficiency.
In order to address limitations involved with color change, the powder industry took into consideration equipment manufacturers’ evaluations and as a result they made several significant changes:
1. The powder booth walls were redesigned to prevent powder from adhering to the inner surface of the booth, as was the case in earlier booth designs. In the new design the powder that sticks to the surface has a very low electrostatic bond. This allows the powder to be blown off the product surface faster and more easily.
2. The base of the powder booth was modified so that it recovers the powder more efficiently. When needed, the base opens up to make all parts accessible for quick easy cleaning.
3. The development of the Magic Center Powder Management made quick color change possible by eliminating the bulky powder hopper. Prior to this, each color required a separate hopper and cleaning each hopper and changing the color required considerable amount of time. The new system utilizes a much smaller amount of powder in the actual system and the powder is automatically recovered and cleaned. (The video below shows an actual animation of how the powder is automatically cleaned within seconds.)
4. The cyclone was introduced. This is a device capable of multi-color recovery and is very easy to clean. The efficient design of the cyclone allows for recovery of 90% to 92% of the recycled powder. The cyclone includes its own easily-accessible sieve, and via a bottom entry just above the sieve, the complete cyclone cone can be cleaned quickly and easily.
Wide Adoption by Manufacturers
The new automatic quick color change powder coating system is now widely used by manufacturers in a wide variety of industries internationally. Two markets in which adoption has been especially high are aluminum extrusion and architecture. However, adoption is expanding. In the past many markets were unable to consider powder due to the time change colors necessitated. This is no longer the case.
About Modean Industries
The management of Modean Industries introduced powder coatings to the United States in 1969 in cooperation with Gema AG, a manufacturer of electrostatic application equipment located in St. Gallen Switzerland, before the company was purchased by Gema USA.
MagicCenter Quick Color Change