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Small misalignment in layers

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Bob
 Bob
(@admin)
Member Admin

Hi,

Lately I've been working on the final quality of my parts and there is one issue that I have not been able to solve. It's about the uneven placement of the layers. I am not sure the reason, so could be misalignment, or maybe Z height variation or even inconsistent flow.

 

I tried many things and now I am a bit lost. They only serious clue I have is that in some cases I could print perfect parts, so the printer is able to do that. This is then my goal, something that I am not able to reproduce:

IMG 2207

And one example of what I am getting now. Both pics are from the same part, just took two to show that the quality is not so bad, but far from perfect.

IMG 2206
IMG 2205

As key info, lately I changed my blower mount and my nozzle (now I am using a MicroSwiss one). At some point during that update process I got that great part. But after a few steps that quality was gone. The only thing I notice is that the new mount was not very stable, and screws tend to be loose so the hotend was moving a bit while printing. However I have ensured that they are tight now and the problem is not gone.

As the new mount has different wiring for the blowers, it is not easy to come back to the stock parts.

What canI test for finding the root cause? 

Thanks 🙂

 

Quote
Topic starter Posted : 07/09/2019 10:45 am
Carla
(@carla)
Member

Hi @Micifu

Have you been able to do the testing we talked about in the other post?

It might be better to deal with one problem at a time because editing settings and so on can affect other parts of the print and so on, plus it will make things more easy to keep track off.

Carla.

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Posted : 08/09/2019 11:13 am
Bob
 Bob
(@admin)
Member Admin

Hi @carla, yes could solve that 🙂

Details in the other post, but it seems the plastic inside the nozzle was too dense or degradated and the molten filament had to find another way to get out... 

Now it should be solved. Did some test with the new set-up but still getting that effect. 

I am tuning again the profile, as some adjustments where done for the clogged nozzle, and will come back with the last test to see if the result is now better.

 

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Topic starter Posted : 08/09/2019 4:58 pm
Bob
 Bob
(@admin)
Member Admin

Back with the final test including some optimization. With the nozzle fixed from the other thread this problem is almost solved. Here you have a picture of a reference cube. Right is the "perfect" one, left the last one I just printed. Not exactly the same quality but almost.

IMG 2210

The face you can see is where table was moving (Y axis). The faces where the hotend was moving are slightly better (X axis).

Not sure what else can help. Maybe adding more tension to the belts, but that right cube was done with same setup, so should not have more tension nor less.

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Topic starter Posted : 08/09/2019 7:14 pm
Carla
(@carla)
Member

@micifu

Sometimes just making sure the rods and that all run nice and smooth can help, when was last time you give them a light coat of oil? The two parts don't look much away from each other, do the cubes have a infill or are they just single walls? sometimes if they have a small infill you can adjust the infill speed so it dont vibrate the print to much what can make small layer shifts. Then the normal jerk settings.

 

If you could post your latest settings that would be handly to see what we can tweak a little.

 

Carla.

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Posted : 08/09/2019 9:00 pm
Bob
 Bob
(@admin)
Member Admin

A few weeks ago following advice from @stefan I did a mechanical check, including belt tension and oil to the Z axis.

Both cubes are empty, with a 2 walls. Here you have some screenshots of the settings and the profile just in case.

Acceleration and jerk are the same in both cubes, the factory values.

temp
temp
temp
temp
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Topic starter Posted : 08/09/2019 10:32 pm
Carla
(@carla)
Member

Hi @Micifu

I don't have hands on with an Ender 3 but looking at the setting i see a few things i would personally would have differnt on my printers for PLA.

Extruder 

  • Extrusion Multiplier = 0.98 (You have 0.90 what seems really low)
  • Extrusion Width = Auto or Manual 0.48

Layer

  • First Layer Height = 110%
  • First Layer Width = 100%
  • First Layer Speed = 35%

Your speeds and temps all look fine, but the above settings i find give the best first layers and filament flow, so if you could give them a try and see how things go and then let me know how it went that would be great thanks.

Carla

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Posted : 09/09/2019 8:48 am
Bob
 Bob
(@admin)
Member Admin

Thanks @carla, I am travelling this week but as soon as I am back I will check those changes and will come back with more pics.

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Topic starter Posted : 09/09/2019 9:47 pm
Carla
(@carla)
Member

@micifu

Enjoy your travels this week and be safe. Hopefully happy printing when you return 🙂

 

Carla

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Posted : 09/09/2019 9:49 pm
Bob
 Bob
(@admin)
Member Admin

Hi, finally back to print 🙂

@carla used you parameters and got some better results but still not stable. Here you have the 4 sides of the cube printed (2 walls, 0 infill, 2 bottoms, 0 tops), using my parameters with your modifications. I used also 4 mm wipe instead of 2. In order, first, second, third and forth layer.

IMG 2218
IMG 2219
IMG 2220
IMG 2221

Axis are discarded I guess as the best sides are one on X axis and other on Y.

Not sure if useful here, but I also printed this square at the same time than a cylinder and got some additional info. First I noticed my retraction is not perfect. Second, harder to explain. As both figures are printed at the same time, it prints two layers from the cube, then 2 from the cylinder and so. In particular in the cube, this first layer printed after coming from the cylinder is different to the one printed just afterwards. I tried to take a high detail picture. This effect can also be appreciated in the cylinder, but it is much smoother than the cube.

Additional pics:

IMG 2225

 

If you look to the left side, you will see all the lines. But when looking at the center of the face, you will notice that half of the layers are thicker as some are printed after traveling from the cylinder, while the other are printed after the others. Could be related?

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Topic starter Posted : 13/09/2019 6:49 pm
Carla
(@carla)
Member

@micifu

One thing to try with the cube is to set the "Extrusion Width" to 0.40 the same as your nozzle and then print the cube again but this time with only 1 single wall, then using calipers if you have some (if you don't look at getting some as they are real handy tool to have when 3D Printing) see how thick the wall is, it should be 0.40mm.

 

If it's out we can then adjust the "Extrusion Multiplier" setting to fine tune the extrusion to make sure we have the right amount of plastic being pushed out.

 

Once we know thats right we can then see how the print turns out and start working on other area's if the problem remains, i know not to long ago you checked all the rods and belts, but might be worth to check them all again and give the rods a good clean,

 

Carla.

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Posted : 14/09/2019 11:56 am
Bob
 Bob
(@admin)
Member Admin

Hi @carla,

Sure, printed those cubes with 1 wall and measured with caliper. 

First printed a cube with your settings, 98% flow, and got around 46 microns (45-47 depending on the wall)

Second cube reduced flow to 90%, and got around 43 microns (42-44).

I did also an extrusion test, and from a theoretical 100mm got 102 extruded. I guess that 2% could help, so I will go for that.

In addition, I am founding this weekend a stringing issue, despite last weekend calibrated it. No matter what I do, I got strings. Not sure what it can be as spent the morning checking everything.

 

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Topic starter Posted : 14/09/2019 7:10 pm
Carla
(@carla)
Member

@micifu

Did you also edit the "Extrusion Width" to 0.40 back from 0.48, because if its still at 0.48 and you got a reading of 46 microns at 98% then you might need to up to 100% flow. Just want to be sure, because the reading should always match when the extrusion width is set at.

ReplyQuote
Posted : 14/09/2019 7:13 pm
Bob
 Bob
(@admin)
Member Admin

Confirmed, I updated to 0.40, so I have a bit of overextrusion right?

ReplyQuote
Topic starter Posted : 14/09/2019 8:14 pm
Carla
(@carla)
Member

@micifu

Yeps if the reading was higher than 0.40 then you psuhing to much plastic. So if you can get that reading to 0.40 with the "Extrusion Multiplier" setting that would be a good start 🙂

 

Carla.

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Posted : 14/09/2019 8:20 pm
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