Again, to be clear, I am trying things I do not necessarily expect to work, to see if they might.
From the prior exercise, found that PTFE mold release spray moved my plain-PLA bearing Z-sliders from bad to passable.
Just tried spraying the PTFE on the XY plain-bearing sliders. My technical evaluation is…
Holy shit.
I am done. This stuff moves.
Completely absurd, how well it works. (Too good to be true. Trying to think of a counter-argument … still thinking.) Please tell me what I have missed, as this is too absurdly good to be true.
Main reason most people use dry bearings, grease, or thick oil is to prevent dripping lube onto the print bed and other related messes. Any liquid/grease will collect dust and need periodic wipe down + re-lube … so there’s some risk that you put on too much and make a mess.
I usually preferr to use LM47 or sometimes even LM48 from LiquyMoly. The last one comes with the highest amount of Mos2 particles from the products that I’ve seen so far. But for bearings with this kind of load (On 3d printers) it probably doesn’t matter if you use ptfe or mos2 based grease. If it needs to be a thin spray I usually like to use Caramba Mos2.
I’ve even tested Caramba mos2 “impregnated” printed Nylon sliding surfaces on anodized aluminium. This also delivers quite impressive sliding capabilities completely without slip stick effects.
By the way, impregnated nylon is in general a quite interesting approach for bearing surfaces. Just check Google for all the papers. It basically delivers all the advantages of nylon (wear restitance) without the disadvantages (slip stick effect) compared to ptfe. And due to the fact that it’s cheaper and easier to manufacture it’s an interesting alternative to POM.
Honestly, POM is a pretty great bearing material if you can mill it. It doesn’t stick-slip and it’s long-wearing. Impregnated POM/Delrin is even better.
@Sven_Eric_Nielsen Searching on impregnated nylon, I found Silnylon. What that what you had in mind?
Also see references to polyurethane, MoS2 and WS2. Do not see mention of 3D filaments (might have missed - though perhaps that is what Igus sells).
Odd thought - there was interest in filament oilers, in the past. While that notion seems to have proved a bit dubious for better prints, I wonder if it might work for lubricant-impregnated prints?
For now, going to stay with just dosing parts after fabrication, in hope that proves sufficient. Can try others things later, if needed.
Also, to add, for the next experiment in driving the four corners of the print-bed in Z, going to try Kevlar cord sliding over PLA.
First laid out what I would need for pulleys. Ended up with 12(?) pulleys per corner(!), which would complicate fabrication considerably. So going to try the simplest thing, first.
Wary of what the Kevlar cord will do to the PLA.
In addition to the experience of @Rien_Stouten , I recall when my father specified Kevlar for an enclosure (on a military project in the early 1970s). The guy who did fabrication had choice things to say, when his usual cutting tools all became quickly dull.
Perhaps when properly lubricated, this will not be an issue. But this is a risk. Will see.
@Ryan_Carlyle@Preston_Bannister
I absolutely agree that POM is a great material for this. If you read carefully what I wrote you’ll notice that I wrote “alternative to POM” and not better
Honestly, whenever it’s possible I tend to use POM in my Job instead of something else because it’s reducing the risks in our cases and I usually have to care about process costs for Tests systems or prototypes.
But for hobbyist’s it’s expensive, difficult and expensive to machine properly and also not the most healthy material when it reaches a certain temperature. Which is also the reason why it’s not a good idea to print with it even though there is such a filament available. (formaldehyde risk)
During my research I found a few papers about “hijacking” the usually moisture absorbing property of nylon and using it as a thin oil absorbing property. Indeed this is possible. And even though it doesn’t deliver the same results like an impregnated sintered nylon part it indeed works and reduces as a side effect the moisture absorption to almost zero because the outer areas of the material are blocked by the oil molecules. Nice side effect, after this oil bath you expect that you’ll not see additional dimensional changes anymore.
You need the right nylon type (so Taulmann Bridge is probably not the best choice) 100% dry and it takes a bit more time. Nylon comes already with a relatively low coefficient of friction. But compared to PTFE the static friction is quite high. This process will give you the same properties like PTFE - Static and dynamic coefficient of friction is almost the same and the general friction is reduced. If I remember the values correctly it’s possible to introduce 3-4% of oil into PA6 and a little bit more in PA12.
Regarding Filament oilers :
I generally don’t like this approach. I think if your printer is not able to print without it something is wrong with your printer. It’s simply not very reliable and reproducible to work with filament oilers. But this is just how I think about it. Obviously a lot of people still like to use this approach. However, a dry filament cleaning system is a must have from point of view.
However, until now I never thought about the possibility to use a filament oiler to produce bearing parts with encapsulated MOS2 particles
Maybe I should reactivate my old test rig for this.
@Preston_Bannister Kevlar is highly abrasive. You’ll chew up PLA fast in sliding contact. Use spectra / UHMWPE line instead. It’s very low friction and similar performance.
