2. Projection mode

Impact treatment can be carried out in machines or systems, either manual or automatic, with the operator located inside or outside the cabin.

Products and abrasives can be projected either pneumatically, the abrasive propellant generally being dry compressed air free from any trace of pollutants (oil, etc.), or mechanically, by means of a centrifugal turbine transmitting the kinetic energy required for the abrasive flow [63][64][65][69][70] .

Four projection modes are commonly used:

• compressed air – vacuum system (suction, suction,...