Printer fails at small perimeters  

Re: Printer fails at small perimeters

That's a good test print and the MK3 should handle it without a hitch. (Just printed one myself).

What layer height are you slicing this at? You may to be suffering from heat creep- make sure your heat break is tight against the nozzle, and that you have good cooling. Check that your extruder fan is turning the proper direction, and is at 100% after the first layer. Also check to see what your minimum layer time is- mine is set to 7 seconds and my print took 30 minutes with a slow first layer. I use 80mm/sec default print speed, with perimeters at 40mm/sec and solid infill at 40mm/sec.

FInally- do a cold pull... you may have a partial clog in your nozzle. Whenever I see symptoms of vast under extrusion, the first thing I do is a cold pull.

Re: Printer fails at small perimeters

That's a good test print and the MK3 should handle it without a hitch. (Just printed one myself).

What layer height are you slicing this at? You may to be suffering from heat creep- make sure your heat break is tight against the nozzle, and that you have good cooling. Check that your extruder fan is turning the proper direction, and is at 100% after the first layer. Also check to see what your minimum layer time is- mine is set to 7 seconds and my print took 30 minutes with a slow first layer. I use 80mm/sec default print speed, with perimeters at 40mm/sec and solid infill at 40mm/sec.

FInally- do a cold pull... you may have a partial clog in your nozzle. Whenever I see symptoms of vast under extrusion, the first thing I do is a cold pull.

Tried with 0.15mm.

Nozzle and heat breake should be fine - checked this also today and fastened firmly with 220°C. But something were strange (I think) - I left the temperature for about 20-25 minutes on 220°C and suddently I had a heat creep in the heat break! Luckily it was PLA and I could disasmble the heat break and heat it up with a airgun. But this means, there are too less cooling from the Noctua fan, so the heat could get up.

The fan is correct, checked double - there are also some arrows for the dumb people. 😆

Re: Printer fails at small perimeters

Tried with 0.15mm.

Nozzle and heat breake should be fine - checked this also today and fastened firmly with 220°C. But something were strange (I think) - I left the temperature for about 20-25 minutes on 220°C and suddently I had a heat creep in the heat break! Luckily it was PLA and I could disasmble the heat break and heat it up with a airgun. But this means, there are too less cooling from the Noctua fan, so the heat could get up.

The fan is correct, checked double - there are also some arrows for the dumb people. 😆

That's kinda heat-creep... except it's not.

https://shop.prusa3d.com/forum/hardware-firmware-and-software-help-f64/filament-jams-in-heatbreak--t15788.html

Read this.
EXACT same symptoms as I had.

Fixed it by replacing heatbreak with non prusa heatbreak,. See my most recent post (pictures) to see what is wrong.

EDIT: the location of your "jam" when you thought it was heat-creep, was at the "neck" of the heatbreak (see warm spot on image)
a true "heat creep" is at the "ambient temp" spot.

Re: Printer fails at small perimeters

Did you read his original post? He already replaced his heat break with the same one you recommend.

I don't agree with your definition of heat creep. It can occur anywhere along the heat break starting at the neck, and depending on the design of the heat break and the nature of the swell in the filament can jamb anywhere along the path of the heat break.

Re: Printer fails at small perimeters

Did you read his original post? He already replaced his heat break with the same one you recommend.

I don't agree with your definition of heat creep. It can occur anywhere along the heat break starting at the neck, and depending on the design of the heat break and the nature of the swell in the filament can jamb anywhere along the path of the heat break.

Holy smokes. I hate their use of heat tube. I never link it with the heatbreak. Your right. 😯

Mechinacally speaking, the only place a jam can happen is the heat break, and the nozzle.

It in theory could be the PTFE, but that should not effect forward feed.

As with my symptoms, was primarily during 'slowdowns' and areas with huge numbers of reactions.

Regarding your slicer, which isn't really your problem. (I can print at very low speeds all day now)
But try to increase your minimum speed for slowdowns. I never tried it, because I wanted to fix it mechinacally.

Did you use thermal paste?

Follow the instructions on E3D for the v6.

I seriously am scratching my head about your issue. It's literally the exact same as my old issue. If I didn't have a 2 week backlog of printing. (150+ hours left, on my current print)

I would slap my old heat break in and see where it fails.

I'm still thinking it could be your heat break.

Re: Printer fails at small perimeters

The fan is correct, checked double - there are also some arrows for the dumb people. 😆

I have a thought. Heat your extruder up to 220, then set it back to zero. Time how long it takes to cool down till the fan shuts off (50C). That will give us an idea of how well your fan is working. Also record ambient temperature when you do this.

Re: Printer fails at small perimeters

The fan is correct, checked double - there are also some arrows for the dumb people. 😆

I have a thought. Heat your extruder up to 220, then set it back to zero. Time how long it takes to cool down till the fan shuts off (50C). That will give us an idea of how well your fan is working. Also record ambient temperature when you do this.

So first, I totaly forget to mention that the printer sits in his own enclosure. So I did two tests with the temperature: one with closed door and one with open/removed door.

So what's good/normal?

It in theory could be the PTFE, but that should not effect forward feed.

I already replaced this too. Tried with a Capricorn XS and now back with a new "original" Prusa PTFE tube.

As with my symptoms, was primarily during 'slowdowns' and areas with huge numbers of reactions.

Yup, same here! But even when I disable reatraction completely it didn't work.

Did you use thermal paste?

I did, had some paste over from my Noctua CPU fan.

Also tried today another CaliCat and it failed at the ears. I waited untill it begans to click, then I choose "Filament change" from the menu and unloaded the filament. See the attached picture, how the tipp of the filament looked. Loading was no problem, went smooth through. It gives me such a headache.... 😐

Re: Printer fails at small perimeters

So, after more testing I can say, I found the troublemaker.
It's indeed a kind of heat creep which fucks up every print, when the perimeters are going small.

As mentioned in the previous post, I have my MK3 in a enclosure made out of wood with acrylic windows. Looks like I made a good job, because the enclosure is really good isolated (maybe also the type of acrylic paint I used helped). I cannot tell what exactly happen, but it must be a interaction with time and temperature. So a single small/short print, will success without any problems. Even a little bigger print could success, when the initial ambient temperature was low enough - maybe around 20°C and not more.

Now let's start the first print. Hotend, heatbed and all steppers will genrate heat and warm up the ambient temeprature zu around 35-36°C - takes about 30°C for heating up. At some point, the "cool air", which is needed for cooling the hotend, is too high and the main heat from the heatblock beginns to crawl up until it's arrives a point, when a "temporatly clogged" problem will occur.

With a lot of retraction, it will speed up. I printed to CaliCats successfully with open door - so the cool air stayed around 20-22°C.

I don't know, if this a failure in the extruder/hardware concept or normal. Maybe I will check my enclosure for integrating some little airflow? In the same time, a little airflow can lead to warping.... 😕

Re: Printer fails at small perimeters

different temperatures for the same filament: PLA with 215, 220 and 230°C (Fillamentum Extrafill PLA)[/list]
Any further ideas, where the problem could be?

you should lower print temp to 200 at most. You are running PLA way too hot, coupled with an enclosure which is not needed for pla at all and very likely a very warm extruder motor with all of the retracts and the PLA is going down way to mushy and cannot cool down fast enough to be a solid layer when the next layer hits.

that enclosure would be great for abs, but for PLA it is not needed.
Is your mk2s in an enclosure also?