I’ve dealt with carbon components quite a bit, not that much though in terms of moving parts.
In the past, especially for my carbon fiber fishing rods I use polishing wax as for car paint on those joints.
That was to both seal the surface and to provide a smoother surface to get a longer service life.
For our printers though I seem to get, how shall I say it?
Conflicting info on the Bambu pages…
We shall clean the rods more or less often in order to remove dust, mainly that fine carbon dust.
But in the same articles it is also stated that the drive system RELIES on this carbon for lubrication.
YES, carbon as in GRAPHITE powder is classified as a lubricant, but not dust resulting from grinding carbon fibers and the resin binding it.
As we have a belt system it can only be rollers moving on those rods and those bearings should be sealed - to prevent dust and other things from entering.
Excessive rod wear and a lack of cleaning will result in stuff building up on these rollers.
Can anyone please make clear whether these rods suffer from wear and tear and if this wear and tear is somehow able to provide lubrication ???
Because if not then I would rather properly seal my carbon rods than to see them slowly turning into dust and requiring a complex and probably costly replacement job.
I could imagine that something like wax while great for hinges might impose too much resistance for the fast movement of the printer. I took away that I should not treat the carbon rods with anything but just swipe them with a dry cloth from time to time. Didn’t question that any further.
I don’t hink that bearings are rollers but some kind of dry gliding bearings, but that is just a guess of course.
After first 2 weeks of printing I used only IPA to clean the rods. There was some black dust on towel. My idea was to check if there will be some difference if I use some lubricant. So I use silicon/teflon lubricant. Just put it a little on towel and rubbed it on the rods. Rods changed color to darker. After another 2 weeks of printing there is almost no trace on white towel. But what is most important, the head moves much quieter, just after application.
That’s not my yellow hilighting. It is Bambu Labs’s highlighting. It’s your printer. Makes no difference to me whether you do or you don’t. Just pointing it out. If the graphite is a lubricant, I never quite understood why we’re advised to remove it during routine maintenance. Does it get fouled or something? I suppose if there were too much of it then it might start falling off onto your prints, making a mess of things. Just my wild guess though. Maybe the reason is something else altogether.
I bet you’re right, because on a couple of occasions the printer complained that the rods were binding or something and that I had to clean the rods. This happened outside of normal scheduled maintenance.
Now THAT finally starts to make sense!
Graphite patches making sure friction is kept low makes far more sense in terms of cleaning needs than wear and tear on the rods.
Leaves the question though how long these pads last and when the time might come to replace them and how…
Graphite dust neither likes other lubes, nor being removed from spots it filled up to even a surface.
That would only leave hard coatings for those rods, hard enough not to bind the graphite but still flexible enough to not chip.
Does not really leave much, does it…
My rods had 10000+ hours on them when I changed the assembly.
There was nothing wrong with the rods, no play in the bearings. The reason I changed them was to get rid of play in the toolhead chassis.
I didn’t print that much ABS or ASA, though.
Yeah, thought that was implied. But rubbing solid paraffin on the rods would maybe also do the trick
I already asked for clarification regarding the self-lubricating bearings. I’m sure the recommendation is not a general one, but more of a band-aid for the motion system as the alternative is slowing prints down in this specific case.
No offense intended. It’s on me. I’m in north america, but I’ve just never heard of mineral oil referred to as “liquid paraffin” before. That seems to be more of a european dialect, maybe eastern european. My only association with paraffin is the wax like material that you melt over the top of home made preserves to lock the oxygen out, or else the same sorta thing that you apply to the bottom of your surf board as a lubricant for surfing down sand dunes in White Sands, New Mexico. Apparently, I’m parochial.
Not what i meant, but pretty sure liquid paraffin is the same stuff as used to wax your surf board - just kept in a liquid state by additives
@Nebur I’ve mentioned your findings in my last post. I’ve no issue ruining my X1C with wet lube, as long as Bambu takes the responsibility for it, which they most likely won’t.
It’s always been an open question as to how long these carbon rods would last. Maybe the time has come where the heavy users are bumping up against those limits? I haven’t worried about it, because I knew others would get there probably long before me, and so it would get sorted well before I reached that point myself.
I had a chat with a friend overseas, he is an engineer and works A LOT with all sorts of carbon components.
Let me try to sum up the chat:
Carbon is really great to save weight but nowhere near the best material in terms of abrasion resistance in line with moving parts.
Whenever he has to make things move plastic washers/bushings are used whenever possible.
Unlike metal rods, carbon rods won’t really tolerate linear bearing and bushings…
Bambu stating ‘self lubricating’ in combination with carbon rods is bogus, no way around it, a marketing gag at best.
With linear bearing out the only option that works for a sufficient time is by going old school.
Meaning a set of rollers is used like on our laser cutters of big scale and such machines.
My friend claims that on a well (ab)used machine a gauge to check the out diameter of round objects would reveal the rods have ‘flat’ areas from where those wheels move.
Maybe someone with an older machine could check this one day ?
We know Bambu claims there is some sorts of wiper to clean and lube those rods.
Usually that would just be carbon brushes to keep them clean as there is no feasible way to auto lube carbon rods.
Graphite blocks would be able to provide lubrication but would also mean they wear down rather quickly.
With the conundrum of Bambu stating self lubrication AND the need to clean the rods from the leftovers we are left with basically nothing.
Only way to know for sure would be to take a machine apart and actually check …
Doesn’t Igus (probably others as well) have some solutions that address this issue?
They seem to make some pretty nice linear motion parts and systems. In their example, with a much, much heavier load, they calculate the wear to be just 0.53 µm/km.
You might even be able to use their comparative wear results shown for other materials to estimate what kind of wear there might be on a bambu labs printer. Upper bound, lower bound, I don’t know. Or maybe the thinnest of justification for a wild guess if nothing else.
That’s an impressive amount of discovery work that you did. I’m surprised they would risk a change as big as that. On its face, it sounds like this could be a big problem that might affect a large number of customers. At least in your case, roughly how many print hours was it before you started to notice that something wasn’t right?
I recently replaced my smooth idlers with toothed idlers in hopes of reducing VFAs (after seeing from positive results from 2 other people). But, there was no visible change to my standard test print:
I also found about 0.003" TIR on the B-motor pulley. But, that’s less than 1% variation on the effective circumference.
I’m very curious if a more rigid, dimensionally pure, and linearly constrained X axis nets you an improvement. Keep us posted!
Sounds promising. Are you planning to fabricate stiffer end pieces, or is there already some other way of sourcing them? By that I mean: if maybe the models were already posted somewhere, maybe you could get them printed in PEEK or some other wonder material, now that JLCPCB, PcbWay, and probably a host of others are offering that kind of service. I tried getting some quotes a year or so ago, and prices then were through the roof, but it seems prices have come down quite a bit since then.
