Robotic system meets or exceeds all project goals and objectives. It significantly improves welding productivity and throughput, while reducing direct labor and increasing safety. Dual robots completely weld parts through all three stages in 4-6 hours. Parts only need to be preheated before each stage. Parts formerly required 3-5 days to complete, due to need to send part back to oven multiple times for preheating/reheating. System requires one operator versus three to four manual welders, allowing skilled welders to be redeployed elsewhere in the plant. Robotic welding improves safety by eliminating workers’ need to reach into tight areas on heated parts to weld manually. Flexible positioner improves productivity and safety by eliminating the need for excessive manual handling and/or part repositioning using crane and hoist. Robotic welding improves welding quality, consistency and aesthetics.
Project Challenges
- Weld two models of pre-tacked frame weldments. Complex parts are thick-walled cylinders with heavy plate separators made of 19.1 mm (0.75") thick ASTM514, a high-strength, high-temperature steel. Weldments are approximately 1,295 mm x 1,115 mm x 1,360 mm (51" x 43.9" x 53.5") and initially weigh approximately 1,450 kg (3,197.3 lbs) each. After three stages of welding, completed frame weldments weigh up to 907.2-1,134 kg (2,000-2,500 lbs.) each.
- Parts must be preheated to 250-400° F. Welds range from 76.2-457.2 mm (3"-18") in length, and each part requires 150-250 multi-pass welds (with each of these welds requiring 3-9 passes).
- Reduce manual welding operation, enabling welders to be redeployed within plant, resulting in an overall labor savings.
- Improve quality, consistency and throughput of the welding operations.
Motoman Robotics Solution
Motoman Robotics provided a modified FabWorld solution, including:
- (2) Motoman extended-reach HP50-20 robots with (1) NX100 DR2C (dual-robot controller).
- (2) Heat protection jackets for robot upper arms. Silicone-coated jacket, heat-resistant to 650° F (343° C) includes zippers for easy installation and fittings for internal forced-air cooling (using customer-supplied shop air).
- (2) Weld packages with Miller Auto Deltaweld 452 450-amp constant voltage power source, Miller interface to NX100 controller, four-roll wire feeder and feed rolls, and interconnecting cables.
- (2) Motoman Tough Gun® torch packages with water circulators. Each includes 450-amp water-cooled, extended-length GMAW torch, wire brake, safety clutch and start-up kit.
- Motoman dual-robot ComArc package with 200V high-speed touch-sensing.
- Reamer/sprayer nozzle cleaning station with wire cutter mounted on accessory stand.
- ToolSight™ comprehensive torch alignment package.
- Motoman MDC-2300M two-axis drop-center positioner with AC servo-tilt/servo rotate beam and center turntable axis; 2,300-kg (5,071.5-lb) capacity; 7.9-sec. tilt axis 180° sweep; 4.8-sec. tooling axis 180° rotation; external axis package, and positioner base plate riser.
- Custom fixture package.
- Operator station on stand-alone pedestal, including thumbwheel switch for program selection and manual jog joystick.
- Common equipment base for NX100s and welding power supplies.
- Cell guarding package, including wire safety fencing with one access gate and positive-break safety switch; arc flash protection curtains; and bi-fold doors at positioner load/unload station.
Fixtures/Tooling Details
Motoman Robotics provided custom manual holding fixtures with hardened fixture details. Parts are bolted into place and no sensors are used.
Ref: ACS-093