Blast Surface Preparation and Finishing equipment is offered in many variations according to the desired process requirements.

A Blast process can be found to be the most commercial process in terms of high achievement, speed of process, environmental considerations and economics.

There are several guises of the term “blast”

• Blast Cleaning – to bring the surface to a clean state without change of tolerance.
• Beadblast – a fine aesthetic sateen type finish, leaving a low micron surface measurement – components normally remain to tolerance.
• Blast Stripping – to remove coatings for inspection and possibly NDT applications.
• Shot blasting – to descale and prepare surfaces for corrosion control.
• Grit blasting – to descale and prepare surface for adhesion purposes prior to coating.
• Stress relieving or shot peening- a highly controlled process applied to critical components.

Each of these processes can be performed as either a dry blast or alternative wet blast option, each having their own merits.

The dry blast option also has a number of methods of delivery:

• Venturie / suction blast
• Pressure blast
• Airless, wheel or turbine blast

A wet blast system and process employs a mechanical pump, water, media and compressed air.

Each method of delivery, be it wet or dry can be offered from a base format, beginning with a manual blast facility and every additional combination to a fully integrated automatic, controlled and validated process, required within a production and manufacturing line.

What is the process?

The projection by accelerating or throwing of abrasive; to “bombard” the surface of the component.

An impact “cleaning operation” that is neither cutting, grinding nor abrading. It is essentially a pounding, battering or bombarding of the work surface by successive impacts of flying media. (By adding speed to the abrasive and employing an abrasive with harder material type characteristics, we can also abrade the surface to key the finish as an alternative)

Abrasive and non abrasive, free flow medias, are propelled either by air pressure, possibly water or by airless centrifugal turbines onto the surface of the component, until fully saturated (covered) and can be precisely controlled. Methods of processing individual, small or large parts, in continuous mode, or in batches of engineered components in order to remove sharp edges, remove flash, de-scale, remove old paint, carbon and other deposits and provide a non abraded or abraded surface.

Abrasive blasting will produce an effect that may combine both a cleaning and finishing action. The finishing effect may vary by controlling such factors as hardness of the abrasive, abrasive particle size, velocity of abrasive stream, angle of abrasive delivered, distance from the work, method of application and work flow.

It can be applied as a preparation to the surface prior to finishing; abrasive blasting is generally used to replace sanding, wire brushing and pickling. Basic abrasive blasting can save from 75% to 95% of the time normally required over hand cleaning. Blasting is considered economical. The abrasives are relatively inexpensive and reusable. The general economic advantages of abrasive blasting lie in the reduction of man-hours required to clean and finish parts and requires only minimally trained personnel, yet still having high productivity per hour.

Abrasive blasting can make a good finish better and cleaner. It is also capable of being adjusted to produce variations of finish to maintain a smooth tolerance, or to a key or abraded Ra, Rz surface specification for bonding. It is estimated that the surface area of metal increases as much as ten times as a result of the abrasive impact action. This increases the surface to which paint, coating or plating can adhere.

For more information on shot blasting please visit www.rosler.com

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Post written by
Haydn Kitchen
Shot Blasting Technical Manager