Printing assemblies

My students are printing a lot lately, some of these are projects that they designed themselves on SolidWorks and some are downloaded from Thingiverse.  I try to keep them balanced whenever possible but for some of my students who have little or no CAD experience we find other ways to challenge them.  One of the ways we try to make them think is to have them print assemblies.  Anyone who has used a 3D printer will attest to the fact that after a while we really want to print something that exceeds the size of our build envelope.  This can be a rather small print as is the case on our Afinia printer (about 5 1/2" by 5 1/2" by 5 1/4") up to a little bit larger capacity on our Replicator 2 (11 1/4" by 6" by 6").

What CAN be done is to build a larger project as an assembly.  This allows the user to overcome the limitations of the build envelope to a certain extent.  Think of Lego's.  Alone, each individual piece is rather small, but by putting multiple pieces together as an assembly you can create quite large things.  This is what students have been trying to work through.  The fit of some of these objects sometimes requires tweaking, which can be one way of teaching students how to use CAD software.  They can start out with a pre-designed object and learn how to "tweak" them in ways to make an assembly fit together much better than the basic design.

This is a microscope design that a student downloaded from Thingiverse and printed.  It uses lenses from the little throwaway cardboard cameras most of us have seen or used at one time or another.  Although most of it worked ok, there are some design alterations that a couple of students are currently working on that should get it to function much better. 

The gear system for raising and lowering the lens tube (this is what acts as a focusing mechanism) has it's issues but the kids should have them ironed out quite soon.

Another assembly that tests our patience is a "snap together" type of assembly.  This one was a lot of fun.  Downloaded from Thingiverse, the print locked together pretty well.  A few minor changes and it should be ready for a small group of LED's in the lamp hood within a week or two.