General Introduction to Shot Blasting
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TECHNICAL BROCHURE General Introduction to Shot Blasting Shot Blasting is a surface treatment process using high velocity steel abrasive. Shot blasting is method through which it is possible to obtain excellent cleaning and surface preparation for secondary finishing operations. Shot blasting is commonly used for: • The cleaning of iron, steel, non-cast parts, forgings, etc. Mechanical cleaning of sheets, rods, coils, wire, etc. Shot peening to alter mechanical properties (increasing resistance to fatigue for springs, gears, etc.) Preparing surfaces to be painted, coated, etc. In general shot blasting concentrates abrasive particles at high speed (65-110 m/second) in a controlled manner at the material thereby removing surface contaminates due to the abrasive impact. Initially in the 1930’s the shotblasting process used compressed air for propelling the steel shot. This method remains in use today for cleaning metal frames and weldments. CYM MATERIALES SA www.cymmateriales.com.ar // info@cymmateriales.com.ar

Shot blast production lines, both manual and automated systems, became possible with the introduction of centrifugal wheel blast machines. The system of shot blasting by centrifugal wheel is more productive than by compressed air and achieves a better more uniform surface finish. The criteria used for selecting the type of shot blasting system depends on the size and shape of the parts, the condition of the surface to be cleaned, final surface finish specification and overall process required. Shot blasting systems are comprised of 6 basic subsystems: 1. Abrasive delivery method: o 2....

Abrasive delivery method: There are two ways of accelerating the steel shot: By compressed air: This system is suitable for lower production applications where maximum flexibility is needed. These systems are very flexible in that the shot can be delivered horizontally through a rubber hose and nozzle assembly. This enables uses in finishing operations of steel frames and weldments thereby replacing hand tools. Because of this, an air blasting machine for a production line is expensive compared to the centrifugal wheel blasting machine. For example to deliver shot at a rate of 1100 kg per...

By centrifugal turbine: Centrifugal wheel blasting is the more common blast cleaning technique as well as the most economical and environmentally friendly method. The turbine delivers abrasive shot by centrifugal force in a specific and controlled direction, speed and quantity. Function of the turbine is similar to that of a fan or centrifugal pump. Shot blasting machines may use one or a multitude of turbines positioned in such a way that the abrasive blast pattern covers the entire surface of the material to be shot cleaned. The shape and size of the parts determine the number of turbines...

2. Abrasive Recovery and cleaning system. Recirculation and cleaning the abrasive shot is required to maintain a consistent cleaning operation. In conventional shot blasting equipment after the shot hits the part the abrasive falls into the collection hopper under the machine. The shot is then carried by gravity or screw conveyor to a bucket elevator. The elevator carries the shot, removed oxides and other contaminates to an air wash separator located in the upper portion of the machine. A combination of baffles, strainers and plates separate these contaminates which are ineffective during...

4. Dust collector system Dust produced during shot blasting is withdrawn from the machinery cabinet and continuously recirculating abrasive by a dust collector. Typical dust collector design uses baffle filters or cartridges. The dust collector not only evacuates dust within the machine but also keeps the surrounding area clean and dust free. Changes in airflow will reduce collector efficiency and therefore result in lower dust extraction, loss of the cleaning power, and contribute to dust in the immediate production area. A properly designed and sized dust collector is therefore critical...

6. Controls and instrumentation The system providing the control and instruction for the starting and stopping all functions such as, elevators, dust collectors, turbines, part handling system, ammeters and time meters for the turbine motors are all placed in a central console. The control panel is designed with sequential startup to assure the different systems are energized in the proper sequence. All systems can be automated for continuous processing that will increase production, reduce operator interaction and consistently maintain a particular surface specification. Abrasive The...

Blast Cleaning and Shot peening machines are widely used in different industries such as: • Cleaning and preparation of profiles and sheets surfaces before painting Portable machines for the maintenance of ship hulls Cleaning of gearboxes, mechanical transmissions, connecting rods, etc. Shot peening of stabilizing bars, springs and elastics, gearboxes, pistons, connecting rods, etc for increasing fatigue resistance. Break shoes and clutches blasting Cleaning of rectified engines components (blocks, pistons, etc). Cleaning and preparation of car and truck tires before painting. Screw...

Metallic structures and profiles: o Cleaning and preparation of steel sheets and profiles before painting. Surface homogenization. Melting of steel, iron, aluminum and bronze. Cleaning and grit removal of melted parts. Remove foils from the framework. Surface homogenization. Milk, Refrigerating and Nutritional Industries: o Cleaning and preparation of metallic furniture surfaces before painting. Cleaning of rubber, glass, aluminum extrusion moulds, etc. Cleaning and preparation of surfaces before being metalized. Painting removal of part load hooks of painting systems. Cleaning and...

Portable machines for the preparation of concrete industrial floors before coating. Iron and steel industries: o Mechanic descaling of coil rod. Mechanic descaling of steel sheets and iron hoops. Mechanic descaling of tubes with and without rims. Descaling of laminated levers by heating. Mechanic descaling of round, hexagonal and square bars for wire drawing operation. Blasting of lamination cylinders. Cleaning and preparation of parts after heat treatments. Cleaning and preparation of internal and external surfaces of metallic drums before painting. Cleaning and preparation of trains and...