2020/wheel vs MGN12 for x-axis

In my previous post I seek for y-axis solution advise. Now my question on the x-axis for an i3 style DIY printer :-)
I am in the early idea finding stage of this project.

What is your opinion on on 2020+wheel solution (https://cdn.thingiverse.com/renders/cb/0d/24/4c/18/78d7be079f0c2406a17c52c294d40b7a_preview_featured.jpg) vs a MGN12 mounted on a 2020 extrution (or something similar).

I like linear guides over the wheels-in-slots type design. In SoM I used a single linear guide screwed to an aluminum tube, but the tube may not be entirely necessary- I didn't use a tube in UMMD, just a 24 x 8mm linear guide. The tube did make mounting the linear guide easier in SoM.

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Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I have 2 printers that are one of each type. Both 6 years old. Used a few times a week for small parts. The one with the plastic wheels has needed replacement wheels every 6 months. It works great for a while then wear becomes a problem. I’ve tried all types of wheel brands too. The one with with Mgn12h sized is as good as day one after 6 years of use.

Good input! That's what I've always suspected about the wheels...

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Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

If the tension on the wheel is not set correctly it will wear quite quickly. There are stiffer wheels from Openbuilds to improve that: [openbuildspartstore.com] . Another issue with vslot motion is that any small dent/chips on the wheel or vslot will create a little vibration, however I don't know if you see it on the print.

Linear rail like MGN12 is another thing. First it requires regular greasing, like every 3 month. Second it might be hard to align them and you have to be patient doing that carefully. Alignment needs to be very good in all directions which could be an issue with extrusions. Keep in mind that extrusion is melted aluminum passing through a shape and then cold down, so like our 3DP it might wrap, twist, shrink and so on. So you could have trouble bolting linear rail on extrusion because of this. Misumi is offering a rectification of their extrusion for this purpose in case of. Note that lots of people did not experience issue by fixing linear rail to extrusions, see this as a warning, it might work and sometimes not. I have seen people using TPU support between rail and extrusion to solve this.

Another solution could be Igus. They have interesting and cheap rails with adjustable play, check the Drylin T serie.

Edited 1 time(s). Last edit at 09/02/2019 05:15AM by gregsaun.

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[github.com] - #BearUpgrade

These wheels are simply unfit for the regular 3D printer. What is amusing is that once some guy started to use them, he got a lot of followers and Chines vendors quickly embrace it as the best invention since sliced bread and flood the market with an other generation of cheap crappy machines !

On the other hand, they make sense for a router (aka CNC likes MPCNC) where it is dusty and a few tenth don't make a difference.

I make my own bushings using Igus filament . Cheap and so far so good.

Linear guides are the top if you can get them second hand of a good brand. To mount them is not that difficult, just follow the mfg specs. Done that a long time ago but for more professional stuff than hobby 3D printers.
Of course if you mount them on a poor frame, good luck. In fact a flexible frame will make you believe they are properly mounted. With Chinese knock off, you may end up grinding your teeth as the balls are grinding their races !

Better high quality oil than grease.

Edited 1 time(s). Last edit at 09/02/2019 06:14AM by MKSA.

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"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)

Honestly MGN12's are all around way more beneficial from implementation than wheels, what I learnt from selecting linear rail carriages for my printer was directly helpful in industry. Just to put that into perspective. They look better, they perform better (even the discount ones), they have more capability (I went on to use them for all axis) - the benefits offset any cost if you plan on ever upgrading your printer (maybe you want to build a coreXY).

My advice is to make sure you get ones as long as possible - because they can be made shorter, while a short one will require you to purchase a new one if its not long enough.

My X axis has a rail which is longer than the extrusion itself, sitting flush at the other end - however the overhanging side is hidden nicely behind a cover. I avoided cutting 15mm off to make it a non-standard length, for future use in an extrusion which is exactly 400mm (or whatever that X axis happens to be, the pictured X axis is 385mm or something).

Before that, a thingiverse designer had 350mm lengths mentioned which I followed for a "mod", not realising they wouldnt sit flush because the lengths of extrusion were 400mm long. In the end they were offset, it looked weird and I re-ordered another 2, at 400mm long. That is the extent of issues I have had with them.