Painting & Powder Coating
All powder coating and much of the painting of metal parts today is done through an electrostatic coating process. A metal part is hung on a metal hook or rack that is then passed by a conveyor line into a booth to be either painted or powder coated. The paint or powder is charged negatively when it comes out of the application sprayer, and the part being coated is charged positively. This ensures a good bonding of the coating on the parts, and reduces the amount of paint or powder required to coating the part. But, with each run through the paint booth, the carrying hooks or racks receive another coating. The coatings can build up to a point that they reduce the electrical contact between the hooks and parts to be painted, with the result that the part is no longer coated properly and much of the paint or powder is wasted. The hooks or racks need to be cleaned before the buildup reaches this point.
Also, parts being coated may sometime need to be recoated. If so, usually the coating that has been applied needs to be removed before the part can be reprocessed. This can be as much of a problem as cleaning the carrying hooks and racks.
SOLUTION:
The coated hooks or racks or parts are hung on a hanging cart or placed on a forklift movable carrier which is then placed on a flat bed cart and placed in our Controlled Pyrolysis Cleaning Furnace. The parts are cleaned as the organic portions of the coatings are vaporized into smoke - pyrolyzed - as the temperature of the cleaning chamber reaches approximately 430 - 480°C.
Emissions generated in this pyrolysis process are drawn through an afterburner operating at approximately 850°C. The afterburner incinerates any smoke or odour, leaving only odourless and harmless water vapour and carbon dioxide to exit the exhaust stack.
After the cleaning cycle only inorganic ash remains on the processed parts. The processed parts are removed from the furnace and moved to a cleaning area where the ash can either be tapped or washed to remove it. The clean parts are then ready to be returned to the finishing line. This process greatly reduces the labour involved in cleaning the carrying hooks and racks.
| Very heavy coating on hangers. | |
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| Before | After |
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After processing at 800º F (430ºC) only ash remains. Slight tapping or washing moves ash. Ready to re-hang on line. |
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