Before working on a surface, the professional must treat it to improve its appearance. He can use various techniques depending on the needs and the desired result. Besides sandblasting, sanding, planing, bead blasting, hydro-gumming, and air-gumming …, there is also shot blasting. This process involves the use of a shot-blasting machine. How does this equipment work? What are the advantages of shot blasting? What should be considered when using this technique?
What is shot blasting?
Shot blasting is one of the surface cleaning techniques commonly used by manufacturers. It generally consists in projecting, at high speed, balls on the surface of an object to generate a bursting of the coating by points.
This process can be carried out on all types of surfaces, in particular on
concrete: scouring and degumming, creation of roughness and a profile, stripping of resins and paint… ;
asphalt and coated surfaces: removal of road markings, improvement of adhesion in slippery areas, removal of polluted surfaces… ;
metal: improving the technical qualities of surfaces.
Why is it advantageous to use shot blasting?
Compared to other surface treatment techniques, shot blasting offers a more satisfactory result on the surface. For example, on metal, it allows to close cracks invisible to the naked eye, which are often due to internal pressure. These cracks cause a waterproofing problem when left untreated. Therefore, shot blasting is the best method to fight against metal corrosion.
It is also the best method to deal with rust and to protect the metal against certain substances such as salt, grease, dust, etc. Industrialists often apply it to steel, cast iron, and bronze. The shot blasting technique is frequently used in the transport industry: shipyards, automobile, aeronautics… specifically in the treatment of engine parts and mechanical parts.
Other advantages: shot blasting is a flexible, fast, clean technique.
What is a shot-blasting machine, and how does it work?
Industrialists and manufacturers use the shot blasting machine to perform shot blasting. It consists of a cabin equipped with inward-facing blast nozzles. It operates as abrasives, glass, steel, or ceramic balls called “shots”. These are projected inside a closed armored box made of steel. Then, they are collected in a tank with the impurities and dusts before recycling. After filtration, the balls are conveyed to the feed hopper.
The balls are propelled by one or more turbines that rotate at high speed. This determines the intensity, speed, and orientation of the bead jet.
There are two projection processes:
Mechanical blasting, in which rounded abrasives are used;
and the pneumatic projection, where angular abrasives are used.
What to consider when blasting?
There are several factors to consider to achieve the desired result when blasting:
the nature of the surface to be treated ;
the nature and size of the shot;
the flow rate and speed of the shot;
the direction of the blast.
The power and performance of the blasting machine also come into play. That’s why it’s important to choose well. As with a blast cabinet, you need to choose a blast machine that can handle the type of workpieces, the quantity to be produced and the degree of finish required.
To know which machine is the most adapted to an activity, it is necessary to ask for advice from a professional.