X-Carriage Bearing Block upgrade for Original Prusa i3 MK2 by Steve-J

Last crawled date: 3 years ago

Edit 2-21-17: Full Size X-Block file fixed, if anyone had any slicing errors it should be fine now.
Edit 12-10-16: This part is not compatible with the Multi-Color upgrade, if you have this part installed it must be removed when upgrading to the Multi-Color extruders.
READ BEFORE INSTALLING
This bearing block is designed specifically for the Original Prusa i3 MK2, it is not designed for and has not been tested with any other machine.
I made this X-Carriage Bearing Block upgrade because I did not want to rely purely on zip ties for the mechanical connection between the X-Carriage, with extruder assembly and precision-adjustable nozzle, and the X-axis bearings. Since we can achieve such precision with z-height adjustments, I feel that if there were a solid mechanical connection in place to take most of the strain off of the flexible zip ties, we would have a much greater likelihood of maintaining z-height adjustments more precisely. It seems like sometimes just loading and unloading filament throws off the z-height, which is understandable with only flexible, nylon zip ties between two really important parts, but maybe we can make it better!!
Now I am not an expert, and I have zero proof that installing these will have any effect, either positive or negative, that said, I do believe it will work. The more people who try it the sooner we'll find out!
There are two versions of the Bearing Block, the FULL SIZE version and the MINI version. The MINI version covers about 67% of the upper X-Carriage bearings and is as easy to install as clip your zips and put it on with new ones.
The FULL SIZE version REQUIRES the replacement of the original z-axis tops with the modified z-axis top file, available here to download, which will allow the proper clearance at every possible point of travel. Specifically near the very top of z travel at 190, if the carriage is all the way to the left, you will crash into the original z-axis top and not be able to achieve full height. So download, print and install the modified z-axis top_remix stl also if you are going to print and install the FULL SIZE version.
The FULL SIZE version covers 100% of the upper X-Carriage bearings and is just as easy to install.
Clip all four of your zips (make sure to support the extruder assembly when you clip the last zip so it doesn’t fall forward)
Install the bearing block (the cut corner is the marker for the top left)
Install four new zip ties!
Make sure to slide the zip tie heads all the way up or all the way down after you clip the ends off so they tuck in for proper frame clearance. You can insert from either the bottom or the top and slide them either way to tuck them in.
For those of you with IGUS or Drylin bearings, this block may help with the issue of deformation from zip ties as the pressure would be more evenly distributed, however I have not tested it with this type of bearing as I don't currently have any to test with. You may need to modify the part to fit properly, try it out and let us know!
So download and print one of these X-Carriage Bearing Blocks and try it for yourself and see what you think, and let us know your results!
WARNING: you may cause damage to your machine if you do not READ and follow the instructions carefully, I am not responsible for any of the following:
Broken machines
Broken eggs
Broken dreams
and anything else you may think of.
BTW. . . .
The entire animal kingdom is preparing to rise up against you. . . .
Unless you download, print and install this part.
:D
DESCRIPTION OF PICS
Note: In the pictures you can see both versions and their clearance from an above-view of the left z-axis top very close up, the MINI clears the original z-axis top part and in the picture of the FULL SIZE one I have already installed the modified z-axis top. The last picture shows the clearance for top-of-the-frame spool holders, there are three pictured, the one in the middle is the original one that shipped with the unit, the far left is one that I modified with a little longer lip and the block clears that one too. . Just fyi