Kossel Mini nozzle wont extrude, clog instantly, help !

My mini kossel work great except that it has never extruded any plastic successfully... It's been more then a month since I'm stuck with this problem. Help would be appreciated.

I cant feed pla by hand, its hard. Nothing get out.

I attached a picture of one of the clog that got out intact.

When freshly unclogged it will dribble plastic a little and then nothing. but when unclog the path is clear...

The fan work continuously on the heatsink.

My nozzle is a E3D v6 clone.

Edited 1 time(s). Last edit at 07/16/2015 09:26AM by Lerathel.

It sounds like it's not up to temperature, so I would double-check the thermistor and firmware settings. Typically you should be able to easily push the PLA through the e3d by hand.

Also, add some high-temperature thermal grease to the upper threads on the heatbreak (not the lower ones). This will dramatically improve cooling and help prevent clogs.

Thanks !!! I applied some thermal paste on the upper tread of the heatbreak, removed the teflon on the nozzle treads and put some thermal grease, I tightened everything at 200 C and right away I began printing ! I made 10 print in the last 2 days without any issue !!!

Glad that helped - it sure solved MY problems. I think you'll find you don't want it on the brass nozzle itself, as it tends to dry out at the higher temperatures (unless you can get some Red Ice 611HTC to try, which I have been unable to source anywhere). The critical thing is the UPPER (not lower) heat break threads

After 3 day it started to automaticaly clog again. I think my cppu thermal paste with a max of 130 degree died. I could not find a higher temp solution. appart from an industial product rated for 1000 degree C, sold in 5 gal only... hahaha. $$$$$.

Look like I will have to spend a lot a money changing the thermal paste every couple days .

source for any thermal grease supporter 250 degree C ?

Hello,

Using thermal grease is symptom treatment - Not problem solving. If it worked as a quick fix then sure. But now you should try to find the root cause for your problems. Also if you have 130 degree on the upper part of the heat break you have a serious problem.

For starters we need to know what kind of e3dv clone you actually have and your setup (what kind of cooling you have, etc). For that purpose you must do the following:

a) Take a photo of your entire hotend assembled
b) Disassemble the hotend and take out the heatbreak. Especially it is important to know if you have a small teflon pipe inside or not (if it truly is all metal). Photos of the disassembled parts.

Also you should post information such as filament size - And you say you made 10 prints with it working - Was it really completely working? No problems at all for all those 10 and then suddenly it jammed again?

Anyways - The fact that your hotend worked for a while is good news. Maybe all you need is to print yourself a new fan duct and buy a new stronger fan - If you have the cheapest 1$ fan then you can get a significant improvement just picking up the 5$ version. Remember that while the nozzle fan (if you have one of those) should not cool to much, the fan for the cooling ribs should cool as much as possible. The closer to ambient you get that thing the better.

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LarsK
Using thermal grease is symptom treatment - Not problem solving. If it worked as a quick fix then sure. But now you should try to find the root cause for your problems. Also if you have 130 degree on the upper part of the heat break you have a serious problem.

No, it is problem solving, and it is even suggested as such in the E3d troubleshooting guide. Stainless steel is a lousy thermal conductor, which is mostly desirable in this part since you want to keep the heat in the heater block/nozzle area, but whatever heat works its way up the heatbreak needs to be conducted away as quickly as possible. Having the thermal grease (not adhesive!) there fills any surface roughness with high-conductivity material and helps matters greatly. This will help produce a sharp change in temperature at the heatbreak. If you get grease that can handle the temperatures, it can also protect the threads of the heatbreak and make it easier to remove from the heatsink. If you have 130 degrees on the upper heatbreak, you do in fact have a serious problem, and the cause is likely that thermal transfer to the heatsink is not happening very efficiently, so you need to solve the problem with thermal paste.

The rated temperature of the thermal grease that is listed is usually the "peak" rating. There is another, "continuous" rating that is almost always not listed and which will be much lower. Usually the stuff dries out pretty quickly above that point. That is why I do NOT put the paste on the nozzle threads themselves, and ONLY on the upper heatbreak threads.

I'm pretty sure I'm using Deepcool Z5, and have had no issues with drying.

Other things to watch out for: Make sure your filament is dry. I find that the E3D nozzle geometry places the actual nozzle exit quite close to the lower parts of the hotend, presenting a flat surface parallel to the build plate just 2mm above the nozzle exit. I theorize that it is more prone to coming in contact with fuzzy/stringy bits of filament and it does seem to get more carbonized filament build-up on the exterior, which does not help matters. Try to keep that clean as best you can.

Another thing to be careful of: The heatbreak is pretty fragile, so be sure when you tighten everything down that you do not twist or bend it!

Good luck, Bill _/)_

Edited 1 time(s). Last edit at 07/22/2015 10:40AM by wfcook.

If he has so high temperatures on his upper heat-break that it dries out any normal CPU paste then he has an underlying problem. Applying better and more sophisticated grease is symptom treatment. End of story.

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LarsK
If he has so high temperatures on his upper heat-break that it dries out any normal CPU paste then he has an underlying problem. Applying better and more sophisticated grease is symptom treatment. End of story.

The reason for the high temperatures is, by definition, a lack of sufficient heat transfer between the heatbreak and the heatsink. This could be caused by the heatsink itself not being adequately cooled, but if he has a working fan in the standard arrangement that is unlikely unless, as the troubleshooting document states, the ambient air is unusually warm. Simple physics. Improve the efficiency of the cooling unit and the problem goes away. What other underlying problem do you think makes his upper heat break fail to cool properly? This would be helpful information, especially if you can describe the mechanism by which another problem would be cured, even temporarily, with thermal grease on the upper heatbreak threads.

Edited 1 time(s). Last edit at 07/22/2015 12:11PM by wfcook.

If you read my post above you will see that I present a good number of possible things to investigate.

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Lerathel
After 3 day it started to automaticaly clog again. I think my cppu thermal paste with a max of 130 degree died. I could not find a higher temp solution. appart from an industial product rated for 1000 degree C, sold in 5 gal only... hahaha. $$$$$.

Look like I will have to spend a lot a money changing the thermal paste every couple days .

source for any thermal grease supporter 250 degree C ?

My advice is to get either a genuine E3Dv6, or an E3D Lite6 hot end.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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LarsK
If you read my post above you will see that I present a good number of possible things to investigate.

I am not arguing for arguments' sake; I would genuinely like to know. I see one suggestion to get a better fan. How is thermal grease symptom treatment and the fan isn't? What mechanism in the E3D clone he is using is causing the upper heatbreak to get hot if it isn't related to heat transfer?

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wfcook
I am not arguing for arguments' sake; I would genuinely like to know.

I would also like to know. For that reason I am waiting for Lerathel to do the steps I lined out and then I am sure our combined knowledge will have this problem solved in no time.

As an off the wall thought, any chance this is a 24v fan on a 12v printer? Myself, I can't imagine a fit bad enough to compromise heat transfer that much that wouldn't be basically flopping around and falling out. Even then, when tightened, the tension on the threads should still make solid contact . . . In my mind, this almost has to be a fan/heat sink cooling issue . . .

- Tim

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LarsK

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wfcook
I am not arguing for arguments' sake; I would genuinely like to know.

I would also like to know. For that reason I am waiting for Lerathel to do the steps I lined out and then I am sure our combined knowledge will have this problem solved in no time.

Fair enough.,