Aligning parts on extrusion in Assembly

daniel_shookowsky

So I finally learned about weldments and the beam feature.  Fantastic stuff.  That simplified creating a frame assembly with OpenBuilds vrail.  Now I'm trying to add some components to that assembly (wheels and pillow blocks and angle brackets).  I think that I'm confusing the approach that I would take to assemble this in the real world with the best means of simulating the assembly in OnShape.  

How do you approach 80/20 or OpenBuilds  extrusion when creating assemblies.  Is there a way to reuse the sketch I created for the frame to create the mate connectors?

https://cad.onshape.com/documents/93d2bb4e3041596dcfc9bd22/w/f0031f4f01db1176b145af45/e/57d0ad342ae459a35960616d

Jake_Rosenfeld

Hi Daniel,

Have you used Onshape assemblies before?  If you're not familiar with our mating system it may be helpful to watch these videos:
https://www.onshape.com/videos/onshape-cad-tutorial-build-your-first-assembly
https://www.onshape.com/videos/assembly-mates

If you want to use the original sketch to define a Mate Connector, it may be easier to create your mate connector in the Part Studio before bring the part into an Assembly.
https://cad.onshape.com/help/Content/mateconnector.htm

If you give us a couple examples of how you would like to mate parts to your frame, I'm sure people would be happy to give examples of how to mate the parts together.

daniel_shookowsky

Take this document for an example.  

The corner connectors are easy to mate, but I can't figure out how to place the pillow blocks so that the wheels would be aligned.

https://cad.onshape.com/documents/93d2bb4e3041596dcfc9bd22/w/f0031f4f01db1176b145af45/e/57d0ad342ae459a35960616d

mthiesmeyer

Hi Daniel,

Should the wheels be able to move within their channel or simply rotate in place? I would look at our relations, you're going to need to use them to relate the motion of two different parts.

Best,

Mike

daniel_shookowsky

Hmm... looks like I need to figure out how to get email notifications from these forums in addition to my other questions.   For the purposes of this assembly, I'm just trying to show what the finished robot should look like.  I'm not at the point with onshape where I'm analyzing motion.  Just trying to figure out spatial relationships and dimensions so that we can order parts and have some kids from 7th-12th grades build a robot   

daniel_shookowsky

somewhat answering my own question I found that the approach that worked for me was to add a mate connector.  I selected the center point of the extrusion (in this case it was 15mm Rev extrusion) and checked the 'move' box and entered a value of 7.5mm.  This added a new mate connector in the center of the channel.  


Similarly, I added a new mate connector on the inside corner bracket at the point at which the radius was calculated from.  Instead of checking move this time, I selected realign and selected a face.  This was repeated with both faces of the bracket