High Energy Centrifugal Barrel Metal Finishing (Harperizing) Services

Principle of Operation

A Centrifugal Barrel machine is typically comprised of two or four barrels horizontally mounted between two main drive turrets. As the two main turrets rotate the barrels rotate in the opposite direction of the turret.

Each barrel is loaded with abrasive finishing media and workpieces from 50% to 90% full. During operation, rotation of the turrets creates a centrifugal force on the media and parts inside each barrel. This force compacts the load into a tight mass, the counter rotation of the barrel causes the media and workpieces to slide against each other.

Centrifugal Barrel machines use high rotational speeds to apply a large amount pressure on the finishing media so that when it comes in contact with the workpiece it does a large amount of work in a short period of time. Centrifugal forces up to 25 times the force of gravity can be generated reducing the cycle times by up to a factor of 30 compared to conventional vibratory equipment.

Metal Finishing Processes

By altering machine operation parameters and media, a wide variety part finishes can achieved from non-reflective to mirror bright. Deburring, radius formation, descaling, rust removal, pre-plate, pre-paint or coating surface preparation are quickly and cost effectively performed in centrifugal barrel machines.

Centrifugal barrel machines are also capable of creating finishes that cannot be obtained in standard vibratory equipment, one example is Ball Burnishing. Burnishing typically creates dense, bright, and highly reflective surfaces. This process utilizes high density media such as steel or porcelain and high centrifugal forces. In addition to brightening surfaces of the processed parts burnishing also increases the surface density which combats fatigue failure, prevents corrosion and stress corrosion, and closes porosity. Burnishing processes that produce a fine matte textured surface finish to mask visual imperfections while providing the mechanical properties described above are also available.

Advantages of Centrifugal Barrel Finishing

• Automated mass finishing process eliminates hand finishing, and produces a more uniform, consistent finish.


• High speed process is 90 times faster than conventional barrel tumbling and 30 times faster than vibratory finishing. Typical processing time of 5 to 30 minutes reduces per part cost as well as lead times.


• Capable of Super Finishing. Extremely fine finishes of less than 1 micro inch are achievable.


• Excels at Ball Burnishing. Ball Burnished finishes are functional and aesthetically beautiful.


• Works well on small workpieces. Fragile workpieces can be processed without damage or distortion.

Processing Equipment

We utilize Harper brand (the genuine Harperizer) Centrifugal Barrel equipment with a 2 barrel turret capable of 25G operation with 11 inch diameter by 11 inch long cylindrical barrels.

Metal Finishing Services in Denver Colorado