I hear Hiwin makes the best linear rails and their MG line is the best for 3D printers. Where should I get them? Only place I’m seeing is AliExpress but there’s zero feedback which worries me.
Aliexpress is a real toss up because the majority of them are counterfeit Hiwins or just out right say they’re copies and not the real thing.
Well here’s what I was looking at. These will give me ~280 mm on the X axis. Sorry I couldn’t get a shorter link and the group doesn’t allow link shorteners.
You should assume any hiwin on aliexpress is a copy. Some are pretty good but you should pay accordingly. Even genuine hiwin is kind of lower end for linear rails.
Yeah, at work we’ve had better long-term use out of THK’s rails than Hiwin’s, specifically THK’s HSR and SHS rails. I think those are total overkill for a 3d printer, though.
You’re going to get sticker shock with genuine name-brand linear rails. A good set of rails costs more than a whole printer these days. Check Misumi, they have a wide range of quality rails if budget is no object.
Ali/ebay knock-offs are hit or miss… your best bet is to get recommendations for specific sellers that others have used.
If your interested in higher end, used linear guides, these guys are pretty good. I bought a pair for a large build I’m doing and was very impressed by what I got. They are as or more expensive than the counterfeits, but they are better quality.
Also, after messing around real quick with the one that I have, I am with @John_Bump on this one for most 3d printers. Mine is going to be around 30"x20"x20" and I want to push the speeds as hard as I can. So I want it sturdy. But these slides are meant to hold over 1,000Lbs. No 3D printer will push near that.
I also ponder how much preload is on new ones. You may find that they are really stiff to move. And since no 3d printer will come close to the loads they are designed to handle, they may never break in. I don’t know that for sure. Just something to ponder.
http://stores.ebay.com/industrialpartsshop/LM-Guide-Linear-Bearing-/_i.html?_fsub=4322380011
http://stores.ebay.com/industrialpartsshop/LM-Guide-Linear-Bearing-/_i.html?_fsub=4322380011
Yeah, the ones I’ve worked with, even the ones that are only like 8mm wide, are still rated in hundreds of kilograms of load. I’ve used them for large machine designs. But, hey, there is nothing you could do with a 3d printer that would induce measurable flex in them. (I do like rails a lot better than unsupported rods, but supported rods with split bearings seem like the best solution for light loads like 3d printers.)
Yes, the rails are overkill, but not by as as much as you’d think. You need to de-rate linear bearings dynamic load rating by about 90% to get an acceptable failure rate after millions of motion cycles, and corner jerks can easily produce several g’s of acceleration as a shock load, and bearing forces can be greatly magnified by overhung loads or overconstraint binding. The small ones (like MGN9 or MGN12) are really a pretty good fit.
I’ve heard of people buying cheap knockoffs and replacing the balls with higher quality ones. But finding the right ones can be an adventure on its own.
@_Spice Gotta love it when they blatantly tell you they’re copies. I remember seeing a hotend on eBay that said it was an E3D V6 but looked nothing like the real thing. I told the vendor that if he sold it properly as what it was I would buy one on principle but as a V6 I wouldn’t.
We have some that are copies. I like them a considerable amount. The comment above break in is true. You can typically select your preload, sealed, etc. select the right one and get to breaking them in.
In the US there are a number of sellers of brand name HiWinn. Womack machine comes to mind first. For the price I’ll use the one we have.
@Ryan_Carlyle The Misumi ones would work fine at a total price of ~$850 for all 8 rails at 12 mm width (2 for X, 2 for Y, 4 for Z) and still keeps me in the rough budget of $1,500 total. The used ones @610GARAGE recommended will come in around $200 cheaper so I think I’m gonna go with the Misumi ones in case I ever need more rails in case I ever end up making a 2nd one or selling the printer. Still gonna document everything and publish it so anyone should be able to make one, but I’ve talked to some people about it though and they might want to buy one. Still need to figure out a controller for the printer, gonna make a post about that now.
@Adam_Steinmark I’ve purchased several dozen profile linear rails on eBay over the years. Mostly high end rails from THK, NSK and IKO. I keep away from Hiwins since you can’t easily tell if they are fake on eBay. I prefer THK. The most I’ve ever spent was about $200 for a pair of new THK SR20 that were 1400mm long.
This Corexy is using 20mm THK and NSK rails. The three rails were about $150 total on eBay. I like to use good profile linear rails on my machine builds.