Tri Mark Cab Door

Study #1 – Cab Door (TriMark)


  • Operator cabs work similar to a car doors with a latch (attached to the door) locking on to a pin that is attached to the cab frame.


  • If the pin and the latch do not line up properly the door will not latch and stay closed.
  • Suddenly stops working properly due to latch misalignment.
  • Due to the large number of components, many engineering hours are required to find the problem


Sigmetrix Tolerance Analysis Solutions Used To Answer The Following Questions:

  1. What parts are causing the misalignment problem?
  2. Are these parts that are purchased from a supplier of manufactured internally?
  3. What step in the manufacturing process is causing the problem?
  4. What should be done to correct the problem?
  5. What should be done to correct the problem? – Invest more in tooling? – Spend more time inspecting parts?
  6. If it is a supplier problem, can this supplier meet the requirements or should a different supplier be used?
  7. How can the design be changed in the future to prevent this issue?



  • Sigmetrix solved problem in 15 days
  • Saved 12 weeks of engineering “problem solving” time per design cycle
  • Shortened assembly adjustment time by 2 hours per machine (6000 machines/year).
  • Estimated savings:  approximately, $600K/ year