MGN15 and MGN15H carriage

[Yaro]

Hi all, i've recently bought an mgn15 rail with an mgn15h carriage to pass from delrin wheels and Vslot to mgn. But i've tryed mgn15h carriage and it's incredibly rigid to movements compared to delrin wheels. It's so hard do move that i think my nema 17 will not be able to move it without block or loose steps. Why is that? my carriage is damaged or need to be set in someway? Maybe mgn15c is more smooth than mgn15h?

I've already have sbr16uu rails and they are incredibly smooth and move on their weight if lightly tilted, i bought mgn thinking are good too.

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[alan_3301]

do you have any documentation for the parts? any part numbers indicating if they are preloaded or not?
did they come already assembled? is there any grease in them?

you can try removing or lubricating the end seals to see if they are dragging.

[Yaro]

I don't have any manuals and no part numbers.

They come already assembled.

The only documentation i have is this:

http://g03.s.alicdn.com/kf/UL8X2YoXa...aaf9fbf7cdcb5b

http://g04.s.alicdn.com/kf/UL8dWnoXh...cafa36e000a133

I've tryed to:

- move it along the rail some times but nothing, still really hard to move.
- tryed to unscrew a little bit the screws on red side, but nothing
- tryed to tight the screws, a lot worse
- tryed to leave carriage and put again beck, nothing
- tryed to use it without bearing balls retantion string, but nothing.
- there is a lot of greese on it

My dubt is, they are low friction or not? Maybe my carriage is broken or not good, or maybe H version have more friction than C version?

I don't know if try to buy another carriage from another supplier, or trash mgn rail.

Do someone have calculations on MGN15 rails friction? Or how smooth they are? To be able to compare to my rails.

[alan_3301]

are they hiwin brand or a knockoff?

[Yaro]

I think chinese knockoff. The carriage work very bad and i trash it. Rail seems to be good, i will try maybe another carriage.

[Uguessedit]

For other folks in the future reading this old old post keep in mind the clone rails need to be well lubricate (I use Way oil) and they need adjustment as out of box they are not set properly. I’ve purchased many sets and they glide like skates on ice and zero resistance. Any that had resistance lubricant solved it 85% of the time and minor adjustments the remainder 15%. I’ve heard of nightmare situations but not seen one personally. The only supplier I naturally avoid is the one who clearly states their rails are copies of Taiwan hiwin and they are poor in comparison. Yes there is a company claiming this and their carriage block is red and black if I recall. If they make a claim theirs are not as good than they won’t do better to future proof their quality control and expect you to eat their practice rails and many others do their best to have comparable quality at anlower price. Be sure to ask a seller they will often tell you if they believe they have a good product even if they state hiwin may have slight or better improvement. Food for thought.

I think chinese knockoff. The carriage work very bad and i trash it. Rail seems to be good, i will try maybe another carriage.

[JoergS5]

There may be another reason, if it's the same like for the MGN12 linear guides: with MGN12, there are Hiwin linear guides with 2.381 mm diameter balls, and there are clones with 2.5 mm diameter balls. One cannot put the Hiwin ball carriages on the clone guides, and not other round also (much too loose or much too stiff). The guides have different shapes also. Maybe the guide or carriage in the original thread was not an original Hiwin one. I tend to buy guide + carriages together to be sure they match.