mate overdefines the assembly

john_minnee507

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?

https://cad.onshape.com/documents/23df8d82f491ccbfb3c92d31/w/606cd1bba2ca45c24a45ca09/e/9d84ca49fcc83966b8b0fe86

NeilCooke

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.

CBowers

Try changing Fastened 3 and 4 to Revolute mates

john_minnee507

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

Delete Revolute 9, change Revolute 1 and Revolute 2 to Cylindrical.

john_minnee507

thanks Neil, that worked. I haven't used that mate before, so I will have to work out the differences

NeilCooke

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.