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First layers are fine, the rest are very under-extruded

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Posted · First layers are fine, the rest are very under-extruded

It's an Ultimaker 1, with the extruder and hotend upgrade. It was working ok for a long time, and recently started this strange problem. I'm not if it's a hardware or software issue.

The first layers are always perfect, and then the print becomes spongy, as if extrusion rate is way too low, or the hotend is jammed. But if I restart the print, than once again the first layers are perfect.

Here is a picture. Left is 30% fill, middle is 80%, right is %100. Notice that the right one is perfect, and rest first 10 layers are also good.

https://www.dropbox.com/s/ex4wu15ihrqnuwd/IMG_20141204_214617.jpg?dl=0

I tried cleaning the nozzle, I tried uploading a fresh firmware, I tried downloading latest Cura and resetting everything. Same results.

Any ideas what is going on?

Thanks.

 

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Posted · First layers are fine, the rest are very under-extruded

Does the print have a lot of retraction points? if you are confident that you cleared any possible jams if there were any, another cause might be that your print has repetitive retraction points that aren't allowing the filament to extrude before it retracts again to move onto the next point. I have had several prints that required several layers layers to consistently retract over an over and not allowing the filament to fully extrude for that point before it moved on. Try decreasing the length of retraction, it might make some stringy bits between those gaps its jump but are easily broken off. I will sometimes drop the preset from 4.5mm to (2-3mm), but I am on a UM2 so it might be different for a UM1.

Hope this Helps!

 

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Posted · First layers are fine, the rest are very under-extruded

what temperature and what speed?

When cleaning the nozzle, did you take it apart?

Look closely at the teflon spacer if it still looks good.

 

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Posted · First layers are fine, the rest are very under-extruded

As the 100% infill print is almost good, i would suspect something wrong with retractions as Scooby said.

Either the Teflon insulator or the filament is too big (is it 2.85mm?).

 

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Posted · First layers are fine, the rest are very under-extruded

Or you are just plainly trying to print to fast and that's why the first layers do work, since they are printen slower

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Posted · First layers are fine, the rest are very under-extruded

The print speed was 50, which I would not call fast. Temp was 220. These settings worked well up until recently. I tried turning off retraction and got the same result. I only took off the nozzle, did not take apart the hotend. I guess it's time to do that.

 

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Posted · First layers are fine, the rest are very under-extruded

Didier, it's an ultimaker 1. Going to 260c will melt the PEEK and kill the hotend. Also, I tried cold-pulling, and it could not get it to work, it always snapped the filament. Maybe this is a symptom of the same problem ?

 

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Posted · First layers are fine, the rest are very under-extruded

Oops i forgot it was a UMO :) sorry i read so many threads a day :)

Cold pull should work, you don't need to go up to 260°c, i usually go to 240°c, if your filament snaps during the cold pull you might need to do it a bit hotter...

But as it's a UMO you can take the nozzle away and check how it looks inside

 

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Posted · First layers are fine, the rest are very under-extruded

I'm encountering a similar problem with my (brand new) ultimaker 2

 

here it is:

http://imgur.com/yiJKYnM

 

at some point my print is brittle. it seems, that somehow the extruder doesn't put out enough material

 

I've running the a adjusted flow rate at 115% and a nozzle temperature @ 225C° for PLA.

 

I'm curious could it the the mentioned retraction setting issue be? @Didier Klein

 

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Posted · First layers are fine, the rest are very under-extruded

From the picture I'd say that you have a problem with retraction since it doesn't start until the printer has to move and retract a lot more than in the lower half. I still have this same problem with PLA since I didn't experiment with it that much but I was able to reduce the problem to almost zero by placing long geometries in between my objects to get increase the pressure in the nozzle again. If it's not that it could be an unstable hotend temperature, I fixed it with thermal grease.

Didn't have problems with Bendlay yet, don't know why.

 

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Posted · First layers are fine, the rest are very under-extruded

I'm encountering a similar problem with my (brand new) ultimaker 2

 

here it is:

http://imgur.com/yiJKYnM

 

at some point my print is brittle. it seems, that somehow the extruder doesn't put out enough material

 

I've running the a adjusted flow rate at 115% and a nozzle temperature @ 225C° for PLA.

 

I'm curious could it the the mentioned retraction setting issue be? @Didier Klein

 

Does it work better if you turn off 'enable combing' in the expert settings for retraction?

 

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Posted · First layers are fine, the rest are very under-extruded

I will try, without "combing". do you have any model for testing these issue? since my model took 5.5 hours to complete and about 2 - 3 hours to the first point, where it starts happening.

 

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Posted · First layers are fine, the rest are very under-extruded

You can use the "Cut off object bottom" option to cut away most of the beginning of the print.

 

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Posted · First layers are fine, the rest are very under-extruded

Hey, I just encountered this same problem on my printer, how did you end up fixing this. Any ideas will be greatly appreciated thank you

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