gr5

But are any of those a problem for your prusa? Maybe there is a slicer setting e.g. "uncheck to leave heaters on at end of print".

1) Did you look at this portion of the print in layer view to see if it switches between clockwise and counterclockwise? 2) Check for play. Push on the nozzle (gently) towards left, right, front, back. It should not move. Push and twist the head until it starts moving. It should not move before the steppers start to move. If it does - this is called "backlash" or "play". There I gave you two things to do - please report back. 3) Maybe more photos of the issue above would help as well. It looks like what you care about is only on the left side of the hole - is this true? Can you photograph from a few more angles and look at the photos to see if the photos are showing the issue well?

I don't remember seeing that before. It looks like you have something turned on that I don't. Do you have "infill wipe" turned on? Or anything with "wipe" in the name? There's a search box just above all the settings.

On the s5 start in the bottom menu thing (the bottom of the left 3 tabs). It's under "frame light". You can dim it while printing. I've done it many times.

not ringing for sure. Is this wall 100% perfectly vertically and horizontally lined up? Or is it tilted (for example wall leans inward or outward. If the model leans both ways this *could* be zebra stripes but I really really don't think so. The wall would have to have a very strange wavy lean to it to get this pattern. It could be infill pattern showing through but if soo it's a strange infill pattern (check that in layer view - see if the infill pattern touches the walls in this strange diagonal pattern). Instead I think it's just one of those weird oscillations where the head comes by and when it's thicker the liquid filament sticks and more is pulled out over the previous bump but in the direction of travel so it's slanted. It's kind of a vibration in the feeder combined with vibrations in the liquid pla in the head. The best fix for this kind of thing is usually to lower the temperature. You could play 2ith 3 different temps 1/3 of the way through the print and keep notes and see what happens. I would go into TUNE menu and lower by 10C 1/3 into the print and if that makes it worse go +10C or if it's the same or better maybe -20C or -15C at the 2/3 point of the print. or try MANY temperatures and use a sharpie to mark the layer where you changed temperature.

If you look at this area in cura layer view you can learn a lot. Cura slices your part and each layer has "islands". That hole adds an extra island. Above and below the hole it's probably printing say left to right but just left of the hole it's reversing directions (or the other way around but either way it is probably going the other direction to the left of the hole - you can check in layer view and use the horizontal scroll to see for sure). So that bulge to the left of the hole is probably related to changing directions and that implies to me you have a loose belt in the Y direction (assuming Y direction is through that hole). How you could possibly get a loose belt on a UM3 is a mystery to me because normally all the belts have hidden tensioners inside the blocks. But I'd check the Y belts. If you put the head in a corner (important) and pluck them and check the pitch with a guitar tuner they should be 80Hz to 130Hz. Anyway - check it out in layer view and see if I was right about the reverse direction. Maybe I'm wrong and that's unrelated. Oh - high friction can also cause this. Put one drop (no more) of light oil (any light mineral oil such as 3 in 1 or sewing machine oil but not WD40 which is not an oil) on all 6 rods up in the gantry and push the head around to spread this.

I don't know much about grease. UM recommends one pea sized drop. I've never added grease except when I clean which is about once per year (and not done as well as I should). But to do a really good job of cleaning it's pretty easy to take the whole thing out of the printer. The screw is basically permanently attached to the stepper so you first have to remove the (larger) cover under the printer (with power off!). That's the hardest step but it's only 2 screws. then unplug the Z stepper. Then remove the 4 screws holding the stepper in place, then pull it straight out the bottom of the printer. Then you can put it on newspaper or something and clean thoroughly with WD40 and toothbrush without making a mess. Me, I'm too lazy and just clean the top part of the screw that's used for small prints as I mostly do small prints, lol.

Like Sander says, 80C is a point to worry. I know someone who was printing PEEK in an ultimaker and he had a custom bed at 160C and the *air* temperature reached 80C and I told him "you are going to destroy your steppers!" but he was lucky enough and didn't destroy the steppers with a 1 hour print. So I think you are safe. Since then he added heat sinks and fans to each stepper but he still prints with 80C air temp (yikes).

Another option 🙂 spray the part with matte spray paint. Use any automotive primer. Then you can give it a coat of matte black. 🙂

It doesn't think you have a heated bed. Try going into machine settings and I think you can tell it there that you *do* have a heated bed.

Also know that you can use Simplify 3D for UM3. I don't have S3D and don't know much about it but there are people on this list who only use it. If you want more details, just ask on this list.

Oh - I just saw the prusa benchmark. That's completely unfair. The lighting is different. Either it's a matt black filament or you didn't position the light to maximize reflections. I see zero reflections on the benchmark. Remember - these tiny ripples are too small to measure with a micrometer. Too small to feel. The only reason you can see them at all is because the black filament is so shiny that it shows very very tiny changes in slope as either a reflection off a ceiling light or off of the ceiling next to the light and the difference of a tiny change in angle is the difference between black and white. Literally black and white.

Wow. Okay. I could talk for 3 hours about this. I was expecting something more severe. First of all glossy black filament shows up changes in surface angle if you hold it up to the light just right. You have to get the angle perfect to see these surface bumps. However it's extremely easy for a human to do this as we do it all the time. We just naturally are experts at holding something so the light catches it just right to see these specular reflections that show off tiny changes in surface slope. However if you tried to measure them with a micrometer you would have a lot of trouble. So one person's "horrible quality" is another persons "fit's so beautifully - the precision is amazing!". And again, dark glossy colors will show this the most. If you go with a matte filament you will have trouble seeing this or if you go with white or off white. With dark glossy colors you get bright reflections and in between the reflections you have vary dark so you get good contrast. These imperfections are pretty normal for me. I don't mind them. They can be removed but it's not easy. Okay - now to how to fix this (for black glossy). Well I would definitely try to find a filament that is less glossy (like carbon fill) but you can still improve all these. Issue #3, "ringing" is caused because of the tension on the belts and spring factor of the belts combined with the heavy head gives you a particular harmonic ringing frequency. The frequency is worst if you decelerate for half the period of ringing. You can fix it by setting the acceleration and speed such that you get a whole period of ringing. Think of pushing someone on a swing. If you push half the period (when they move away from you) then you can maximize the swinging. If you push equal amounts when they move away and also when they come back, the swing only swings once. If you measure the distance between lines and know the print speed for that wall you can divide speed/spacing to get frequency of ringing. Those look like 1mm and if print speed was 30mm/sec then your ringing is 30Hz. To cancel ringing you want ringing frequency = acceleration / speed. So if outer shell speed is 35mm/sec and ringing is 30Hz you want acceleration to be 1050mm/sec/sec. If you print at 100mm/sec you want acceleration to be 3500mm/s/s. UM3 can handle acceleration up to 5000 no problem. #2 The vertical lines in the last photo are almost certainly infill showing through. If you are only printing vertical walls you can uncheck "infill before walls". Or you can do more shells. 3 shells should hide this nicely usually. 2 shells might be enough. #2 The #2 arrow to "ghost lines" may be infill or it may be just a common oscillation related to extruder, print speed, resonances. If it's resonances, I have found lowering the print temperature helps a lot - right to the point of almost underextruding. You can play with this in the TUNE menu and keep notes such that you can test 10 different temperatures all on one part (say a cube) and use something to mark the part as you print it to know which layer had the change (like whiteout for a black part or a sharpie for a light colored part). If cooling doesn't help try slowing down also. #1 - I'm not sure what this points to. Is this the horizontal line? it could be underextrusion but more likely it's a dirty Z screw where the bed moves down too little on a few layer changes then suddenly moves slightly more on this layer change. Using thicker layers (e.g. .2mm layers) can help with this but best is to also clean the Z screw. A dirty Z screw will create lots of horizontal layer lines like this. Typically always in the same or similar spots. Since your parts don't seem very tall you might just clean the top half of the screw or top 1/3. I use paper towels and a screw driver to get in the cracks. Or you can use q-tips. WD-40 is okay for cleaning only - not for lubricating. I recommend some limited cleaning to see if it gets better. The Z screw is a triple helix so get all 3 grooves. It helps to have one person moving the bed up and down (with power off) while the other keeps something in the groove. In general printing slower and cooler will fix all of these issues but who wants to print everything at 10mm/sec?

@Dkdaigle could you explain in more detail please? Show exactly where it works and doesn't?

Definitely turn off brim for this part. Also I agree that the issue is probably "coasting" and so it may print just fine. Or maybe you need to turn off coasting or tweak it a bit. I have never tried it myself.