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Turro75
(@turro75)
Estimable Member
RE: Z banding issues

https://www.thingiverse.com/thing:4735060

here You can find the stl I use to check axes alignment

Posted : 23/01/2021 10:59 pm
Nizmox
(@nizmox)
Eminent Member
Topic starter answered:
RE: Z banding issues
Posted by: @skreelink

Warping is sadly, the nature of the beast, especially with large, flat objects. As far as it being out of square, it could be the model or (since there's very open insides) the forces are pulling it as it cools, it retracts a little and warps. Either downscale the lid a little when you slice it (say 98-99%) so it drops in easier, or you can try changing the extrusion multiplier under the Filament Settings tab to 95-97. The extrusion multiplier is good if you're slightly overextruding, which will bulge corners and push a little more material out which could interrupt the stresses and warp a little. From what I can see in your image, it could use a slight reduction in the multiplier.

 

As far as the bed visualizer, don't worry about it too much, as that's what the probe is for. Compensating for these differences. 🙂 I would say you can also try a raft, but you're already maxing out the build plate. Also make sure to let it fully cool down before removing it from the bed, especially thin/large objects. Besides just the stresses of pulling on them, while still warm the plastic isn't fully hardened and can be pulled, stretched, and deformed some and then it cools and sets that way.

Apologies it takes me a while to get back to you each time, living a busy life with two kids and a new kitten gives me not a lot of time to tinker with my printer, well not without being yelled out by my wife anyway haha.

I did try downscaling the lid to 99% and it's unfortunately too small, i haven't yet messed with the extrusion multiplier. I have ordered a digital caliper and when that arrives I plan to calibrate the extrusion properly, then I'll reattempt the print and see if it helps. I have also tried to adjust the ZX axis again but haven't yet reprinted the same model to see if it helps. I do notice consistent issues with the prints not being square but it seems like these are the first where it's really affected anything.

My friend also pointed out the model I'm using is actually pretty poor, it has tiny nibs which is meant to lock the lid in place and he noticed it's missing two holes for them on this particular model so that does not help. I'll report back in with how it goes.

Thanks again so much for your help I really appreciate it and you've been very patient with me!

Posted : 25/01/2021 9:43 am
Nizmox
(@nizmox)
Eminent Member
Topic starter answered:
RE: Z banding issues
Posted by: @turro75

I suggest You implementing the silicone bed leveling mod o place some strips of paper tape to get a better flat bed.

then print the attached (edit... not allowed uploading a stl) to check all axes are properly aligned, XZ can be easily adjusted by following the official prusa guide, for the others...good luck.

for XY You could try this https://www.thingiverse.com/thing:4378040

the YZ can be adjusted ensuring the X rods are aligned to the dotted lines in the heat bed (without PEI sheet).

 

Hey, thankyou for your advice!

I am interested in the silicone bed leveling mod, the only issue is trying to get the exact parts I need in Australia. It would take a while to order them all but I'm considering it. With regards to the tape suggestion, do you have any more detail on that? I assume it's placing tape on the underside or the removable bed? What kind of tape do you use?

I'm going to try the YZ axis shims and see if this helps any. I'll make sure I remove the PEI sheet. I'm not sure this will solve my issue as the bed seems to be raised in one corner and dropped in the other three but it's not a linear drop, it's a very weird shape so I imagine messing with skews will only get me so far. Definitely going to try it though. I've ordered some PETG to try the shims, only have PLA at the moment.

Many thanks!

Posted : 25/01/2021 9:48 am
Turro75
(@turro75)
Estimable Member
RE: Z banding issues

@nizmox

have a look here which shoul clarify what I mean

https://forum.prusa3d.com/forum/user-mods-octoprint-enclosures-nozzles/prusa-mini-silicone-bed-leveling-mod/paged/9/#post-336934

You can find paper tape in any hardware store as it is used during wall painting at home. Ah the right english name is masking tape...

https://www.amazon.com/AmazonBasics-Masking-Tape-Inch-Rolls/dp/B07QHSKGMH/ref=sr_1_11?dchild=1&keywords=paper+tape&qid=1611584208&sr=8-11

I think it is fine print the shims even PLA.

have a look at this video

 

Posted : 25/01/2021 2:36 pm
Nizmox
(@nizmox)
Eminent Member
Topic starter answered:
RE: Z banding issues
Posted by: @turro75

I suggest You implementing the silicone bed leveling mod o place some strips of paper tape to get a better flat bed.

then print the attached (edit... not allowed uploading a stl) to check all axes are properly aligned, XZ can be easily adjusted by following the official prusa guide, for the others...good luck.

for XY You could try this https://www.thingiverse.com/thing:4378040

the YZ can be adjusted ensuring the X rods are aligned to the dotted lines in the heat bed (without PEI sheet).

 

I gave the masking tape leveling a shot today, and it was actually incredibly simple to get the bed flat using this with octoprint, and then doing some ZX axis adjustment at the end. I was super excited that this may have at least solved the bed leveling issue, all my Bed Visualizer values were sub 0.1. However I then realised that while it had solved the level bed issue, it unfortunately created another issue. When I attempted the first layer calibration, I noticed the filament didn't stick to the bed in one section. I repeated it and the exact ame thing happened again. I then realised the mod unfortunately affects heating the bed. I was having issues in one corner where I had had to use more than a single layer of tape and the tape must be insulating the bed from the heating.

All that said, it was worth a try and I'm glad I attempted it. I am going to do the silicone mod when the parts arrive.

With regards to the YZ adjustment, I think this is actually the cause of my prints not being square. The x axis is pulling slightly forward towards the front of the print bed. I'm going to fix this when I have time, but I am waiting for my calipers to arrive before I can properly fine tune it.

Posted : 26/01/2021 6:32 am
Turro75
(@turro75)
Estimable Member
RE: Z banding issues

I don't think bed temperature has a big role in first layer, I mean it is really important avoiding warping only. Especially with PLA which can successfully printed even with the bed cold. I think Your bed is dirty, clean it by hot water and dish soap, don't touch it as fingerprints on bed are the worst think can happen and retry.

Posted : 26/01/2021 1:36 pm
Nizmox
(@nizmox)
Eminent Member
Topic starter answered:
RE: Z banding issues
Posted by: @turro75

I don't think bed temperature has a big role in first layer, I mean it is really important avoiding warping only. Especially with PLA which can successfully printed even with the bed cold. I think Your bed is dirty, clean it by hot water and dish soap, don't touch it as fingerprints on bed are the worst think can happen and retry.

Hey there, I think you might be right. I re-taped the bed and gave it another shot. I was having issues in a particular spot but after printing a calibration sheet with multiple points on the bed and adjusting z I think it is actually working. I haven't yet printed a large print, but i'll post back with how that goes and if I experience any warping issues.

 

Posted : 27/01/2021 7:24 am
Daniel Cardona
(@daniel-cardona)
Eminent Member
Z banding on MK3S+

 

Posted by: @nizmox

So another update in my journey.

After stumbling upon a thread about the bondtech extruder I noticed a few people mentioning that they needed to change the retraction length. So I changed the retraction length to 2mm, and also enabled "Retract on layer change". And wow, I suddenly noticed a massive difference.

The 20mm cubes I was using as a test print to reproduce the problem suddenly started printing near perfectly, the z-banding issues were gone. I was not expecting this to make much of a difference to be honest so was estatic that it did.

I then went back to trying to print a board game insert component I have been trying to print since buying the printer and while it was much improved, it still had one very obvious banding issue. Back to being stumped...

My friend suggested I try another filament. I had been avoiding changing filament as I felt in theory prusament should be best, and if I couldn't get it working with Prusament then it's unlikely to work with anything else. But it was worth a shot, so I loaded up some Esun PLA+ (white). I first tried to print the same cube, and again it was perfect. I then retried the board game insert component again, and wow, print perfection. I then printed a 2nd piece that was very similar and again print perfection.

So I'm not sure what to make of it, but a few possibilities...

  • Prusament might need a temperature adjustment, possibly lower? I'm using the 215 recommended though.
  • Maybe the extruder screw needs tightening or loosening for Prusament, the feel of Prusament is a bit different to Esun PLA+
  • My Prusament roll (that came with my printer) is defective.

I'll endeavor to keep posting here as I explore in hope it helps someone else.

I have the same banding issues but I'm using an mk3S+ and right now they are driving me crazy. I checked the belt tension with a printed tension meter ( yep, a great piece of kit) checked for loose bolts, pulleys, condition of bearings, recalibrated everything from the LCD menu, and still, I have this damn banding, from a solid fantastic quality printer that turned out doing ugly prints and I have it for about 2 months max. So now that I stumbled into this thread I saw that you by enabling ''Retract on layer change'' got better results afterward.

My question is, in the Prusa slicer you set the Retract on layer change under the filament settings/filament overrides or in the Printer settings/extruder 1?

if it's from the filament overrides there's another Box to tick just near the Locked lock, did you tick that box too? and did you also tick the option from the printer settings too?

Kind regards

Daniel

Posted : 29/10/2021 7:47 pm
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