Print issue

gloomyandy

@jens55 Check the gcode for the object and look to see what is happening at those points in the model. It sounds a lot like that is a place at which retraction is being used to me....

cosmowave

@jens55 Are you sure that the extruder is transporting the filament properly? Eventually it slips during some moves.

mikeabuilder

The same void or bump defect at the same place on two prints suggests to me some setting issue. And when I say "same defect" I mean really the same - photos of both are hard to tell apart - not just "crappy at this corner". And consistent wiggles on straight lines don't count and are probably mechanical.

But assuming really the same, I've had issues like that which were fixed by adjusting Pressure Advance and Input Shaping. Possibly also max acceleration and jerk settings as these affect the beginning and end of lines. Those things show up in places where the print head is accelerating or decelerating. I've used this part to investigate. It has some straight sections to allow max speed, some sharp corners to test braking and a lot of corners with decreasing radii on subsequent layers. I found that when I could print this well, I could print everything else. decreasing raduis part.stl attached part to

jens55

Thanks guys, lots of things to try out here.
I did check the gcode and found a possible connection between a whole bunch of very tiny infill moves and the printer then starting to print the inside and outside lines. I have just started a print in petg with the walls set to 3 which eliminates those tiny infill moves. I am looking forward to see what the results of this test will be.
I previously said that I tried printing the same model in PLA - as it turned out, the two spots where there had previously been a lack of filament were still present although much less noticeable. I also did some maintenance on the printer and hopefully this latest print will show an improvement in the overall surface finish.
With this issue happening after a large number of very tiny infill prints, I am wondering if there is a retraction/unretraction issue after all. I don't recall when and in which context but I seem to recall a previous situation where the unretract moves did not keep up completely with the retract moves causing filament starvation.
Just for curiosity sake - I have a retraction of 6.5 mm happening at a speed of 25 mm/sec. Unretract happens at the same speed. Does that seem to be viable setting or am I maybe unretracting too fast causing a tiny jam causing starvation?

jens55

Good news - the version of the model printed with 3 walls printed without the issues that the 2 wall model had. I will look into my retract settings to see what I can improve.

Norder

@jens55
The fact that this error always occurs in the same place, I believe it is due to the combination of the geometry of the component, the direction of movement of the nozzle and the Z-hop with retraction values that are too high.
6.5mm with a direct extruder is clearly too much.
The retraction length on my direct extruder is set at 1.5mm.
I would not go beyond 2mm.
I would set the retraction speed to 35mm/s.
6.5mm is more of a value that fits a Bowden extruder with a 1m+ long Bowden.

The print on the photos doesn't look very nice either, it has a lot of artefacts (vertical lines) which are probably caused by the defective ball bearing of the idler pulley.

Also, the print looks like over-extrusion, these things could be the cause...

The entered diameter of the nozzle or filament in the slicer is not correct.
The flow in the slicer is set too high (over 100% or factor 1.0).
The E-Steps from the extruder motor are wrong.

If it's not overextruding, the nozzle could also be too hot for that filament.
It is best to take the average of the temperatures specified by the manufacturer. If it says 210°C to 230°C, then take 220°C.
If the print looks how it should look, then use test prints to determine the exact flow for the respective filament. But you should do a PID tuning beforehand, then print a heat tower to find out the ideal temperature for the respective filament and the E-Steps and all other settings (filament diameter, nozzle diameter etc.) should also be correct, otherwise has determining the flow makes no sense and only creates new problems.

The solution cannot be to switch from 2 wall lines to 3. Even with 1 wall line, there must be no holes.

Google Translate
-- Original Text --

Das dieser Fehler immer an der gleichen Stelle auftritt, da glaube ich es liegt an der Kombination von Geometrie des Bauteils, Bewegungsrichtung der Düse und dem Z-Hop mit zu hohen Rückzugswerten.
6,5mm bei einem Direkt-Extruder ist eindeutig zu viel.
Die Rückzugslänge bei meinem Direkt-Extruder ist mit 1,5mm eingestellt.
Ich würde nicht über 2mm hinaus gehen.
Die Einzugsgeschwindigkeit würde ich auf 35mm/s stellen.
6,5mm ist eher ein Wert der zu einem Bowden-Extruder mit 1m+ langem Bowden passt.

Der Druck auf den Fotos sieht auch nicht gerade schön aus, er hat viele Artefakte (vertikale Linien) die vermutlich vom defekten Kugellager der Umlenkrolle stammen.

Auch sieht der Druck nach einer Überextrusion aus, diese Dinge könnten die Ursache dafür sein...

Der eingetragene Durchmesser von Düse oder Filament im Slicer sind nicht korrekt.
Der Fluss im Slicer ist zu hoch eingestellt (über 100% bzw Faktor 1.0).
Die E-Steps vom Extruder-Motor stimmen nicht.

Falls es keine Überextrusion ist, könnte auch die Düse zu heiß sein für dieses Filament.
Nimm am besten den Mittelwert von den Temperaturen die der Hersteller angegeben hat. Steht dort 210°C bis 230°C, dann nimm 220°C.
Wenn der Druck so aussieht wie er aussehen soll, dann ermittle anhand von Testdrucks den genauen Fluss für das jeweilige Filament. Du solltest aber vorher ein PID-Tuning machen, dann einen Heat-Tower drucken um die ideale Temperatur für das jeweilige Filament heraus zu finden und die E-Steps und alle anderen Einstellungen (Filamentdurchmesser, Düsendurchmesser etc.) sollten auch korrekt sein, sonst hat das ermitteln des Flusses keinen Sinn und verursacht nur neue Probleme.

Die Lösung kann nicht sein, von 2 Wandlinien auf 3 umzustellen. Selbst bei 1 Wandlinie dürfen keine Löcher entstehen.

Norder

P.S.:
At 80mm/s and 240°C for PETG it should be more than 20% cooling.
With the speed and the not too large component that you are printing there, it can be 100% fan if the fan is normal.

There are also extreme fans that almost blow a component off the print bed at 100%. In such a case, 20% is probably better.

I usually print at 40mm/s and only use a fan for PLA and PETG for small areas (printing time under 10 seconds per layer) and for overhangs.
From 60mm/s, the fan always runs at at least 40% from the 2nd layer.
At 80mm/s it always runs at 100%.

jens55

@Norder, thank you for your thoughts. I have just tripped over a significant issue that I was not aware of. My extruder motor is rated at 1000 ma but I had set the config file for 800 ma. As it turns out, at just a tad under 5 mm/sec extrusion rate into the air, I start skipping steps. With the motor rated at DC input voltage, I could in theory go up to 1400 ma and still be within specs since I am feeding AC to the motor and RMS of 1400 ma is about 1000 ma. I am not clear on what happens if the motor is stationary but has not yet reduced to idle current (does the motor receive a DC drive voltage when stationary which could theoretically be 1400 ma which is well above rated current)
Anyhow, I have increased the stepper current (M906) to 1000 ma and that seems to solve some of the skipping issue. I am in the process of printing another copy of the model.
I am going to do another test with 2 mm retraction. What is your un-retract speed set at?
Yes, the printing artifacts have been bothering me for a long time. I took the time today to check each idler and clean any belt residue from the idlers. I also had a slight setup issue with one of the idlers. I did a print after the tear down and the artifacts seem to be significantly reduced. It is too early to tell for sure but I think that one of the things I did today significantly improved surface finish.
You misunderstood my thinking about going from 2 walls to 3 walls - what that switch did was to change the way the model is printed. I realize there shouldn't be holes in either scenario but doing the switch got rid of all the tiny infill steps and also completely changed the way the model is printed. Going to 3 walls, with the changed way the model was sliced, eliminated the two large holes.
Anyhow, I am making great progress and I am optimistic that both the underextrusion as well as the printing artifacts can be eliminated.

Ps.: I just looked at the print that is currently printing and it would appear that things have improved 'dramatically' !!!!

deckingman

@jens55 I would highly recommend using firmware retraction if you are not already doing so. Mainly because it allows you to change settings "on the fly" as a print is progressing. You need to find the best setting for your machine and your hot end. What other people use on their machines is largely irrelevant. There are plenty of retraction test parts out there. Choose one and using firmware retraction, you can play around with distances and speeds to your heart's content. Once you have determined the best settings for your machine, then you can either keep using firmware retraction or put the settings that you have determined into your slicer profile. Remember that different filament types may need different retraction settings. Similarly, for part cooling. You need to determine what's best for your machine, using your fans. What other people use with different fans is again irrelevant. Print some temperature towers, preferably ones that have bridges and overhangs. Once you've determined the best temperature, print them again and play around with part cooling to determine what works best with your fans. You'll definitely need to do that with each filament type.

jens55

@deckingman, I have the intention of printing out test objects for temperature and cooling. I need to read up on firmware retraction - I have only ever used the Cura slicer settings so I don't yet know what is involved in setting up for this different mode. I can certainly see how 'on the fly' settings can greatly speed up finding the right settings.
Thanks

The latest test print came out much better than before but can still use further improvement. I have increased the extruder current to maximum but I think that determining proper print temperature should be my next goal. It could be that 135C, my current print temperature, is too cold causing the extruder to work too hard.

The vertical print artifacts are virtually gone even though I have not tuned the belt tension yet. I have ringing of course but that is an entirely new aspect that I need to learn about.

Who knows, maybe one of these days I will get to print an object that is useful. It would be an interesting turn of events

Norder

@deckingman The settings of other users are to be understood as guidelines to get to the ideal values for your own printer more quickly.
Therefore it is not irrelevant what other users have for settings.
You are guaranteed to use the settings of other users to get to your goal faster, right ?

@jens55
I use 35mm/s as retract speed (PLA, PETG, ABS und Nylon).

60mm/s sounds better, but can lead to problems because the viscous filament cannot retract properly in this very short time of retraction and further printing and the effect could therefore be reduced.
10mm/s would be too slow (TPU excluded) and would rather slow down the overall print.

35mm/s works very well with most printers.
With TPU, these values will probably not work, since these values are much lower and with very soft TPU you should not pull back completely.

But each filament has its own settings. It may even be that PETG from company A needs different settings than PETG from company B. The differences for the same type of plastic are then more likely to be found in the temperatures than in the length or speed of the retraction.

Regarding the extruder motor...
Watch the temperature of the motor as you change the mA numbers.
My guideline is 50°C to a maximum of 60°C, in which the motors may heat up after a long press (without housing).
If they got too hot, I reduced the mA again.

The motors can withstand higher temperatures without damage, but they should not be overused.
If they get too hot, the mA is too high, the printing speed is too high in the long run or something is running too hard because of dry or jammed bearings, etc.

They must be running well, not skipping steps, and not doing the work normally intended for a more powerful engine.
In the end, my guide value is the temperature after a long press.

Google Translate
-- Original Text --

@deckingman Die Einstellungen anderer User sind als Richtwerte zu verstehen um schneller an die idealen Werte für den eigenen Drucker zu kommen.
Daher ist es nicht irrelevant was andere User für Einstellungen haben.
Du hast Dich garantiert auch an den Einstellungen anderer User orientiert um schneller an Dein Ziel zu gelangen, oder ?

@jens55
Ich nutze 35mm/s als Rückzugsgeschwindigkeit (PLA, PETG, ABS und Nylon).

60mm/s hört sich besser an, kann aber zu Problemen führen weil sich das zähflüssige Filament in dieser sehr kurzen Zeit eines Rückzugs und Weiterdruckens gar nicht richtig zurückziehen kann und somit der Effekt gemindert sein könnte.
10mm/s wäre zu langsam (TPU ausgenommen) und würde eher den gesamten Druck verlangsamen.

35mm/s funktioniert bei den meisten Druckern sehr gut.
Bei TPU werden diese Werte wohl nicht funktionieren, da sind diese Werte viel geringer und bei sehr weichem TPU sollte man gegebenenfalls auf den Rückzug komplett verzichten.

Aber jedes Filament hat da seine eigenen Einstellungen. Es kann sogar sein das PETG von Firma A andere Einstellungen braucht wie PETG von Firma B. Die Unterschiede bei gleicher Kunstoffart sind dann aber eher bei den Temperaturen als bei der Länge oder Geschwindigkeit des Rückzugs zu finden.

Zum Thema Extruder-Motor...
Beobachte die Temperatur des Motors wenn Du die mA Zahlen änderst.
Mein Richtwert ist 50°C bis maximal 60°C in denen sich die Motoren nach einem langen Druck erhitzen dürfen (Ohne Umhausung).
Wurden sie zu heiß, dann habe ich die mA wieder reduziert.

Die Motoren können höhere Temperaturen schadlos überstehen, aber man sollte sie nicht überstrapazieren.
Werden sie zu heiß, ist die mA zu hoch, die Druckgeschwindigkeit auf dauer zu hoch oder etwas läuft zu schwer wegen trockener oder verklemter Lager etc pp.

Sie müssen gut laufen, dürfen keine Schritte auslassen und sollten nicht die Arbeit verrichten die normalerweise für einen stärkerer Motor gedacht ist.
Mein Richtwert ist am Ende die Temperatur nach einem langen Druck.

jens55

@Norder said in Print issue:

@jens55
I use 35mm/s as retract speed (PLA, PETG, ABS und Nylon).

Yes, you have mentioned that before but you did not mention your setting for the speed you use for un-doing / reversing the retract. I am curious what you use for that setting.

Norder

@jens55
At the same speed.

jens55

@Norder, thanks!

Norder

@jens55
I think I once tested two different speeds with TPU. But then I went back to the same values.

My nozzle is made of tungsten carbide and is coated with ceramic on the inside, so it is very smooth and no filament sticks to it.
Back in the day with the brass jets it was a little harder to find the perfect retract setting. Brass nozzles behave a little more in the direction of a "diva".

deckingman

@Norder said in Print issue:

@deckingman The settings of other users are to be understood as guidelines to get to the ideal values for your own printer more quickly.
Therefore it is not irrelevant what other users have for settings.
You are guaranteed to use the settings of other users to get to your goal faster, right ?

If the machines are identical, then possibly. Otherwise, I stand by my comment that the settings that other people use, on different machines, are irrelevant. In fact, I'd go as far as to say that they can be misleading and serve to prevent people from finding the optimum settings for their particular machine. I would say that your advice to the OP about what percentage of part cooling fan speed to use is a case in point. You specifically stated that at 80mm/sec and 240 deg C the part cooling fan speed should be more than 20% for PETG. That sweeping statement completely disregards numerous factors, not least of which is the number and power of any part cooling fans as well as the arrangement of any ducts. That setting might work best for you, but for other machines with unknown numbers of fans of undetermined power, the only true value is somewhere between zero and 100%.

jens55

@deckingman, while I agree with your sentiments especially in regards to cooling, I also appreciate the information Norder posted. Cooling is a bit of a red herring because as you say, nobody knows what exactly my situation is. On the other hand, I can infer a starting point if someone tells me they are running 10% or they are running 1000%. While the starting point might be wrong, it gives me more confidence (yes, possibly wrong confidence). In any case, I appreciate both of your inputs !
The issue with 'feed' was mentioned several times in this thread and while not directly pointing to the issue, it got me exploring stuff and helped me find a setup problem that I have not been aware of for at least a year. So while my setup is totally different from other peoples setup, the information given was still valuable for me.
It is always understood that any settings shared are just that, shared settings, that may or may not apply to my specific setup.

Again, thanks to all that chimed in on this thread!!! I have learned from your input!

Norder

And that's exactly what it means... these are pure recommendations and values that you can but don't have to follow.

I think we're all grown up and educated enough that I don't have to write every time I give data, so I don't take it over 1:1.
That's what common sense tells you, or am I wrong?
@jens55 at least understood it exactly as it was meant.

To the fans...
If someone writes that they print at 80mm/s and use 20% fans and then I look at the photo of the print result, where my experience tells me that these 20% could probably be too little, then I write it and write how my settings are so that you can orientate yourself on them if you want.
If that is then described as misleading, then what is the point of this forum?

And some components of a printer are not that different, a direct extruder is a direct extruder and 6.5mm retract is simply too much for 99% of the extruder models.

But I am happy that @jens55 understood it correctly and that it helped him further.
Was my intention.

@jens55
How are your print results now?
What have you done so far and what has helped more or less?

Google Translate
-- Original Text --

Und genau so ist es auch gemeint... es sind reine Empfehlungen und Werte an die man sich orientieren kann aber nicht muss.

Ich denke wir sind alle erwachsen und gebildet genug dass ich nicht bei jeder Angabe von Daten dazu schreiben muss, diese nicht 1:1 zu übernehmen.
Das sagt einem doch der gesunde Menschenverstand, oder irre ich mich da ?
@jens55 hat es zumindest genau so verstanden wie es gemeint war.

Zu den Lüftern...
Wenn jemand schreibt dass er mit 80mm/s druckt und dazu 20% Lüfter nutzt und ich mir dann das Foto von dem Druckergebnis ansehe, wo meine Erfahrung mir sagt dass diese 20% vermutlich zu wenig sein könnten, dann schreibe ich es und schreibe dazu wie meine Einstellungen sind, damit man sich daran orientieren kann wenn man möchte.
Wenn dass dann als irreführend bezeichnet wird, ja wozu hat dieses Forum dann noch Sinn ?

Und so verschieden sind manche Bauteile eines Druckers nicht, ein Direkt-Extruder ist ein Direkt-Extruder und da sind 6,5mm Retrakt zu 99% der Extrudermodelle einfach zu viel.

Ich freue mich aber das @jens55 es richtig verstanden hat und es ihm weiter geholfen hat.
War meine Absicht.

@jens55
Wie sind denn jetzt Deine Druckergebnisse ?
Was hast Du bis jetzt gemacht und was hat mehr oder weniger geholfen ?

jens55

@Norder said in Print issue:

@jens55
How are your print results now?
What have you done so far and what has helped more or less?

The print results are dramatically better but unfortunately still not what I would call 'good'
I no longer get the two spots where the major under extrusions happened. Even knowing about the under-powered extruder motor, I do not understand what exactly caused the two distinct areas of failure rather than seeing a distributed general under extrusion. I suspect it is based on the sequence of printing actions prior to those two spots since changing the printing actions eliminated the holes.
I also get far less tiny holes in the print but they do still exist. The problem is more acute as the print gets over maybe 15 or more mm tall. I also still get what I would call 'streaking' where individual layers aren't placed exactly over top of each other. I would normally suspect this to be mechanical in nature but this is not an issue when printing with PLA which would indicate print settings.
I have reduced retraction to 2 mm and might try reducing it further. Most of the improvements were the result of increasing extruder power.
I have reduced the vertical printing artifacts to a large degree but because the surface finish is still below par, it is difficult to tell if the issue (vertical marks) has been completely fixed. The issue was strictly mechanical (idlers not running smoothly) as was expected. I still have ringing but have not done anything so far to fix that - it is not an issue of significance until everything else is sorted.
In my digging on the internet, I have come across mention that too large a retraction can in fact cause pock marks. This is something I was not aware of.
My next efforts will be to optimizing retraction and print temperature which hopefully will address some of the remaining issues.
If I didn't have a substantial inventory of petg, I would just stop printing with it but I do have a large pile of spools so I must power through this problem one way or another.
I have had limited time for sorting things out but will be getting back to it shortly.

jens55

I swear, I spend more time fixing and adjusting my printers than actually printing stuff.
The one issue that I fixed is the idler that wasn't running entirely smooth. Unfortunately, a ton of other issues cropped up.
The insufficient power to extrude that caused my to increase the motor current .... while the jury is still out on that one, it would appear that it was caused by a bad connection of the motor wiring harness to the board that provides the extruder drive. While I can't be sure, I have verified that the motor was extremely weak, the motor had plenty of power on a different driver board, when I plugged the motor back into the original board, it once again had proper power. The only explanation that I can come up with is that at least one of the contacts had a high resistance. There were several power cycles involved so maybe the electronics needed resetting? I normally don't shut the printer down which causes other funky issues after a few days.
The feed power got noticed because the feed became extremely inconsistent and I spent considerable time trying to find the cause for that. In the process of taking the hot end/extruder apart several times, I found a bit of crap in the Dragon hot end and cleared that out but I have no idea if the recent problems may have caused the crap to get lodged in the hot end. I also cleaned out some crap in the extruder gears. A chunk of filament was hiding behind one of the two feed gears. Again I do not know when this happened or if it is related to the motor issues.
The petg I am using is recommending 230-240C for the hotend temperature. A temperature tower indicated that 235 was not enough. I switched to 250C.
I switched to 3 mm retraction from 6.5 mm
I found out that my 40W hot end heater is insufficient to reach 250C if there is any part cooling at all. I have ordered some 50W heaters.
I will probably need to re-do all my test prints because if the filament feed was poor, the calibration results are suspect.
Sometimes I regret that I started monkeying around with printers. My first printer, a CR-10, seemed to always work .... but then the CR-10 was a lot simpler and maybe I was wearing rose coloured glasses at the time.
Anyway, I thought I would provide an update in case anybody was wondering what the status was.