A global producer of equipment for construction, agriculture and other industries was looking to reduce labor cost, improve product quality and increase its production volume.
- Robotically weld frames and lift arms to construct a skid steer loader, instead of relying on manual welding.
- Ability to position four different frames (up to 3.0 m x 1.8 m x 1.7 m) to keep all welds in the flat or horizontal position.
- Accommodate frames for welding on all sides, inside and outside the weldment.
Motoman Robotics Solution
Yaskawa Motoman developed a custom robotic welding solution measuring approximately 6.2 m x 6.9 m, that included:
- Two extended-reach, six-axis Motoman® MA3100 welding robots with a 3,121 mm horizontal reach and 5,615 mm vertical reach. These robots offer a wide work envelope and can be placed close to workpieces and equipment due to a small interference zone. Each robot features an integrated torch cable to simplify programming and reduce cable wear.
- A two-axis, MDC-2300 drop-center positioner. This servo-axis tilt/rotate positioner features a payload of 2,300 kg and maximum tooling sweep diameter of 4,000 mm to accommodate the large part sizes. Coordinated motion between the tooling axis and the robot provide increased travel speeds.
- Each robot is equipped with a Miller Auto-Axcess® 450-DI weld package and a water-cooled Binzel torch. The digital weld interface offers one-key navigation between the robot program and weld settings in the Arc Start File.
- AccuFast, Touch Sensing and ComArc seam tracking were added to improve precision, productivity and quality.
Custom fixturing to hold the frames and lift arms was designed and provided by Yaskawa Motoman. Weldments are loaded into the fixture offline. The loaded fixtures are docked on the positioner using a forklift. A fixture ID signal determines whether a frame, LH lift arm or RH lift arm fixture is loaded. A touch sense routine validates the part identification based on the operator’s selection at the operator station.
AccuFast, a non-contact seam finding sensor, utilizes a commercial point laser which saves cycle time due to its ability to search at fast speeds and elimination of wire clipping. Thru-wire Touch Sensing and ComArc “through-the-arc” seam tracker compensate for inaccurate work pieces.
ComArc measures arc characteristics to pinpoint variations between the robot’s taught path and the desired path.
- Frames can be welded in 110 minutes, and lift arms in 30 minutes, greatly increasing the speed and rate of production compared to the manual welding process.
- The tooling design enabled changeover from lift arms to frames in less than five minutes.
- Robotic welding provided greater weld repeatability, improving the quality of the welds.