Why is my mate assembly overdefined?

sylvan_blake

My mate assembly is overdefined. I'm pretty sure all of my measurements are correct and I'm using fastened mates. My problem occurs when establishing the second mate between the under arm cushion and the side support and the second mate between the handle and the side support. I have also tried slider mates but I get the same problem. Thank you.

https://cad.onshape.com/documents/806a70347326d9f6bb51727f/w/2adfaf81e763939fc7de6edb/e/96e003633d280eeaa7218674?renderMode=0&uiState=65f9c3454ca40d549131cd0d

Matt_Shields

Onshape only requires one to constrain a part.  A Fastened mate fully constrains all 6 degrees of freedom of a part.  In your assembly:

Part 1 <1> is fixed
Fastened 1 fixes Part 1 < 3>
Fastened 2 fixes Part 2 <1>
Fastened 3 fixes Part 1 <2>
Fastened 4 fixes Part 1 <4>

Any more mates will overdefine your assembly.

Matt_Shields

Onshape only requires one to constrain a part.  A Fastened mate fully constrains all 6 degrees of freedom of a part.  In your assembly:

Part 1 <1> is fixed
Fastened 1 fixes Part 1 < 3>
Fastened 2 fixes Part 2 <1>
Fastened 3 fixes Part 1 <2>
Fastened 4 fixes Part 1 <4>

Any more mates will overdefine your assembly.

GregBrown

Each (rigid) body has 6 degrees of freedom. One fasten mate constrains 6 DOF…

You have 6 bodies, and one is  already “fixed” so you need to constrain 5x6 DOF. Therefore 5 fastens will fully constrain it. 

If you suppress Fasten 2 and Fasten 4 all will be good on your model. And since you used one slider this leaves one DOF free to drag.