Guyson Corporation has designed and built an automated indexing table grit-blasting machine integrated with a component handling robotic arm that loads parts onto the blast system from an in-feed conveyor and unloads them to a take-away conveyor. The unmanned Model RX-1400-RB is capable of process cycle times under ten seconds.
The robot selected for this machine-tending application was the compact Fanuc LR Mate 200iC. It is mounted on a pedestal at machine height and fitted with a custom-engineered, pneumatically actuated, finger-like gripper designed and fabricated by Guyson to match the contours of the component-holding fixtures of the blast cabinet.
In the RX-1400 design, six or twelve fixtures are equally space around the perimeter of the 66-inch diameter turntable, which is rotated by a precision cam indexer. In the six-spindle configuration, there are two active blast stations inside the grit-blasting chamber, each with a cluster of eight suction-blast guns adjustably bracketed at the correct angles and stand-off distances for coverage of targeted surfaces and mounted on a linear actuator located on the roof of the blast machine. During the timed blast cycle, the guns traverse at the programmed speed for the prescribed distance and number of strokes. Blasting is followed by an air wash blow-off cycle for the removal of residual media and dust.
The grit-blast cabinet itself is 95 inches wide and 101 inches deep, including the overhang of the vacuum return catch tray at the front loading station. Safety interlocked access doors on the sides and back of the process chamber allow convenient access for gun inspection, adjustment and periodic maintenance. Pneumatically actuated sliding doors seal the front of the machine, preventing the escape of media or dust and reducing the sound level during blasting operations.
A normal cycle for the part-handling robot begins with removal of the finished component from the left-hand fixture and placement of the part on an indexing take-away conveyor. Then the component from the right-hand fixture, which has been blasted on one side only, is picked up, inverted to expose the second side to blasting and placed on the left-hand fixture. An unfinished component is then picked from the in-feed conveyor and placed on the right-hand fixture.
Because the RX-1400-RB is designed for uninterrupted operation in a high-volume production environment, the system includes some special features to ensure the integrity of the surface preparation process. Electronic sensor technology is employed to constantly monitor the level of grit in the media supply hopper that feeds the blast guns. When a low media level is detected, fresh grit is automatically added to the system, and when the supply of grit in the adder hopper is low, an audible alarm summons an attendant to replenish it. The blasting air pressure is monitored and dynamically maintained at the level specified in the process recipe by a digital regulator under closed loop control, and a sensor and fault indicator alert the operators if there should be inadequate pressure in the compressed air supply to the blast system.
Prospective users of automated or robotic blasting equipment are invited to submit sample components for free laboratory testing and application engineering evaluation at the Guyson factory in northeastern New York State.