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Nozzle / Flip Back Problem

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First of all I have never been so upset and unhappy with such an expensive product.

First thing when it arrived was it looked like used 100 times.

Full of scratches from the glass plate to the metal parts.

The First print went horrable wrong, the thing that moves the motor wasn't assembled correctly.

Then the stopper on the motor was missing (extrem loud noise when resetting positions) afer 3 days no response from you build it myself.

Then finally my printer worked. But only for maybe 1 month.

Now I have the Problem that the material gets pushed back constantly.



First thing I did remove where the screws at the feeder delivered with the ultimaker.

With this cheap tool you are sending to open the screws, the only thing it really does is killing the screws.

So the Feeder wasn't that tight assemled like bevor and I had to buy new screws.

I thought maybe also my nozzle could be the problem.

So I bought a new one, but that was the wrong one, there is no spare Part in your shop.

I also printed the Test it has wholes all over the place. The only thing that helps, is to set the printing temperature higher than 245° but I'm using your PLA and 210° seemed best for my prints. When I set the temperature to 210 degrees and the speed under 30mm/s maybe a third from what is expected comes out of the nozzle.

Please help me, I'm struggling with my printer since day one!



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Hi Sebizzle :wacko:

Yes, something like that, it has also started at my place.


First, you should decide yourself what you want to do:

- Would you like a lot of experimenting, and try to solve the existing problems themselves?

- You might want an eternity on a few expensive parts waiting for?

- Or do you want, return the machine?

So what is your choice?


I have, decided after much consideration time for point 1.


If your new and not cheap machine looks like a shabby second-hand unit, then there really is not much to think about, immediately return it.



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thanks for the quick reply.

The thing is I actuall really need the printer so sending it back is no option at the moment.

I guess it will be on the way for weeks...

Even a bad print is better at the moment than no print.

So it's not usual that the metal parts have scratches all over ?

Could you maybe give me any hints what to look for ? Or what you did ?

The last thing i did know was to clean the inside of the nozzle with a file.

That seemed to help.

And the other thing ist the flip back seems to occur less, when the srew on the feeder is not tightend at all.

But then again the Print isn't complete solid because the filament sometimes isn't pusehd back correctly when retracting.

It's really complex at the moment to look and monitor all of that.

Thanks in advantage



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First, make sure you have updated your machine with the latest firmware: http://software.ultimaker.com

A lot of issues regarding z-calibration and filament feeding has been resolved past weeks, so it is really worth updating.

Make sure your filament has a diameter smaller than 3mm, that it does not have flat parts from grinding and that there is no contaminations in the bowden tube.

Your problems sounds a bit like when my teflon insulator did not reach the nozzle and half molten filament ended up in the space there causing excessive friction: http://umforum.ultimaker.com/index.php?/topic/5953-idea-on-underextrusion/&do=findComment&comment=55227

I bought my machine almost half a year ago and I had to do some minor adjustments for it to work good, but it was not scratched or damaged in any way.


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thanks very much.

I will try the firmware update later.

I'm not quite shure if I already updated it to the latest one.

My Filament has a Diameter of 2.85mm im using the one from igo3d and also the one from ultimaker (guess they are the same).

Wow you are a real professional =)

I guess it will take me some time to understand this completly.

Thanks very much for the effort you made on that article.

The community was really the Thing that made me buy an Ultimaker.

A buddy of mine works with makerbot and the new generation is just the Troublemaker.

I will report on that when I checked the firmware update.

It wasn't like damaged, 2 parts weren't just assembled correctly and the stopper was missing.

If you are not a technican at ultimaker it just takes you time and nervs and thats not what i expected.

All the Metal parts have scratches and the glas had 2 scratches, so it just looks like used....

It's just sad for the eyes when unpacking the box and so on...

Again thanks very much.


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the new firmware didn't solve the Problem...

The feeder keeps flipping back.

The only thing that helps is untighen the feeder screw at the feeder.

But if I do that it sometime grind it self so far in the fillament that it can't be moved at all and it's not enough filament coming out.

Is there any possibility to turn off this "prevent cold print" function ?

I read in an thread about this.

Greetings and Thanks for help much appreciate.


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it looks like i've found a setup for my printer that solved the problem:

In Cura I chose the following setup:

Layer Height 0.2

Shell Tickness 0.8

Bottom Thickness 0.6

Fill Density 20

Print Speed 25

The Print speed like in other post is the key.

I'm using the Ultimaker Blue PLA.

In the Material Settings I've set the Temperature to 230°.

The Screw from the feeder is untightend nearly completly.

So the white thing on the side is close to the top site.

I will now do a complete Test-Print and then report back.

The Problem with this Setup will be that small holes or steps with no material will not be clean at all.

With the high temperature the material keeps flowing while the Printer is retracting.

Printing with low temperature around 210° results in flip backs every 10 seconds.

I've tested IGO3D and the Ultimaker Fillament and I've tried 3 different roles of them.

So the Problem shouldn't be here.

Also that Problem didn't occur on my first prints.


Is this like in the tolerance of the Products ?

Or is it still a Problem of the Printer?

And sorry for my mistakes in gramar and in writing =)

Also I couldn't like your answers it always tells me that I reached my limit.



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It is normal to get the extruder click backs on the first layer, if your bed leveling is incorrect. The head can be too close to the bed so it is hard for plastic to escape.

After the first layer, it shouldn't happen with the settings you quoted.

What version is your firmware? (See maintenance -> advanced -> version) on the printer.

Retraction should also work ok at those speeds. You might tweak the settings a bit in the materials settings - try 5.5mm retraction length.

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unforunately it's not happining just on the first layer.

It happens throughout the complete print.

Anders told me to update my Firmware because of signifikant improvments here.

I did that but still no success.

Yes retraction is working the only Problem is, I Need to print over 240°C and then the PLA becomes very liquid.

So when the Filament is pulled back, the material keeps flowing because it's not affected from the pullback.

That all happens beacuse the material is to liquid, the Ends are also not clean at this temperature.

Like I said printing at 210°C what was my preferred temperature results in constant flip backs.

The only Thing I believe would help is a new nozzle.

I don't know what else it could be.

Or someone can tell me how to turn off this cold fuse prevention.

Thanks and Greetings


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Maybe you make a short video with your smartphone, so 30 to 60 seconds. You film while the printer is running, the inner corner regions and the print head, each for a few seconds. Maybe so, anyone recognize something important. At best, you're recording from all moving parts, including the little black box (material feeder) on the back wall outside.

A still image / photo from the resting print head would be useful, I think. Focusing on the highly visible white plastic part (ColdEnd).

Then you post the link here for us. You can also upload videos in the forum, use the gallery options in your personal profile view.



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yesterday night, the Fillament was grinded again.

So because of the Hole that was generated the Fillament couldn't be moved at all by the Feeder.

The Problem again, the Printer worked the whole night trough without putting any Fillament through it's nozzle.

I guess I will need to unscrew the nozzle and file it again from the inside....

This happend like 3 times before.

Could this have also killed my nozzle ?

Has anyone every needed a new one after something like that ?

For me it's very sad that I just can't buy a new nozzle for the UM2 and have a try if thats working.


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thanks for the reply, I will check on that as soon as I'm home.

What is a Nozzle that expensive ?

I thought about 30€ or something like that.

And where can I buy one, the shop has None.

Than it's cheaper than working like 3 hours on it.

That was my conclusion.



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just read the grat Article from GR5.

The Thing he wrote at Point 8, is the same Thing that also happens in my Place.

When I start printing, the Filament curles and touches the Side of the Nozzle.

So today I will try the Atomic Clean.

Much thxs. I wanted to like everything you wrote me, but I'm not allowed....



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oh man I get the Feeling I made a mistake buying this machine.

Normally like I wanted, I would just buy a spare part to save my self tons of work.

Then you know for shure if that part is damage and can start your Investigation.

But at the Moment I'm just relying on guessing and the Help of the community.

Theres not even a technical reference that I could use as a guidline.

It's one Thing to say the technique is not that evolved.

But it's another Thing, to be missing a technical documentation that helps on Troubleshooting for a Product that Needs Troubleshooting from the Beginning.

Thank you really very much for all the effort and time. You are not even the ones getting payed for that.

Much appreciate.



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thank you very much!

I will save this one immediately =)

What I ment was something like Microsoft Support.

The Problems are known, but just not documented.

I'm working in IT-Security and normaly when you have such a complex Product you have a Support Site.

Maybe I'm stupid but it took me a Long time to find out, that the Nozzle is cloaked when the Fillament curles at the start or starts sticking to the Nozzle.

I just got to this Point thanks to your help =)

So today I will clean the Shit out of my Nozzle =)

Really thanks very much!



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Sebizzle. I cannot argue with your point about the support and documentation. Documentation should be a relatively fast and easy thing to accomplish, and a few helpful guides would be a great addition to new printers being sold. I guess at the moment, this lack of documentation is being replaced with this community.


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thanks for that felt Kind of stupid =)

If you just have no experience you stuck on every new Problem.

I guess so but community is one Thing, Professional Support the other.

There is no way I would recommend such a complex Product with that cheap Support and Documentation.

But I wanted to stop complaining, it is how it is =)

I put all my hopes in the Nozzle cleaning and then Report back to you.

By the way when will I become a Member to be able to like articles and give credit to the Guys that helped me ?



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so the Atomic Nozzle Clean is over thanks to GR3.

This is the Result:


And this is the Nozzle:


I filed the Nozzle from the Inside.

Now I'm doing a Test-Print and will report back to you.

But it looks like it didn't help....

There were defintely, some burned parts inside of the Nozzle.

Do you maybe want a Video of my print starting?

If it helps ?

Thanks again and Greetings


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Hey sebizzle

You've marked to live in Germany, you can easily communicate in German?

If other methods do not help, then >>>

Print head burnout (MINOR REQUIREMENTS):

- The two cables on the print head (HotEnd), these each end in a pod >>>

!!!They must be removed absolutely first !!!

- With a small beak pliers the heating cartridge and temperature sensor cartridge can be removed.

- Very gently rotate to the metal cartridges and pull cautious.


!!! Watch out !!! NO VIOLENCE !!!


- If you have done that, then you can heat print head quite easy.

- Use a storm lighter or a soldering iron and heat the HotEnd nice and even.

- With an adjustable soldering iron should suffice 275-325 degrees. The largest opening from the print-head lay loosely on the tip of the soldering iron.

- PLA residues are burned, but residues remain which need to be removed finally.

- Do it to ascend so long to no smoke and no more bubbles.

- Then you let everything cool completely on a fireproof surface.

- You need for removal of combustion residues one at best, new, unused, 3mm Universal drill.

- Take the drill without a machine, and carry him into the upper nozzle opening.

- Careful up and down movements, plus rotational movements solve combustion residues sufficient.

- Finally, the HotEnd should be thoroughly blown out with compressed air.

- Check before assembly, the nozzle opening, keep the upper inlet opening to the light.

- Seems no light to pass through, then helps a fine wire from a wire brush or a GRAY injection needle Number 20 (0.42x19mm).


- External cleaning, particularly near the nozzle opening please do not forget. It works well with a small brass brush, which is usually applied to the spark plug cleaning. Do not use harder materials / metals for cleaning.

DONE and have FUN



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ja kann ich, dachte nur das wäre nicht so angepasst, so dass andere auch was davon haben.

Nicht falsch verstehen =) Aber gibt es dazu Bilder ? Ich weiß immer nicht genau wie die Komponenten heißen.

Hast du was an deinem Ultimaker getauscht? Feeder oder so ?

Hab echt vielen Dank für deine Hilfe!

Ich wäre echt so aufgeschmissen ohne Leute wie dich.

I did the Cleaning Method from GR3 (thanks again for that great Tipp) several times.

Intersting thing is the first half hour printing at 210° results in just a few flip backs.

After the first half hour they increased and I needed to increase the temperature every 15 minutes to reduce the amount of flip backs.

Very Strange thing is now I get Flip Backs even at 245°... But only a few and they are not really visible...


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