When I first setup my emblaser I had a bit of a problem with the right gantry carriage. There was quite a bit of wobble from left to right. This was partly due to having the belt a little too tight, and little bit due to print of the carriage itself. I reprinted the carriages and properly set the belt tension. After a while I noticed that it was beginning to lean a little. It wasn't much, but enough to make the belt not want to sit properly. Since there is only a single rail on the y axis there isn't a lot to hold the carriage perpendicular.
I decided to give a redesign a try. I contacted support and Domenic was able to help me out. I can't give him and the rest of the folks at Darkly Labs enough thanks. They were extremely helpful in letting me experiment.
Here is a rendering of the idea that I had.
The extra rail is 20mm away from the original rail. I chose to keep the new rail a little closer to the original than the rails on the "x" axis. I didn't want the rail brackets to have to be too tall. The rest of basic dimensions are identical to the original design. I wanted to make sure the belt tension process would not change. I added a spine down the back of the bracket to give it a little more support since it was taller.
I also changed the type of retention system for the bearings. I had a difficult time getting the clips to stay put and decided to use screws to attach the clips to the carriage.
Here are some actual pictures of the end result.
I was going to post a video as well, but I don't know if that is really necessary. There is no noticeable difference in how the unit operates after the change. Except, of course, more stability in the "y" rails. I re-ran the calibration image and it looks great.
I didn't attach the bearing retainers for a couple of reasons. First, they are in there *very* securely. I had a very hard time snapping them in. Secondly, I didn't have screws that worked well. I don't really like using screws in plastic, but I don't think it will be a problem.
Just about the only thing I don't like about how it turned out most likely is due to my 3D printer. The gantry carriages printed great. I couldn't have been more please. The rail brackets are what gave me fits. I sized the holes at 8.2mm which is an appropriate size for receiving an 8mm rail. That same size was perfect for the gantry carriages. For some reason the rail brackets measured around 7.6mm. I must have re-printed them 3 times before I gave up and just made the holes bigger. PLA is usually pretty good about retaining size. I want to re-process the STL files to have two different rail brackets. One the "right" size and one the size that I had to use. Look for those files in a future update.
Sorry for the long read, thanks for looking. Now I need to go find something to cut.