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msb64x
(@msb64x)
Eminent Member
Horizontal waves in the top of the print

I'm trying to print a sword blade in several sections and I'm seeing some strange waves in the top of the print and I'm not sure what's causing it. 

It seems like maybe to nozzle is dragging it to one side for a dozen layers and then in the other direction. That's all I can think of.

I printed it in line with the Y-axis with brim .15mm layers 25mm/s. I'm thinking about trying again with some custom support blocks on the bottom to try and hold it more steady side-to-side. Would it be better to print diagonally maybe?

This topic was modified 4 years ago by msb64x
Posted : 28/04/2020 4:08 am
Neophyl
(@neophyl)
Illustrious Member
RE: Horizontal waves in the top of the print

Check your x (and Y) axis pulley set screws to make sure they are tight and are screwed down to the flat on the motor shaft.  That's the usual cause of little layer shifts like that so it would be my first thing to check.

Posted : 28/04/2020 5:51 am
msb64x
(@msb64x)
Eminent Member
Topic starter answered:
RE: Horizontal waves in the top of the print

@neophyl

I have checked that and they're tight and in the correct position. If that were the case I'd expect these shifts would be happening on the entire print. These waves only started around 45mm up and got worse and worse as z increased becoming noticeable at ~80mm.

Posted : 28/04/2020 6:04 am
Neophyl
(@neophyl)
Illustrious Member
RE: Horizontal waves in the top of the print

In which case all I can think of is that the part is bending slightly due to its height and thin cross section which I think is what you suspect is happening.  Do you have z hop enabled on layer change ?  Whats the size of the 'blade' ? How many perimeters are you using ?

Posted : 28/04/2020 6:32 am
msb64x
(@msb64x)
Eminent Member
Topic starter answered:
RE: Horizontal waves in the top of the print

@neophyl

3 perimeters, 10mm thick, 70mm wide, and this section is 115mm tall. I usually avoid using z hop since it usually leads to extra stringing, but that might help in this situation.

Posted : 28/04/2020 6:48 am
Neophyl
(@neophyl)
Illustrious Member
RE: Horizontal waves in the top of the print

Yeah it might be dragging along with no z hop but with the z hop you might still get small sways but it should stop accumulated error.  With a sword blade cross section I dont think you will get much external stringing if its the only object on the print bed.

Havent printed a full sword blade in parts as yet (its on my to do list 🙂  but I did a large mandalorian styled dagger in a single part on my cr10 and I aligned it just like you did with the Y axis as thats the biggest moving mass.  It was about 320mm high, the only issue I had was some of the infill pattern appearing on the outer skin.  Mainly down to the cr10's crappy v wheel system and the fact that I was running a 0.6 nozzle on the large printer to print faster.

Posted : 28/04/2020 6:57 am
Rexphil
(@rexphil)
Active Member
RE: Horizontal waves in the top of the print

Where can I activate this z hop option ? I am printing a RC plane and wing elements are high with very thin walls and extruder seems to be colliding (noise coming out of the printed part like  a drum head) while bridging from one side to the other side of the print and then I get the same effect as shown by msb64x.  Belt on x and y axis are tight

Posted : 28/04/2020 9:54 am
Neophyl
(@neophyl)
Illustrious Member
RE: Horizontal waves in the top of the print

@philippe-p7

Its under Printer Settings>Extruder>Lift Z.  If you have a normal prusa printer added profile like a MK3 it should already have a positive value like 0.6mm in there already.  

Posted : 28/04/2020 10:52 am
Rexphil
(@rexphil)
Active Member
RE: Horizontal waves in the top of the print

ok thank you, I have indeed 0,6 mm should be enough isn't it ?

Posted : 28/04/2020 11:40 am
Rexphil
(@rexphil)
Active Member
RE: Horizontal waves in the top of the print

I found the issue as I did imported a printer configuration recommended by the plane designer and in this config it is set to 0mm I modified it to 0,6mm and just launched a new print. Let see how it works now

Posted : 28/04/2020 11:54 am
Neophyl
(@neophyl)
Illustrious Member
RE: Horizontal waves in the top of the print

@philippe-p7

Well 0.6mm is 3 whole layers at .2 and 4 layers at .15 so it should be clearing the layer its just deposited, so I dont think your issue is the same as what msb was having.  Without seeing the setup/model/settings you have its impossible to say.

You could start a new post on the Prusa Slicer section of the forum (right at the bottom) and atatch a zipped up version of your .3mf file.  In slicer go, Project Save As>  and save the project, then zip it up and attach (as the forum doesnt except most file types).  A .3mf saves the model(s) on the plater and all the settings used so it makes it much easier to potentially debug.

I do know that there have been many posts with issues relating to RC plane wings due to the way they are constructed model wise (the slicer sub forum has several, just search for 'RC plane').

Posted : 28/04/2020 12:51 pm
msb64x
(@msb64x)
Eminent Member
Topic starter answered:
RE: Horizontal waves in the top of the print

I just finished reprinting the same section. This one I printed using some support blocks on the sides and printed at 45° and still without Z-hop. It looks like those changes helped a lot and I didn't get any of the waves from my first print. I have another section next that's a lot taller so I will definitely use Z-hop on that one. I definitely don't want to risk that issue on an 11 hour print.

Posted : 28/04/2020 5:08 pm
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