First off, I have to have I am really intrigued by the design of the carriage. I think I might have shot myself in the foot with the middle joiner assembly. I was trying to figure out how to put the assembly together and I wound up snapping middle joiners. I thought I could get aways with a crazy glue repair seemed like a good idea at the time. I think this locked in angular misalignment in the x-y axis.
The failure occurred where the bolts put the too halves together. I think there where a couple of things I could have done to have improved the quality of the print. For one thing, I didn’t use support. Next try… I will add support. The other issue that I had was that I had printed these parts one at a time. One issue that happened where the failure occurred, I don’t think the plastic had enough time to cool between layer. I think I could have addressed that by printing out more than one part at once and this would have made the small cross section prints stronger. (Have my cooling fan directed a little better probably wouldn’t hurt either)
One thing I’m curious about. It seems to me that it’s going to be hard to keep all the axes orthogonal because of stack up errors on the assembled printed parts . It seems to me that if you add a square reference, say a extruded aluminum square tube and build off that, the errors wouldn’t accumulate as much. Have you ever considered this?