Why does this assembly fail when I add one more revolute mate?

This is a robot arm design I created based on a reference design I found online. However, when I try to connect any two of these blue-colored parts using revolute mates, one of the joints (circled in orange) fails to work properly. They move in a different way, losing the revolute mate-connecting the joint…

Does anyone have an idea why this happens or how I can fix it?
Thank you… I’m still learning and would really appreciate any guidance!

https://cad.onshape.com/documents/42332c986bd06c2f97175de5/w/e243344c5da92a04bde15132/e/fc6f6a86cbdb797a2d70893e?renderMode=0&uiState=690f4fc7c74d15bfb6e2f60d

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Answers

  • MDesign
    MDesign Member Posts: 1,471 PRO

    I would probably change how you approach mates a little. Let the bolts be the last thing you mate. connect the holes to each other first so that you can easier troubleshoot where the problem may lie.

  • eric_pesty
    eric_pesty Member, pcbaevp Posts: 2,935 PRO

    The revolutes are likely "fighting" each other in the "Z" direction.

    Change some of your revolutes to cylindrical to fix the issue