3D Printer Linear Rail Comparison - Hiwin vs Robotdigg: Part 1

[@ALex-qc4lf]

The "looseness" is called preload. These rails can be manufactured with different amounts of preload from "no preload" which means it will just fall when you tilt it to strong peload which means you need to apply quite some force. The preload has a few effects, would suggest you read up on this :)

[@Bluuplanet]

The magnetism is okay. That means they've added carbon to make the stainless stronger/stiffer. If it were a non-magnetic stainless, it would be much softer.

[@falcon02012]

Due to this difference, ferritic stainless steels are generally magnetic while austenitic stainless steels usually are not.

[@telelaci2]

Precisely. Austenitic is used in food industry, expensive like hell.

[@gzcwnk]

"lower grade" can be harder SS and wear better.

[@telelaci2]

Where high strength and hardness needed they use neither ferritic nor austenitic stainless steels, but martensitic and precipitation hardening grades of stainless steel.

[@royjaskowski905]

If you want to go by grades, the 300 series are non magnetic stainless steels, while the 400 series are magnetic.

[@gzcwnk]

The reason the carriage is often on the rail already is the carriage is often matched to the rail as they are not made so accurately.

[@mxmxbearing8328]

We produce high temperature resistant all-metal linear guide blocks

[@GENcELL2014]

Stainless steel can be magnetic, 430 grade stainless steel is magnetic for example.

[@simonmerrett]

Thanks - I know that it's a quick check people might do and may wonder whether the rail they *don't* have is the same.

[@simonmerrett]

I decided not to use the cheap unbranded ones because so many people complain about the variable (and often poor) performance. For me, this is about upgrading my printer and going with cheap rails would likely be a waste of time and money. As you can see, the rails aren't attached to a printer yet so I can't tell much beyond what I cover in the video.

[@jeroenvandend]

could you mix the rail and the carriage? maybe the rail is good but the carriage is not so a cross between a cheap rail and a pricy cariage could mean a big difference in total price

[@ruyvieira104]

By the way, how close are RobotDigg dimensions to Hiwin's? Could a project drawn with the cad files from Hiwin be assembled with "equivalent" RobotDigg parts?

[@heinzhaupthaar5590]

It should be. Dimensions of linear bearing block standard models are pretty much standardized to allow interchangeability. As long as you buy genuine products and not knock-offs from ebay or Ali you should be fine.

[@darthnegativehunter8659]

in order for a fair comparison you must open, and fully clean all parts, and lubricate them using the same lubrication.

[@simonmerrett]

If that's what you are prepared to do before installation, then you are correct.

[@adamfilipowicz9260]

Robotdigg rails are great for DIY Projects.. But if your doing something commercial or need real precision.. get the good stuff.

[@digibluh]

this. QA is a bit questionable. i've had carriages with chips on the metal the bearings roll on making it bumpy.

[@heinzhaupthaar5590]

I wouldn't even use them for better DIY projects, just for things that have no requirements whatsoever regarding smoothness etc. Even here, from a reputable German distributor who's not exactly known to be cheap, you can get proper CPC gear for example at around 200€ for a 300x300 printer, with light preload, precision H, endseals and lubrication storage pad + built in silence & ease of mind. I think you can get proper taiwanese quality products even cheaper, at around 100-150€ if you look around a bit.

[@svengoosen3519]

@@heinzhaupthaar5590 where do you get good, affordable rails from germany?

[@heinzhaupthaar5590]

@@svengoosen3519 Hmm, strange. The comment got auto deleted, I'll have a look later what might be the blacklisted word I used.

[@heinzhaupthaar5590]

@@svengoosen3519 Got deleted again... I'll try in three parts: Sorry for the delay, let's try again: You can get CPC gear at Dold Mechatronic for example, the 200€ estimate was based on their prices. They're not known to be particularly cheap though.

[@BoyanSilyavski]

I believe your review is a bit misleading. The only thing that could be different between them is surface precision of rails and surface precision of balls. And hardness of balls and hardness of rails. Especially the second part of your overview where you try some dubious test. Its metal on metal, so depends on the preload carriage they will behave differently. Even light preload will have some kind of twist. On my 2 meter gantry CNC with 3 hiwin blocks each side, the gantry could move 10-15 cm one side only before it racks. What i came here to see is if the chinese rail block moves at all and if it move smoothly enough without any considerable effort. I wanted to see if the Chinese bearing block has a different ball retainment from the HIWIN. I have tried 20 size Chinese once and it had very funny plates retaining the balls, instead of the ball being inside of the block like the Hiwin. FYI the 20 size you can fit Hiwin block to Chinese rail and it moves smoothly. You should have tried the hardness of the rails, if the Chinese rail is really hardened. Thats what matters.Litle roughness of balls is not abig deal if motor is powefull enough. What matters is after a couple of months if the chinese rails are scratched from bearing balls in the carriages

[@simonmerrett]

Boyan Silyavski that's great insight for everyone, thank you. I don't know what hardness test would be appropriate, given my limited equipment. Please run the tests you suggest and post the results for the benefit of the community - it sounds like you have plenty of experience that would be valuable to others.

[@BoyanSilyavski]

I have written about that on CNC forums, but couldnt find it. Basically then the chinese bearing block, when looked from below had steel plates that were screwed to the block. Once you unscrew the plates the balls drop. Hiwin on other side, has the balls retained by the assembly itself, no additional plates looked from below. So what i was looking to see if they still make the chinese rails like that, as this was 2 years ago. The hardness can be tested with a knife, as file has hardness ~61HRC, and rails clam hardness of 56HRC. Obviously no good. BUt a kitchen knife blade should be there, around 56HRc. Just try to scratch them, some where not visible, say on ends and see for your self. At the end i guess i have to spend 25 euro to do a test here. Anyways, its good to know they are sliding at least , as my test purchace then was even not sliding properly

[@telelaci2]

Boyan, I think your note is also misleading. Because you can't measure those parameters precisely at home, you should buy very precise and expensive equipments for thousands of dollars, if you'd like to do that. You can't measure the sizes with a caliper (even if Mitutoyo), and you can't measure the hardness just like that. At a Japanese serious guide rail, its precisely defined what part of the rail and how thick layer, how hard and how flexible, how rigid. You don't even know what to measure, what is good, what is bad, you are not a mechanical engineer. Its not something to judge by poking the car on the rail with fingers, how smoothly it runs. And you can't measure or judge an other parameter what is very questionable at a Chinese product. The consistency of the quality. By the way this is why simple measuring is pointless. Quality Assurance does not exist in a Chinese firms, this is a one of the reasons why they are cheap (except when they are manufacturing for a Western firm), the quality is random, one could be perfect (its rare) other other one is unusable. You have to buy 3 pieces and if you were lucky, you got a good one. If you were lucky. But at least it was cheap, isn't it And the quality is random for another reason, the lack of competence, knowledge. They usually copy something, but they don't understand the details, they are not qualified professionals. Monkey-see monkey-do. Hiwin or TBI-Motion is far from the really precise and high quality Japanese or US or West-European products, but its much-much more better than any noname brand, its fine for amateurs and its still affordable. Do not buy noname crap, its waste of money, you'll pay double price for that later.

[@BoyanSilyavski]

I think you are mistaken about Hiwin. Its top linear rail producer. Not some no name factory. You are right, i can not measure what a laboratory will do. But as a knife maker i do know how to measure hardness of rails. Which is what matters mostly here

[@telelaci2]

I was talking about noname Chinese things, like this Robodigg. I linked horror videos above, how do they manufacture things. Its like 30 years ago in USSR in the communinsm. Hiwin and TBI Motion are not Chinese and not noname, and they are brands. Not the topmost ones, but not so bad neither. And they manufacture thing with robots, CNC machines, in a clean co-ordinated factory. And they have Quality Assurance. Totally different from Robodigg. You wont't see the difference with a caliper, that was my point.

[@Damjanhd]

What are results of using this?

[@eugenkrause5556]

wonder if these ina slightly larger format would be strong enough for CNC. So they have no rotational resistance? They just come right off when you torque them to the side?

[@danifem]

Exactly I what I was looking for thanks!

[@ameliabuns4058]

is the robodigg still doing good? I got chinese rails from another brand and after just a month they started to have a bit of play which sucks :( re lubricated and cleaned them too...

[@simonmerrett]

Hey Amelia, love your work! Yes the Robotdigg rails are still good for me. Probably a few hundred hours on them now. In the process of building a new machine but the rails will transfer across to the new one. Hope they work out for you if you decide to get some - remember 4+ years is a long time in which quality could have improved or reduced so I can't offer much insight into the current offering from robotdigg. Worth a try though.

[@JShel14]

hahahaha, turn on closed captions @1:03

[@simonmerrett]

Justin those filthy robots!

[@danamccarthy5514]

Stainless is still magnetic, it is still a steel alloy, just with additives like nickel in the alloy

[@RuiSjm]

Robodigg block fit in hiwin rail? thanks

[@simonmerrett]

Sorry, didn't check and I'm not going to take the machine apart to find out.

[@gzcwnk]

Just as an aside I dont think "hiwin" on aliexpress is real hiwin its just a pirate copy, but they seem to work OK.

[@creamofbotulismsoup9900]

You're absolutely correct you won't find real/genuine Hiwins on Ali, however the counterfeit rails do appear to be much better than the cheap knock offs. The whole idea is to sell rails that are good enough to fool people into thinking they're real so that people end up recommending them to others, just like what the author of this video basically did. Frankly I'd do the same, real Hiwins are bloody expensive.

[@henrychan720]

I’m building a CNC mill and I have been thinking, instead of using 1 set of expensive rails, what if I use 3 sets of cheap rails on each side? I don’t really care about the friction cause I will be using lead screws. (Probably also 2 per side for anti backlash)

[@MF175mp]

No reason to use more than 2 rails per axis but be sure to buy the ones with heavy preload

[@mnrobards]

Sorry did not get past first 60 seconds. Don’t understand what etchings have to do with quality

[@richard3365]

That was how to identify them, as there are a lot of knock-offs available on the internet. The whole point was that this is a "true Hiwin vs this specific brand of knockoff". I'll save you the trouble, though ... he pretty much determined they were nearly identical. The Robotdigg had very slightly more preload (preload is what makes it harder to slide/push, the Hiwin carriage could slide freely from just a tiny amount of tilt and could easily have fallen off the rail if he wasn't careful), and they both required oiling (Hiwin specifically states to do this, BTW) to run smoothly. Basically, if you don't want to (or can't) shell out the money for a Hiwin, a Robotdigg will do pretty much the same job for a fraction of the price.

[@Vido89]

Where did you ge genuine Hiwin rail ?

[@simonmerrett]

I'm sorry that link seems to be dead in the video description - I've added a note to it for others. The store is (now) called linkcnc Store on Aliexpress and they don't appear to sell MGN range rails and carriages any more. They are currently selling 15mm HGR rail range but that's more expensive and perhaps heavier than you would want for a 3D printer.

[@karenwang8944]

I can provide you with Hiwin linear guide rails. My email: [e-mail]

[@digibluh]

proper grease and they don't move at all at any angle. usually ep1/ep2 recommended by hwin.

[@keithofarns8738]

did you do any dynamic load tests? part 2 of this series? thank you

[@simonmerrett]

This kzbin.info/www/bejne/r2nYpaWtpK-qgpI ?

[@individualone]

Let's try magnetism..you know magnetic position lock? It should work...my brother has a globe that it magnetically locked in place but can spin? So if we used a similar system for 3d printing axis I believe it would work for smoothness!?

[@jdittmann1977]

The precision of most name brand linear rails (Hiwin, THK, ISO, etc) is overkill for most 3d printing applications. Buying & cleaning up a name brand used set or rebuilding a Chinese clone is a great way to get the performance while saving some money

[@Celciusify]

The big gain of going for Hiwin isn't precision, it's that they're more robust. You can have higher acceleration, which matters a lot if you've got a big or fast printer.

[@1Saltyone]

with these linear carriages by hiwin, i have used on cnc glass cutting tables ( 4.7 m by 4.2 meter sheet glass up to 12mm thick . just so you get the idea that i mean big machines using a pair of rails on each axis , with a plate to join both,) very close tolerance needed so zero stress, but with a sharp blade cut the outside plastic lip seal off the 2 ends of carraiges, THEY ARE V SEALS AND I HAVE NOTED THEY CAUSE THE FRICTION ,

[@chrisw1462]

We can see right away that the Hiwin should have less loading (less friction) than the clone, but the real test will be, as you said, deflection and vibration. BTW, I understand 'mil' is supposed to be short for millimeter, but there really is an english measurement called a mil - it's one thousandth of an inch. While I acknowledge that those of us still using english measures are a minority, and we REALLY need to get rid of it already, it's still a bit confusing. I had to pause the video and check the scale on your micrometer to be sure which you were using.

[@fredriklindgren4126]

Since we're nitpicking, he's using a vernier caliper and not a micrometer :)

[@ipadize]

i, for myself, only go with the real stuff in the future. Tried cheap hiwin knockoffs, the carriages almost fell off the rails. Never again gonna get knockoff noname brand stuff again.

[@sudrienet]

Hi, does somebody know a regular and serious Chinese reseler where we can buy HIWIN products or best IKO? thanks

[@telelaci2]

Serious Chinese, that is paradoxical. Its serious or Chinese. By the way, you can buy it on eBay, and if you think its fake you can ask for eBay Buyer Protection.

[@orionchu7238]

the only real way to buy a hiwin product is through a credited distributor. 90% of chinese stores selling Hiwin products are fake. It also doesnt have to be hiwin, many other taiwanese companies offer some very good product as well. pm me if you need more info.

[@telelaci2]

Selling fake and expensive things on ebay is a bit risky. Because eBay policy is : if you received a counterfeit product you don't have to return it, but seller must refund all costs + shipping. So seller loses everything for nothing, and you got a counterfeit but usable product for free.

[@orionchu7238]

Not talking about Ebay, lots of stores jumped to aliexpress, wish and bangood for that reason alone. since there is no real way to determine if it is fake or not (unless through testing ) also some fake rails are so bad that it doesnt matter if ebay sides with the buyer, they dont lose money at all.

[@telelaci2]

Btw, I'm too malicious, don't listen to me. Actually I know a Chinese seller who is honest in my opinion, and sells Hiwin and TBI-Motion stuff. TBI-Motion is another Taiwanese brand like Hiwin, not Chinese and its about the same quality as Hiwin. They make linear guides and ballscrews just like Hiwin. The Chinese firm is Noulei, and this is the official eBay shop : www.ebay.com/usr/sven.wei He has one negativ feedback, but obviously the buyer was the idiot, he accepted a damaged parcel from the postman. That is silly, he can't blame the sender for that, because no any post office accept damaged parcel at dispatching. I think you can buy from Noulei, they look serious firm.

[@TrasteIAm]

Wow, those dents on the right @1:03 indicates to me that the rail is made of pure chineseium, not exactly precision machineing.

[@simonmerrett]

Are you talking about visible dents or friction spots you can perceive through the "smoothness" of motion or sound of the movement? If it's visible dents, it may be oil residue. Which rail (Hiwin, Robotdigg or both)?

[@TrasteIAm]

Sorry, i edited my comment to be more specific, i mean those on the right @1:03, it looks like pretty big dents in the metal, but maybe its just oil?

[@simonmerrett]

The little vertical line over my little finger? I think that's where the rubber seal has wiped oil/dust residue and then changed direction, depositing it in a line. Addmittedly, it could have come out of the factory cleaner but I don't think it's a mechanical quality problem. If you are thinking of a different dent, obviously none of this explanation resolves your concern so please add more detail and I'll try to help clear things up. I have no interest in defending the quality of either product - just trying to help people make their own decisions.

[@TrasteIAm]

Much appreciated, i am all for utilizing cheaper "copies" and a lot of the time, the chinese manufacturers are the same or related to the "real" brands, but then there are the copies of the copies and those are usually not worth the money. The tricky part is to find the good ones, so most of my initial research goes into finding the sellers on ebay or ali that have clear differences in the specifications or descriptions and order one from each, if its crap i dispute it and get a refund, if its good i order more, and if its borderline i usually let it slide(no pun intended) with a comment or some (private) feedback to the seller. I really appreciate your videos and your responsiveness, and sorry if i sound like i am whining, it was not my intent. This is very good research input for me and i am no expert by any means on linear rails, CNC or 3D printers, i just assume that if something needs precision, it needs to be smooth and should not sound too much. :D

[@sudrienet]

Please never use oil but special lithiuim grease for slider !

[@MrExo_3D]

Robotdigg sells "Hiwin" rails too.. are they real?

[@m3chanist]

Try your magnet on a THK, an NSK or a Thompson, same result, no austenite. Your metallurgical assumptions are incorrect, 400 series stainless is commonly used for good rails, ferritic, martensetic and duplex alloys and all of them ferromagnetic.

[@theflydies]

probably 440 Stainless

[@MooreIntLtd]

I would always go for the quality version for now , Unless its only a hobby train set kids 3d printer for now

[@ADXMODELS]

15-5PH grade SS is magnetic.........whereas 304L SS, often use in brackets in aeronautic industry isn't.....so magnetic is not a reliable way to see if it is SS or not sorry.......

[@karandex]

preloading on both is bit different

[@simonmerrett]

Yes, but it's interesting that +3DprintedLife thought that the Robotdigg carriage has a low level of preload and it turns out that the the Hiwin has even less.

[@karandex]

How are they working? Thinking of getting these over generic green ones. Have you used the cheap ones?

[@simonmerrett]

Hi Karan, I replied to your question in another comment which I forgot to submit as a reply to you (sorry - it was meant as a reply to you).

[@ThomasTomiczek]

Just watching - ouch. Nice how you measure the etching TOTALLY IGNORING THAT YOUR CALIPER CAN DO THAT BECAUSE IT HAS ATTACHMENTS FOR THAT. Ouch.

[@simonmerrett]

Have you got a timestamp for the section you're referring to? I don't know which part of the video you think I was "measuring the etching" in. Are you referring to where I measure the hole spacing at around 3:40?

[@justkeen18]

only 300 series stainless steels are non magnetic....

[@misiukowalski5653]

Eh...I wouldn't trust the Chinese seller selling Hiwin's at half price.

[@so_bendy]

Try PMI rail and carriages. You can get them from www.matara.com

[@simonmerrett]

HardTekBen good thinking. I don't need any more rails for now. The disappointing thing about that website is that they don't have any prices. Whenever I see an "enquire" button instead of prices, I usually pass by as it's just too much effort with little likelihood of a low price (depending on the comparator). Then they just add you to some email marketing list you didn't give them permission to. Hopefully it will help someone though.

[@Dr.Stein99]

You have to use 15mm rails. 9mm really poor quality. Balls need to be continuous, not missing any space gaps.

[@varmint243davev7]

400 series stainless is magnetic. 300 series stainless is not. That is pretty basic knowledge, and for me automatically invalidates anything else you may have to say in your "review".

[@Route1Reels]

Uh, what? It seems to me like he was demonstrating that for viewers who don't have this common knowledge who might buy the cheaper one and think they got ripped off. He uses the magnet on the name brand one to demonstrate how it too is magnetic so you shouldn't be worried. Or am I missing something here in reading the context? I don't see how this demonstration invalidates the video?

[@victortitov1740]

he didn't say "it's magnetic so it's not stainless". I hope people know that most kitchen knives are stainless, yet very magnetic.

[@telelaci2]

I wouldn't go for the Robodigg. kzbin.info/www/bejne/qKnQXnmZo7t6psk#t=30.464579 They are not even smart enough to not show this piggery. What kind of competence and professionalism is this ? What precision would you expect from those parts ?

[@BoyanSilyavski]

What did you expect? Tesla factory?

[@telelaci2]

I did not expect anything. I just showed that they were a joke. That firm has nothing to do with precision mechanical parts manufacturing. And yes I could have expected a modern factory, they have the technology (I mean China), hundreds of modern and famous Western brands manufacture devices in Chinese factories. This is not that kind of factory, but a scam, they manufacture craps for eBay not for industry.

[@FrozenHaxor]

@@telelaci2 They get away with it because they match the carriages to the linear bar stock with different size ball bearings, crude but works.

[@JamesZJi]

Seems most of you don't know Hiwin is also a Chinese brand.

[@certified-forklifter]

they produce in germany too, in fact very near to where i live =D

[@MF175mp]

I thought it was Taiwanese

[@tingandtinko]

No. Hiwin is Taiwanese brand.