Thermal spray equipment accelerates the dispersion of heated coating material from a spray torch towards the workpiece. The deposited material forms a coating on the surface. Specifications for thermal spray equipment include technology and type. Automation and mounting style are also important parameters to consider. Manual thermal sprayers are designed or capable of operation under manual control. Automatic devices require a CNC controller for either full or semi-automatic operation. Typically, automatic thermal spray equipment changes or adjusts abrasive media and other parameters such as speed, applied load, or coolant / lubricant flow. In terms of mounting styles, choices include bench or tabletop, cart or hand truck, floor or skid, handheld, machine or reciprocator, and trailer or vehicle.
Thermal spray equipment differs in terms of technology. Cold spray processes use a stream of compressed gas flowing at ultrasonic velocities to propel and impact particles on a substrate. Electric arc thermal spray processes use an electric arc heat source to melt the consumable coating material. Powder, rod and wire flame spray technologies feed a consumable material into a gun where a flame melts and atomizes the particles. Rokide® (Saint-Gobain Abrasives, Inc., Norton Company) is a proprietary rod flame spray process. High velocity oxy-fuel (HVOF) thermal sprayers use an axial feed system to inject the powder or coating media into the center of a stream. Laser cladding thermal spray equipment directs a laser beam at a surface to form a molten pool. Powder or wire is then injected into the beam and melt pool.
Some types of thermal spray equipment use plasma spray, plasma transfer arc (PTA), radio frequency (RF) or induction plasma, shrouded plasma spray, or vacuum plasma spray technologies. Plasma spray processes feed a consumable powder into a gun where plasma melts and atomizes the particles. Plasma transfer arc (PTA) is a welding process in which an arc formed between internal electrodes in a gun generates plasma. Radio frequency (RF) or induction plasma systems use an electrical field to induce a current in and then sustain a plasma heat source. Shrouded plasma (arc spray) thermal spray equipment uses a gun with a surrounding nozzle to create a ring of inert gas around the stream of heated particles. Vacuum plasma spray (VPS) is a plasma-spraying process in a controlled-atmosphere chamber.