Case Studies / Arc Welding / Automotive Exhaust Components II

Motoman Robot Arc WeldingFlexible system welds final and subassemblies with minimal changeover between part models. Easily achieved cycle time rates. Cell runs up to 24% faster than requirement. Met or exceeded customer’s quality expectations.

Project Challenges

  • Automate welding of three different models of exhaust manifold final assemblies and subassemblies.
  • Accommodate batch production with minimal changeover between part models.
  • Parts are steel. Final assemblies are approximately 1200 mm x 200 mm x 420 mm (57.2" x 7.9" x 16.6") and weigh approximately 10 kg (22.04 lbs.). Each final assembly includes two 12.7-mm (0.5") long slot welds to join two tabs to the flange. Next, a 6-mm, 360-degree lap weld around a 57.15 mm (2.25") pipe joins the flange to the converter, and another joins the converter to the flex pipe. Subassemblies require 4-mm, 360-degree fillet welds on a 25.4 mm (1") boss.
  • Achieve production rate of 178,000 assemblies per year, at 4,750 hours per year.
  • Achieve 96-second cycle time for final and subassemblies.
  • Meet customer’s requirements for quality and consistent welds.

Motoman Robotics Solution

Motoman Robotics provided a flexible workcell with a high-speed positioner, including:

  • Motoman six-axis UP20 welding robot with XRC 2001 controller.
  • Robot base riser.
  • ThermalArc welding package (Customer supplied), including power sources, wire feeder, torch, and water circulator.
  • Universal welding interface assembly.
  • Contact tip change box.
  • Manual TCP check station.
  • Motoman VMF-500 S5D five-axis, two-station, tilt-rotate positioner. AC servo-driven with 500-kg (1,100-lb.) capacity per side. Tilt
  • xis rotation speed 0-8.6 rpm; tilt axis torque 3,000 Nm. Rotate speed 0-16.8 rpm; rotate torque 1,060 Nm. Station switching speed 0-8.6 rpm (180-degrees in approximately 6 seconds); station switching torque 2,050 Nm. Maximum swing radius 750 mm (29.5-in.). Includes external axis packages, positioner base, robot-to-positioner spanner, and slip ring kit for tooling I/O communications.
  • Allen-Bradley SLC 5/04 PLC package.
  • PanelView 1000 operator interface.
  • Common equipment base for XRC and welding power supply.
  • Cell guarding package, including wire safety fencing with one access gate and positive break safety switch, arc flash protection curtains, and light curtain at positioner load/unload station.

Fixtures/Tooling Details

Motoman Robotics provided two final weld fixtures, each consisting of one final assembly fixture and one collector subassembly fixture. Fixtures accommodate all three part models, as well as the lower collector stamping and sensor plug. Detail change-out is minimal (<10 minutes) and does not require hand tools. Fixtures are pneumatically clamped and include part-present and clamp-open/closed sensors.

Ref: ACS-049

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