Unit that stores powder in a hopper and meters it into the carrier gas, typically with a rotating disc or wheel (volumetric) or with a load cell controlling loss of weight (gravimetric). Feed rate, usually in grams per minute, has to stay steady, because surges and dropouts show up directly as thickness variation and porosity. Moist powder, worn discs and kinked hoses are the usual troublemakers.
Powder feeder is drifting, it says 45 grams a minute but the catch test came back 38.
Do a catch test, collecting powder into a bag for a timed minute, whenever the feed rate looks off; a volumetric feeder's display only shows the setpoint.
Also heard as
- feeder
- hopper
- powder hopper
Related terms
Carrier gas
The gas stream, usually argon, that carries powder from the feeder through the hose into the spray jet.
Spray rate
How much feedstock goes through the gun per unit time, usually in grams per minute or pounds per hour.
Pulsing
Uneven powder delivery that makes the spray stream surge and flicker instead of flowing steadily.
Feedstock
The raw coating material fed into a thermal spray gun, as powder, wire, rod, cord or liquid suspension.