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Unsuccessful Nozzle Cleaning

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I have an UMO with dual extrusion. The second nozzle has not worked since purchasing my ultimaker from the previous owner. Reading through the forums I came to the conclusion the nozzle was probably clogged.

I attempted the atomic pull method, but I could not free the bowden tube from the print head. Perhaps I did not push the white piece far enough down, but I was pulling the bowden tube with enough force that I decided to stop before I damaged the printer.

Undeterred I decided just to remove the old nozzle and replace it with a clean one. When I removed the old nozzle, I found it filled with burnt filament. After putting on the clean nozzle I returned the temperature to 210. I tried to extrude filament using the extruder wheel, but no filament came out of the nozzle head. I turned the temperature up to 260 and continued turning the extruder wheel and only a few drops of red black liquid came out of the nozzle (my PLA is grey) and it began to smoke lightly. So, I put the printer on cooldown and removed the new nozzle, now it too was filled with melted filament, but the filament was still grey.

What should I do now?

 

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Remove the nozzle from the alu block. Reverse out the filament. Cut a clean end to the filament on an angle and feed it back in without the nozzle in place and with the head cool. Ensure that the filament feeds easily without the nozzle. It should come all the way out.

If it does, there is no reason why it shouldn't extrude assuming your temp sensor is reading accurately If it doesn't then something above the alu block is messed up. This could be the PEEK insulator or the Teflon coupler or even possibly the tube is crammed too hard into the telflon coupler that the end of the tube is pinched.

You can see the parts here on page 46:

https://www.ultimaker.com/spree/uploads/240/original/Ultimaker_Original_assembly_manual_v1.1.pdf

One way to get the bowden tube out is to remove the nuts holding the fan on then loosen the four large screws about 3/16th of an inch pulling the alu plate down. This reduces the preload on the tube. Remove the clip and push down on the retainer. While keeping pressure on the retainer, pull the tube out. Reversing this process, preloads the bowden tube so that it is pushing back on the retainer looking it in place.. See the instructions above.

BTW the melted filament in the nozzle is normal.

The one with the burnt filament might be saved by super heating it over a gas burner or blowtorch. Be careful with a torch, I've only down this with a gas stove and I don't think it can get brass hot enough to melt. The filament, particularly if it is PLA will burn out. The nozzle will become black but keep heating it and all the crap will burn off and you will end up with a dull brass finish

When held up to a bright light, you should be able to see through the .4mm hole.

 

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that was probably a cool zone blockage.

switch off .....

if you can't get the bowden out (sometimes it needs a bit of encouragement while you are pressing down with needle nozed pliers) then don't be afraid of taking the whole hot end apart so that you can then (switch on) warm up the heater and (switch off) push from below to release the blockage - only to about 140 and then I use a piece of cut coat hanger (gentle not to scratch anything) - that should set you back right.

30 minutes max :)

 

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Nvm I went ahead and did it by going to 210 then shutting off the machine to let it cool. Surprisingly, the plug was PLA. There was some burnt fragments that may have been a different filament. But most was the PLA I was feeding it. I can now clearly see through the hole. Should I reload the PLA and see if it will extrude?

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I tried to put the nozzle back on and it seems the threading in the aluminum heating block is stripped. I tried two different nozzles and both start angling sideways when I turn them into the aluminum block. I'm not sure why it stripped so easy, how much is this going to cost me? Where do I get a new aluminum block?

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You can get parts from UM. They aren't particularly cheap and when you add shipping and waiting, it's a PITA.

I think the constant heating and cooling of the block and related components makes them soft or slightly distorted. Add in the fact that the threads will most likely have PLA in them and cross threading them is a likely occurrence.

I had a similar issue when I broke down the entire thing and couldn't get the isolator tube threaded back into the PEEK part straight regardless how much I tried. I even boogered the part of the tube that threads into the alu block using pliers to steady the part while trying to get it to thread back in straight.

Of course those parts were backordered (and might be still be BO'ed).

Since you are hard pressed to do any more damage, I suggest you go to Home Depot or similar store and get something like this:

http://www.homedepot.com/p/DEWALT-Metric-Tap-and-Die-Set-17-Piece-DWA1450/204787392

I think the 5 or 6mm tap and die was the one that cleaned up the tube and PEEK insulator. If you haven't used a tap or die, google around. In the case of existing threads, if you can, start the tap on the reverse side and it should start pretty easily. Be careful since it will very easily cut a new set of threads making the situation worse. When it starts cutting/fixing and you feel resistance, go a quarter turn into the resistance and then a half turn back. This breaks up what is being cut in the hole. BE CAREFUL NOT TO BREAK THE TAP. Then use the same size die on the nozzle threads being careful to start perfectly perpendicular and into the existing threads such that you aren't cutting new threads. Do the same thing, 1/4 into the resistance and then 1/2 back. It is unlikely you will break the die.

This says it's a 6MM thread: https://github.com/Ultimaker/UltimakerOriginal/blob/master/1054_Nozzle_0.4mm/B1054-A2P-A.PDF?raw=true

If you can't make the existing parts work, you need to determine what you need to replace ...

If you had to completely rebuild the filament path in the extruder, you would need these parts:

https://www.ultimaker.com/products/nozzle

https://www.ultimaker.com/products/peek-isolator

https://www.ultimaker.com/products/isolator-tube

https://www.ultimaker.com/products/heater-block

https://www.ultimaker.com/products/isolator-coupler

In my experience, either the heater or temp sensor will stick in the alu block so -

https://www.ultimaker.com/products/heater-cartridge

https://www.ultimaker.com/products/thermocouple-sensor

 

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it is tough to strip a thread undoing the nozzle.

are you putting it back in when everything is warm?

Before i put the nozzle back in I heat the head up to 200 for a minute to get everything nice and fluid, turn it off, offer the nozzle thread up to the block by lightly holding it in the opening - the heat quickly transfers and I give it one or two turns before it gets too hot to hold, and then either pop on some heat gloves, or use a spanner to finish off the seating.

you do need to be gentle - firm but gentle.

I have probably done this on each of my two machines 100 times as I tend to change nozzles (size or to clean) twice a week and have had the machines over two years - so far worked every time!

 

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Since you aren't cutting new threads just chasing the existing ones, you don't need a top quality set. You only need a 6mm tap and die, the t-handle and the die holder.

Check auto parts stores, they might have them. Just be sure you get the right size, 6mm per the nozzle doc. You might be tempted to not buy the t-handle and the die holder but they are important to getting the threads started square.

 

 

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I heated up the block for a several minutes, then tried to insert the nozzle again. Unfortunately, it still went in sideways... :(

I may try the tap and die, but only if I can burrow one from someone. I cannot justify the cost as I will likely never use it again and ebay offers replacement parts for almost the same price as the cheapest tap and die set I can find.

 

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