P1S Oozing effects

Hi,

with my brand new P1S printer, I printed several different models, but always have those little “hairs” in my prints. Google said, it is an “oozing” or “stringing” effect when filament comes out of the extruder when the nozzle is just moving to another place.

I have tried different filament types (PLA from eSUN, ABS from eSUN, another PLA with silk optics), I have tried different models and double-checked the filament settings. I tried different setting presets and see the problem in all of them.

Currently, I am using mainly all settings from the preset 0.22 Standard. I am using the delivered 0.4 nozzle. For testing purposes, I changed the following settings, but it had no impact to the printed strings at all:

(German version of the software)
Filament Düsentemperatur und Betttemperatur - tried different values between min and max of the used filament
Rückzug
zurückziehen beim Schichtwechsel true
Rückzuglänge 5
Rückzuggeschwindigkeit 80
Während des Rückzugs wischen true
Z-Hop beim Rückzug 1
Z-Hop-Typ Spirale

Also, I did a manual calibration of the filament and entered the K-value - with no change to the print result.

Are there any ideas what could be the reason and what I can try next?
Thanks in advance.

This is not just ooze (excessive extrusion). As the nozzle moves around the inside of the hole, it is also moving away from the previously printed surface, so the filament is not being pressed firmly into place and the nozzle pulls it away.

Interior threads make this situation worse if you use an outer/inner wall order. Near the peak of the thread, you are printing on air. There is nothing for the filament to adhere to, so on that layer it stretches across the hole until it becomes a part of the thread closer to the root.

Try switching to the inner/outer wall order.

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Hi Ikarus,
thank you for the explanation, that sounds very plausible.
The wall order in all my tests before was already set to inner/outer. Below that setting, there is a checkbox called is_infill_first (Zuerst die Füllung drucken) which was not checked. If I understand your explanation correctly, then checking this option would avoid that parts of the thread is printed “in the air”, i.e. before the adjacent infill is printed.

Here is the result of a print with that option checked:

The options of the wall order are:
inner/outer
outer/inner
inner/outer/inner

Which ones of them are worth trying?

just tried inner/outer/inner, without a change in the result

PETG and ABS will string if not dry. I can’t say I’ve ever had PLA string.

If moisture insn’t the problem slow down on the threads. To test that simply load it up and change to quiet mode. If it improves than you know speed is an issue.

Moisture should’nt be the problem as I have unpacked new filaments from their original packaging (vaccum package incl. dehumidifier bag).

Could you tell me where I find the button for the quiet mode? Is it available for the P1S?

I just tried manually halfen all the speed values in the speed tab of the project. The result was still the same.

First, vaccum pack filament can be very wet. Don’t assume it’s dry just because it’s new.

You can set it for quiet mode from the slicer.

You can do it from the control screen on the printer but I can’t remember which screen/icon to use. I haven’t seen my screen in quite awhile.

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This was a helpful hint, I didn’t know this, thanks.

I have now tried another test with silent mode and also enabled Arachne mode - with the same result as always. I got a bunch of strings in the inner of the thread.

I have the feeling that the problem lies in the thread itself, it seems to be too fine to be printed. I have not found any printer setting which had an influence on those strings.

The thread is of type M12x0.5. I have heared that due to its small slope, 3D printing of this thread is not easy. If someone managed to print a similar thread, please report it, I am curious to learn how to do it. Until then, I see the thread as ‘unprintable’.

Thanks for all the help.

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M12X0.5 has a depth of 0.25mm, printing such a tiny triangle shape would even be challenging with an 0.2mm nozzle and strength of the thread flanks would also be very poor even if you can get it to stick.
If you want to try anyways then lower your layer height to extra fine 0.08mm

Just to visualize 0.4 Nozzle filament layering with a 0.5mm pitch thread:

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I did all my tests with 0.08mm layer hight anyway (I used the template 0.08mm Extra Fine).
Do you think it would be worth to try a different nozzle?

Ok you didn’t mention that before.

Sure you can try a 0.2mm nozzle and it will be able to get a little more detail printed on the thread profile but IMHO a 0.5mm thread pitch will still be too fine for FDM printing to get a nice fitting functional thread.
You would be better off to print a smooth 11.5mm dia bore and cut it with a M12X0.5mm tap but depending on your filament material even that can be challenging since materials like PLA or PETG are not easily machined and with such a fine thread it may tear the flanks of the thread when cutting unless lubricated really well during cutting.

Your print is like printing PETG using a bowden printer without proper presure advance.

My first thinking is it is too hot and the printing is too slow so the the pressure isn’t built up in the nozzle properly, like filament more liquid state than gel like state.

Can you share your print settings, like nozzle temperature, bed temperature, flow ratio, max volumetric speed, cooling fan speed, min print speed… Those settings can shed some light on why your print is like that.

I normally just use bambu lab PLA / PETG / ABS profile on noname filament and it works just fine. I only have to adjust the bed temperature for better adhension. Sometime I adjust flow ratio a bit for finet une, but the basic bambu lab profile is quite okay.

Btw, the M12 lens mount you’re printing is a very small print, which slow printing setting is applied to. When I print something small like this with relatively very short layer time, I just print 2 of them and place them a bit far apart to increase layer time to help layer cooling.

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Thank you for this hint. Learned something new today :slight_smile:

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I am using the BambuLab default profile for the PLA from eSUN as I use exactly this filament.

(Sorry for the German text in my screenshots)


Temperature is 220°C, the filement states that it works between 210 and 230°C.

Adhersion seems to be ok for this model, the print finishes without the object coming loose.

I had also experimented with Retraction (“Rückzug”) and Z-Hop types, but changing those values had no impact on the result.

I have performed a flow dynamics calibration of the filament and entered the corresponding K factor of 0.05.

I will now try to print two of them as you mentioned and post the result.

The print finished. The results are similar to the ones before.

Try to use BBL PLA profile with higher volumetric speed: 21 mm3/s.and see what happens

Print with higher speed might help with stringing as more plastic is squeezed out of nozzle so that proper pressure is built up. The travel movement must be fast enough so that the pressure is not loosing at the end of travel and start extruding at new location. As printer must calculate when it should start extruding to build up pressure and when it should retract to release pressure in advance before finish the extrusion line, hence the name Pressure Advance

  • Too much pressure at nozzle → less plastic goes out of nozzle as we want → under extrusion + oozing since printer cannot release pressure enough for travel movement.
  • Not enough pressure at nozzle → less plastic comes out (underextrusion). Given extrusion was calibrated, then the right amount of plastic comes out but it doesn’t build up the right pressure hence still have oozing problem.
  • Just enough pressure at nozzle → right amount of plastic and no oozing

I have an anycubic mega i3 and a wanhao mini, both retired, that produces the similar problem. I tried BBL generic profile for ABS before, it did not go very well with X1C at my work place. Since then I just stick to the BBL profiles for my P1S at home, like Bambu PLA basic.

Oh by the way, if you print PLA, you should remove the top cover glass or at least raise it so that the hot air can get out. With PLA, you want chamber temperature to be around 30degC or lower, basically, the faster PLA cool down after getting out of nozzle the better result.

Edit: Just saw that you you print with layer height 0.08mm. This is uneccessary. I print only with layer height 0.2mm using 0.4mm nozzle and I could barely notice the layer line. Unless I have to print fine text, I rarely swap to 0.2mm nozzle (aliexpress) and print with that fine layer height

These were good hints, thank you.
I printed with:

  • Bambu PLA Basic
  • speed of 21 m^3/s
  • layer height of 0.2mm

grafik

  • There were fewer strings, but they are still there (maybe just fewer because of the less amount of layers)
  • It is still noticeable that the surface is not smooth, it looks like some settings are wrong. Of course, I did this test with the default Bambu PLA setting and used eSUN PLA filament, there might be a mismatch in flowrate settings, etc. But, I had this kind of odd surface on all my previous tests, too. Even after calibrating the K-Factor.
  • The worst thing: The thread is not working! I cannot screw anything into it. Maybe, 0.2mm layer height is too coarse? Maybe, the 0.4mm nozzle is too thick? Is it worth to try a 0.2mm nozzle?

3D printed thread never worked for me from the default thread from Fusion360. These threads are meant for CNC machining, with tight tolerance.

But normally with 3D printing, male thread is 0.1 to 0.2 mm larger and female thread is 0.1 to 0.2mm smaller. Unless you can change the thread tolerance to +0.5mm in your design, it would never work.

My solution is just to tap it after printing for both male and female thread