Anet A8 suddenly prints like crap

I have had this printer for about a year now, and initially it printed fabulously. In the last two months that has all changed, without me changing a thing.
Really, I haven't so much as tightened a belt (they are all just fine, incidentally). I have been using 3D printers for almost two years now, and built several. This one has me stumped.

I use CURA 3.4 and Simplify3D 4.1.1 as my slicer/printers
I am using Octoprint on Rpi B (the original one, not the 2B or 3.
My A8 has lots up upgrades on it to stiffen the frame. It has a custom carriage with a genuine E3Dv6 and an "Itty bitty belted extruder" on it.
I am running Marlin 1.1.8 using the suggested configuration for the A8.
Here is my printer


I have, in the last few weeks:
Checked the belts
Checked the extruder for excess grindy stuff
replaced the nozzle
leveled the bed
zero'd the bed, several times, all just fine.
Cleaned the glass
fiddled with temperatures, first layer heights, speeds, layer widths, extrusion speeds and distances, no help. I have tried every trick that I know.
This happens with eSun PLA, eSun PETG, Colorfab nGen (which is the most bullet-proof PLA I have ever used!)

I am unable to get a decent first layer. The S3D 90% height first layer does not squish. The CURA +50% first layer with extra filament does not squish. It is like it refuses to do what I tell it. My height is good (width of paper for layer 0), the hardware is not binding, rattling, shaking of skipping. Subsequent layers look poor, lots of stringing occurs, every problem I can imagine seems to be happening.
I am ready to scrap it and start over... So, if anyone has any ideas, I am out them, I'd appreciate it.

Here is a classic example of what comes out of this printer now. This is a print that is using the CURA "Breeze wall" option, it REALLY made this print look bad. That is not what the breeze wall usually does...


I am completely out of ideas. Clearly I am overlooking _something_ but I do not know what it is...

Thanks all,
DLC

Edited 1 time(s). Last edit at 02/02/2019 05:20PM by dlc60.

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Kits: Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head, TronXY X5SA Pro(E3DHemera).
Scratch: Large bed Cartesian, exchangeable heads, Linear slide Delta, Maker-Beam XL Micro Delta, 220x220CoreXY.

That looks a lot like what my I3 started doing before I scrapped it.

Mine had the additional complication just before then of forgetting how to print a circle, but that was a more simple matter that the belt holder on the Y axis was doing something weird, and I was able to fix that.

I would suspect some issues with the extruder for the blobbing and layer issues that your print shows. In my case, the extruder was unsalvageable, and changing it out was more of a hassle than I was willing to deal with. I was also never entirely happy with the print quality in the first place.

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MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts

Quote
SupraGuy
That looks a lot like what my I3 started doing before I scrapped it.

Mine had the additional complication just before then of forgetting how to print a circle, but that was a more simple matter that the belt holder on the Y axis was doing something weird, and I was able to fix that.

I would suspect some issues with the extruder for the blobbing and layer issues that your print shows. In my case, the extruder was unsalvageable, and changing it out was more of a hassle than I was willing to deal with. I was also never entirely happy with the print quality in the first place.

When the print job goes to crap, it is almost always the extruder/hot end. That is my experience.
This printer was _fabulous_ for a long time, the best prints of my stable of printers. Then...
On another of my printers I discovered that the lameo 30mm fan on my E3Dv6 was not giving the needed airflow and the heat break was not going well. But that one kept getting jams as well as poor retract performance.
This one is not jamming. And the inability to get a layer 1 "squish" is also a new one.
I am reaching the "dump it" mindset too, but I don't mind rebuilding bits of the printer so I may go after that carriage to remake it.

Thanks,
DLC

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Kits: Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head, TronXY X5SA Pro(E3DHemera).
Scratch: Large bed Cartesian, exchangeable heads, Linear slide Delta, Maker-Beam XL Micro Delta, 220x220CoreXY.

I also suspect it's the extruder slipping or a half blocked nozzle, motor skipping steps, filament being blocked, constricted, entangled and/or moisture in the filament, bubbles in the filament or inconsistent diameter. Maybe the hobbed bolt is crammed full of plastic and losing grip. Try swapping out the stepstick.

And seeing the bottom of the print there's quite a bit of backlash/compliance judging by the 'pairing' of infill lines and infill not or barely touching the perimeters. All very familiar problems I used to have with a i3 clone before I scrapped it to build a corexy 3d printer.

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

Quote
imqqmi
I also suspect it's the extruder slipping or a half blocked nozzle, motor skipping steps, filament being blocked, constricted, entangled and/or moisture in the filament, bubbles in the filament or inconsistent diameter. Maybe the hobbed bolt is crammed full of plastic and losing grip. Try swapping out the stepstick.

And seeing the bottom of the print there's quite a bit of backlash/compliance judging by the 'pairing' of infill lines and infill not or barely touching the perimeters. All very familiar problems I used to have with a i3 clone before I scrapped it to build a corexy 3d printer.

I have primarily worked on the extruder and hot end. I checked the hobbed bolt, no gunk, replaced the nozzle, no change. My extruder does not use herringbone gears, so there is no gear backlash there (its belted). The pressure arm has good tension, there is no sound of filament shaving going on. I have a fan moving air across the step sticks, they aren't overheating.
Your comments about the backlash have me thinking that maybe I need to increase stepper current. This printer is only a year old, but the fact that it printed beautifully one day, and total disaster the next means something changed characteristically or failed somewhere in the chain. I have been meaning to replace the "Y" bed stepper because it has always sounded a bit noisy. Might be a good time to just do that.
Hmm.
I just updated Octoprint on my Raspberry Pi model B at about that time, I wonder if the newer code does not like the old Pi hardware (Yes, this is a Rpi B, not Model 2B or 3B, B, as in the original Rpi.) I have noticed that some arcs on my prints now print in a jerky fashion, as if something has trouble calculating it. I have been meaning to update that to a new Rpi 3B, I will see if that does anything.

thanks,
DLC

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Kits: Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head, TronXY X5SA Pro(E3DHemera).
Scratch: Large bed Cartesian, exchangeable heads, Linear slide Delta, Maker-Beam XL Micro Delta, 220x220CoreXY.

Don't forget to check the screws are tight. Also have a close look for cracks in the printed components.

The jerky motion is the problem, if it's not smooth printing arcs then it will blob due to back pressure. It could be that the gcode volume is too much for the serial port to handle. See if you can raise the baud rate or limit the sliced detail. Also check the jerk setting. If it's set too low it may stop at the end of every g1/g0 command.
I can't imagine sending gcode to the 3D printer is that taxing on the processor though. It could point to sd card/filesystem issues, or background processes that may bind up the pi.

As for the backlash, unless the motor is worn out, it's more likely loose belts and other mechanical issues. Just grab hold of the hot end (while cold) and grab the motor pulley or belt, try the same with the bed. Any movement in the system will produce backlash.

Edited 1 time(s). Last edit at 02/07/2019 09:16AM by imqqmi.

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

Come to think of it, although the pictures you've posted are very low res but if I'm not mistaken the first layer seems good. Do you print the first layer at a lower velocity? You could try slicing the model with that speed and see if things improve?

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Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]

I once had a very similar looking problem.
It was the heatbreak not beeing secured in the cold end.

Nozzle, heatblock, and heatbreak were tight as they should, but heatbrake was loose in the cooling fins.

Quote
Dancer
I once had a very similar looking problem.
It was the heatbreak not beeing secured in the cold end.

Nozzle, heatblock, and heatbreak were tight as they should, but heatbrake was loose in the cooling fins.

Mine is tight at both ends (I thought of this too, as I have seen it happen before). It just seems like the hot end cannot deal with any back pressure, setting it a little closer to the bed with the same flow rate now causes it to put out too little plastic. It can only pump out plastic at much higher from the bed first layers.
IOW, for a .4mm nozzle and .2mm layer height, I used to set the first layer to 90% (.18mm) and 100% flow to get a better "squish". Now, even though the head is no closer to the bed than before, that setup gets me the "starved plastic" sputter. Only by setting my layer to .3mm (150%) do I get a proper layer laide down, but it isn't "squished" at all, so my first layer shows distinct traces instead of the nearly smooth surface it used to make.

I wonder if there isn't something occluding the heat break. It isn't the nozzle, I have replaced that with a new, unused one which made no difference.
I will tear the whole thing down and look for that now. SOMETHING changed without any mechanical, filament or firmware changes. The search is making me crazy!

DLC

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Kits: Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head, TronXY X5SA Pro(E3DHemera).
Scratch: Large bed Cartesian, exchangeable heads, Linear slide Delta, Maker-Beam XL Micro Delta, 220x220CoreXY.

My printer was doing that. Switched bearings and reset it up. Worked fine for 1 print.

My issue is that its seems to want to print the same layer a few times. It will do the first few layers fine, then the print goes to shit. If you leave it, it will continue and finish fine. Except it looks like after a few layers it will reprint the same layer a couple of times, then correct itself.

Ever heard of that?

Quote
Ocliptor
My printer was doing that. Switched bearings and reset it up. Worked fine for 1 print.

My issue is that its seems to want to print the same layer a few times. It will do the first few layers fine, then the print goes to shit. If you leave it, it will continue and finish fine. Except it looks like after a few layers it will reprint the same layer a couple of times, then correct itself.

Ever heard of that?

Never seen that one before.

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Kits: Folgertech Kossel 2020 upgraded E3Dv6, Anet A8 upgraded E3Dv6, Tevo Tarantula enhanced parts and dual-head, TronXY X5SA Pro(E3DHemera).
Scratch: Large bed Cartesian, exchangeable heads, Linear slide Delta, Maker-Beam XL Micro Delta, 220x220CoreXY.