Ugly Layer Issues, Help!

I've been getting some seriously terrible looking layers on some of my prints, still no idea what's causing them and I've made multiple modifications to the printer for stability and usability but none seem to have had any effect on the lower layers...here's an example of what's been happening. It would seem that the layers are offset, but it's as if they're evenly spaced and they appear on both sides almost identically. Definitely a deformation too, as you can see that it fades off near the top to become more normal. The thick indented lines in the walrus flipper are deformations too... it's pretty bad

 

I had layer issues too. I had to take off the heated bed and tighten the loose bolts.




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Ok thanks, and once I remove the two anchor points on the print bed it should slide off? Or do I have to remove it by other means

 

Also check the tightness of the large bolts holding the bearings and check the bolts holding the stepper. I have had the large bolts, the set screw and the stepper bolts all loosen up at some point! Come to think of it, I also had the X stepper set screw, the Z screw clamp sets screws and the Y drawer rail bolts all loosen!

 

Ha! Well the bolts and screws seem to be all tight, I added a belt tensioner though and am about to give it a test

 

BTW - this would not be belt slippage. That would cause permanent layer shift not the striations seen in the print. I sometimes get periodic layers like that but nowhere near that bad. Could this be due to a loose hot end or loose belts? Let us know if the tensioner helps. I'm surprised that one was not included on your machine. Did your's ship earlier than November?

 

Make sure the Allen screws are right on this guy. If it's loose it causes problems.


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I found this really good article on the reprap forums: Taxonomy of Z axis artifacts in extrusion-based 3d printing . I have not completely digested it yet but hope it will shed some light on these layering issues. I do get them on some prints at a 1.41mm interval which is the 5/16 imperial coarse thread pitch.

 

I tried setting my print to .3 instead of 0.2046 like they recommend and the print is looking smoother.

By the way, this green filament is really nice. Lays down thick and smooth. I am running at 190.

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I have exactly the same problem. My Robo3d is new (receive it 1 mouth ago) ! This current week, I get time to test it and get the ugly issue. (I'm frustrating cause I ordered a fully assembled robo3d, and it seem not professional)

 

I notice that layer z-artefact frequency is exactly the same that robo3d z-bolt. I suspect one of the 2 z-bolt are off-centered or curved. taht make different layer height depending of the angle of the bolt

 

Yes, I will check bolts and belt on drive part and after, if all is ok, I will check the 2 z-bolt (im sure taht one z-bolt seen on at 7:07 are off-centered with the z-step-motor or curved). I have no material here to unassemble the robo3d (verify all bolts/belt one the drive parts and on the middle plate (z-part)). Taht will take me some time

 

Take off your bed, tighten the bolts and tighten the y gear set screws x 2

This has been the main problem with layers. Once tightened post your results.



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Wow, thanks for all the help. Although I was thinking that maybe it might be a different issue completely... just an idea. The right threaded rod for the Z axis is leaning actually quite a lot to the right when it's at it's lowest point, which causes the top of it to create unwanted circular motions as it spins. So when the rod spins to the point where it is straight up and then leans to another side again, I was thinking it might be lowering and raising a small amount every time it does that, and causing the evenly spaced little lines by squishing the layers outward (the lines go around the entire print, not just one axis). It would also explain why the lines disappear after the print head reaches a higher point, because it is keeping the threaded rod from those unwanted movements higher up and thereby putting each layer at the height that it should be. If this is the case, then how could I straighten the rod, or the attachment point of the rod, whatever part isn't straight

 

I'll still be removing the bed for tightening, but just an idea

 

when the z is moving and the threaded rod makes the circular effect, does the smoothed rod next to it also move? if not then you are fine. im sure around 90%+ of people here have an odd threaded rod circular effect. i do and i wondered the same thing but in the end it did not effect the print.

 

ok thanks, and yeah the rod isn't moving