Thermal Spraying

Plasma spray booth eliminates oxygen without a vacuum

When metallic powders are used in atmospheric plasma spray processes, the reaction between the metal particles and oxygen inflight to the substrate tends to introduce unwanted features into the coating. Shrouding the path between the torch and the substrate with inert gas is a common solution, but the turbulence of the process can allow oxygen to penetrate through the inert shroud. Thus, while gas shrouds are the more economical approach, they are not the most effective. Spraying within a vacuum chamber can mitigate oxidation, but can be time-consuming as the exchange of production parts requires the pumping down and venting of the chamber.

With this custom machine, Progressive Surface offers an alternative approach that displaces the oxygen in the machine with argon up to a user-defined level. The atmosphere within the machine is then circulated through a dust collector and chiller before being returned back to the spray booth, thus minimizing argon consumption. The oxygen level is monitored throughout the process and can be controlled via argon additions. Components being coated are robotically transferred from and to an airlock, which can be sealed from the spray booth and quickly purged of argon or oxygen. This way an operator can change components without altering the atmosphere in the spray booth or, if desired, without shutting down the torch and feeder(s).

• ABB IRB2600 manipulating a Praxair TAFA SG-100 plasma torch
• Spindle and airlock capable of 19 inch diameter parts up to 8 inches tall
• Locking safety doors to control operator access to the cabinet interior
• Chiller to cool recirculated argon atmosphere
• CITS Pro Computer Integrated Thermal Spray operator interface
• Closed-loop gram rate controlled powder feeder (optional)
• Tecnar Accuraspray integration (optional)