Why is top panel truncated in my assembly?

michael_mcewen

Hey there, can anyone help me solve a problem?  See: https://cad.onshape.com/documents/6d16ccd579e3780a766bb971/w/02933cd4fb2dc81806672180/e/f31dbd210dabdbcb97a611bd

 If you look at the top plate sketch, it measures 17.5” x 17.5”.  I extruded it to ¼”, then built the subsequent panels after first creating new planes for those panels.  At some point along the way, the top panel appears ¼” shy of meeting the front panel.  I check the sketch, the extrusion, the front plane, and I can see no errors, and yet still the panel will not close.

 This is the second time this has happened on 2 different box assemblies, and I cannot for the life of me figure out how to fix it, or why it happened in the first place.

Thanks a lot,

 Michael

daniel_splawski

When you make a sketch you have the option of selecting a plane or any flat surface on an existing part.  In this case, you'd have to select the 0.25" surface on the edge of the top piece.  I've created an example model so you can see how it's done.  Also, I've used the hole feature to create some holes before I mirrored the pieces.  

https://cad.onshape.com/documents/da6bef69141526fbf26b393d/w/46a868bccb83cdcad3e69fe4/e/d19fe398940ebcfb243de6d3

daniel_splawski

It's not public, so I can't see exactly how the planes are created. Also, I don't see the 1/4" gap that you're talking about in the shared file.  As a result, it's very difficult to speculate as to what the issue might be.  

If I were constructing the same object, I would avoid all the additional planes and base my sketches directly off of the surfaces of the original 17.5"x17.5" panel, that way you guarantee that their location is always referenced correctly from the initial piece.  Also if these parts are all symmetrical, using the mirror function keep things a bit cleaner.  Depending on how you've designed your holes in the sketches, it might be easier to avoid extruding them in the first place or just marking them using a vertex and actually using the hole command to create them, that way their size can be adjusted dynamically.    

michael_mcewen

Thanks Daniel.  If I don't create a plane, how does one make a sketch on a plane offset from the origin?  Is there a way to offset from a plane?

daniel_splawski

When you make a sketch you have the option of selecting a plane or any flat surface on an existing part.  In this case, you'd have to select the 0.25" surface on the edge of the top piece.  I've created an example model so you can see how it's done.  Also, I've used the hole feature to create some holes before I mirrored the pieces.  

https://cad.onshape.com/documents/da6bef69141526fbf26b393d/w/46a868bccb83cdcad3e69fe4/e/d19fe398940ebcfb243de6d3

michael_mcewen

Hi Daniel,  Thanks a lot.  I tried this method; much easier than my approach and less problematic!  Also, that hole feature is new to me.  Pretty cool for sure.  Thanks again.  -Michael

daniel_splawski

The hole feature is superb... It has all the standard and metric hole sizes built in and you can select weather you want clearance holes or holes for tapping. Not to mention the counterbore and countersink parameters.   

michael_mcewen

I'll have to explore that feature more!