Robot system meets or exceeds project requirements for welding axle crossmembers that include three subassemblies and opposite sides of a final assembly. Robot system achieves 98-second cycle time (including sweep time), which is 5.5-19.7% faster than 103.7-122 second requirement. Robotically welded parts meet customer’s stringent specifications to achieve required automotive quality standards. System provides high-throughput welding cell that minimizes need for skilled manual welders.
Project Challenges
- Provide robot system to consistently weld one model of mild steel automotive axle crossmembers that includes welding three subassemblies and two sides of a final assembly. Desired production rate is approximately 29-35 parts per hour with a cycle time of approximately 122-103.7 seconds. Final welded assemblies are roughly 673.1 mm L x 108 mm W x 95.3 mm H (26.5" L x 4.25" W x 3.75" H) and weigh approximately 5 kg (11 lbs).
- Parts must meet customer’s stringent weld specifications to achieve required automotive quality standards.
- Provide high-throughput
Motoman Robotics Solution
Motoman Robotics provided a modified ArcWorld V-6400XHD with quadruple robot control (QRC), including:
- (4) Motoman SSA2000T robots.
- NX100 QRC robot controller.
- Overhead robot structure for wall-mounting robots above positioner.
- (4) Miller AutoAxcess weld packages – 450 Amp, air-cooled.
- (4) Tregaskiss reamer/sprayer nozzle cleaning stations.
- (4) ToolSight™ comprehensive torch alignment packages.
- Modified MRM2-1200M3X positioner – AC servo-driven, coordinated three-motor dual headstock/tailstock trunnion positioner with 1,200 kg (2,646 lb) payload; 4-m (13.1') extended span between headstock/tailstock faceplates; 3.25-second sweep time; 0-16.9 rpm tooling index time; and 1,000 mm (39.4") maximum part diameter.
- Fixture package.
- Allen-Bradley SLC 5/05 programmable controller package.
- MotoHMI with touch screen display of key cell functions and fixture status.
- Cell guarding package, including 2.5-m (8') H woven-wire perimeter safety fence with (2) access gates and positive-break safety switches; arc flash protection curtains; and light curtain at positioner load/unload station.
Fixtures/Tooling Details
Motoman Robotics provided two crossmember fixture frames, one per side of the positioner. Each frame includes five sets of custom fixtures; three for welding subassemblies and two for opposite sides of a final assembly. Poke-yoke fixture design prevents parts from being loaded incorrectly into the progressive fixtures that include pneumatic clamping. Various part and clamping sensors are included.
Ref: ACS-113