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Case Study

Oversized Weldments Case Study

A manufacturer of large welded dump truck components needed to comply with their customers request to control the welding sequence, meet scheduled delivery dates, and ensure that weld size and quality is consistent from part to part.  

Project Challenges

  • Provide a robotic arc welding system with enough reach to access welds on parts up 161” long and 97” wide.
  • Provide robust positioners and tooling that allowed safe and easy reloading of large parts using an overhead bridge crane.
  • Gain customers approval to utilize more aggressive welding procedures to reduce welding cycle time.
  • Provide sensing technology to locate welding joints and accurately shift weld locations to the current joint location.
  • Use sensing technology to find welding joint locations before welding and alert the operator if the joint location is outside specified tolerances.

KC Robotics Solution

KC Robotics integrated a system using a Yaskawa MA 3120 welding Robot and a Miller Continuum welding system with a water-cooled torch.  The combined maximum horizontal reach of the robot and torch exceeded 3.5 meters or 137”.

Two Servo driven Headstock Tailstock positioners were installed to accommodate tooling frames capable of holding and rotating parts up to 97” diameter and 161” long. One positioner can be reloaded while robotic welding is in progress on the other.

More aggressive welding procedures using metal core wire and 85% argon/15% CO2 shielding gas were developed by KC Robotics and approved for use.

Simplified laser sensing programs were written to minimize teaching time, locate non-standard welding joint configurations, and alert the operator if weld joints are outside specified tolerances. (The calculated shift amounts are displayed on the teach pendant.)

KC Robotics provided programming, programming assistance, and training to customer’s personnel. Training included advanced programming for using laser sensing to find unusual joint configurations.

Stairs and platforms were provided for locations on the large welding frame where personnel needed access to fixture coupling mechanisms.

Results

  • Like all robotic welding, this system increased productivity, improved quality and reduced waste.
  • The size of the parts being welding for this customer required specialized equipment to meet quality standards. Servo driven Headstock Tailstock positioners now automate the process of rotating the part, allowing welds to be applied in sequence that distributes heat evenly and controls distortion.
  • The welding sequence resulted in a significant improvement in the flatness of the bottom (floor) of the part.
  • Weld size, weld quality, and welding sequence are consistent on every robotically welded part.
  • Arc-on time is reduced because higher robotic welding travel speeds are used. Robotic welding increases arc-on time and throughput. The sentence highlighted is incorrect.
  • The laser sensing program reduces the amount of rework by detecting the weld joints before welding and alerting the operator if the joint location is out of tolerance.
  • Before automating, manual welders had to climb on the parts to access weld joints. Since installing the robotic welding system, operator fatigue and risk of injury has been reduced.
  • KC Robotics not only fulfilled with all the customer’s needs, we trained their personnel so they now have more desirable jobs.