Z banding issues with new preassembled core one
Hi, I just got my core one. Beautiful looking machine however I have had some issues on first test prints.
I like the voron design calibration cube as a test print since it has a bunch of challenging features. I downloaded the one that is available on printables(1) and sliced it using the default speed profile, 0.2mm layer height. I'm using the default 0.4mm hf nozzle that comes with the core one. This was sliced on prusa slicer, latest non alpha release.
Unfortunately, there is significant z banding in the prints. For reference, here is a picture of the cube. Left is my prusa mk4. Middle is the core one on speed profile. Right is core one on structural profile. (The structural profile is about the same speed as the speed profile on the mk4.) As you can see, there is more banding on the speed profile, but there are still significant bands on the structural profile.
Link to photo, because the forums are preventing me from uploading: https://photos.app.goo.gl/BXrecnHgiQanR9zE6
A support person told me this was normal and I should slow down my outer perimeter. But, it is not normal in my experience with prior prusa printers. From what I can read such banding is usually cause either by issues with the extruder or with the z axis binding. Since my probably applies to whole layers, I assume we are skipping z axis steps somehow.
Is the z axis meant to be lubricated? My lead screws seem pretty dry. Perhaps there is a small amount of lubrication but it's hard to tell. Any other suggestions on how to resolve this? Or should I be looking into getting a return authorization? Do your core ones have the same issue?
1: voron design calibration cube: https://www.printables.com/model/758730-voron-design-calibration-cube
Fixed: Z-banding issues with new preassembled core one
I added a small amount of grease (same as the grease that's on the bearing rods of my mk4) to the lead screws of the core one. After this, the z axis got a little quieter and the banding issues went away. New picture (again, forum will not let me upload).
https://photos.app.goo.gl/EbxKVhXh41zyi8SG6
(After grease on the left, before on the right. Same gcode. Speed setting on the core 1 compares favorably to the speed setting on the mk4 now, and its about 50-70% faster.)
RE: Z banding issues with new preassembled core one
Hrm, I spoke too soon. One other variable I changed at the same time is that I was holding the printer steady during the entire print because I was trying to see if the wobble was causing issues. I did another test immediately afterwards and once again got a bunch of banding. My new idea is that maybe my work surface isn't steady enough, and, combined with the top-heaviness of the Core One's momentum, that is causing some kind of issue. I'm doing another print with the printer set on the ground now.
I would also note that the foam rocking pads that are meant to damp vibration seem to be having the opposite effect. The printer wobbles a lot less when I put it up on four rigid feet.
RE: Z banding issues with new preassembled core one
Keep us posted on your results.
RE: Z banding issues with new preassembled core one
Placing the device on the floor seems to have helped a lot, but there is still significant banding. I'm going to try for another support person.
RE: Z banding issues with new preassembled core one
Okay, I spoke to two folks from support. First guy was really curious and helpful. Had me try a bunch of sensible things that ended up not working to help with the prints. Then his shift ended and he transferred me to a second guy. The second guy was like, well what if you slow down the perimeters to 50mm/s. My personal feeling on this is that if I want to print slowly I can just stick with my MK4.
The print did come out perfectly. But I don't know what that proves if anything. At this point I intend to open a return request since we don't seem to be making any forward progress.
Like any mechanical assembly 3D printers can get shaken in transport and the first few uses may be less than optimal. In use the parts run-in and usually work themselves back into place. By all means register your early concerns in case they don't resolve but for the first week or so stick to functional prints where fine details, tight tolerances and cosmetics are less important and then work through your first maintenance session. Issues that persist after that do matter and should then be addressed in detail.
https://help.prusa3d.com/article/regular-printer-maintenance-core-one_829710
Use the Add media button to insert pictures.
Cheerio,
RE:
While I wait for Prusa to get back with an RMA I printed a couple more things. Here's a ruined marble auger piece from the Core One. This was on the structural 0.2mm profile. For reference, the part overall is 70mm tall.
The lower band here implicates more than ten layers and it's a wonder we didn't get total layer separation. It looks like certain bridging on the inside of the part caused problems for the Core One. (Edit: actually, this break is well above the point where the interior bridging happens. There is nothing unique about the layers where the lower defect occurred either.)
The top band is maybe 3-4 layers tall. There is no internal irregularity in the part at this height. No reason I can think of at all to have banding here.
RE: Z banding issues with new preassembled core one
This would be very frustrating.
Does the banding always happen at the same point/layer, irrespective of model being printed?
--> MK4 - MK4S - MINI+ - MMU3 - Accelerometer Guide - BambuLab A1 Combo <--
What is the orange filament?
Cheerio,
RE: Z banding issues with new preassembled core one
The banding occurs at different layers on different prints. It seems to often occur where bridging or other complex features are demanded, but not always.
The filament is this elegoo orange filament.
The print uses the matching profile from PrusaSlicer.
Ultimately I spent the whole evening last evening with another support person and did a bunch more test prints. They asked if I could check if the bands occur when I make a really large print and that's when I decided to cut off the debugging because I felt like we were just throwing things at a wall to see what might stick. Why would the defect occur on small and medium prints but not large? And even if we found no banding occurs, how would that help me when most of my prints are small and medium? It didn't feel like the support team had any real theory as to what was happening. I don't know how to value my free time but even if I value it very cheaply I have spent ten unenjoyable hours now on with prusa support and that is driving the TCO of this printer to too high of a level. I do applaud the patience of the support personnel for trying to get to the bottom of things with me.
check if the bands occur when I make a really large print and that's when I decided to cut off the debugging because I felt like we were just throwing things at a wall to see what might stick. Why would the defect occur on small and medium prints but not large?
(S)he was probably trying to discover whether the error depended on the time spent printing, whether there was some build up of heat or charge causing an intermittent disruption; it would have moved down by a few layers if so. OTOH longer extrusion runs allow for more interlayer cooling.
I asked about the filament because those whispy strings look odd. Your filament might be a little damp but that's not your immediate problem.
I don't know Elegoo filament 'though I believe it has a reasonable reputation.
My instinct in these circumstances is to try a cold-pull. I don't think you have an automatic cold-pull in your LCD menu so adopt the old manual cold-pull.
The procedure doesn't seem to have been written up for the Core One yet - go to: https://help.prusa3d.com/article/cold-pull-xl_445071
and scroll down to the non-automatic method. The nextruder is the same so the procedure given will work.
Cheerio,
RE: Z banding issues with new preassembled core one
Appreciate the advice but I'm just gonna start an RMA. If the printer is indeed jammed this early in its life that would be pretty unfortunate. I'm sure that the prusa team will get to the bottom of it.
RE: Z banding issues with new preassembled core one
I do not know if I have z banding, but I do know my layers don't adhere, and I thought it was fixed when I could print a couple of benchies with prusa galaxy black and flashforge sparkly and my elegoo matte pla did almost as good one separate on cabin. But today it is back to not doing anything, I have tuned my belts swapped nozzles with mk4s, which by the way after I used the nozzle and some filament that was failing in the core one, the mk4s printed a perfect print. I have made sure my nozzle is the right distance from the heat break. I have used all the profiles suggested, I have slowed things down, sped things up.. it fails for PLA and it fails for PETG, have not wasted any more filaments. I am not a mechanic, and this is beyond me, and I feel your frustration. I have doctor appointments for days away from home, but when I get back I guess I will deal with customer service. The first time I opened my door, the printer crashed, I thought it was supposed to just pause.. it asked me if I wanted to send the report, like a dummy I did not click yes. It started right back up. So last night I did a hard reset on my printer. Then the z axis failed, where it had not the first time, I drug out the tuner and tuned the belts. The first time I tried to print with it, it tried to tip over. Well, I know I have it on a weak table so I put concrete paver underneath. I had to resort to a strap to keep it from tipping over. It worked great for a while, but no more.. I am gonna test one more time with the galaxy black. I have tried prints I have printed before and they don't work. But the same prints sliced for the mk4s print perfect on it.. no issues. I feel I got a lemon and it is beyond me and I just am stressing out over it. I cannot stress as that can speed up my sarcoidosis, and not good for my heart. My husband threw away my box so am I "scre...." for sending it back if that is decided when I have time to call customer service?
Sorry to dump on your post, but I feel you have tried all the things I have tried to no avail. I am tired of it.. this is the most expensive printer I have ever bought and I just never thought it would come out of the box having to work on it... I don't want to work on it, I just want it to print like everyone else's. To say I am disappointed would be putting it lightly, and I love Prusa printers. I talked my nephews into buying them and one nephew bought 4 for where he works to include the xl, gave him mom one, and has 3 himself. He is gonna purchase an XL.
Jo
RE: Z banding issues with new preassembled core one
It really is a shame that this has happened with your printer and unfortunately there are reports of similar issues happening too. Hopefully though, the community along with customer support can put their heads together and get everyone's printers working the way they should.
Best wishes.
Scott
RE: Z banding issues with new preassembled core one
I was able to tear mine down a bit, and fix my issue, and I am being sent a new part for it. They were more than willing to take it back, and do warranty work, then send it back. But once I could focus and my doctor appointments were done, I decided I would pull the top, and get more serious, which I did and so now it is printing great. I just have one part I need in case it fails, and I see they have shipped it. I love my Prusa machines, and I now love my Core One.. I never want to speak badly, but I was so very sad with it for a while.. Happy once again.
Jo
RE: Z banding issues with new preassembled core one
What part? My Core One has very bad VFAs, as do others'. Please do tell!
I was able to tear mine down a bit, and fix my issue, and I am being sent a new part for it. They were more than willing to take it back, and do warranty work, then send it back. But once I could focus and my doctor appointments were done, I decided I would pull the top, and get more serious, which I did and so now it is printing great. I just have one part I need in case it fails, and I see they have shipped it. I love my Prusa machines, and I now love my Core One.. I never want to speak badly, but I was so very sad with it for a while.. Happy once again.
Jo