Guyson Corporation has supplied a custom- engineered automatic blasting system to upgrade the precision and uniformity of surface preparation for an optical component manufacturer. The Model RXS-400 spindle-blast machine processes a family of parts that require a chemically blackened finish.

Abrasive blasting and bead blasting are accepted methods of surface preparation for a variety of coating, finishing and surface treatment processes. In addition to quick removal of surface oxidation, blasting can effectively blend-in light scratches or superficial imperfections, impart a desired texture that contributes subtly to the final appearance of the component and produce an overall uniform surface condition that benefits subsequent finishing processes.

In this case, the purpose of automated blasting is light and even etching of target surfaces to enable consistent production of a non-reflective matte black finish. The fact that all the components are essentially cylindrical in shape led to the selection of a rotary spindle blasting machine that uses a fine mineral grit with extremely low iron content. To withstand production use with such harsh blast material, numerous abrasive protection features such as rubber cabinet lining and bronze blast guns with boron carbide nozzles are required.

The Model RXS-400 has two spindles mounted on a 180-degree-indexing turntable, so a part is loaded during the timed blast cycle. Inside the sealed blast chamber, multiple suction-blast guns are positioned on a linear ballscrew/ballnut actuator. Nozzle motion in the vertical axis is programmable for each different component, as is the speed of spindle rotation and the duration of the blasting and blow-off.

A full-depth side door is provided to allow access to the finishing enclosure for adjustment, inspection, and maintenance. A wrap-around work table at the front of the machine facilitates staging and smooth handling of components. Surrounding the zone of the workstation where automatic door operation and table indexing take place is a safety light curtain that instantly disables all motion if the operator is not clear.

Prospective users of automated cabinet-blast systems are invited to submit sample components for free laboratory testing and application engineering evaluation at the machine builder's factory in northeastern New York State.