What is causing this banding around layers with detail?  

Re: What is causing this banding around layers with detail?

I don't see any off sizes or custom cut option. Since the MK2/S uses these rods to define the printer's print area, exact rod size is unfortunately critical. I'm pretty sure MK3 will use weird sizes too. "Table" motion is not a concern, it is noise. The MK3 will work perfectly as shipped, with all that new metal, it will likely be louder than a banshee. But there is hope, I've read an article with new ground up software that works on vector instructions that smooths out stepper motion. What this means is silent, accurate and from their estimates, twice faster printing with no new hardware. Though I believe a whole new breed of slicer or abandoning STL may be required, I for one welcome the death of that ancient file format.

Re: What is causing this banding around layers with detail?

@samling
I've been running the Misumi set on y-axis for a while an noticed growing growl with use. Could be debris or bearings wearing in but the 1-in-3 oil evaporates quite quickly and has a very unpleasant smell. Although I felt grease was overkill, with sealed bearings, I had some Super Lube sitting around that I stopped using because the stock bearings kept spitting out black goo and out of desperation switch to Super Lube on Misume because of the horrid smell and you know what, it works, it works quite well. Grinds are gone, bed is smoother, and with Misumi, there is not nearly as much black goo to clean off. It is ever so slightly stiffer but stock steppers can rip your finger off so should be no problem. 1-in-3 is going back to door hinge oiling duty with Super Lube returning to my "3D printer stuff" drawer. Apologies, I stand...er sit corrected.

Re: What is causing this banding around layers with detail?

Good to know Stephan, I've got some grease sitting around that I'll use when and if I decide to try the Misumis again. For the moment I've switched back to the FMC08s; with the bearings ruled out as the cause of the banding, at least in this particular case, I didn't see any reason not to.

On that note, I've finally been able to continue my experiments with printing that case cover from the original post. A couple notes on that front:

- White Hatchbox PLA seems to be more difficult to print smoothly; I've seen this sentiment echoed by others as well. It wants a lower temperature than my other spools (which are PLA+ so that makes sense); the original post was done at 200C, while today I tried 206C and 195C. It looks like I need to try 200C again as 206 was too hot and blobby, while 195 seems to have printed a wall with some subtle but consistent zebra stripes of banding. Pictures below.
- The slicer continues to play a big role in this, especially in getting to the bottom of why these artifacts show up consistently in certain places. My friend astutely pointed out that the heatmap of print speed that Simplify3D generates lined up with the artifacts, suggesting that the issue could be related to the speed, which itself could be related to how slicers are interpreting that part of the print (I'm not sure where it's deriving the speed for those layers since it speeds up considerably once it hits layers with the text detail).

I've got some more things to try tomorrow. Thanks for the follow-up Stephan, I'm glad you're finding some middleground with the Misumis in terms of quality and noise level.

Here are the pictures of the ribbing. Notice that it's on both faces equally; my first suspicions are either that I'm printing too cool (195) and/or the profile I'm using needs tweaking. It's a profile by matteo found in the Simplify3D settings thread that uses a 0.95 extrusion multiplier and 0.44mm extrusion width. I'm going to try a more vanilla profile tomorrow to see if it mitigates this. Any other advice is appreciated.

[Edit] After some more experimentation this morning it does look like some combination of temperature, extrusion multiplier and extrusion width are the primary causes of that ribbing. I settled on a multiplier of 0.93 and a width of 0.43. These multiplied together give a value of 0.3999 - I don't know if that's significant and/or that product should be as close to the nozzle width as possible, or if I'm just making wild guesses. At any rate it largely decreased the amount of blobbing and ribbing that was happening during the print. Currently printing something that isn't a square or cube for once, we'll see how it turns out.

Re: What is causing this banding around layers with detail?

I'm also using Misumis and superlube grease with good results. I have the Misumi rods too, they seem much better quality than the stock ones.

Re: What is causing this banding around layers with detail?

I went ahead and ordered some super lube grease which will get here tomorrow. I would love to use them if I can mitigate the sound, and as you said the 3-in-1 was a no go. I'm looking forward to trying them again. Any recommendations as far as cleaning the bearings beforehand? I've got three fresh ones still in the package that probably still have whatever oil that comes on them on it.

Also, what (if anything) do you put on the rods?

Re: What is causing this banding around layers with detail?

2¢
I might be repeating myself from another thread but Misumi support told me the bearings are drop-in ready shipped. The pouches, as you've found, are hermetically sealed and full of shmoo. Unless Misumi is yanking my chain, no need to prep beyond whatever your OCD compels of you. 😆

Rods, parallel is key. Just in case you don't have the numbers handy I've reverse engineered Prusa provided SCAD and DFX to get 170mm Y-Rod span, thus a feeler gauge should be 162mm to ensure parallel. Oh, yeah, just clean Iso and light coat of Super Lube is what I done did. But your bearings seem great, in fact I'm thinking about getting myself a set since you seem to report no slop. IGUS states slop is part of the plan, which is most definitely NOT Prusa Research's plan.

Re: What is causing this banding around layers with detail?

Actually, I do believe the FMC08s have a very slight amount of slop, now that I understand more about what I'm looking for. It may not be significant but there does seem to be the slightest amount of rotation around the Z axis. My understanding after watching Tom Sanladerer's youtube video on Igus dry bushings is that that's by design, as you said.

If the grease is for the rods and not the bearings, I'll try switching back to the Misumis sooner rather than later, as there's no need to wait for the grease, which I can apply after the fact. Any other tips for noise levels with them?

[Edit] Grease arrived this morning after ordering it last night. 🙂

Re: What is causing this banding around layers with detail?

I'm happy to report after some light grease application to the rods (following a thorough wipedown with 99% isopropyl) and then packing the Misumis with it, double-checking my measurements and squaring everything up (thank you for the 162mm measurement Stephan, I believe I was half a mm too wide last time which may have caused the grinding), the Misumis are on and everything is still rather quiet! Not silent like the polymers but far, far better than before and something I can definitely live with. Going to do some calibration with the modified RC2 firmware with hyperfine leveling that was released last night!

Also I ordered a set of PSFJ8-330 rods from Misumi, which should help with the slight amount of slop I feel when twisting the bed around the Z axis. This is no different than the polymers really, mostly I'm more confident in having rid myself of any stiction.

Re: What is causing this banding around layers with detail?

I have also tried hackneyed dampening that has been successful. Bearing "bark" has been mitigated with use of 1mm foam shims between bed frame and Misumi bearings. This might introduce a little bit of bed tilt that you may not want having gone with Misumi kit. I can report print is exactly the same, and noise is reduced, again particularly ridding y-move bark. Note if you try this, don't be alarmed if you see binding/stiction when testing with one bearing with foam shim, when all three are in, it will glide smooth again.

Re: What is causing this banding around layers with detail?

Very interesting. So far the noise level has been very acceptable. There's a bit of rattle of the bearings, but they no longer sound like they're riding over grains of sand. Once I (eventually) finish my enclosure, it will probably be a non-issue altogether. [Edit] Just out of curiosity, do you have an STL for the shims?

After spending some time getting everything mostly dialed in again, I'm printing a new XYZ cube (mostly to test linear advance in 3.1.0-RC2), and it looks fantastic. There are still a few artifacts on the corners and such that I'm sure better settings can fix, but weird random layer shifts as well as noticeable lines between sections of the print seem to be gone.

Thank you everyone in this thread, and especially you StephanPark, for all of the help. I'll continue experimenting and see if there aren't more things I can tighten up (figuratively and literally), and of course I'll post results of the Misumi rod swap when I get those, probably sometime next week.