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Second layer problems


Cazze

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It looks like the hotend is having flow issues. Maybe since the first layer is usually printed slower, once the print speed picked up it couldn't keep pushing out the plastic. What speeds and hotend temperature are you printing at? Another cause could be the tension screw on the extruder. That looks like a bowden setup so that can exacerbate any problems.

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I would look at cooling as well - you may be over-cooling on second layer - you may want to ramp the part cooling fan up a little slower.  It's hard to tell whether the flow is there or not - there is a lot of balled up material there that *could* account to the gaps.  I would tend to think you're not outrunning the hot end but just not getting stuff to stick.

It looks mostly like an adhesion problem to me - as @atrushing mentioned, the first layers tend to go down slower but they also tend to go down hotter (less cooling fan - often times *no* cooling fan)  I do PLA with no fan on the first layer and typically step the fan up through the first few layers.  Something like 20% on the second layer and 50% on the third layer (and never hitting 100% - I used to but the StealthBurner seems to have way better cooling flow so I now top out at 70% for PLA after the first few layers).

For me, when I've had problems like this, I go slower and hotter until I got a handle on it and then started cranking things up again once I get things to stick.

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I agree with atrushing. That is either a classic sign of printing too fast. You need to slow your print speed. And he was right as well that the first layer may print just fine because slicers are default set to print the first layer slower (unless you change it) to get good bed adhesion. Go back and look at the speed the first layer is printed at and start with that for a number for your regular speed. I guarantee you will not be able to print faster than around 80 mm/sec (maybe go up to 120) unless you have a high-flow hot end installed.

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I got "no cooling" for the first 5 layers. Printing at 230°, not seeing problems on the temp output in mailsail. I'm used to print black eSUN ABS+ and have no problem with that. Now I'm printing White eSUN ABS+ and noticed this. I'm running a print now @ half normal speed and it seems to work better so I thing i have a flow problem with the hotend or I need to recalibrate the extrusion multiplier for this white filament.

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Your temperature is too low. You should be at 240C - 245C to print ABS. That right there could solve your problem. Also, white filament is one of the more difficult ones to print. I also have seen a lot of negative chat concerning eSUN ABS+. A lot of people out there hate it. If you want to print ABS, use KDP brand or the printed solid brand I have had good luck with too. Try upping your temperature and check your speed and those two things should solve your problem.

 

Edited by SuperBoppy
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eSun recommends a print temperature for ABS+ of 230-270C so you are at the very low end of the range.  Bed temp 95-110C.  Try at least 250C, but be mindful of too much first layer adhesion if you are printing on flat PEI. What's your 2nd layer volumetric flow rate?

Normally have my ABS prints start when the chamber reaches 43C (14 minutes) .  With large prints, I bump that up to ~53C before starting the print which can take over 1/2 hour to preheat.  I had a 310 x 150 print where the first layer took like 30 minutes. The frame was still expanding (with a starting temp of 43C) when the second layer started resulting is very poor second layer adhesion.

I've never been a fan of eSun ABS+ because of it's lower plastic deflection temperature compared to ABS.  A Voron should have no issues printing straight up ABS.  I have seen differences with eSun white pigment  ABS+ and ABS filaments versus other colors - doesn't flow quite as smoothly; clumpy.  For flat print bed surfaces, I use FR4 with Vision Miner Nano Polymer which is far superior to PEI in bed adhesion and durability.

 

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On my side, cannot get decent layer adhesion with eSun ABS+ under 260-270°C (Stealthburner with E3D V6 / CHT nozzle, and Mini Stealthburner / Revo High Flow)... Black and Ice White.
This filament produces nice parts, has good bed adhesion, and does not warp... As it doesn't warp, weak parts don't show layer separation... Parts just fail later. Not happy... A 0.2 and a 2.4 to be reprinted sooner or later... (so far, so good, crossing fingers)

Chose this filament because as a Voron noob, I believed it was the "official" Voron filament. 🤦‍♂️

There's one thing you didn't tell : what is your layer height ? Had similar results with thick layers. I stopped printing it over 0.2 mm (0.4 mm nozzle)

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Happy new year to all!

It is funny to have second layer problems 🙂 When you look on the net, here at the print quality troubleshooting guide from Simplify3D, or at 44 common 3D print problems (I used to look at these sites to see what my problem was when I started out printing), none of them mention a second layer problem. A lot of first layer 🙂

Amazing that all you guys use a Voron and none have similar problems. I am sure you all have these 80 euros a set Titanium backers installed🙂

This was the most frustrating problem I ran into, when I had built my 2.4 350 and wanted to print a part, that would take longer than half an hour. After half an hour, an hour, my print would fail. When I thoroughly read Ellis' guide, I found out what was going on... Luckily I did, otherwise I would have thrown away the Voron 2.4 350 I had just built...

Thermal Drift. 

Check out this image: https://raw.githubusercontent.com/VoronDesign/VoronUsers/master/printer_mods/whoppingpochard/extrusion_backers/images/test1_comparison.png

from https://mods.vorondesign.com/detail/ewDI1Cntz7urtuq3Cm9wGQ

 

The middle one, is what happens to your second layer. The blobs of white is the second layer NOT adhering to the first, because the distance has increased and your extruder is pushing out plastic, but it is not enough to fill the gap and adhere to the first layer 🙂

As you can see in the graph on Ellis' page, after 60 - 120 minutes after you start your print, the center of your bed is already 0.2mm further away from the offset you used to start the print at the first layer.

I hope it makes sense...

Either heat your chamber for 2 hours before starting a print like that, or get some backers. Ellis also mentions what options you have. (I bought 3 rails, cheaper than stainless or titanium backers for me)

All the best wishes to everyone for 2024! 

 

Edited by Dirk
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Posted (edited)
18 hours ago, SuperBoppy said:

I agree with atrushing. That is either a classic sign of printing too fast. You need to slow your print speed. And he was right as well that the first layer may print just fine because slicers are default set to print the first layer slower (unless you change it) to get good bed adhesion. Go back and look at the speed the first layer is printed at and start with that for a number for your regular speed. I guarantee you will not be able to print faster than around 80 mm/sec (maybe go up to 120) unless you have a high-flow hot end installed.

Speed was indeed the problem. Was printing @ 120 mm/sec. I'm still on a legacy VORON 2.1 with an E3D V6. 105 mm/sec was almost good, but will print the next level @ 80 mm/sec as you said. Will also raise the temp from 230 to 240. Will post a picture of the result. 

Also, I never had problems with eSUN ABS+. I like the black matt look of that vendor. Also, it is very easy to get it here in Belgium.

Edited by Cazze
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100mm/s, 0.4mm width and 0.2mm layer height you should have no problems. 8mm3/s. It's under the E3D V6 limits (12-14). But it requires a much heigher temperature, and some compensation on the extruder side (like 102-105% or even a bit more). You print way too cold. Could make your extruder slip.
 

Edited by YaaJ
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Yes, white plastic shows irregularities, because we can see any minor irregularities as shadows. On the YT chanel 3D Musketeers, Grant (?) very often rants against white filaments, and they avoid this color for the models they print for their clients. He also says that the white pigment is titanium oxide, and is very abrasive.

I re-read my previous post, it is unclear : the compensation is for higher flows, at the limits of the hotend (above 120 mm/s)

A question : are your walls printed inside to outside, or outside to inside ? I get really bad results when printing this filament inside to outside, sometimes looking like layer shifts.

BTW, these models are not easy to print !

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On 1/2/2024 at 2:33 PM, YaaJ said:

Yes, white plastic shows irregularities, because we can see any minor irregularities as shadows. On the YT chanel 3D Musketeers, Grant (?) very often rants against white filaments, and they avoid this color for the models they print for their clients. He also says that the white pigment is titanium oxide, and is very abrasive.

I re-read my previous post, it is unclear : the compensation is for higher flows, at the limits of the hotend (above 120 mm/s)

A question : are your walls printed inside to outside, or outside to inside ? I get really bad results when printing this filament inside to outside, sometimes looking like layer shifts.

BTW, these models are not easy to print !

Inside/outside/infill is the sequence it was printed. Maybe I should reverse next time to see the difference.

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26 minutes ago, Cazze said:

Inside/outside/infill

Outside/inside/infill will give best results for the floors and walls. For the roof, it may vary on how it has to be printed (orientation). I'd print it outside to inside, but on its side, so the right angle is laying on the bed, as a horizontal V (pretty sure it was printed this way...).

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