PLA curling at the nozzle

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GAP
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PLA curling at the nozzle

Post by GAP » Tue Sep 28, 2021 9:21 am

I bought my first roll of PLA (Flashforge) and it is curling as soon as it comes out of the nozzle and doesn't stick to the bed.
All the prints I have tried on the first pass the plastic ends up as a big clump of plastic bunched up on the nozzle and anything that sticks to the bed is dragged off.
Nozzle temp of 200C and bed of 60C (default).
Any ideas?
Graeme
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Re: PLA curling at the nozzle

Post by Trevor Thompson » Tue Sep 28, 2021 9:26 am

There are two thoughts that cross my mind:

Have you zeroed the nozzle? I would check the setting of the distance between the nozzle tip and the bed.

What is the bed condition? is it clean.

More I think about it the more likely the first is likely to be the issue.

Trevor

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Re: PLA curling at the nozzle

Post by ge_rik » Tue Sep 28, 2021 9:40 am

The head should be so close to the bed it doesn't have a chance to curl. Have you levelled the bed since installing the new filament?

If that doesn't work, try raising or lowering the print head temperature by 5C to see if it makes a difference. If not, try another 5C etc

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Re: PLA curling at the nozzle

Post by philipy » Tue Sep 28, 2021 10:44 am

Make sure that there isn't a little bit of old filament stuck at the edge of the nozzle hole. Even when the nozzle is hot it can cause the extruded filament to bend sideways and stick to itself and that can give the effect you describe.
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Re: PLA curling at the nozzle

Post by -steves- » Tue Sep 28, 2021 1:54 pm

Agree with all above, check that offset distance before going any further. Sounds way to far away, so please double check. Hope you sort it, let us know, :thumbup:
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Re: PLA curling at the nozzle

Post by GAP » Tue Sep 28, 2021 8:59 pm

Thanks for the ideas will look at the nozzle and adjust the temps.
I did not level the bed after changing filament but will also look at that, it will be a good opportunity to change the springs to the ones I saw recommended in a "how to video".
Graeme
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Re: PLA curling at the nozzle

Post by GAP » Tue Oct 05, 2021 12:25 am

I had another go at printing the object after cleaning the nozzle and the PLA still curls at the nozzle and does not stick to the bed at either 60C or 0C.
This really has me baffled as I successfully printed another object using the exact same filament and did not move the printer or change any settings.
Nothing changed between the 2 prints in fact the first attempt at printing this object was immediately after the the first object was printed.
I have now imported it into Tinkercad and laid it flat on the bed as I noticed the original was vertical on the bed.
I am slicing it and will have another go plus I am adding a brim.
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Re: PLA curling at the nozzle

Post by GAP » Tue Oct 05, 2021 6:23 am

Rant On;
I am now of the opinion that the root of my problem is the garbage Flash Forge PLA that I bought, it has the consistency of fencing wire being that stiff and inflexible.
It strings just like hot melt glue and no matter how clean I have the nozzle it curls straight out of the hole and sticks to the side of the nozzle.
While doing the test strip down the side it does not extrude till halfway down the first pass (even after pre-heat PLA) and when it does stick there is a birds nest of filament.
After the test print there is not a clean break when the nozzle moves to the print area but a thin string that drags the test print with it (no adhesion to the plate at all).
In my last attempt the brim outline is sort of laid down then after that the strings are just randomly laid.
The brim is not even one quarter printed when it is dragged off the plate by the build up of stringing.

Final decision is that the Flash Forge PLA I bought is a total waste of money, even the PLA that came with the machine performed better.
I even tried to do the dog test print that I successfully did with the Creality PLA and that did not even lay the first run of the base before it was dragged off the plate.
I have ordered some Creality PLA for the people who I bought the printer off and will see how this goes but at the moment "White Elephant" is coming to mind.
Rant Off;
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Re: PLA curling at the nozzle

Post by philipy » Tue Oct 05, 2021 8:18 am

Doesn't help to solve your problem, but I wonder if the PLA has absorbed moisture? Simple logic would suggest that moisture absorption ought to equal softness but in fact I've found that an old roll can go very stiff and brittle whilst still on the reel and sometimes won't even pull as far as the extruder because it spontaneously breaks into short pieces. If it does actually extrude, the print then fails as soon as another dodgy bit gets to the nozzle.
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Re: PLA curling at the nozzle

Post by ge_rik » Tue Oct 05, 2021 9:42 am

You have been unlucky, Graeme. I've certainly not had any of the problems you describe. Maybe I've just been lucky.
After my freebie roll of filament was used up, I moved over to Amazon Basics PLA, and it seems to have been very reliable by comparison.

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Re: PLA curling at the nozzle

Post by -steves- » Tue Oct 05, 2021 2:14 pm

GAP wrote: Tue Oct 05, 2021 6:23 am Rant On;
I am now of the opinion that the root of my problem is the garbage Flash Forge PLA that I bought, it has the consistency of fencing wire being that stiff and inflexible.
It strings just like hot melt glue and no matter how clean I have the nozzle it curls straight out of the hole and sticks to the side of the nozzle.
While doing the test strip down the side it does not extrude till halfway down the first pass (even after pre-heat PLA) and when it does stick there is a birds nest of filament.
After the test print there is not a clean break when the nozzle moves to the print area but a thin string that drags the test print with it (no adhesion to the plate at all).
OK, the test strip down the side. Mine sometimes extrudes half way down the first bit but often doesn't extrude until starting the second strip, either way, it don't matter, it's a test strip, that's what it's there for, ignore it as it always comes out lumpy and bumpy.

The fact it is not ceasing extruding is not always an issue as mine sometimes leave a little trail there, but not much, however in this instance I would do one or both of the following:

a) Move the nozzle closer to the bed, see next paragraph.
b) Reduce the nozzle temp to 200 or even 195, it's a suck and see process, you could try doing temperature blocks, you can find them on Thingiverse. These are just a couple of many. https://www.thingiverse.com/thing:2729076 https://www.thingiverse.com/thing:2615842

GAP wrote: Tue Oct 05, 2021 6:23 am In my last attempt the brim outline is sort of laid down then after that the strings are just randomly laid.
The brim is not even one quarter printed when it is dragged off the plate by the build up of stringing.
You have bed adhesion issues. This is one of a few things, but I will go with gut feeling to start with and work down. This might help a few others?

a) You still have the nozzle too far from the bed, get it closer and keep trying closer and closer, at some point it won't extrude, at that point, just go back a couple of 0.01mm's until it's working as expected.
b) You need to be using some sort of bed adhesion "stuff". Try hairspray, if not Pritt stick. The second works well but requires the bed washing fairly frequently. The first one I have never tried but I have heard very good results from others and if you have some it's a free starting point.
c) your bed isn't level, double and treble check
d) Your filament has so much moisture in it that it's useless, bin it and buy one a decent highly recommended one what you can get hold of.
e) You have a blockage in your nozzle, caused by an over heated tiny bit of PLA not letting it extrude properly, to fix this, replace the nozzle.
f)You have an issue with the hot end and it is moving because of a loose screw, find and tighten
g) One of the the Male Straight Pneumatic ends has excessive play, find and replace.


GAP wrote: Tue Oct 05, 2021 6:23 am Final decision is that the Flash Forge PLA I bought is a total waste of money, even the PLA that came with the machine performed better.
I even tried to do the dog test print that I successfully did with the Creality PLA and that did not even lay the first run of the base before it was dragged off the plate.
I have ordered some Creality PLA for the people who I bought the printer off and will see how this goes but at the moment "White Elephant" is coming to mind.
Rant Off;
Creality filament is "ok", but far from the best stuff out there, I have had moisture issues before with their filament. This is why earlier in the thread I said I use a heater box on both my regular 3D printers, even with new PLA. There is method in my madness.

Keep trying and you will succeed, painful as it is right now, it will get better, until one of the above goes wrong and you start fault finding again, it's like a never ending circle. I hope the content in here helps. :thumbup:
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Re: PLA curling at the nozzle

Post by Trevor Thompson » Tue Oct 05, 2021 3:29 pm

I agree with everything Steve has said.

Im not convinced that the filament is the problem.

You have two MAIN issues:

Extruder too far from the bed
Adhesion problems

Steve knows more about the other things he has identified - and I am sure he is correct.

I was looking at my extruder as it was extruding - and there is no way the molten filament could curl and not touch the bed - it is almost touching the bed.

Trevor

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Re: PLA curling at the nozzle

Post by GAP » Tue Oct 05, 2021 9:37 pm

Another thing I noticed late in the afternoon my bed temperature is 38C as soon as the printer is switched on, I put it down to the fact that the printer is in my steel shed which the internal temp at this time of the year can reach over 40C if it is locked up.
Might have to investigate using a fan to cool the plate.

I am going right back to square 1 and setting the Z axis and then do a full bed level again.
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Re: PLA curling at the nozzle

Post by philipy » Wed Oct 06, 2021 6:03 am

I wouldn't have thought that an ambient bed temperature of 38-40 deg would be a problem. My normal first layer temp is 60deg and then it drops to 50 for the actual print.
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Re: PLA curling at the nozzle

Post by GAP » Wed Oct 06, 2021 8:20 am

The thing that has me really perplexed is how I could do a perfect print using the filament and them a print started less than 5 minutes afterwards causes all sorts of grief.
Graeme
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Re: PLA curling at the nozzle

Post by philipy » Wed Oct 06, 2021 10:20 am

Two things come to mind as possibilities:
One is that you inadvertantly altered the Z height. I don't know how easy that would be on your machine.
The other is that you have got a bit of a nozzle blockage. I know Steve said to fit a new one in that case, but I've never found that necessary. I've had a few blockages after switching fillament types, which I cured by heating the head a little above the normal temperature for the higher melting point of the two. Then carefully pushing a length of fine phosphor bronze wire up from the bottom and gently wiggling it around. Then extrude a short length of filament to clear it and let it cool dow to normal temps.
Of course after that you then need to reset the Z and the levelling. :roll:
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Re: PLA curling at the nozzle

Post by -steves- » Wed Oct 06, 2021 11:57 am

philipy wrote: Wed Oct 06, 2021 10:20 am Two things come to mind as possibilities:
One is that you inadvertantly altered the Z height. I don't know how easy that would be on your machine.
The other is that you have got a bit of a nozzle blockage. I know Steve said to fit a new one in that case, but I've never found that necessary. I've had a few blockages after switching fillament types, which I cured by heating the head a little above the normal temperature for the higher melting point of the two. Then carefully pushing a length of fine phosphor bronze wire up from the bottom and gently wiggling it around. Then extrude a short length of filament to clear it and let it cool dow to normal temps.
Of course after that you then need to reset the Z and the levelling. :roll:
As Philip said, you can "sometimes" clean them, but I have had nozzles that while they appear to have been cleared and extrude correctly, within 10 - 15 mins of restarting printing they clog again, this is where I have found there is a tiny solid bit or "plastic fluff" or filament that somehow never clears, no matter what you try. For this reason and the price of a nozzle I just bin them and fit a new one. The first time I found this, it took me 2 days to find the problem as "I knew" the nozzle had been thoroughly cleaned and was extruding properly for as much filament as I wanted to extrude. Also cut off the PLA before the extruder and bin all of that too as after a blockage the PLA inside the tube can cause another blockage when it gets to the nozzle, no idea why but it can and does.

I run both my printers 24 x 7, one I never switch off unless essential as it saves the settings to the SD card and not on board, which is crap as I rotate about 10 cards through both printers, so it saves to one card and by the time I have to switch it off I never know which card to put in to get the settings back, so I have to reset the z height again. PITA! :oops:

Let us know how you get on, once printing you will be a happy puppy.

P.S. Are you saving the Z height settings and restoring them, then double checking they are still the same before printing?
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Re: PLA curling at the nozzle

Post by GAP » Wed Oct 06, 2021 9:17 pm

The Z height is set by moving the nozzle till it just touches the plate then adjust a microswitch till a click is heard.
When the switch operates the Z nozzle is supposed to be just above the plate.
There is a zero offset setting but apart from some experimenting it defaults to and that is where I leave it.
I am wondering is the coating on the glass plate has lost its adhesion properties after I cleaned it with isopropyl.
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Re: PLA curling at the nozzle

Post by -steves- » Thu Oct 07, 2021 7:38 am

GAP wrote: Wed Oct 06, 2021 9:17 pm The Z height is set by moving the nozzle till it just touches the plate then adjust a microswitch till a click is heard.
When the switch operates the Z nozzle is supposed to be just above the plate.
There is a zero offset setting but apart from some experimenting it defaults to and that is where I leave it.
I am wondering is the coating on the glass plate has lost its adhesion properties after I cleaned it with isopropyl.
Is this the video you used to set the bed? https://www.youtube.com/watch?v=4JSa_r8xgX8
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Re: PLA curling at the nozzle

Post by GAP » Thu Oct 07, 2021 9:56 am

-steves- wrote: Thu Oct 07, 2021 7:38 am
GAP wrote: Wed Oct 06, 2021 9:17 pm The Z height is set by moving the nozzle till it just touches the plate then adjust a microswitch till a click is heard.
When the switch operates the Z nozzle is supposed to be just above the plate.
There is a zero offset setting but apart from some experimenting it defaults to and that is where I leave it.
I am wondering is the coating on the glass plate has lost its adhesion properties after I cleaned it with isopropyl.
Is this the video you used to set the bed? https://www.youtube.com/watch?v=4JSa_r8xgX8
It was one that I looked at.
Graeme
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