Implementation: Y axis

A project log for Reprap Neumann

An easy to build, open source self replicating 3D printer with a rock bottom bill of materials that maintains accuracy when reproducing

ttnTTN 04/17/2015 at 09:192 Comments

Ok, so I'm basically going for an Prusa i3 like machine that is close to 100% printed. I would like to avoid using linear rods or bearings, as good rods and bearings aren't cheap.

In a worst case scenario, if my printed rails fail I could always fall back to linear rods but I'd really like to avoid it if at all possible.

In theory, if I can get a printable axis that has 0.8mm error in linearity in it, and it can position to an accuracy of 0.6mm then I should be able to have the machine self replicate.

I've been doing some designing and here's what I have at the moment:

I'm using FreeCad 0.15 and povray for rendering. Both are free, open source and are available here and here.


I needed a machine to print on. Since the Icepick Delta wasn't printing accurately enough for my purposes I rebuilt my repstrap into a proper reprap (this was some weeks back) and ordered parts for Reprap Nuemann. Ever so much better than the my original repstrap:

And printed:

Features a robust belt clamp and adjustable tensioner:

It works nicely, though, there is an issue: the rail is printed with the top face down. When the part is removed from the build platform it warps. With each rail that I printed I attempted to fix the problem by adjusting my heated bed temperature, less fan, very good first layer adhesion to no avail. End result is that the carriage motion isn't linear and that the rollers have slop near the ends.

In the next iteration I'll redo the rails so that the face of the rail facing the camera is position upward on the print bed and is bolted to the frame. this way, if, when warp occurs, it will be straightened with help of the frame and not affect the linearity of the motion of the carriage, since the opposing side also had the same warp, but opposing. That is, if the frame hasn't already pulled it all straight.

I'll leave it as it is right now, and get to work on the Z and X axis.


phrogjlf wrote 02/21/2021 at 14:19 point

What about rotating the rails 90* so the inside face is on the platter, rather than the rail?  We've had a similar issue printing patterns for casting the parts of an aluminum Flask for a permanent cope and drag.  Not sure how else to compensate for the uneven shrinkage, short of printing with an inverse curvature.

  Are you sure? yes | no

Scott wrote 03/14/2016 at 16:27 point

I love this rig .  Re printed rods vs linear rods , have a look at my Maker frames projects . I think I only have 1 up here so far , but i have more on youtube. in this video i show using L shaped aluminum extrusion as rails . 

you could simply cap your plastic rails with L extrusions to make them very smooth , and possibly lower your print times.  i used 1/6th x1/2 extrusion , and it's about 3.50$CAD for 4 feet .
Love your idea here man , i my have to try something simmilar.

  Are you sure? yes | no