Adding an Openbuilds Openrail Y axis to a Taz 3/4/5

Now that the X axis modifcation is nearly complete, I’m officially starting on the Y axis. Partwise this one will be much more simplistic than the X axis, except it is going to require 4 very precise holes in a heated bed mounting plate. I’m waiting on parts for my initial mockup Y axis (unless someone has a spare Taz y axis they want to send me? No? didn’t think so) so this one will likely be a couple weeks in progress before I have anything significant for it.

I’m going with the same Openbuilds wheels I used for the X axis, but a pair of 20mm x 40mm rails this time instead of the single 60mm unit.

Here are the initial mounting parts:

You will need 4 of the corner pieces, and 6 of the support pieces for the Y end. The support pieces are there to provide additional axial rigidity along the bed travel path.

Aside from the additional holes in the bed plate, this modification will be largely bolt on, and will require no firmware modifications.

My current thought is to make some printable drill guide templates. This is one of those projects that is going to work great if you get the holes right, and not at all if they are off. The other option would be to try and make some sort of intermediary printed part and mount the openrail hardware to that, which would probably work in the short term, but it wouldn’t be strong enough in the long run to matter. If anyone has a better idea, please let me know what you think.

As with all of my projects, this is hereby licensed under the GNU-GPL Creative Commons - Attribution license
Openrail_y_support_1_0_astl.stl (124 KB)
Openrail_y_Corner_1_0_a.stl (176 KB)

Any pictures of this installed on your machine?

Not yet, I don’t even have all the parts in yet. The new rails get here tomorrow, then I need to build a mock up Y axis to make sure everything fits and I get the spacing for the holes that will need to go into the bed mount plate spaced exactly right. It’s probably going to be a little while before its all in.

Here is a first look at the mock up. I’m printing a nonfunctional Y axis endplate right now to go with these parts to get the bed position.

That piece of extrusion represents the existing Y axis extrusion on one side of the TAZ. The real thing is obviously going to be longer than that, but you get the general idea. The mid span supports are designed to provide support against downward and side deflection of the Openrail 20x40mm rail, along with a small amount of anti lifting force as necessary. These will fit around the bed mounts. That should be the only printed parts required for this upgrade aside from the optional drill hole positioning templates for the bed once I get them done

Here’s the rail mockup. I don’t have a spair set of lower Y axis rails, so I made do with 2 shorter mismatched pieces. On the real Y axis the pieces will be further apart proportionally to the length of the rail. Next and final step will be locating and drilling the 4 precision holes in the new X axis plate I have on the way for that very purpose, then installing it on the TAZ. Right now I have about 0.05mm +/- deflection at the center of the existing rods according to my dial gauge. I’m hoping this will remove about half of it, with the X axis piece removing the other half. The picture of the gantry plate is just there to show what kind of hole arrangement will be needed on the bed plate. Eventually there will be 4 wheels, 2 on either side of the bed, with adjustment cams on the right hand side.

I finally got the mock up put together well enough to get the measurements I needed to construct the Bed Plate modification. This is basically just a stock Taz 4 style bed plate with 4 additional holes in it. I’ve also uploaded 2 drill guides. The intent of those parts is that you bolt them down to the bed plate in the existing holes for the existing rod bearings as shown in the picture below. You then use that to either mark, or help drill the required holes. I have no idea if these are going to be a help or a hinderance. The two hole sizes required are 4.975 and 7.2mm. I haven’t checked my bit sets to see what drills those actually correspond to, but it should be two standard size bits.

I also realized that I had the end mounts 4mm too tall for some unknown reason. If you already printed them, you can just lop that bit off. Otherwise the Y corner 1.1 file has the corrections.
bedmodification.dwg (63.6 KB)
Drill Guideplate Lg hole.stl (52.6 KB)
Drill Guideplate Small hole.stl (50.5 KB)
Openrail_y_Corner_1_1_a.stl (178 KB)

DWG file of the bed plate itself
bedmodification.dwg (63.6 KB)

Got the plate drilled and the Y axis mounted. Here is a video of the initial run in operation:

and some pictures!

And more pictures. The one rail that looks like it is a degree off is, I need to adjust the back plate on the Y axis, I’m going to wait until the print is finished before I do though. SO far everything is working great. The individual layers are getting a much better bond to one another as well, which is an interesting side effect I wasn’t expecting.

Psssst. Got pics of a print?

I even have pictures of a comparison before and after pic. It’s fairly small so it is somewhat difficult to photograph correctly. In the pictures showing both objects at the same time, thje one on the left, closest to the camera is the “After” picture. I deliberatly angled the parts so the lighting shows the worst of the layer offset. Its hard to tell from the picture but the part closest to the camera definitly looks a little bit better in person The first part was printed with jus tthe X axis mod, and in itself is an upgrade over my previous prints.
After X and Y upgrade
After X upgrade, before y

And here are a couple of comparison pictures of the post XY upgrade piece and a very similar piece printed on the stock X/Y axis. The main difference in the part is the shape of the holes on the bottom that is not visible in the picture. Everything else is the same model.
Before X and Y upgrade
The X/Y upgrades have minimized some of what I had always thought of as Z wobble, which I was not expecting. I still have a small amount, but between the before and after part, it’s more noticable on the before one. That could also be a side effect of the reassembly process i suppose, but I like to think I’m pretty good at putting these back together by now.

Just ripped the Misumi hardened rails out of my Taz 5 and installed the Openrail. Without printing anything, all I can say is that it’s super smooth and quiet. The force required to move the build plate is considerably less than the stock setup.

Took me a good 2.5 hours and I guess the 500mm rails needed to be cut. That kind of threw me off a bit as I figured it was a drop in. It was getting late so I just hacked it up with a jig saw. I could have done a better job but I was getting impatient as i wanted to sleep haha.

Running a 50cm test cube at the moment so I’ll see how it looks tomorrow morning. However, looking at the first layer or two, it looks a lot nicer than what I was able to do with the Misumi rods.

Oh and my parts are printed with eSun PETG.

One caveat is that I wasn’t sure what drill bit equates to 7.2mm so I just used a 7mm drill from my metric set. The hole was slightly too small for the eccentric spacers to fit in but I was able to take a slightly smaller drill bit and used it as if it was a file to remove a bit more material. That did the trick and the e-spacer was able to fit nicely and snug

For the 4.975 holes, I just used a 5mm drill. The drilling jig made it nice to drill but I was thinking maybe it would be nicer to make it slightly thicker to help guide the drill better. Downside is that you need longer m3 screws to hold the piece down.

Next up is X and Z, with more parts on order

Print didnt take that long so I ended up staying up:

X axis:

Openrail Y:

Clearly, Misumi rods + ball bearings are not the way to go. For anyone looking to do that, please do not. Stick with the Igus or do this conversion

Nice Job! That turned out great! It’s interesting to see how much of a difference the Y axis makes all by itself. I never had the Y axis in without the X. That’s a greater level of improvement just from replacing the Y than I would have expected. Thank you very much for posting the pictures!

I ordered the 7.2mm bit from Mcmaster Carr specifically for that bed hole. The drill guide could definitely be made thicker, I’ll post some of those later.

You shouldn’t have had to cut the Y rails. The X rail needed trimming, but the Y went in fine on mine. I ordered the 20mm x 40mm x 500mm pieces for the Y axis. How much were yours over, and which model taz did you start with? Mine was a 3 to begin with, maybe the rails are different lengths?

Mine was about 5mm too long on a Taz 5. I eyeballed it with a jigsaw so I definitely could have done a cleaner job cutting it. I will do the X as soon as the new parts come in. The openbuilds site is a bit funky because I swore I clicked on a 500mm length and when I received the rail it was a 250mm in my order :question: Not an issue since I had to order stuff for Z as well

Huh. That’s definitely odd about the extra 5mm. Good to know for future people that may build these though, I’ll add it to the notes.

I’m working on an updated X backplate for the printed backplate version. The milled backplate is fine as is if you went that route. The printed one that exists right now is a bit too thick.

Are you going to use the standard Z endstop target, or the Micrometer based one? I don’t have the exact part number for the micrometer listed anywhere, but I can find it if you want it. It does seem to help keep the level exactly where I want it

I haven’t gotten that far. I only saw that you posted the Z axis openrail the other day and all I’ve did was go through the list of parts and ordered them. Do you mind explaining a bit about the micrometer body? I looked at the project on thingiverse and I’m afraid I’m not sure what the difference is/will be. Do you mind posting a quick rundown?

Also, for your Z Axis, have you thought of incorporating anti backlash in? Since we already have to buy stuff from openbuild, you could maybe design it to use one of these: