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neo-ninja

Extrusion problem

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Hey guys,

Having some extrusion problems and not sure what is causing it. The material flow seems very inconsistent on my um2 causing early failures...in first few layers

I have tried cleaning out the nozzle with atomic pull and everything seems fine.

I changed Teflon could lee not long ago (maybe 200 hours) I am using an Olson replacement (cheaper quality?)

The feeder I cleaned out and seems to be pushing material ok.

The printer has now done around 2k hours could it be something else?

My y axis belt seems a bit loose in the top too but still moves fine (should I replace?)

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The Teflon coupler from 3D Solex is not glass filled and will be more prone to deforming, Its recommended to use this with the I2K washer. Might be good to check it again.

If the belt is loose on the top you can loosen the pulleys on that side so the can rotate and let the tensioner even out the tension. Then re-tighten them again.

Have you tried different rolls? are you using a low roll?

Could be a lot of causes, any pictures of the problem?

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Hi Labern,

When you say check the teflon again, what am i actually checking as each time I have changed it, it doesn't really look that damaged maybe a bit blackened around the entry and exit points but as soon as i change it works fine.

The reason i ask, is every time i have had to change it, it has been pretty stuck and i have ended up having to be quite aggressive to get it out.

I will try loosening the pulleys

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The Teflon gets squashed and so the inside near the exit becomes more narrow. It can be hard to see. In the past I have re drilled it out to the correct size and gotten a few more months. If you print a lot of abrasive material then it can also get to big and cause issues.

You could print a wedge tool to separate it from the Steel Nut to aid in removing it. If you are unable to design this then I could draw one up tonight.

If you do remove it for replacement then i recommend you use THIS or THIS as these can help prolong the life as you will no longer have the spring constantly applying force and deforming the Teflon.

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I have only been printing with PLA. Nothing else the first Teflon coupler i had lasted easily 1500 hours, these last two seem to have only lasted maybe 200 hours each, but the middle one i was using alot of retraction.

Wont those parts just melt away?

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No they don't melt. Teflon is a good insulator so it's not very hot at the top. The problem where it deform's is where it touches the hot end.

It may not be the Teflon that is causing all you issues but if your not using the glass filled ones then the lifespan will be shorter. 200 hours is pretty short though. How big is the gap between the teflon and steel nut? it should be about 1mm if this is to big then the increased spring tension can also shorted the lifespan.

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Thats huge and maybe your problem

gap should look like the one in this photo.

5a33106ad7275_UM2Nozzle.thumb.png.b055dcc813f33467296c2fc420369a5d.png

are you using the olsson block as well as teflon coupler?

 

Oh wow that gap is tiny?! I have pushed my teflon all the way in, and its at least 0.5cm the teflon wont go any further in. Also your head seems to stick out alot further then mine.

This picture is an old one so ignore the lifting prints, but I haven't used the printer since.IMG_4547.thumb.JPG.eae5d92a88ef2aa7889c04daf0e418ce.JPG

IMG_4547.thumb.JPG.eae5d92a88ef2aa7889c04daf0e418ce.JPG

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You turn the steel nut, round metal bit with holes in it to adjust how much the nozzle sticks out and the gap of the white teflon bit.

You have to have a gap between the teflon and steel nut but to much isn't a bad thing.

You also need to make sure the hot end doesn't touch the fan shroud.

here is a picture to explain it further. (it has the Olsson block installed but same rules apply)

mind_the_gap2.thumb.png.bacd86bbd8163b879d052b95ed6420c2.png

mind_the_gap2.thumb.png.bacd86bbd8163b879d052b95ed6420c2.png

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Holy guacamole! No one has ever said that before that i have seen.

So in effect once its built i should unscrew the nut to make the gap bigger?

How do i make sure there is a gap between the fan shroud and heater component?

 

You turn the steel nut, round metal bit with holes in it to adjust how much the nozzle sticks out and the gap of the white teflon bit.

You have to have a gap between the teflon and steel nut but to much isn't a bad thing.

You also need to make sure the hot end doesn't touch the fan shroud.

here is a picture to explain it further. (it has the Olsson block installed but same rules apply)

mind_the_gap2.thumb.png.bacd86bbd8163b879d052b95ed6420c2.png

 

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if you turn the nut towards the left then the nozzle will go up, the teflon gap and gap between the nozzle and fan shroud will also get bigger.

I normally put it together and screw it so the teflon gap is about 1mm (red arrow). then put the fan shroud on and look through the edge and see if there is a gap (purple arrow). if its touching then i wind it up a little bit more till there is a gap.

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if you turn the nut towards the left then the nozzle will go up, the teflon gap and gap between the nozzle and fan shroud will also get bigger.

I normally put it together and screw it so the teflon gap is about 1mm (red arrow). then put the fan shroud on and look through the edge and see if there is a gap (purple arrow). if its touching then i wind it up a little bit more till there is a gap.

 

You sir are awesome! I am going to try now! Thankyou!

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