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mate overdefines the assembly

john_minnee507
john_minnee507 Member Posts: 5 ✭✭
in Community Support
I can't seem to get these mates to work and I can't figure out why. I was doing great when things started to going bad. (Assembly 1 was working brilliantly then went bad. Assembly 2 was going well, with both pistons working fine, then I started to go backward. Now I can't get the revolve connection to work and I don't know why. What am I doing wrong?


Best Answer

  • NeilCooke
    NeilCooke Moderator, Onshape Employees Posts: 6,092 image
    Answer ✓
    Having too many revolutes can cause the system to bind up due to tolerance issues - cylindrical adds a translational DOF that eases that. You wouldn't have guessed without me telling you.
    Senior Director, Technical Services, EMEA

Answers

  • CBowers
    CBowers Member Posts: 50 PRO
    Try changing Fastened 3 and 4 to Revolute mates
  • john_minnee507
    john_minnee507 Member Posts: 5 ✭✭
    Thanks, I tried that, but it still does not help. Theoretically if the mate between the piston and conrod are revolute these would not need to be revolute mates.

  • NeilCooke
    NeilCooke Moderator, Onshape Employees Posts: 6,092 image
    Delete Revolute 9, change Revolute 1 and Revolute 2 to Cylindrical.
    Senior Director, Technical Services, EMEA
  • john_minnee507
    john_minnee507 Member Posts: 5 ✭✭
    thanks Neil, that worked. I haven't used that mate before, so I will have to work out the differences
  • NeilCooke
    NeilCooke Moderator, Onshape Employees Posts: 6,092 image
    Answer ✓
    Having too many revolutes can cause the system to bind up due to tolerance issues - cylindrical adds a translational DOF that eases that. You wouldn't have guessed without me telling you.
    Senior Director, Technical Services, EMEA

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