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Extruder needing higher temperature to print PLA - UM2

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I have been printing an order on my UM2 for the past few weeks. (Purchased in January 2015)

I started printing it with PLA (ColorFabb) at 210 C; Layer Height 0.2 mm; Speed 60 mm/sec.

The more I printed the same file, I started experiencing issues of feeder skipping and under extrusion especially while printing the brim.

Thus, I raised the temperature to 220 C, then to 225 C and now 240 C. If I lower the temperature any less than 240 C, the extruder starts under-extruding and the feeder starts skipping a lot. Now the problem occurs while printing the brim as well as the actual object. (Layer Height 0.2 MM; Speed 60 mm/sec)

Using 14.12 Cura Firmware since newer versions created issues while printing.

My print quality has greatly deteriorated. Some layers are missing.

Can anyone explain how to fix this issue?

-Small

 

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In the short term reducing the speed to say 30mm/s might get you a result. BUT you are masking a problem, as anon says quite possibly a nozzle clog. If not then most probably a fault with your feeder system. I would not expect the colorFabb filament to be causing a problem but worth taking a selection of measurements.

 

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small,

I am having the exact same problem.

I bought my Ultimaker 2 (December 2014). We started printing PLA at 210 at a print speed of 35-40mm/s. Anything faster and it would skip and have under extrusion problems. After about 90-100 meters of printing we started getting under extrusion problems at 210 C going 35 mm/s. we had to change the temperature to 230 C and keep the slow speed of 35 to just barely make the print work. We had extremely bad issues printing overhangs or even closing top surfaces. Now we have to print at 235 C at 30 mm/s and it has started to burn the plastic when creating flat top surfaces.

Throughout this whole process we have cleaned out the nozzle using the atomic method multiple times so I doubt that we a clogged nozzle.

We also have PLA from ColorFabb.

Any help on this would be extremely helpful!

 

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I doubt this applies to these issues but if you have run a lot of filament and of different types requiring high temps, check the inside of the Teflon coupler.

I had my UM1 for more than a year and have printed a combination of PLA and XT.

The higher temps required for XT probably caused my coupler to deform. Also I overdid the "preload" method of engaging the bowden clip on the print head.

The coupler looked normal from the outside but a ridge developed on the inside. The temperature had to be raised more and more so that the filament softened above the brass tube.

One symptom of this was that it was almost impossible to use the atomic method.

 

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I tried the atomic method. During the cold pull, I noticed that there is a small blob right below the triangle at the end.

Please see pictures attached. I do not recall seeing such in the past.

Cold Pull

Cold Pull

Cold pull

Could that be due to the deformed coupler?

@gr5, I have been experiencing this issue even in a fresh filament reel. I haven't removed the coupler to see if its deformed yet. But I felt there was definitely friction while moving the filament up-down in the coupler.

 

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Do the atomic pull. And use white, as then youll be able to see any crap left over from another time in the nozzle. I have exactly the same issues and it turns out i just didnt clean my nozzle out well enough. Pushing through colorfabb white pla a few times solved everything. I used to print at a higher 220 but now am back to the standard 210. Keep doing the pull until the nozzle is visibly clear and there are NO particles of black visible on the plastic you are pulling out of it. For pla i heat up the end to 260 then let it cool to about 85 and carefully rip it out. Its looks for the pics you are not letting it cool enough before whipping it out. Sometimes you can let it cool too much and you have to heat it up tp 260 again and start over. But the end should look like a pencil, not all wobbly like in the pic you posted.

P.s. Dont worry about the blob , and in my opinion to do the atomic pull correctly, you have to keep pushing the filament into the nozzle even while it cools down so you visibly see it slowing down coming out of the nozzle due to the lower temps and, so that its tight against the inside of the nozzle when you pull it out. Just heating it up pushing it in and cooling it down and then wipping it out will not be enough from experience. Then the shape of the filament should be more like the inside of the nozzle.

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I just got my second UM2 last week. My first one doesn't skip and I run it at 210C default w/o an issue. On my new one I have a couple of issues including this one. My older one I can run .1mm layer at 60mm/s w/o an issue. With the new one I have to run it at 50mm/s with a layer of .15 or else I get skipping and under extrusion issues. I've done the atomic pull cleaned the nozzle but it still doesn't run as well as my 1 year old UM2.

My second issue is the long screws that hold on the had don't fully tighten. The back left screw sticks up almost 6mm. The hole is tapped but it still doesn't fit. I can't believe it made it to shipping with this obvious flaw.

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Well the bowden might be too tight against the white teflon part. That might be one difference.

Regarding the 4 long screws - that sounds pretty bad - I would get that fixed first. Seriously. Before it runs out of warranty or you break something or whatever. Please update your country settings in your profile. Your english seems pretty good so I'm going to guess USA - if so then the support service is pretty good there (It's in memphis if you bought it through the website). Create a support ticket at support.ultimaker.com. Include a photograph or 10 second video about the screw issue.

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For pla i heat up the end to 260 then let it cool to about 85 and carefully rip it out. Its looks for the pics you are not letting it cool enough before whipping it out. Sometimes you can let it cool too much and you have to heat it up tp 260 again and start over. But the end should look like a pencil, not all wobbly like in the pic you posted.

 

260 is actually to hot for PLA as it burns it and can carbonize in the nozzle leaving hard deposits. I would recommend only going to 240deg.

If you have been printing with Higher temp materials like XT or ABS then use them for the atomic pulls as you can then increase the temp to 260 without burning them.

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180C is plenty hot enough for atomic pull for PLA on the hot side - at 180C you want to push the filament in, and then let it cool to the lowest temp where you can still pull it out. For the standard UM2 nozzle that's around 90C - 95C. Going up to 260C is a waste of time because you have to wait longer for it to cool.

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Hi @Aphinan the other variable you need to consider is layer height as this affects the volume of filament you need to extrude for a given temp. and speed. E.G you can use a lower temp. for .100 layers than you can for .300 layers, with the same speed.

Anyway do not worry about using a low temp.; if you can then that is your benefit, you will normally get a better result

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If it is a UM2 (not +) you might also have a temperature sensor which reads too low a value so that the real temperature is much higher. I used a good multimeter with thermocouple to measure the temperature inside the nozzle and at 200°C display value, my multimeter showed 223°C. After switching to the Olsson Block and a new sensor (still old version which came with the printer) I read 208°C. I also checked the multimeter with boiling water and it showed 97°C.

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When doing an atomic pull, if you have a thick blob in the area where the nozzle meets the teflon coupler, this means the teflon coupler is deformed: it has become wider at the bottom. I had the exact same thing after a few hundred hours of printing.

If you do a normal atomic pull (=with pulling very hard) you risk dislocating the nozzle or teflon coupler, or even bending the rods.

I would suggest you try a more gentle atomic pull, as described in my manual here:

https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/

This has far less risk of doing damage, because it is specifically designed to prevent that thick blob, and it requires only very gentle pulling.

But that of course does not repair the basic problem: the worn out teflon coupler. So I suggest replacing the teflon coupler too.

Further, if you are near the end of the filament spool, where filament is wound extremely thight, I suggest you manually unwind a few meters of filament and manually straighten them a bit. Then let it roll up on the spool again, so that it is now sitting very loose on the spool. A bending radius of 30cm is optimal for minimum friction in the bowden tube. A straight filament is optimal for minimum friction in the nozzle. So a bending radius of 50cm seems to be a good compromise and works best for me. Found out by trial and error.

Geert

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