The Protector, a crash-detection device for robots, removes tooling from a crash situation and automatically resets itself.
The National Manufacturing Co. Inc. of Chatam, N. J., thought it had successfully automated the loading/unloading of its 10-station, 45-ton press when incorporating a robot to do the job. However, the company, a producer of deep-drawn enclosures for the medical, electronic, and aerospace/satellite industries, failed to specify a crash-protection device on the robot. And as a result, it took only one crash for the robot to sustain heavy damage, forcing the shop to manually tend the press. It was a time-consuming process because part runs were averaging 250,000 pieces.
To keep such situations from happening again, National Manufacturing installed the Protector, a crash-protection device from ATI Industrial Automation. The device absorbs a crash and resets itself with minimal downtime.
In operation, the Protector is adjusted to support typical loads experienced by the robot arm in all directions: angular, compression, and torsional. When preset limits are exceeded, the compliant Protector absorbs the impact energy through a pneumatic chamber.
National Manufacturing sets up production runs according to customer specifications. The shop then programs these specs into the robot controller, which lets the robot accurately perform the specific load/unload operations for each run. In addition, for every customer and part, the shop has to train the robot.
Minor crashes during training can add hours or days to the setup procedure. "With crash protection," says Daniel DiAndrea, project engineer at National Manufacturing, "we set the crash sensitivity to allow for minor misalignment of parts, and together with the Protector's reset feature, we minimize downtime."
After a crash, the Protector uses precise locating components to reset within 0.001-in. of its original position. Its breakaway points are set at a given pressure and are independent of whether the crash resulted from a movement or torque load. To avoid nuisance tripping of the system, its switch is set to actuate within 0.7° of angular or 0.005 in. of axial motion.
ATI Industrial Automation