Powder Coat

Specifications:

• Part Size: Up to 3' x 4' x 4'
• Batch Size: Small (6 lbs of powder) to Medium (50 lbs) to Large (500 lbs)
• Conveyor Speed: Variable, 2–12 feet per minute
• Cure Temperature: Variable, up to 500°F
• Cure Time: Variable, no limit

Powder coating is a finishing technique that offers both economic and performance advantages over many conventionally applied liquid coatings. Economically, powder coatings have bottom-line savings in three key cost areas—materials, energy, and environmental compliance. Material costs are low because usage efficiency is high—up to 98% of overspray is captured and reused. Energy costs are low because spray booth and bake oven ventilation is reduced. And powder coatings are environmentally compliant because powder coatings contain no VOCs and generate no hazardous wastes during application. Performance-wise, powder coatings are desired for many coating applications due to their high durability.

Powder coatings also provide quality finishes and surface properties that rival those of liquid coatings. Technological advancements make powder coatings versatile enough to meet finishing needs that range from primers to chemical agent resistant coatings. The electrostatic powder spray processes in the Main Demonstration Factory use many types of thermoplastic and thermosetting materials such as epoxies, polyesters, acrylics, vinyls, and PVC. These coatings can be used to meet the coating requirements for metal substrates such as aluminum, brass, bronze, steel, and zinc. Advances in powder coating chemistries now meet the processing requirements of nonmetallic, thermally sensitive substrates such as fiber-reinforced plastic, composites, wood, glass and ceramics.

The powder coating line in the NDCEE Demonstration Factory consists of a multimetal pretreatment line, a temperature and humidity-controlled spray booth, and a curing oven.Parts are cleaned and pretreated in a seven-stage pretreatment line, then conveyed into the spray booth. Powder coating application starts with fluidization of the powder, where a feed hopper mixes powder paints with compressed air. This fluidized powder is pumped from the hopper to spray guns. The system has eight automatic corona guns on vertical reciprocators, two manual corona guns and two manual tribomatic guns.

Parts are momentarily stopped inside the booth and sprayed with the fluidized powder. The coating overspray is trapped by the booth air filters, segregated and then recycled back to the guns. Coated parts are then conveyed to the curing area to be cured in a gas-fired convection oven or with electrically powered infrared lamps.