Impact fusion is the packing or partial melting of powder particles occurring within application equipment. When powders travel through the application equipment from the feed hopper through the powder pumps, hoses, and guns, friction can occur, causing the powder to pack together in a fused or semi-fused state.The packed powder can start out as a small obstruction that continues to grow restricting powder flow or breaks loose causing a finishing defect. Any area of the powder delivery equipment is a potential site for impact fusion, including the powder pump, the delivery hose, and the gun. Therefore impact fusion can be controlled by eliminating or minimizing friction as well as the sites for potential powder build up.
To prevent impact fusion:
- Keep powder hoses short with minimal sharp bends – reducing friction
- Clean and replace tubes, hoses, pumps, and nozzles on a regular basis
- Reduce your reclaim - powder may be too fine causing easier fusion
- Control powder gun flow rates - excessive air pressures and powder feed rates will increase the amount of impact fusion
- Maintain a clean, moisture-free air supply