this post was submitted on 15 Feb 2024
11 points (100.0% liked)

3DPrinting

15595 readers
100 users here now

3DPrinting is a place where makers of all skill levels and walks of life can learn about and discuss 3D printing and development of 3D printed parts and devices.

The r/functionalprint community is now located at: [email protected] or [email protected]

There are CAD communities available at: [email protected] or [email protected]

Rules

If you need an easy way to host pictures, https://catbox.moe/ may be an option. Be ethical about what you post and donate if you are able or use this a lot. It is just an individual hosting content, not a company. The image embedding syntax for Lemmy is ![](URL)

Moderation policy: Light, mostly invisible

founded 1 year ago
MODERATORS
[email protected]
[email protected]
[email protected]
[email protected]
11
Linear rail mod on Anycubic Kobra 2 (sopuli.xyz)
submitted 9 months ago* (last edited 9 months ago) by [email protected] to c/[email protected]
6 comments fedilink hide all child comments
 

I've been contemplating switching the rods that my X and Y axis travel on to linear rails instead. The current hardware is double SS rods with SG15 bearings, with an eccentric nut to adjust tension on the rods.

Unfortunately these rods are not evenly spaced on my Y-axis. They're closer together at the back than at the front, deviating with 0.5mm. So the rollers are either too tight at the front, or too loose at the back, meaning the bed wobbles a bit when using the front of the bed, or skips layers due to higher resistance on the rollers when using the back of the bed. I could lower the movement speed, but I would rather fix the actual cause of the issue.

I have some suspicion that the rollers are also not rolling smoothly on the rods and sometimes slip/skip on them instead.

And then I came across the Voron switchwire and Ender3-to-switchwire conversions. Now I'm not really willing to fully rebuild the printer as a switchwire, but changing to linear rails on Y and X axes is not a massive rebuild and considerably cheaper. I would keep the existing threaded rods for the Z-axis.

I would use the hardware I have now (motors, pulleys, belts, bed-mount, belt tensioners) with minor modifications to accommodate the rails instead of the rods currently used.

Are there any caveats to be aware of when using linear rails?

you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] 1 points 9 months ago* (last edited 9 months ago) (1 children)

I thought your frame acts also like a rail for wheels.

There is a single extrusion, in the middle, running parallel to the Y axis below the bed, with rods on both sides that the bearings travel on. So it's not affected by the squareness of the frame. I would only be using a single linear rail for the Y axis.

Likewise for the X axis, there is a single extrusion mounted between the two vertical extrusions, with rods on that the print head travels on, again this is not affected by squareness either. I would also only be using a single rail for the X axis.

Squareness of course comes in to play when the print head is positioned relative to the bed, but I actually have decent (and consistent) print quality.

[–] [email protected] 1 points 9 months ago

Using single rail for each axis would exclude most of the issues I was concerned about. When I mentioned frame squareness, I was thinking about all geometric tolerances including rails being prallel/perpendicular to the frame.

Honestly my knowledge about linear rails becomes kinda useless after seing how people use them on their printers. Example: mounting them on alu extrusions or using them as a frame should be wrong, but looks like many people have good results.

Again, someone who solved that issue on the same or simmilar machine might be much more of a help than anything I wrote