I got the X carriage printed and assembled over the past few nights. I decided to make this out of 2 parts and use ABS+acetone to glue them together. I have used this method in the past to join parts and it gives a
very strong joint with none of the brittle-ness you see in superglue joints.
After posing the question to the ORDBot forum, I made the decision to remove one wheel from the carriage and use 3 wheels - 2 fixed (top) and 1 adjustable (bottom).
I also made some small changes to the hole pattern on the bottom face of the carriage, to give more adjustability to the extruder position, and to make sure a custom hotend mount plate I have will fit. I added the side triangular walls and the back face bevels for support and to give the acetone+ABS glue a larger surface area to bite on. I added 2 screw holes at the tops of the braces to help make sure the 2 parts go together flat.
- X Carriage Pieces in Print Orientation
These parts printed flat, but after I removed them they developed fairly serious warp issues. These are the first parts so far I've seen warp, and unlike the Z plates, for example, you can't "pull" them flat to the extrusion because the X carriage isn't bolted down firmly - it rides on wheels. I was able to remove most of the warp by heating the parts up to 110C on the bed and slowly cooling them down, combined with some "artful" bending. They are not perfectly flat but they are much better than they were.
- Warped Part
EDIT: I've been asked to include some post-warp-correction pictures. These are the best I could do:
- Back Piece Flatness Check
- Bottom Flatness Check
To glue the pieces together, I sanded the mating face of the bottom piece to flatten the surface out (the mating face of the back piece was against the glass - no sanding needed), then used a small paintbrush to apply a liberal coating of acetone+ABS glue to the mating face of the bottom piece. At nearly the same time I squash the pieces together as fast as possible, get the screws started, and get the carriage into a clamp before the acetone evaporates. After the initial set I went back and applied more glue to the joint to make sure it was filled and fully bonded.
- X Carriage Being Glued
After about an hour I took the parts out of the clamp and checked for flatness. Overall I think the part is usable, but I will very probably replace this with a metal part when they become available from Bart - what I have now is not an ideal solution.
- X Carriage Assembled
That about covers it. Still waiting on my shipment from Misumi to begin putting things together.