Trying to fix our school's Original+, cannot figure out what's going on with our hot end....

[DexterTechCoach 0]

Hello, all! Complete and total novice here, at my wit's end after working on our printer for hours! We have an Original+ in our makerspace that our students (5th and 6th graders) are DYING to use, but I cannot seem to figure out this problem....

Below are pictures of filament after attempting the atomic method several times. As you can see, the tip is coming out clean, but the filament seems to be melting/burning above the extruder head. I am using the exact temperatures specified for the atomic method and am making sure to pull the filament straight up when it has cooled. We had an issue earlier in which the nozzle clogged and melted filament collected at the top of the heater block, which has since, to the best of our ability, been cleaned up.

Pictures of our current issue

So far, I have tried:

 

[*]Replacing the aluminum heater block

[*]Replacing the hot end isolator coupler

[*]Adjusting the tension on the feeder wheel

Does this look like an issue with the hot end isolator tube, the peek isolator, or the nozzle? We're stumped at the moment :(

[neotko 1,417]

How many atomics done? Maybe is just some left particles of other filament or dirt. I would keep doing stomics until they come clean. Also maybe, if is abs debris, it might need an atomic with abs or with nylon.

I would not change much. The first things that can damage over time to s the ptfe coupler, and ofc the nozzle (even though it can last years and years if you don't use abrasive materials).

Could you post photos of the hotend to see if there's something wrong? Also double check that the bowden doesn't pop and is fully inserted into the ptfe coupler.

[DexterTechCoach 0]

Thank you so much for responding!

 

How many atomics done? Maybe is just some left particles of other filament or dirt. I would keep doing stomics until they come clean. Also maybe, if is abs debris, it might need an atomic with abs or with nylon.

Have done at LEAST 10 over the past few days.  Have only ever used high-quality PLA with this printer.

 

Could you post photos of the hotend to see if there's something wrong? Also double check that the bowden doesn't pop and is fully inserted into the ptfe coupler.

We had an earlier issue with molten PLA oozing on top of the heater block. Per suggestions here, heated the block until the PLA was pliable and scraped it off.  After tightening the hot end isolator tube (while the block was warm) seemed to fix the leak.  Still have some PLA lingering around the assembly - planning on working on this later

Bowden is fully inserted when assembled.  If it gives you (or anyone else) any additional clues, when we do a test print, the first few layers come out just fine, but get progressively spaced out and messy before the printhead stops extruding all together. Example below:

Thanks again for problem solving with me.  We are so frustrated at the moment...

[neotko 1,417]

Did you tighten the peek/barrel with all assembled and hot? Is possible to over tight it and deform slightly the peek inner screw. This makes more pressure on the ptfe coupler, making its like span shorter. I would take out the ptfe coupler and check the tip for deformation.

If you plan to replace it, get a TFM version (for umo, not um2) on any 3dsolex reseller, tfm is a much better coupler that should give much more print hours. Normal coupler can last from 50-200h tops at pla temps. And ofc it can still work, but the deformation on the long term can generate leak inside the peek/barrel, this affects the retraction making semicold parts between coupler/barrel and can generate this kind of errors.

Ofc, before replacing it, check the tip of the coupler for deformation/brown color.

Edited January 25, 2017 by Guest

[valcrow 144]

Are there teeth marks on the filament? There should be some diamond shapes pressed into the filament from the feeder gear wheel. The most common problem I see with new UMO users is they don't latch the feeder properly causing no tension to be put onto the filament.

Check this part of the video to see how the latch is suppose to be locked. This is an older UMO so it will look different than a UMO+ but the concept is the same. You need to squeeze the two parts together and then drop the black dangly latch down to lock it in place.

 

This may seem obvious to seasoned users but I've seen a bunch of people not do this correctly causing problems right from the get go.

[jameshs 42]

I would try some other filament that you know to be 'fresh' (I have had this happen on older filament).

At the same time I would order all the components for a new hot end and start with a fresh set-up - sometimes it is too gunked up to carry on working - so nozzle, heater, thermister etc.

But start with new filament as the nozzle looks clean from one of the shots and it is gradually either clogging or over heating the filament.

Check that all the heating routines and temps are for PLA and not for ABS - and drop the temp until the PLA just works.

[DexterTechCoach 0]

Did you tighten the peek/barrel with all assembled and hot? Is possible to over tight it and deform slightly the peek inner screw. This makes more pressure on the ptfe coupler, making its like span shorter. I would take out the ptfe coupler and check the tip for deformation.

 

I did tighten it when it was hot. My next hunch was to replace the PEEK, if not the whole hot end to start new.

Just put in a new PTFE coupler, so that's not the problem.

[DexterTechCoach 0]

Are there teeth marks on the filament? There should be some diamond shapes pressed into the filament from the feeder gear wheel. The most common problem I see with new UMO users is they don't latch the feeder properly causing no tension to be put onto the filament.

 

Yep!  Tension looks good on the feeder, and we've been loading it correctly.  Good thought, though!  I can totally see how that's a common issue with us newbies

[DexterTechCoach 0]

I would try some other filament that you know to be 'fresh' (I have had this happen on older filament).

 

Yep...have done that too.  I'm kind of leaning towards just replacing the hot end and starting fresh....

[neotko 1,417]

There's something I don't understand. On your photo I can see threads of the barrel.

Are you sure you didn't install it in on the opposite direction??

As you see in this img by @gudo you shouldn't see threads on top of the aluminum block

[DexterTechCoach 0]

There's something I don't understand. On your photo I can see threads of the barrel.

Are you sure you didn't install it in on the opposite direction??

 

Oh yikes! May be! I will definitely look into that. Good catch - thank you so much!

[gr5 2,167]

In the photo of the side of the blue part some layers look overextruded and some look underextruded. This is most common if the Z axis is moving strange distances which is most common if it is very dirty.

Try Pushing the bed down and then cleaning the Z screw a bit with some tissues. You can twist the screw with one hand while letting the axis pull the tissue up or down the threads. Repeat a few times over 5 minutes and then reapply grease. Just concentrate no the top 1/3 of the z screw as that is what you will use the most and where you will see a difference right away.