ROTARY SHOT PEENING SYSTEM FOR MACHINE TOOL COMPONENTS

Guyson Corporation (Saratoga Springs, NY) has designed and manufactured a rotary indexing spindle-blast machine for metallurgical shot peening of proprietary machine tool components to dramatically increase the service life of the tooling. The suction-blast peening system incorporates special features to control the cold working process and ensure consistent impact treatment results.

The six-station rotary table of the automated blast machine is mounted on a precision cam indexer that accurately steps the fixtured components through isolation, peening and blow-off chambers within the abrasion-protected cabinet. At two shot peening stations in the blast enclosure, the component-bearing spindles are rotated at controlled speed during the timed process cycle. The spindle rotation speed is adjustable.

Multiple blast guns are pre-arranged at the shot peening stations, rigidly held in position on telescoping and adjustable brackets, so the correct angle and offset of each nozzle is maintained to ensure the impingement of shot on target component surfaces. To simplify shot peening of similar components that vary in height or diameter, the blast guns are affixed to a ballscrew-ballnut linear actuator at each peening station. The position, stroke and speed of nozzle motion is programmable and synchronized with component rotation.

Many peening system features, especially the configuration of the controls and associated electronic monitoring and regulating capabilities, are largely dictated by the shot peening specification to be met, whether an OEM's internal process spec or aerospace material specs such as AMS-2430, AMS-2432 or AMS-S-13165. In any case, one of the key elements is to maintain strict control over shot sizing, a critical factor in ensuring the uniformity of the compressive stresses induced in the shot peening process. Shot size control is accomplished by the addition of a vibrating screen classier in the media reclamation system to remove over- and under-sized shot.

Shot peening process control technologies that can be incorporated in the automated system include shot flow monitors, closed-loop blast pressure and shot flow control, facilities to maintain peening shot sphericity, shot supply level sensing and automatic replenishment, plus enhancements to the human-machine interface (HMI) and central microprocessor to support data acquisition and logging of process parameters for statistical trending and documentation purposes.

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Guyson Corporation, 13 Grande Boulevard, Saratoga Springs, NY 12866-9090, 518-587-7894, guyson.com, e-mail: jccarson@guyson.com.