gr5

What "aluminum pieces"? I believe everything you need to buy is listed in the bom.xlsx file. Everything else is stl files that you can print. One of the items in the bom links to the feeders which have their own bom.

I just looked at some of the design files for this - really good work. Quite impressive. Instructions for the feeder are fantastic. There are some clever innovations in this. I love that you included a bom with links to where to get the parts. This just seems very thorough. I see also that you included the firmware both compiled and git source code (so one can see the changes you had to make). Very impressive.

Yeah, replace the Z parts. I've never done it but you can replace the Z screw with a misumi bearing. I don't know the part number. Are you in USA? Getting a super high quality, extra expensive Z nut costs only maybe $5 I think and it's much better quality than the default bearing that comes with UM printers I believe. That's what people say who've replaced their Z bearing. If you google this list and misumi: site:ultimaker.com misumi bearing or site:ultimaker.com misumi nut Like that - you can find quickly a part number (trust any post by neotko - he has replaced these items and is a 3d printing genius). Looks like maybe LHFSW12? That's just looking at google search results - I didn't click on the forum topic. Oh - maybe that's the bearing and you need the Z nut instead which leads us to: There's also the Z rods and bearings. Those Z bearings have a channel with lots of ball bearings in them. When you had the z screw out it would have been good to slide the bed up and down and feel the resistance - see if there are bad spots. Sometimes the two Z rods are not parallel or some other strange thing. Usually the problems are with the z screw being dirty but it's quite possible it came from sticky bearings. It's also possible (less likely but it happens) that you are having intermittent underextrusion. This seems likely if it happens only on one layer and on the entire layer because it should happen more throughout and sometimes on only half the layer. But I've seen what looks like Z issues solved by simply cutting the speed in half and later diagnosing some feeder problem or a bad core nozzle, etc. More pictures for us are helpful to see if it's always the same spot and if it's entire layers or just the outer shell ocasionally and so on.

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.