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Extrusion Application Processes

Extrusion Application Processes: Aluminum Extrusion Painting, Color, Protection, Electrostatic Spray Coating, Automated Bells, High Volume Production Runs

In approximately 1960, the window industry saw the first application of paint to aluminum extrusions. The metal was not pretreated as it is today and the coating selections were limited. However, painting brought about a huge boost to the entire aluminum extrusion market as the place to be for growth. It added color and protection to a rather dull looking oxidized substrate.

Pretreatment Before Painting Click for Larger Image

Painting helped co-ordinate the windows with the rest of the home or structure. It also took the market from "anodizing only" for the very high-end architectural and commercial uses and created new and more vibrant looks.

	Rinsing at Pre-Treat  Click for Larger Image

As this momentum continued, improvements like double panel, thermally separated glass came along to improve insulation properties. Innovative curtain wall designs emerged as did new and improved residential glass enclosures. It ushered in a new era in the aluminum extrusion industry that is far from over.

There are two methods of spraying coatings on aluminum extrusions: Horizontal and Vertical.

Horizontal Spray Painting with Automated Bells Click for Larger Image

Horizontal Spray Coating

This method is usually preferred for coating complex panels that cannot be hung on a vertical line such as, louvers and prefabricated systems.

The typical layout begins with hanging the aluminum component on specially designed racks or hangers, then onto a conveyorized line. From the loading area it travels through a cleaning and pretreatment process that removes the soils and dirt from the substrate. It also puts an approved chemical treatment, chrome or (non-chrome in some instances), on the metal to promote adhesion of the paint and deter the formation of salts or corrosion.

Following this key step, the metal is ready for painting. Normally three sets of opposing booths are in place to apply primer, topcoat and clear if specified for architectural finishing. Horizontal applications typically need a combination of both manual and automatic electrostatic equipment.

At Superior Metal Technologies, we use this horizontal method for our production runs.

Vertical Spray Coating

This describes the method of hanging the metal during the pretreatment and painting processes. Usually long runs of extrusions are coated with either one or two pairs of opposing omega-shaped booths. These are strictly automatic, electrostatic rotary systems, capable of faster line speeds and more volume. All other steps are basically the same as with the Horizontal method.