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Underextrusion with Ollson block (less with normal nozzle)

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Heya

I've been getting more problems again with my ultimaker 2.

The only material I use is PLA.

I've really had a tough time printing stuff (made a thread some time ago and the problems vanished for only a small amount of time).

I had switched out my (then) new Ollson block for the original nozzle again, because the ollson block clogged super quickly for me and just generally extruded badly.

Yesterday, I tried installing the Ollson block again, together with a new steel coupler, teflon couple and a I2K insulator, all from 3Dsolex.

But alas, I'm still suffering from underextrusion after that.

The nozzle head I put in was almost completely clean but it made no difference.

I have the steel coupler twisted all the way down and half a twist back.

5a3314c0533aa_2015-12-0823_13_21.thumb.jpg.112b1cbacde640afb8735e25c9390aba.jpg

5a3314c0c9147_2015-12-0823_13_37.thumb.jpg.7bd457858c438552de5a04e121a8d640.jpg

As far as I can see, the nozzle doesn't touch the fanshroud either.

5a3314c120353_2015-12-0823_14_03.thumb.jpg.7c6cd3150281aa4c968e517907065a19.jpg

This is the kind of result I'm getting.

I've tried printing it hotter but that had no effect either.

I've been starting to feel kinda hopeless with how many problems I'm running into :(

Thanks in advance

5a3314c0533aa_2015-12-0823_13_21.thumb.jpg.112b1cbacde640afb8735e25c9390aba.jpg

5a3314c0c9147_2015-12-0823_13_37.thumb.jpg.7bd457858c438552de5a04e121a8d640.jpg

5a3314c120353_2015-12-0823_14_03.thumb.jpg.7c6cd3150281aa4c968e517907065a19.jpg

Edited by Guest

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With the stock heat block it works perfectly?

Maybe your temp sensor is dead?

I guess you tried with various filaments? What is the brand of the filament?

On your picture it looks more like over-extrusion but i might be wrong (hard to see)

 

I don't think it's the temperature sensor, because I've switched the ollson block for the original nozzle before. I DID get a heater error when I tried an extrusion test, but after that I move the fanshroud around a bit to make sure that it doesn't touch the nozzle anywhere.

I didn't get the error with the print in the picture so I guess that's okay.

I've been experementing with REAL pla (yes, REAL is the actual brand) now, got a spool of black and one of blue.

It's indeed kinda difficult to see what happens on the print because it's black, but it shows underextruded layers and layers being inregular.

I always print at 210C with a speed of 30mm/s

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56675aa5f0ede.jpg

Your assembly looks not good. There must be no gap between the steel nut and the aluminium plate. And maybe it's only the perspective, but it seems that the nozzle and the PTFE coupler does not building a straight line.

Both is essential!

I assume, that you have some serious leaking inside the filament path now. You have to take it apart (again) and make sure that all parts are really clean before you assemble it again.

There has to be a perfect fit between all parts (heater block, steel nut, I2K and PTFE coupler) - any gap somewhere and you're lost...

In contrast: there _has_ to be a gap between the heater block and the fan shroud. It's not visible on your photo but perhaps the whole heater block is stucked somewhere? How does it look from the back side?

Edited by Guest

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Unless it was changed in the last few months the IPM teflon coupler is NOT working properly with PLA. PLA stick to it and cause clogging. It is clearly stated on the 3DSolex website.

I cannot tell if its the IPM or another one but with the shape it has I would say its an IPM. (mine was black).

What teflon piece do you use?

Edited by Guest

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It's not an IPM coupler indeed.

I tried re-assembling the head again and it works better now so there's that (the small gap between the steel coupler and aluminum plate stays, but that's really just because of how the steel coupler from 3dsolex is made).

I also bended the fan shroud a bit so it isn't touching anymore so that works for now I guess.

5a33150227ac0_2015-12-1212_38_11.thumb.jpg.f0aeb3a7aae354c26e0a03d11cb9b243.jpg

The next problem though is the one I seem to be getting the most.

random layers that are underextruded.

No idea what causes it

This was printed with 3Dprima on 210C and a speed of 30mm/s.

Also, I want to try labern's fan shroud, but I feel like PLA won't really work for that. Any suggestions?

5a33150227ac0_2015-12-1212_38_11.thumb.jpg.f0aeb3a7aae354c26e0a03d11cb9b243.jpg

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Try another filament brand (maybe you have some UM filament left which came with the printer?), doesn't matter if it's better or not but just to separate the filament as a source of the problem. A good thing to check is also the filament diameter; be careful with filament above 2.95mm.

For the fan shroud you may take any copolyester or PET as well as ABS or PC.

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There are a few causes for bad layers like that - one is tangled filaments. The most common though is Z issues where the Z plate suddenly drops a mm.

There has been a problem with UM printers that are less than about a year old where they Z driver overheats and cuts off for only a second but long enough for the plate to drop.

The fix is to lower the Z current to 1000ma. I would try it just to see what happens. Also put your filament on the floor behind the printer - that makes a HUGE difference for me getting rid of these gaps.

You should be able to set the Z current using the menu system on your printer but be aware that when you power cycle the printer that setting will get lost (also Simplify3D overrides that value with gcode but Cura doesn't touch it).

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Have not been able to test the 1000ma yet.

The filament keeps getting stuck in the nozzle now when I try an atomic pull, resulting in a snapped of piece staying in the nozzle.

Doing the extrusion speed test results in it failing at around 5mm3/s - 6mm3/s and last time even at 3mm3/s

The 3Dprima filament is between 2,9 and 2,95.

Edit: I also took the head apart and found a piece of filament still stuck in the ollson block with the nozzle removed

5a3315069a183_2015-12-1218_06_04.thumb.jpg.5a558948276ab84cb6b025ab6c6dc5f3.jpg

5a3315069a183_2015-12-1218_06_04.thumb.jpg.5a558948276ab84cb6b025ab6c6dc5f3.jpg

Edited by Guest

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I have 2 thoughts - one is that you are doing atomic pulls at too cold a temp. It should be around 90C but every temp sensor is different - for some people it should be more like 100C or 105C.

The other thought is: "is that ultimaker brand PLA"? There was a bad batch recently - the filament was too brittle. It breaks all the time in the bowden and causes prints to fail because the broken piece get stuck as it enters the head.

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I have 2 thoughts - one is that you are doing atomic pulls at too cold a temp.  It should be around 90C but every temp sensor is different - for some people it should be more like 100C or 105C.

The other thought is: "is that ultimaker brand PLA"?  There was a bad batch recently - the filament was too brittle.  It breaks all the time in the bowden and causes prints to fail because the broken piece get stuck as it enters the head.

 

I've actually tried putting it hotter but to no avail.

And the material was 3Dprima, not ultimaker.

The fun thing is, I tried my other material, the black one from the first post, and I've had problem with it getting stuck this time so, idk, weird.

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Well obviously if it's warm enough the filament will be a liquid and won't break off so sharply in the nozzle! Your nozzle is heated, right?

Here is what cold pulls are supposed to look like. The pull on the left was at a warmer temperature. It will/should never be a sharp break - instead it should stretch out very thin before breaking.

coldpull.thumb.JPG.5e36c6eec637e5eef2d8a55e49841c15.JPG

coldpull.thumb.JPG.5e36c6eec637e5eef2d8a55e49841c15.JPG

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I just realised I missed a 'no' in my last reply, the black material did NOT get stuck, but came out kind of like your left atomic pull, except longer (which is what i've gotten like 99% of the atomic pulls I did since I've gotten my printer).

I tried setting it to 100C cooldown for the blue material and I was able to pull it out this down, although I didn't really get any nozzle shape into it and also very stretched out.

It DOES print though with both materials but there's still one problem.

The only problem that seems to be left is the shell walls not fusing together.

5a3315205c8aa_2015-12-1421_09_11.thumb.jpg.1188bb7eebfaabc009ba388de2572ddb.jpg

I guess it's not really easy to see because it's black and I can't really get a closer picture that doesn't get blurry, but there's a small gap between the shell walls, making the print less strong and I THINK also failing overhangs (45 degree overhangs looking terrible even though that should just work about right).

This is on both materials too and when pushing the materials through the nozzle it comes out just fine, doesn't seem to be anything else stuck in the nozzle either.

5a3315205c8aa_2015-12-1421_09_11.thumb.jpg.1188bb7eebfaabc009ba388de2572ddb.jpg

Edited by Guest

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If 45 degree overhangs look terrible try more fan. Is the fan at 100% by the time you get to the overhang? Fan is super critical for overhangs.

Regarding walls not touching infill - it's usually underextrusion. While printing - go into the tune menu and do a few layers at 10C hotter, than another 10C hotter until you get to 240C. do several layers at each temp. Then also try slowing down by 50%. If none of that works try increasing flow by 10%, then 20%, then 30%, then 50%. Stop trying these things if infill touches walls. Do all of these tests on the same print, take notes as you do it. Consider marking the part with a pen or taking a photo with each setting. Cell phone cameras are usually very good at getting quite close. Also consider using a light color filament if you will be taking photos - black is indeed very difficult to photograph.

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I pull mine at 70 deg on olsson block to get them to look that way.

 

Wow!  Your block must be hotter than mine.  I usually do 95C.

 

Same here. With the 0.25mm nozzle I even have to pull at 66°C. With 0.4mm at 72°C. I have my Olsson block well isolated from the fan duct.

Edited by Guest

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