Powder Coating Troubleshooting Guide
Chapter Eight: Powder Coating Recovery Equipment
General Design Principles
Powder coatings are efficient in their use partly due to the ability to recover and reuse the excess overspray from the coating booths. The recovery system consists of three components: the booth which contains the excess powder, the collector which retrieves the excess, and the filters which clean and return the air.
- Allows for a contained area for the application and containment of excess powder
- Provides a controlled atmosphere with safe operating levels of powder cloud density
- Permits the maximum possible exposure time of the parts to the powder cloud
- Optimize the powders cloud concentration towards the parts and away from the booth walls
- Separates the powder from the air stream exhaust
- Allows for a maximum retrieval rate of oversprayed powder
- Permits a central collection area to reintroduce reclaim powder into the virgin powder
- Allows for the return of cleaned conditioned air, either heated or cooled, back into the coating area
Conventional Recovery System (Cyclonic)
Cartridge Recovery System
Daily Booth Maintenance
- Cartridge, final filter, or baghouse magnehelic pressures should be checked daily.
- Collector filters and final filters should be changed when magnehelics reach preset numbers.
- Guns, pumps, and hoses should be inspected daily for wear, holes, and impact fusion.
- Voltage and current of guns and power source must be checked monthly to insure maximum charge.
- Booth should be cleaned at least twice a day to keep reclaim powder mix to a minimum. Preferably 4 times a day or every two hours. This will reduce the exposure of the powder to moisture and "trash."
- UV detectors must be checked and cleaned daily to ensure they are working correctly.
- Always stay alert for signs of moisture or oil on any of the system components. Perform maintenance immediately if any is found.
- Keep records of all the checks done and maintenance performed to the finishing system and line.
Color Change Considerations
- Guns should be disassembled and blown out with compressed air.
- Powder feed hoses should be blown out or with extreme color changes they should be replaced with dedicated hoses.
- Pumps, injector blocks, and venturis should be disassembled, inspected for wear, then cleaned with compressed air.
- Booth floor, walls, and ceiling should be cleaned with a squeegee, while the recovery system is running.
- Sieve, virgin, and reclaim feed hoses and collector cyclone should be thoroughly cleaned.
- Powder hoppers should be cleaned thoroughly or replaced with dedicated color hoppers.
- All areas which will be in contact with the powder must be wiped or vacuumed clean, including the inside of the booth and hoppers.
- Multiple booth with roll on/off tracks will allow one booth to be cleaned while another is coating. This will reduce downtime as well as the risk of contamination.
- Additional dedicated color cartridge units, hoppers, and sieves will also significantly speed up color change times.