ONCE (ONe-sided Cell End effector)

The ONCE system is designed to drill, countersink, and measure fastener holes in the Boeing F/A-18E/F Super Hornet TEF's (trailing edge flaps). Like many of Electroimpact's systems, ONCE consists of three major sub-systems: the positioner, the multi-function tool platform, and the workpiece fixturing unit. The uniqueness of this system, however, lies in the positioning system - a 6-axis articulated robot arm. To date, conventional industrial robots have been unable to meet the high accuracy requirements set by the Aerospace industry. This is mainly attributed to the number of joints and their methods of feedback. However, the repeatability of the industrial robot tends to be very good, usually less than 0.012" within their work envelope. The combination of good repeatability, high payload capacity, and larger work envelope has helped to merge the industrial robot with the aerospace industry.

The positioning robot selected for this system was the Kuka Robotics KR350/2 with the KR C1A motion controller. The KR 350 is capable of lifting, accelerating, and positioning a payload of 350kg (770 lbs). The articulated arm offers maximum range of motion versus the common parallelogram robot. The maximum reach of the KR 350, from the center of the base to the tool mounting flange is 2535mm (8.3 ft). An additional linear 7th axis is used to increase the work envelope.