Motoman Robot Machine Loading Aluminum Wheels

Summary

Met customer's machine loading requirements. 56-second cycle time achieved; over 6% faster than the 60-second requirement.

Project Challenges

• Provide flexible robotic system to accurately locate and handle cast aluminum wheels that weigh approximately 18-20 kg (40-45 lbs) and nominally measure 355 mm (14"), 381 mm (15"), 406 mm (16") and 432 mm (17") in diameter, each with up to five widths.
• Locate wheels to avoid flashing lines during clamping and also when wheels are chucked in lathes.
• Minimal manual changeover.
• Meet required cycle time of 60 seconds per wheel.
• Improve productivity and safety - reduce injuries and worker's compensation claims arising from repetitive movement of heavy wheels.

Motoman Robotics Solution

• Motoman Robotics provided a highly flexible robotic material handling solution, including:
• SK120 robot with MRC controller
• Off-the-shelf mechanical dual parallel wheel gripper with customized details
• Two Allen-Bradley SLC 5/04 PLCs. One controls infeed conveyor, integration with lathes and robot information. The second controls outfeed conveyor and elevator.
• Four remote PLC racks - one per lathe, one on infeed conveyor, plus MARIO card in MRC
• Two Customer supplied lathes. Lathe #1 turns back edge of the wheels and Lathe #2 turns front edge
• 2.4-m (8-ft) gravity roller reject conveyor 2.4-m (8-ft) belt-driven live roller (BDLR) infeed conveyor with three zones. Includes pneumatic stops, toggle escapement lever arms, cam followers to stop wheels, centering grippers, lift and rotate device, ultrasonic sensor to detect wheel tabs, and photo eye sensors to check wheel presence
• 30.4 m (100-ft) of ceiling-mounted Hytrol EZ Logic sensor-activated, zone-powered, BDLR conveyor in curved and straight sections
• Vertical conveyor (elevator) at end of outfeed conveyor that discharges wheels in opposite directions. Two tool boxes to hold chucks for the Okuma lathes. Tool box sensors check tool presence/absence against requirements of program selected
• Integrated work cell protection, including 2.4-m (8-ft) high wire fencing, two interlocked gates, photo eyes, and light curtains on elevator

Fixtures/Tooling Details

Motoman Robotics provided end-of-arm tooling, consisting of an off-the-shelf mechanical dual parallel wheel gripper body with customized details, including eight sets of roller details (two rollers per gripper finger). Motoman also provided pneumatic fixtures on the infeed conveyor that are used to stop, locate, center, lift and rotate wheels for orientation purposes. A continuous ultrasonic frequency sensor at the load station locates a tab common to each wheel casting. Locating pins on the pop-up device require manual changeover between wheel sizes, as do the chucks on the lathes.