Motoman Robots Arc Welding Heavy Equipment Weldments

Motoman Robotics provided two identical custom systems, each with two EA1900N robots on servo tracks welding large heavy-equipment weldments on a heavy-payload MHT-3100 headstock/tailstock positioner.

Summary

Robot systems dramatically improved productivity. Depending on part number, weldments that previously required 3 hours to weld manually can be robotically welded in 50 minutes; others that required 5-6 hours to weld manually can be robotically welded in only 90 minutes. System robotically welds areas that are ergonomically difficult for manual welders, such as 1.2-m (4') down into a channel between two plates. Robotic welding improved quality and consistency. Due to part design limitations (torch access), project would have been considered a success if the robots were able to weld 70% of the total weld length. However, robots far exceeded customer’s expectations and are able to access and weld more than 90% of the total weld length.

Project Challenges

Provide two duplicate systems for processing large, pre-tacked heavy equipment weldments from four part families, with interchangeability to quickly adapt production from one part type to another.
Provide a compact welding cell that utilizes the minimum floorspace that production and safety concerns allow.
Provide the most cost-effective solution, giving priority to the most difficult-to-reach sheet-to-bottom plate internal welds, with secondary importance to brackets and other components within the same cavity.
Robotically weld parts with access that is difficult for manual welders to reach.
Improve productivity and provide consistent, quality welds.

Motoman Robotics Solution

Motoman Robotics provided two dual-robot systems. Each includes:

(2) Motoman EA1900N “Expert Arc” welding robots.
(2) NX100 robot DR2C Controllers.
(2) Servo tracks with 4.0-m (13.1') L travel.
(2) Miller 450-Amp Auto-Axcess® weld packages.
(2) Weld dress-out packages
Motoman ComArc dual-robot seam-tracking and 200V touchsensing packages.
(2) Binzel 45-degree torch packages – 600-Amp, water-cooled with water circulators.
(2) Reamer/sprayer nozzle cleaning stations with wire cutters.
(2) ToolSight™ comprehensive torch alignment packages.
MHT-3100 headstock/tailstock positioner with 6,300 kg (13,889.5-lb) maximum load at 90 mm (3.5") offset CG and 5-second, 180-degree rotation. Includes MotoMount™- compliant tool mounting system.
Operator station on stand-alone pedestal.
Enable/disable key operated station – fence-mounted in NEMA enclosure on inside of fence. Disable position prevents servo power from being engaged in Teach or Play mode.
Common equipment base and table.
Cell guarding that meets ANSI-RIA R15.06-1999 safety standard, including: 2.5-m (8') woven wire perimeter safety fence with one interlocked personnel access gate; (2) interlocked load/unload gates (one at each end of cell); arc flash protection curtains; audible alarm horn; and teach interlock to identify gate as being open.

Fixtures/Tooling Details

The customer was responsible for providing manually clamped fixtures for this project. Details in the fixtures are manually changed out to accommodate four different part families.