Case Studies / Spot Welding / Automotive Part Assemblies


Motoman Robots Spot WeldingAchieved 36.5-second average cycle time, which is 4.5 seconds (11%) faster than the 41-second goal.

Project Challenges

  • Automatic fixtures that allow access for multiple vertical and horizontal spot welds.
  • Meet specification for 5-7 mm (0.2-0.28") diameter weld nuggets. Parts are zinc-coated 1.25-2.5-mm thick 1008 mild steel.
  • Achieve 41-second cycle time.
  • Achieve production rate of 560,000 assemblies per year, based on two 7.5-hour shifts and 240 days.
  • Meet torque spec for projection-welded pin of 113.4 kg (250-lbs) of push-out force.
  • Welds must be able to withstand destructive test.

Motoman Robotics Solution

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

  • Two Motoman UP130 robots with XRC DR2C controllers.
  • Two steel robot base plates and spanner to positioner base plate.
  • Two Medar 3000S AC welding controls with one interface pendant.
  • Two Centerline Voltza™ Transgun packages.
  • Two water chillers.
  • Two Semtorq tip dressers with stands.
  • Motoman high-speed, AC servo-driven MSR350 rotary positioner with 350-kg (771.75-lb) weight capacity per side, 2.5-second sweep time, and a two-position, 1.5-m (60") tabletop diameter turntable.
  • Operator station with color PanelView™ 600 interface
  • Allen-Bradley SLC/500 PLC.
  • Integrated workcell protection, including cell guarding, light curtain, arc screen and curtains, and safety-interlocked gate. Additionally, Motoman provided:
  • Dedicated TECHweld single-shot projection welder with dual infra-red Opto-touch buttons for activation.
  • Medweld™ 3000S controller for projection welder.
Ref: ACS-032