MBe International - Arc spray

Interestingly, the first Thermal Spray patent filed my Max U. Schoop in 1915 referred to an electric current as a heat source. Whilst the main thrust of the early Thermal Spray industry was focused on the Combustion Wire systems, the Electric Arc spray patent lied dormant up until the early 1950’s.

Schematic diagram of the electrical arc spray process

This is thought to have been because of the difficulty in creating a stable DC electric current which made the systems unreliable.

Because the Electric Arc spray process utilises a higher heat source temperature and uses a twin wire feed system, spray rates can be higher than with the Combustion Wire systems. Also, because the system uses electricity to produce it’s heat source, rather than compressed gases, the coating costs are generally lower for equivalent wires.

Electrical arc typical coating properties table

Principle of operation

Two wires are fed through converging contact tubes and tips at a constant speed. The contact tubes and tips facilitate the transfer of DC electric current to the wires. A DC electric arc establishes itself between the two wires and thereby the heat source is produced.

The higher the current (Amps) availability of the power supply unit, the higher the achievable spray rates.

Some power supply units utilised in the Electric Arc spray process are derived from standard electric arc welding units with minor modifications. Some manufactures however, design and build power supply units specifically for the Arc Spray process.

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