ONCE (ONe-sided Cell End effector)

The multi-function end effector (MFE) designed for ONCE is based on proven technologies used on Electroimpact's larger machines, but scaled down to meet the lighter weight, smaller envelope requirement for use with the robotic positioner. Once in position, normality feedback is obtained by an array of 4 contact sensors centered about the MFE tip. The MFE features a servo-controlled "push-up" axis, which applies pressure to the workpiece during the machine cycle. The pushing load is user programmable and load cells integrated into the tip of the MFE produce feedback to the CNC. The push-up acts to stabilize the positioner and workpiece, decrease interlaminar burrs between materials during drilling, and enable the unit to produce accurate countersinks since the panel position remains against the MFE tip. Once push-up is established, the various tools are presented to the fastener position via the servo controlled shuttle table. All process tools are mounted to this shuttle table and are modular in design to allow for ease in removal/installation. Process tools used on the ONCE MFE include:

• Drill Spindle: 0-6000 rpm, 160 in-lb continuous torque servo spindle motor with resolver feedback and digital drive. Spindle feed is controlled via servomotor with linear encoder feedback. Actuation is achieved via an inline ball screw. The spindle is 4.0" in width and approximately 70 lbs. The tooling interface consists of an HSK40C taper with a manual release drawbar mechanism.
• Hole Probe: 2-point ball contact device with LVDT feedback - typical accuracy of +/-0.0002". Tips are interchangeable and zeroed every cycle against a known reference. Compliant pads offer protection against misalignment. The probe is 2.0" wide and approximately 25 lbs.
• Resynchronization Camera: NTSC video format with crosshair generator with LED light source integrated into the tool tip. The camera is 1.0" wide and approximately 7 lbs.