Shot Blasting is the process of cleaning a surface such as iron, steel, cast-iron parts, forgings, rusted pipes, iron bars, engine and automotive parts by blasting abrasive material such as steel shots or steel grits at very high velocity utilizing the centrifugal force generated by high speed rotating disk in a shot blasting machine. Shot blasting is also used to alter the mechanical properties or various components, increasing resistance to fatigue for springs, gears, etc.
Compared to sandblasting process shot blasting does not produces large amounts of dust and is much more environment friendly. A shot blasting machine is like a closed chamber so the dust particles generated at the time of blasting process remain inside the chamber and does not pollute the environment.
Shot Blasting Machine is used in almost every industry that works with metal components:
Ship Building and Ship Yards
Aerospace and Aircraft Maintenance
Iron Castings and Other Metal Foundry
Forgings
Rail
Car and Bus Painting
Alloy Wheels Cleaning
Shot blasting is also used to clean floors, roads and outer walls at construction sites.
Other applications of shot blasting include cleaning of under water pipes and tanks before coating or re-coating them to prevent corrosion.
When we talk about shot blasting then it is important to remember that we are referring to a shot blasting machine which works by directly converting electric motor energy into kinetic abrasive energy by rotating a centrifugal wheel at a minimum of 60 kg per minute which can go upto 1200 kg per minute.
With such high amounts of accelerated abrasive a shot blasting machine is used to derust, descal, deburr, desand or clean large metal parts or surfaces that cannot be cleaned effectively through other traditional or manual processes.
Difference between shot blasting and sandblasting is simple to understand. In sandblasting compressed air is used to propel the abrasive towards the surface that needs to be cleaned and in shot blasting a centrifugal wheel is used to propel the abrasive toward the surface using an electric motor.
Advantages of Shot Blasting:
Shot Blasting is inexpensive and time saving and also abrasive material is reusable which makes shot blasting extremely affordable.
Cleans and smoothens a metal surface without any damage to the surface.
Economical to use and environment friendly as it does not produces very less amounts of dust compared to sandblasting.
Prepares a surface for coating or re-coating applications effectively.
Smoothens a rough surface and roughens a smooth surface effectively.
Flexibility of using various types of abrasive materials that can be used in a shot blasting machine depending on the surface that needs to be cleaned such as glass beads, steel shots, steel grit etc. makes shot blasting the most preferred method of cleaning or preparing different metal surfaces and components.
Factors that affect the Shot Blasting process and its effectiveness:
Condition of the surface or the metal part that needs to be cleaned and the contaminants deposited on the surface that need to be removed.
Velocity and the abrasive used to treat the surface.
Working Condition of the shot blasting machine.
Size of the abrasive.
Hardness of the abrasive material.
Level of humidity and temperature as exposure of metal surface to the environment makes it susceptible to oxidation.