Extruder skips mid print randomly/Infill pattern problem

dc42 · 17 Jan 2018, 21:08

Does the problem occur if you extrude into free air at 4mm/sec ? e.g. with the nozzle hot and clear of the bed, send G1 E100 F240.

If the extruder drive is losing its grip on the filament, you may need to increase the pressure adjustment in your extruder drive.

if it is maintaining its grip but the extruder drive skips back occasionally as indicated in your video, you need to increase the extruder drive current. I suggest 1400mA.

If the hot end is getting blocked, check that the heatsink fan is running continuously and keeping the heatsink cool.

Saltlife716 · 17 Jan 2018, 21:27

1. Problem does occur if I extrude in free air using G1 E100 F240. Alot actually

The extruder drive is loosing it's grip on the filament, but I think that it's more of the extruder is trying to give it more filament than needed, or the hotend is having trouble pushing the filament out as needed.

The first layer and half of the second layer print perfectly, for it to do it randomly but never on the first layer. It just seems like if it was because it wasn't gripping right it would be doing it more often.

2. I did raise the current up to 1400mA and had the same results, so I brought it back down to 850mA.

3. Hotend isn't getting blocked, apart that it is brand new and I haven't really been able to print all that much, the fan is running 100% and the heatsink is cool to the touch.

Saltlife716 · 17 Jan 2018, 21:38

The one thing that is making this weird, is that I just upgraded to a DuetWifi and I had none of these issues when I was on RUMBA. I meant that as another clue, not as a comparison.

Saltlife716 · 17 Jan 2018, 21:53

When I tightened the tensioner more it got rid of the filament skipping, but then it started doing "the video" thing at about the same frequency as the skipping was.

dc42 · 17 Jan 2018, 22:26

Could it be a temperature calibration issue? For a given indicated temperature, the actual temperature may have been higher on your RUMBA setup than it is on the Duet. So you might be extruding at a lower temperature than before, resulting in more back pressure from the hot end.

Have you configured the correct thermistor parameters in the M305 P1 command in config.g?

Saltlife716 · 18 Jan 2018, 00:06

I've used temps for this spool of PLA from 190 to 210 with the same results.

I have run a M303 H1 S240 twice, once before i hooked anything up to the hotend (just bought it a couple weeks ago), and once with filament through it, fan on, and sock on

Saltlife716 · 18 Jan 2018, 00:22

Hmm.. I just ran it again and now all of a sudden it says

Warning: Heater 1 appears to be over-powered. If Left on at full power, it's temperature is predicted to reach 447C.
Auto tune heater 1 completed in 355 sec
Use M307 H1 to see the result, or M500 to save the result in config-override.g

I was staring at the temp for like 90% of the test, the highest it got was 248, and it didn't send that message until it said it was completed. Even then it was cooled down to around 140 when that message got sent.

Saltlife716 · 18 Jan 2018, 00:34

You can see the temp, the graph, and the times. It just doesn't make sense.

dc42 · 18 Jan 2018, 08:04

What do you think doesn't make sense? That message is produced when the firmware has calculated the heating parameters, which it can't do until it has measured the cooling rate. It's common to see that message ever since E3D introduced the silicone socks.

Saltlife716 · 18 Jan 2018, 13:42

@dc42:

What do you think doesn't make sense? That message is produced when the firmware has calculated the heating parameters, which it can't do until it has measured the cooling rate. It's common to see that message ever since E3D introduced the silicone socks.

Oh, I didn't know. Just didn't know if I should save it since it was saying 440c.

Martin_S · 18 Jan 2018, 14:29

And how about the bowden path? If you feed it by hand, do you find any resistance?
I once had a filament that was just a bit thicker and it got stuck inside the bowden tube.

Saltlife716 · 18 Jan 2018, 15:26

So should I save the M303 results even thou it says something about 400c?

Saltlife716 · 18 Jan 2018, 15:27

@Martin_S:

And how about the bowden path? If you feed it by hand, do you find any resistance?
I once had a filament that was just a bit thicker and it got stuck inside the bowden tube.

Nah no resistance when I push it through. The tube itself is maybe 2 weeks old.

Saltlife716 · 18 Jan 2018, 17:54

I have checked and calibrated extruder steps and current.
I swapped stepper drivers.
I changed stepper motor wiring.

About to put it my previous hotend and see if I get the same issue…

Saltlife716 · 18 Jan 2018, 19:59

@BDubs:

What happens when you jack the current up to like 1.2 or 1.4A ?

Going from 800 to 850 is like nothing…50mA is nothing to these motors.

When i bring it to 1.4A, it acts the same.

Saltlife716 · 18 Jan 2018, 19:59

I put my previous E3D v6 on the printer, and the same happens

Saltlife716 · 18 Jan 2018, 20:24

Extruding 10mm of filament at 5mm/sec, skips the entire time

Trojan3D · 18 Jan 2018, 22:39

Hi Saltlife,
From what I can see, the temperature is one of the issues, so you should just raise up to 220 degrees minimum if not 230!
Your extruder is fine printing the skirt because S3D give usually less plastic during the process.
The temperatures reading change every time from a board to another, it doesn't mean that Duet is wrong, you should try to point an IR probe to the heater and see what is really going on near the nozzle.
Your extruder shouldn't skip steps as in the video, should grind the filament instead, so, I would raise the current to a decent amount and then step back until the motor is running fairly warm if you don't know the motor technical details.
The motor is not retracting, is just the effect of the stall, the filament act as a spring as your is a Bowden and the pressure is just doing that because the moment your motor stall, the rotor has no more torque and become loose.

My 2 cents
Regards

Saltlife716 · 19 Jan 2018, 19:04

@Trojan3D:

Hi Saltlife,
From what I can see, the temperature is one of the issues, so you should just raise up to 220 degrees minimum if not 230!
Your extruder is fine printing the skirt because S3D give usually less plastic during the process.
The temperatures reading change every time from a board to another, it doesn't mean that Duet is wrong, you should try to point an IR probe to the heater and see what is really going on near the nozzle.
Your extruder shouldn't skip steps as in the video, should grind the filament instead, so, I would raise the current to a decent amount and then step back until the motor is running fairly warm if you don't know the motor technical details.
The motor is not retracting, is just the effect of the stall, the filament act as a spring as your is a Bowden and the pressure is just doing that because the moment your motor stall, the rotor has no more torque and become loose.

My 2 cents
Regards

I will try raising the temp to 220 when I get home and see if that works. Thanks.

T3P3Tony · 19 Jan 2018, 19:33

@Saltlife716:

So should I save the M303 results even thou it says something about 400c?

Just to clarify this message means that if the heater cartridge is allowed to draw full power, with no control, it could reach about 440C. This is not a configured parameter its a warning generated to make you aware that the max temperature if the control fails could get to a dangerous level. This is not control electronics specific but dependent on the heater cartridge, your power supply voltage, and the cooling rate of the heatblock (which is changed by having a silicone sock on it).

So yes you should save the results using M303, and also be aware that an electronics failure could lead to a very hot hotend!