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Shotblast booths

shotblasting

CFW builds shotblast booths to the highest standards, ensuring that legislation is adhered to and reducing air pollution. We supply a wide variety of fans and equipment and we can also undertake turnkey projects to meet exacting specification. We also stock many fans, components and accessories.

Shotblasting uses a blasting device that fires an abrasive at a surface at high velocity (up to 110 m/s) to alter it. The possible applications are many, but include:

  • Cleaning metals and parts by removing rust, paint or other coating materials.
  • Removing minor flaws from surfaces.
  • Preparing items for secondary finishing processes.
  • Shot peening to improve the physical characteristics of the target.
  • Adding a texture or finish to certain surfaces.

Some possibilities depend on the blasting medium and device that are used. Preparing metal surfaces for painting is one of the most common uses.

The abrasive is fired onto the part by one of two methods: compressed air or a centrifugal turbine. The compressed air method is more flexible, since the shot can be fired horizontally through an assembly with rubber hoses and nozzles. It is typically used in lower production. Metal frames and weldments are ordinarily cleaned with compressed air shotblasting, so that hand tools are not needed. However, the equipment is more expensive than the centrifugal wheel machine.

Automated shotblasting systems typically consist of the delivery system, a dust collector, a system for abrasive recovery and cleaning, a blast cabinet, part handling equipment and controls and instrumentation. For a compressed air system, the delivery system comprises a shot blaster gun, an air compressor and a hopper, which conveys the abrasive material to the gun. The gun is often contained in a booth for manual shotblasting.

The abrasive used varies widely, ranging from pumice, which can remove paint from wood without leaving marks, to hard aluminium oxide. The hopper is filled and compressed air is used to fire the shot at the work piece. In many cases, the equipment can recover the shot for reuse. With turbine shotblasting machines, the shot is generally steel or another metal.

Shot blasting produces a considerable amount of dust, which is removed using a dust collector. The machinery cabinet, abrasive and surrounding area is kept clean by having the dust collector reduce pressure in the machine. Baffle filters or cartridges are the ordinary key components in these dust collectors. Changed airflow can lower the efficiency of the dust collector, resulting in an increase in the amount of dust around the shotblast machine. The dust collector’s design and capacity is therefore important for effective shot blasting.

The blast cabinet contains the abrasive and dusts. The access openings for material in the cabinet are made to avoid spilling abrasive. The cabinet is constructed from carbon steel with an inner lining of abrasion-resistant materials. Special steel alloys are used for areas that are exposed to high-velocity shot.

The means of handling and conveying parts that are to be shotblasted depends on the type of part. For centrifugal wheel shotblasting, tumblast, spinner hanger machines or wire continuous machines may all be used. Controls and instruments are usually centralised and can control every aspect of the system.

Ordinarily, shot falls into a collection hopper after being fired and is moved to a bucket elevator, either by dropping into it or by a screw conveyor. An air wash separator uses plates, baffles and strainers to separate out contaminates from the shot. Cleaned abrasive is then returned to the blasting cabinet.