Why is shot cleaning important?

Shot cleaning is the operation of separating and eliminating the contaminants that accumulate in the abrasive during the shot blasting process: mill scale dust, rust, foundry sand, worn shot particles too fine to remain useful and other coarse contaminants. This operation is carried out by the machine's abrasive cleaning system — separator or gravitational separator — continuously during the process.

The presence of contaminants in the operating mix has direct consequences on process quality and cost. Fine contaminants do not contribute impact energy but do consume conveying capacity, block dust collector filters and, in surface preparation for painting processes, can deposit between the roughness peaks and valleys. When paint is applied, those contaminants become trapped between the coating and the metal, reducing adhesion and accelerating premature corrosion of the system.

For the shot blasting of cast parts the effect is even more critical: the presence of 2% sand in the shot considerably increases wear of machine components — blades, rotor, control cage, liners — compared to the same process with clean shot.

A well-regulated cleaning system allows operating costs to be kept under control, achieves blasted parts free of contaminants and maintains stable and reproducible roughness profiles over time.