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simmonsstummer

Why i always get underextrusion.

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Hi Simon,

It is great that you have started with a picture, but could you also include what machine you are using and what the current settings are you are using?

What material is this?

Do you have a new or old Ultimaker?

Looking forward hearing from you!

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Hi Simon,

Didn't recognize your lastname, there are a few Simon's around here ;)

Glad to hear you are still sticking around!

You know you can update your profile so it shows what machines you have?

In all of your time with your Ultimaker, have you ever replaced your teflon/PTFE part?

I don't know if that is actually the cause, but that has the tendency to start showing signs of wear after a while. How long that while is depends on what material you generally use, retractions, printtimes. So many variables..

Have you ever done the Atomic Method, in an attempt to clean your nozzle?

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Have you used different materials to determine if that is the problem?

Is the filament old, or has it been in the sun for a long time, or anything else that could have made it brittle?

If you bent/break the filament by hand, does it bend or does it break immediately?

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You might want to drying out the filament first, which is simple enough. Put it in a plastic bag somewhere really warm with some desiccant beads or rice.

Next, try printing really slowly, around 25mm/s or 30mm/s and this bit is important: watch the print. This might give you an important clue as to what is happening.

Finally, and this is something I think I will be saying a lot in the future: get an Olsson block and two or more 0.4mm nozzles. That way you can change your nozzle in 20 seconds and eliminate the single biggest problem.

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If your prints start fine, then underextrude after a few hours, it might be a problem with your feeder. Maybe it's chewing up the filament an loses grip as more and more material gets caught in the wheel?

It could also be that the feeder stepper motor overheats after some hours of use, which leads to skipping steps.

I've heard on several occasions that people had to mess with their motor current settings in order to get the printer working right.

It could also just be bad filament. Black filament can be more difficult to print with than brighter colors (I guess the kind, or the amount of color pigments makes a difference). Maybe try another color with the same settings?

 

...

and this bit is important: watch the print. This might give you an important clue as to what is happening.

...

 

Also, listen to the printer! Problems like the feeder motor skipping steps can be heard if you're listening carefully.

/edit:

It sucks when you have a problem that doesn't occur at the start, but only some hours into the print. If you can, get a video camera and record the printing process. Then you can search the video for the moment where the print starts failing.

Edited by Guest

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Thank you very much to all of you.

 

get an Olsson block and two or more 0.4mm nozzles. That way you can change your nozzle in 20 seconds and eliminate the single biggest problem.
that's interesting.

Where and what?

 

Have you used different materials to determine if that is the problem?

Is the filament old, or has it been in the sun for a long time, or anything else that could have made it brittle?

I don't think to store bad the filaments. Other filaments (like the orange for example) works fine. The black break immediately. Maybe it's just a matter of pigments inside... but i don't know how to avoid this behavior. Mostly because is starts well and then go suddenly bad.

so:

 

It could also be that the feeder stepper motor overheats after some hours of use, which leads to skipping steps.

I've heard on several occasions that people had to mess with their motor current settings in order to get the printer working right.

But for now is something i don't wanna try. Despite all with other filaments all it's fine.

I think is the filaments and maybe the nozzle who is somehow damaged.

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Olsson block is certainly an interesting alternative hot end to look into.

Quite a few users use it already.

@swordriff, where can you get one near Italy?

If your filament breaks immediately it usually is not a good sign.

Imagine this behavior in the bowden tube, a lot of friction will be the result which creates under extrusion. I think the problem lies with the filament in this case.

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Olsson block is certainly an interesting alternative hot end to look into.

Quite a few users use it already.

@swordriff, where can you get one near Italy?

If your filament breaks immediately it usually is not a good sign.

Imagine this behavior in the bowden tube, a lot of friction will be the result which creates under extrusion. I think the problem lies with the filament in this case.

 

well all my filaments breaks in a simple way.... even the one who works.

Should they bend or something like that?

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They shouldn't break like it is a dried up branch, but rather like a fresh strand which you have to bend and rotate to make it snap.

I would be surprised if this makes sense.. but I couldn't think of a better way to describe it right away :p

Usually there is this little inside of white (which I suspect to be PHA?) which makes it tougher to break.

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Simon,

Just to check the basics, could you post a closeup picture of the UM2 head? Also check the feeder at the back of the machine. Maybe, after many hours of printing, the feeder is full of filament debris and so the new filament has trouble passing through.

Then inspect your bowden tube for any big/ugly scratches (can happen if you pull out the filament that formed a plug). Take a look at the marks on the filament where the knurled mantle of the feeder turns. Does it grind down the filament there when you experience under extrusion?

Sometimes there are some odd circumstances where a clean looking nozzle simply won't let filament pass through. Even if you take the nozzle off and you can look through the tip, there could be some gunk stuck to the inner walls. I borrowed a heat gun from a friend and I am using it to clean up the nozzles (using the Olsson Block here and it is great). I think a heat gun is way better then burning the nozzle with a Bunsen burner.

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Take some brand new pla from the spool and break the last 2 inches off. Repeat for the black filament. There should not be a significant difference. Old PLA gets very brittle and has to be thrown out. for me it takes a year or two. I suspect (not sure) that some chemical is leaking out and if you keep the spools in plastic bags when not in use they last longer. My filaments usually last a few years (if I don't use them up first!) - I keep most of them in a large sealed box.

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I find its usually a slow jam. The head is not 100% clean, but looks as if it is. Look real close and make sure its a 'perfect shape of the inside of the nozzle and if there is even the slightest dent or anything like that its not clean. Also print off the roll. I can almost guarantee if you do that you will be fine. Even with weird hydraulic pressure occuring with my pfte and two horrific jams that burned my nozzle for like 6 hours, i sorted it with 32 odd atomic pulls. Now its all good. I just have to make sure to do my atomic pulls gently now due to the hydraulic pressure.

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just like you everything was going great....then complete failure, burnt out nozzle and filament was ground to dust by the feeder.

and seriously consider printing OFF the roll, i see they even do it on the ultimaker front page! lol.

5a3310df3bc9c_ScreenShot2015-09-07at17_06_47.thumb.png.be4e5552108bf60a7d48b136d0426719.png

I have lots of old PLA lying around since 1 year, from UM and Colorfabb and have had no problems at all. But maybe i've been lucky. Printing off the roll alleviates a lot of tension.

20150907_170329.thumb.jpg.3b4996354d30e3c71752e7ff2993d05f.jpg

5a3310df3bc9c_ScreenShot2015-09-07at17_06_47.thumb.png.be4e5552108bf60a7d48b136d0426719.png

Edited by Guest
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and seriously consider printing OFF the roll, i see they even do it on the ultimaker front page! lol.

5a3310df3bc9c_ScreenShot2015-09-07at17_06_47.thumb.png.be4e5552108bf60a7d48b136d0426719.png

I have lots of old PLA lying around since 1 year, from UM and Colorfabb and have had no problems at all. But maybe i've been lucky. Printing off the roll alleviates a lot of tension.

 

In fact what you see here is Perpetual Plastic Project printing with their recycled filament.

They only fabricate small pieces of filament on these units to maintain a certain level of quality, thats why they don't coil it.

There are more users who print off the reel, for me personally that has resulted in more troubles then advantages because it tangled up on me most of the times. But if it works for you, it works for you! There are many roads that lead to Rome :)

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Fair enough, but still, if they print like it cant be bad, and........it does eliminate a lot of problems and uneven filament issues in the model I can say that for sure. After using this method I get no clicks from the feeder at all what so ever as opposed to always hearing them intermittently and them driving me crazy wandering why they are doing that irritating noise. Printing like this made me not worry about leaving long prints and worrying about tangled filament at all. just make sure to lay it perfectly not overlapping any coils, don't just pull it off the roll and hang it on the holder randomly or you will get a tangle obviously, trying to make things as print friendly in ALL areas as much as you possibly can is the secret to the best quality prints (even though it should be fairly common sense!)... the only downside is you cant lay that much at the back for heavy use of filament prints.

20150906_221354.thumb.jpg.828af5dfd51d6fda79ca9916b8297d1e.jpg

I stopped measuring off exact amounts as it got boring and a tad wasteful so now i just get as much on as i can fit now, and its kinda having a small roll, but without the friction of the filament holder which i still think is angled badly and shouldnt be poking straight out of the back but at a slight angle towards the feeder.

20150906_221354.thumb.jpg.828af5dfd51d6fda79ca9916b8297d1e.jpg

Edited by Guest

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i agree about the waste, but i don,t cut off tiny pieces any more, and as this printer is not mine i want to get the best i can with the stock equipment. if you show me where to buy the parts and stuff id give it a go but i dont have the time to research this at the mo as i'm going through a bad patch at work and have enough to worry about as it is, on top of maintaining the printer and doing my daily work and the usual life problems. id love to be able to do everything but i just dont have the time, thats when i resort to paying for stuff. i do a lot as it is, lol.

bearings wont stop a tangle unfortunately so if i want something almost guaranteed perfect i know im highly likely to get it off the roll. i do print on the roll, but only when the filament used is too much to cut off the roll. my early prints where all on the roll, so its not completely useless, but the angle of the roll holder would greatly benefit from being at a slight angle towards the feeder as the fact that its straight means its always pulling harder towards the printer when its further away on the roll which shifts the filament and most likely is responsible for a large proportion of tangles.

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diag.thumb.jpg.86732623b53c32cdf3f3d79d4d589aff.jpg

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