Flexible dual-robot system accommodates various sizes of pre-tacked parts and provides required access to welds. System meets or exceeds requirements for weld quality, part throughput, cycle time, and changeover. Solution is approximately five times faster than manual process, with better quality, low spatter.
Project Challenges
- Improve weld quality and part throughput over manual welding process.
- Provide flexible robotic workcell capable of accommodating various size pre-tacked parts (skid steer loader chassis) and accessing required positions for welding.
- Weld four different part models ranging from 1,971.5-2,257.5 mm L x 495.3-762 mm W x 155.6-290.8 mm H (77.62"-88.88" L, 19.5-30" W and 6.125"-11.45" H).
- Parts are carbon steel with average thickness of 6.35 mm (0.25").
- Achieve required cycle time of approximately 2.5 hours per part, depending on model.
Motoman Robotics Solution
Motoman Robotics provided a flexible dual-robot solution, including:
- Two EA1900N robots controlled by one NX100 DR2C (dual-robot) robot controller. Robots are wall-mounted from MotoSweep™ beams.
- Two MotoSweep overhead radial transport beams.
- Two Miller 450-Amp Auto-Axcess® weld packages, including interface to robot controller, four-roll wire feeder, feed rolls, and interconnecting cables.
- Two Motoman ToughGun® 500-Amp water-cooled welding torch packages, including cabling and water circulators.
- Reamer-type torch cleaner, pneumatic wire cutter and anti-spatter sprayer on floor-mounted accessory stand.
- Dual-robot Motoman ComArc seam-tracking with high-speed 200-V touch-sense package.
- Motoman MDC-2300M two-axis drop-center positioner – Drop-center beam with center turntable axis; AC servo-driven with 2,000-kg (4,400-lb) capacity, 152 mm off-center CG at rated load; tilt axis speed of 2.8 rpm, and tooling axis speed of 2.8 rpm. Dual external axis package included.
- Common equipment base for robot controller, water circulator, and welding power supplies.
- Operator station mounted in NEMA enclosure on stand-alone pedestal. Functions: job start, emergency stop, hold, alarm reset, and servo power-up. Palm buttons for cycle-start activation. Ready signal light and alarm indication light. Lighted pushbuttons indicate clamp complete/unclamp complete. Positioner auto/manual switch. Two-digit thumbwheel selector allows operator to choose from up to 100 programmed jobs.
- Cell guarding package that meets ANSI/RIA R15.06-1999 safety standard, including: 3.05-m (10') H wire safety fencing with one access gate and positive-break safety switch; arc flash protection curtains; interlocked sliding double bi-fold gate at positioner load/unload station; lock-out tag-out switches at operator station; and ceiling-mount robot fail-safe clips.
Fixtures/Tooling Details
Motoman Robotics provided a holding grade welding fixture package that features hardened locators, hydraulic clamping, clamp-closed sensors, and adjustable locating details which allow the fixture to accommodate four different part models. Manual changeover is required between parts. Fixtures are labeled to identify changeover positions. Quick changeover estimated at 15 minutes for an experienced user.
Ref: ACS-068