First-pass transfer efficiency is the weight of powder deposited divided by the weight sprayed, and on open parts with corona guns it commonly runs 50 to 70 percent. It falls with poor grounding, wide rack spacing, small parts, Faraday areas, back ionization and too much air. Overall material use counts reclaim and can pass 95 percent, but high first-pass efficiency still saves booth wear, color-change time and labor.
Transfer efficiency dropped off a cliff this week, I bet half these hooks have no ground.
Grounding and rack density move first-pass transfer efficiency more than any gun upgrade.
Also heard as
- TE
- first-pass transfer efficiency
- FPTE
Do not mix it up with
- Reclaim: Reclaim recovers what transfer efficiency missed; a shop can have high material use and still poor first-pass transfer.
Related terms
Reclaim
Oversprayed powder collected from the booth and fed back into the system for reuse.
Ground
The electrical path from the part through hooks, racks and conveyor to earth that lets charged powder stick.
Back ionization
Tiny electrical discharges inside an overcharged powder layer that repel new powder and pit the finish.
Wrap
Charged powder curling around edges onto the back of a part that the gun never pointed at.