Materials E-Guide
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At Oerlikon Metco, we know our customers have unique needs and application goals, so we offer the widest range of spray gun options to ensure we meet your exact expectations. Our HVOF spray guns are the choice of thousands of customers worldwide, and are renowned for reliable and consistent performance. Most likely, we have the ideal HVOF equipment for your application.
HVOF Spray Guns
General Comparison of Gas Fuel and Liquid Fuel HVOF Technologies:
Which is right for your application? Let us help you decide on the technology that’s right for you. Only Oerlikon Metco has the experience you need for both gas fuel and liquid fuel HVOF technologies.
| Comparison | Gas Fuel HVOF Spray Gun | Liquid Fuel HVOF Spray Gun |
|---|---|---|
| Gun | Water-cooled Diamond Jet Gun | WokaJet-410 Gun |
| General Characteristics | ||
| Fuel Options | H2, CH4, C2H4, C3H6, C3H8 | Jet-A or Kerosene |
| Combustion Pressure | ~ 0.55 MPa (80 PSI) | 0.55 to 0.83 MPa (80 to 120 PSI) |
| Gas Velocity | 1800 to 2100 m/s (5900 to 6900 ft/s | 2000 to 2200 m/s (6500 to 7200 ft/s |
| Particle Velocity | 450 to 600 m/s (1475 to 1975 ft/s) | 475 to 700 m/s (1550 to 2300 ft/s) |
| Powder Injection | Axial feed (hotter zone) | Radial feed (cooler zone) |
| Powder Injection Pressure | Higher | Lower |
| Spray Rate | up to 120 g/min (16 lb/h) | up to 200 g/min (26.5 lb/h) |
| Consumption Comparison (typical utility consumption per hour of operation) | ||
| Fuel | 43800 l (1670 ft3) H2, or 5280 l (200 ft3) C3H6, or 5280 l (200 ft3) C3H8 | 28 l (7.3 gal) kerosene |
| Oxygen | 18420 l (700 ft3) | 61400 l (2335 ft3) |
| Water | 600 l (160 gal) | 2375 l (625 gal) |
Your choice of a gas fuel or liquid fuel system will depend on many factors that can include:
- Configuration/geometry of the part to be coated
- Substrate composition
- Coating material to be applied
- Desired coating thickness
- Applicable customer coating specifications
- Desired as-sprayed surface roughness
- Desired finished surface roughness
- Desired coating internal stresses
- Number of parts to be coated
- Size of coated area
- Utilities to be used (process media, air, water, etc.)
How Does a HVOF Spray Gun Work?
HVOF spray guns are a part of a thermal spray coating system in the HVOF process. The HVOF process efficiently combusts oxygen and a gaseous or liquid fuel to produce high kinetic energy with controlled heat input. The coating material, in powder form, is introduced into and uniformly heated by the hot gas stream to a molten or semi-molten condition. The flame and powder are accelerated by a converging/diverging nozzle (air cap) to produce supersonic gas and particle velocities, which propel the powder particles toward the substrate to be coated. The powder particles flatten plastically upon impact with the substrate; cooling and solidifying to form the coating. High particle velocities, uniform heating and low dwell time combine to produce coatings that are very dense and tightly bonded to the substrate. Coating chemistries are more predictable and coatings have fine, homogeneous microstructures.
Liquid-fuel HVOF gun. Gas-fuel HVOF gun works slightly different.
