Best print head mount option on X-axis

Bought an assembled Folger Tech FT5-2 printer with a custom extruder/hot end mount.....shown as "current" in the attachment.
It introduces a bit of wobble at the nozzle.
I want to minimize that wobble by adding a second linear bearing/rail. Three options I'm considering are shown as A, B and C in the attachment.
What might be the best way to go... A, B, C? I'm thinking "B". Or another approach?
Thanks much.

Edited 1 time(s). Last edit at 08/17/2019 10:43AM by DanL.

One linear guide should be enough. It has two rails/bearings built in, so is equivalent to setting up two rails in parallel, except that in the linear guide they are better aligned than you could ever hope to set two independent rails.
Linear guides aren't supposed to have any play in the bearing blocks. Cheapo guides used in kit printers in which the appearance of quality is more important that the actual thing, often have sloppy linear guides.

Have you considered replacing the crappy linear guide with a decent one that doesn't wobble? I have two printers with single linear guides for the X axes and there's no wobble in either. I used high quality, Japanese-made linear guides bought via ebay for very reasonable prices (but probably slightly more than a crappy hiwin knockoff).

Here's one: [www.ebay.com]
and another: [UEAAOSwySlaS-3K" target="_blank" rel="nofollow">www.ebay.com]

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

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the_digital_dentist
...Have you considered replacing the crappy linear guide with a decent one that doesn't wobble? I have two printers with single linear guides for the X axes and there's no wobble in either. I used high quality, Japanese-made linear guides bought via ebay for very reasonable prices (but probably slightly more than a crappy hiwin knockoff)....

Duh....I should have thought of that....great idea. I don't think I want to buy the used ones listed though. What are some "high quality" brands that I can check out? I need a 40cm long rail.
I will likely try one of the configurations I show since I have a couple extra guides (crappy ones) on hand.

Will post my observations.

Appreciate your fast response...thanks.

You did not specify what type / kind of extruder / hotend you will be using?
Direct, Bowden, ---- looks like E3D Titan

Original FT-5 hung extruder / hotend below a horizontal linear rail



713 maker makes a beefy aluminum mount

[713maker.com]

"I will likely try one of the configurations I show since I have a couple extra guides (crappy ones) on hand."

It appears your designs were a forgone conclusion?

Will you be milling / printing your own brackets?

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cozmicray

It appears your designs were a forgone conclusion?

Will you be milling / printing your own brackets?

Yep E3D Titan.
Geez....sharing my thoughts on options...not foregone conclusions. Design options I show use cheap, simple 1.5" x 1/16 aluminum angle. Drilling a few hole patterns is all that's required, so easy to test different approaches.
Will try different approaches that might be promising.
The original FT design sucks, even as presented by 713 maker. I had that and it's a wobbler. Take a look at the distance from point of swing (I call it "Center Of Wobble") at the guide rail to the tip of the nozzle. The farther that distance, the farther the wobble arc becomes at the nozzle tip. The FT design absolutely maximizes that distance, especially on the longer Volcano setup.
I'm trying to tuck the nozzle tip as close to the C.O.W. as possible. Also gains maybe 50mm Z height vs FT design. Just experimenting....and asking for thoughts.
I'll post details after experimenting for a while.

Edited 3 time(s). Last edit at 08/17/2019 07:18PM by DanL.

Digital Dentist....Mark R....
Just realized you are one and the same....another DUH on my part.
Hit your blog on this topic without realizing the duplication
Sorry.

THK, NSK, IKO, Bosch, Rexroth, Thomson are all quality brands. So is HiWin, but there are a billion knockoffs of HiWin parts so you never know if you're getting real ones unless you buy directly from HiWin which would probably be too expensive. Buying any of the quality brand parts new will be very expensive. You can often find new-old-stock listings for quality parts on ebay- you just have to look through a lot of too-expensive stuff and be patient - new listings show up hourly, so if you don't see something that will work today, you might see what you need tomorrow.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Thank you.
I've made up a new mount to test....option A. Surprisingly, it slides very smoothly after some tweaking of rails. Need to test at elevated chamber T, then will attach belt and test print.
Will post observations.
I will be looking for a high quality linear guide for the X when I get more time in November. I'm finding that I like to tweak the printer as much as actually printing.

Quote
DanL
I'm finding that I like to tweak the printer as much as actually printing.

Welcome to my world.

Finally tested the x-axis double linear guide idea to stabilize the wobble of the print head.
Again, did this not based on the conclusion that it was the best approach, but because I had an extra "low quality chinese" rail on hand. I made up the new mounting brackets from aluminum angle. The new extruder mounting also brought the nozzle upward toward the rail, decreasing the suspended length and degree of swing.
Had to play around with alignment of the double rails, but was able to get very smooth motion along the whole x-axis.
Pics show the setup.
With the old setup - single rail and nozzle suspended well below the rail - each line of print was "scalloped" and I sometimes saw some slight shift in a few layers. With the new setup, the print lines are very much smoother and I no longer see any layer shift at all.
These are casual observations, but I do think there has been a noticeable improvement.
The next thing I want to try is a single high quality rail. Thinking of using Misumi in a size wider/larger than the current size in order to get better extruder head stability (less wobble). Thoughts on that?
Looking specifically at Misumi IKO MV25C1R400H. 23mm wide rail.
Again, I just enjoy playing with the mechanical stuff as much as printing...just a hobby.

Edited 1 time(s). Last edit at 12/20/2019 08:17AM by DanL.

Here are the pics

Very nice.
Sorry that I'm late to this thread, I only occasionally come here.

I wanted to offer an alternate suggestion for improving the rails in case others find this useful. One thing I've seen mentioned many times about the cheap Chinese Hiwin knock-offs is the rails and carriages are usually pretty good (within needs of 3D printers), but the bearings (balls) are absolute crap. You can buy replacement quality bearings fairly cheaply and rebuild the cheap rails for a nice upgrade in stability and smoothness. I bought a pack of 500 from McMaster Carr for ~$5 fully expecting to have to rebuild my rails when they came in, but I was lucky and got decent rails to start with.
If you search youtube for "mgn12 rebuild", you'll find lots of info on it. One guy in particular did a great job tearing into them and showed one that was mis-machined, but only in the return-path where tolerances don't matter much. Once that was cleared with a drill-bit and the rails rebuilt, they were much improved: [www.youtube.com]

Quote
glabifrons
Very nice.
Sorry that I'm late to this thread, I only occasionally come here.

I wanted to offer an alternate suggestion for improving the rails in case others find this useful. One thing I've seen mentioned many times about the cheap Chinese Hiwin knock-offs is the rails and carriages are usually pretty good (within needs of 3D printers), but the bearings (balls) are absolute crap. You can buy replacement quality bearings fairly cheaply and rebuild the cheap rails for a nice upgrade in stability and smoothness. I bought a pack of 500 from McMaster Carr for ~$5 fully expecting to have to rebuild my rails when they came in, but I was lucky and got decent rails to start with.
If you search youtube for "mgn12 rebuild", you'll find lots of info on it. One guy in particular did a great job tearing into them and showed one that was mis-machined, but only in the return-path where tolerances don't matter much. Once that was cleared with a drill-bit and the rails rebuilt, they were much improved: [www.youtube.com]

Great video. I honestly asked about this three months ago and nobody had an answer. I have opened up the three carts I had, cleaned them, regreased them and put it back together and voilà, they didn't fit on the rails anymore! I have no idea what happened but I had to buy new carts.

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http://www.marinusdebeer.nl/