Strange extrusion/temp problem

[vmos]

Hi

I’m having problems with my P1S and I hope you can help me identify the cause.

I’m not sure whether to call the problem underextrusion or a partial clog. Recently, I started getting poor finishes on the top layers.

Since I was doing a multi-color print, I thought the nozzle might be dirty, so I replaced the entire hotend, but the problem persisted. After doing more tests, I realized that the imperfections in the top layers were due to missing lines in the previous layer.

At first, I thought it was an extruder issue. I checked the gearing but didn’t find anything unusual. I ran tests without the AMS and then without the PTFE tube, but the results were the same. Finally, I tried printing at 250°C instead of the default 220°C, and then the layers printed correctly.

While all this was happening, I was researching and found a similar problem where the solution was to replace the extruder board. So I bought a replacement and installed it, but the result is still the same. I hope someone sees this and can help me diagnose the source of the problem.

So far, this is what I’ve done:

• Check gear Extruder (everything looks in order)

• Test feeding without AMS

• Feed directly without PTFE tubing

• Replace hotend

• Complete recalibration

• Reformat microSD card

• Replace extruder controller board and recalibrate

• Check extruder motor

• Replace hotend thermistor

For all the above tests, Bamboo PLA was used. It was tested with a recently purchased, new spool, and the default profile for Bamboo PLA was also used.

The fact that it works by raising the temperature makes me think it’s an electronics issue, as if the reported temperature isn’t the actual temperature. For this reason, I also changed the hotend thermistor with no luck.

I tried measuring the nozzle temperature using a multimeter, but the difference is more than 30 degrees (220 on the printer, 185 on the multimeter). I performed the same test with my A1, and the difference was 20 (220 on the printer, 200 on the multimeter).

I tried slicing with Bambustudio in its latest version as well as with OrcaSlicer

Thanks in advance for any help!

[Olias]

Kudos for doing an exhaustive troubleshooting and letting us know what you’ve already tried, this helps narrow down much of the remaining troubleshooting options.

One test you might try is to create a smaller test model so that you can repeat the test multiple times. What I typically do in a situation like this is to create a model that has a specific stroke pattern such as monotonic. Then I first change the rotation of the model along the x/y plane(Z axis) and see if the orientation of the striping follows the model or the head movement. Then I repeat this test by changing the angle of the top level in the slicer. Although the slicer does not expose the angle setting for the top layer, I have had luck by changing the infill patter direction and that has influenced the top layer direction, you’ll have to experiment.

The Goal

What you’re trying to expose is whether or not this is a nozzle direction issue or a flow issue. If the flow gaps change with orientation, that might mean that the belts need to be cleaned or calibrated, refer to the wiki on how to do that. If it does not have any affect, then I’m afraid you back to square one.

You did not mention it but I’m assuming you already reset the filament profile to default. If not, try using another profile like Generic PLA and see if it has an affect. If it does, that then switches the theory back to flow and temp issues you suspected earlier. Unfortunately, it then comes down to trial and error as to what settings are actually contributing to this issue.

[lkraus]

I suggest that you perform a full clean and lube maintenance, and then recalibrate the printer. That corrected a problem I had, which was very similar to the top picture.

[vmos]

I already did this but it didn’t help with the problem

[vmos]

I’m going to test this tonight. Do you think it’s too early to think about changing the board that goes on the back of the extruder?

[Bullocks]

In addition to what olias mentioned, It might be good to test this with a 1-layer thick entire-bed-size test square.

Because the suspected “missing” line is buried underneath printed lines, it obscures how that missing/incomplete line was made. It may also be good to verify it happens on layer 1 as well as on the other layers (layer 1 generally has no fan, larger line width aka pressure, etc).

If the line looks like it just trails off and then starts abruptly again, it might be your extruder, extruder gear, or extruder gear tensioner. I would also suspect AMS feed problem or filament tangle sort of thing, but you said you tested this with AMS fully removed, so I’m gonna go with extruder. Tension is fairly easy to set/reset and is worth a try.

[vmos]

The first layer prints fine because it prints at a speed of 90, if I remember correctly, but when the speed increases to 210 for subsequent layers, the problem arises at 220°C. I’ve tried lowering the speed to 120-150 with a generic PLA, but the result is the same. If I raise the temperature to 250°C, then it prints normally.

[Bullocks]

250 for PLA. Interesting. I’m not sure what it means but its relevant. If you are in the room with the machine when it prints at 210 or whatever your normal is-- as it gets to these ragged areas, is the extruder audibly clicking and/or visibly backdriving?

Its strange that its survived red and black rolls, and old and new hotend.

[vmos]

Today I continued testing, and this time, on two occasions, the extrusion stopped completely. There was no clicking sound, which is usually heard when the nozzle is clogged; it was simply printing without extruding anything.

I stopped the print, tried unloading and loading the filament, and it did so without a problem. I restarted the print, and it started normally. The first time, I turned off the printer, removed the hotend, and turned it back on to check if it was the extruder motor, but it worked normally. This happened twice; it hadn’t happened in previous tests.

I’m currently using firmware 01.07.00.00. I haven’t updated to anything more recent due to connectivity issues with Orcaslicer. I don’t know if updating the firmware would help.

[MiniMart]

Do you have an AMS.

If so the problem might be there.

I was having filament feeding problem and it turned out it was a broken part in the AMS. In the lead up to this part completely breaking I was actually having some print issues but having had the printer for only 4 weeks I never connected the bad print to a filament feeding problem.

Just a thought…

[Milosh_Keat]

Seems to be friction in your filament feeding path or an upcoming nozzle clog. Do the cold pull procedure and check your filament paths for debris inside the PTFE tubes.

When the cold pull doesn’t indicate any debris, try different slicer version just to find evidence it’s software not hardware related

[vmos]

I’m still running tests. I wanted to thank everyone who left a comment on this post. The last test I did was printing at a maximum volumetric speed of 10 mm/s, almost half of the default 21 mm/s profile, and at 220°C. The part printed correctly, which means the problem might be with the motor or the extruder. I’ll see if I can change the extruder gears and test again.

[vmos]

Yesterday I replaced the extruder gears with the reinforced ones, and the result was the same. So far, I’ve replaced:

-Small extruder board
-Complete hotend
-Thermistor and heater
-Extruder gears

I only need to replace the motor and the rear electronic board to have a completely new print head…

Is there any way to print without the front cover? This would allow me to see if there’s any issue with the gear movement, or if there’s a way to extrude the filament at 21mm with the print head fixed to see if there’s any problem with the gear movement.

[Steve_KA5YFC]

Could you post the.3mf file?

[vmos]

Hello everyone

I’m still having the same problem. I hadn’t posted an update because the last thing I changed was the cable connecting the two extruder boards, and it took me a while to make the change, and surprise, surprise, there was no change.

However, I noticed something interesting that makes me think the problem is with the motor. I did this print after the printer had been off all night,

and as you can see, it’s almost perfect. This other print was done 15 or 20 minutes later,

and you can see the result. This makes me think that the problem appears when the printer heats up, so to speak, and in fact, I’ve repeated this test twice, and the result is the same.

Seeing that when I lower the volumetric speed to 12, for example, I can print correctly makes me think the motor doesn’t have enough power to push the PLA at 21 mm/s.

I’ve also ruled out a temperature issue since, as I said before, the print completes well at lower speeds, and the first print, when the machine is cold, also worked fine. It prints correctly, perhaps the motor starts having problems and skipping steps after extended use. I’ve also tried observing the gear and it seems to me that there are times when it doesn’t rotate, but I’m not sure because of the toolhead’s rapid movement. Currently, the extruder motor for the P1s is out of stock at the store; I’ll see if I can get one and test it.