Ebay SINTRON Kossel Mini full kit

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o_lampe
Don't take the nozzle diameter for granted.
I got 0.3 nozzles from china, which are 0.4 and vise versa...
-Olaf

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Sir_Death
Nozzle was free before printing - could see through. PTFE tube is down all the way through heatbreake - there was a Problem after building the printer, so I had to disassemble and
reassemble it, therefore I'm sure, how it is assembled now.

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Sir_Death

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Sir_Death
Nozzle was free before printing - could see through. PTFE tube is down all the way through heatbreake - there was a Problem after building the printer, so I had to disassemble and
reassemble it, therefore I'm sure, how it is assembled now.

Nozzle was jammed this morning after unattended night-print...
I think - or at least hope - I found the problem. - The screw which is pressing the heatblock onto the heatcartridge broke in the middle, so it was not correctly pressing the two parts together anymore...
Will have to drill it out this afternoon and reassemble.
Nozzle got jammed, because PTFE-Tube got widened at the end, and so PLA crystalized.. (Thats why I started dissasembling, because cold pull did not work anymore - so I found the broken screw...)

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nebbian

Quote
o_lampe
Don't take the nozzle diameter for granted.
I got 0.3 nozzles from china, which are 0.4 and vise versa...
-Olaf

What's a good way to test this?

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nebbian
Also while we're on the subject, I read somewhere that you should have an extrusion width that is slightly larger than the nozzle size. I've always just used an extrusion width equal to the nozzle size. Can you confirm/deny?

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Sir_Death
Nozzle was jammed this morning after unattended night-print...
I think - or at least hope - I found the problem. - The screw which is pressing the heatblock onto the heatcartridge broke in the middle, so it was not correctly pressing the two parts together anymore...

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Sir_Death
The PTFE Tube should reach down through the heatbreak until touching the back of the Nozzle (in the heatblock), so 1.75mm Filament is directed to the nozzle correctly.

We will see, when I've cleaned it up and reassembled, if it works as it should...
Would it be a good Idea to apply some thermal compound on the heatcartridge to ensure best thermal Transfer to the heatblock?

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hacker

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Sir_Death
The PTFE Tube should reach down through the heatbreak until touching the back of the Nozzle (in the heatblock), so 1.75mm Filament is directed to the nozzle correctly.

We will see, when I've cleaned it up and reassembled, if it works as it should...
Would it be a good Idea to apply some thermal compound on the heatcartridge to ensure best thermal Transfer to the heatblock?

I thought it ends halfway in the heatbreak? I need to check that once I'm home, because I happen to have original hotend lying around ready for disassembling I'd say PTFT tube *is* kinda cold zone wherever it is, maybe not too cold ;-)

Perhaps I'd try some thermal compound on heatbreak threading to improve thermal transfer to heatsink. And would triple check how well heatsink is colled.

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hacker

Perhaps I'd try some thermal compound on heatbreak threading to improve thermal transfer to heatsink.

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Sir_Death

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hacker

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Sir_Death
The PTFE Tube should reach down through the heatbreak until touching the back of the Nozzle (in the heatblock), so 1.75mm Filament is directed to the nozzle correctly.

We will see, when I've cleaned it up and reassembled, if it works as it should...
Would it be a good Idea to apply some thermal compound on the heatcartridge to ensure best thermal Transfer to the heatblock?

I thought it ends halfway in the heatbreak? I need to check that once I'm home, because I happen to have original hotend lying around ready for disassembling I'd say PTFT tube *is* kinda cold zone wherever it is, maybe not too cold ;-)

Perhaps I'd try some thermal compound on heatbreak threading to improve thermal transfer to heatsink. And would triple check how well heatsink is colled.

Consulting E3D Assembly Instruction at
http://wiki.e3d-online.com/wiki/E3D-v6_Assembly#1.75mm_Universal_.28with_Bowden.29´
it tells you:
"The tubing should be inserted from the top of the now assembled hotend and pushed as far down into the hotend as possible."
With the chinese hotend PTFE Tube is able to go down till the end of the heatbreak.

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GrAndAG

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hacker

Perhaps I'd try some thermal compound on heatbreak threading to improve thermal transfer to heatsink.

Just FYI.. Regular (usually for computer coolers) thermal compound is not designed for high temperature, such as in our case. It will degrade rapidly. But it worth to try, if it solves the problem (at least for short time) - you found the problem.

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GrAndAG

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hacker

Perhaps I'd try some thermal compound on heatbreak threading to improve thermal transfer to heatsink.

Just FYI.. Regular (usually for computer coolers) thermal compound is not designed for high temperature, such as in our case. It will degrade rapidly. But it worth to try, if it solves the problem (at least for short time) - you found the problem.

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Sir_Death

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GrAndAG

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hacker

Perhaps I'd try some thermal compound on heatbreak threading to improve thermal transfer to heatsink.

Just FYI.. Regular (usually for computer coolers) thermal compound is not designed for high temperature, such as in our case. It will degrade rapidly. But it worth to try, if it solves the problem (at least for short time) - you found the problem.

That is exactly the Point which worries me...
So first I'll just reassemble it, as it should be, and check again...

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Koenig

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Sir_Death

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GrAndAG

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hacker

Perhaps I'd try some thermal compound on heatbreak threading to improve thermal transfer to heatsink.

Just FYI.. Regular (usually for computer coolers) thermal compound is not designed for high temperature, such as in our case. It will degrade rapidly. But it worth to try, if it solves the problem (at least for short time) - you found the problem.

That is exactly the Point which worries me...
So first I'll just reassemble it, as it should be, and check again...

Don't think you need to worry to much about it, where the fins are it shouldn't be such extreme temperatures.
It would be another matter if you tried putting thermal compound where the heatblock is (threads to nozzle, around heating cartridge).

E3D actually recommends putting thermal compound on the heatbreak where the fins are.

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hacker

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Koenig

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Sir_Death

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GrAndAG

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hacker

Perhaps I'd try some thermal compound on heatbreak threading to improve thermal transfer to heatsink.

Just FYI.. Regular (usually for computer coolers) thermal compound is not designed for high temperature, such as in our case. It will degrade rapidly. But it worth to try, if it solves the problem (at least for short time) - you found the problem.

That is exactly the Point which worries me...
So first I'll just reassemble it, as it should be, and check again...

Don't think you need to worry to much about it, where the fins are it shouldn't be such extreme temperatures.
It would be another matter if you tried putting thermal compound where the heatblock is (threads to nozzle, around heating cartridge).

E3D actually recommends putting thermal compound on the heatbreak where the fins are.

Oh yeah, sorry if I wasn't clear (and I almost wasn't), I meant heatbreak threading where it goes into heatsink, of course.

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Koenig

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hacker

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Koenig

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Sir_Death

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GrAndAG

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hacker

Perhaps I'd try some thermal compound on heatbreak threading to improve thermal transfer to heatsink.

Just FYI.. Regular (usually for computer coolers) thermal compound is not designed for high temperature, such as in our case. It will degrade rapidly. But it worth to try, if it solves the problem (at least for short time) - you found the problem.

That is exactly the Point which worries me...
So first I'll just reassemble it, as it should be, and check again...

Don't think you need to worry to much about it, where the fins are it shouldn't be such extreme temperatures.
It would be another matter if you tried putting thermal compound where the heatblock is (threads to nozzle, around heating cartridge).

E3D actually recommends putting thermal compound on the heatbreak where the fins are.

Oh yeah, sorry if I wasn't clear (and I almost wasn't), I meant heatbreak threading where it goes into heatsink, of course.

That would not be very smart to do that as you really want as little heat transfer between those two parts as possible.
It would be much better if there was a thermal insulator compound to put there.

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Tha_Reaper

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Koenig


That would not be very smart to do that as you really want as little heat transfer between those two parts as possible.
It would be much better if there was a thermal insulator compound to put there.

But you also don't want the heat to creep up to the PTFE tube and start melting plastic higher up...

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Tha_Reaper

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Koenig

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hacker

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Koenig

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Sir_Death

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GrAndAG

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hacker

Perhaps I'd try some thermal compound on heatbreak threading to improve thermal transfer to heatsink.

Just FYI.. Regular (usually for computer coolers) thermal compound is not designed for high temperature, such as in our case. It will degrade rapidly. But it worth to try, if it solves the problem (at least for short time) - you found the problem.

That is exactly the Point which worries me...
So first I'll just reassemble it, as it should be, and check again...

Don't think you need to worry to much about it, where the fins are it shouldn't be such extreme temperatures.
It would be another matter if you tried putting thermal compound where the heatblock is (threads to nozzle, around heating cartridge).

E3D actually recommends putting thermal compound on the heatbreak where the fins are.

Oh yeah, sorry if I wasn't clear (and I almost wasn't), I meant heatbreak threading where it goes into heatsink, of course.

That would not be very smart to do that as you really want as little heat transfer between those two parts as possible.
It would be much better if there was a thermal insulator compound to put there.

But you also don't want the heat to creep up to the PTFE tube and start melting plastic higher up...

Quote
Sir_Death

Quote
Tha_Reaper

Quote
Koenig


That would not be very smart to do that as you really want as little heat transfer between those two parts as possible.
It would be much better if there was a thermal insulator compound to put there.

But you also don't want the heat to creep up to the PTFE tube and start melting plastic higher up...

Some guys even apply PTFE foil on the part of the heatbreak going into the heatblock, to stop the heat from going into the heatbreak.

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hacker

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Sir_Death
Some guys even apply PTFE foil on the part of the heatbreak going into the heatblock, to stop the heat from going into the heatbreak.

I considered that, but I'm also worried that it might be a bit too hot for PTFE? Gotta do the research perhaps.

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Sir_Death

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hacker

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Sir_Death
Some guys even apply PTFE foil on the part of the heatbreak going into the heatblock, to stop the heat from going into the heatbreak.

I considered that, but I'm also worried that it might be a bit too hot for PTFE? Gotta do the research perhaps.

Wikipedia tells me PTFE has its melting Point at 327°C
https://de.wikipedia.org/wiki/Polytetrafluorethylen

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nebbian

Have you adjusted the motor driver currents? You stick a jewellers screwdriver in the little trimpot, and measure the voltage between the screwdriver and earth, while slowly nudging the screwdriver back and forth. Mine is set to 0.45V.

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Tha_Reaper

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nebbian

Have you adjusted the motor driver currents? You stick a jewellers screwdriver in the little trimpot, and measure the voltage between the screwdriver and earth, while slowly nudging the screwdriver back and forth. Mine is set to 0.45V.

Checked mine, it was 0.3V. Had a lot of skipping so I cranked it up to 0.45v. Much less skipping, but now on a longer print my PLA bent inside the extruder after the gear and before the PTFE tube. Created an ugly mess... I suspect a hot extruder is at fault for making the PLA more plyable.

Any way to combat this?

IMG_4506.jpeg

IMG_4507.jpeg

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nebbian

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Tha_Reaper

Quote
nebbian

Have you adjusted the motor driver currents? You stick a jewellers screwdriver in the little trimpot, and measure the voltage between the screwdriver and earth, while slowly nudging the screwdriver back and forth. Mine is set to 0.45V.

Checked mine, it was 0.3V. Had a lot of skipping so I cranked it up to 0.45v. Much less skipping, but now on a longer print my PLA bent inside the extruder after the gear and before the PTFE tube. Created an ugly mess... I suspect a hot extruder is at fault for making the PLA more plyable.

Any way to combat this?

Like this?
[attachment 65335 IMG_4506.jpeg]

Add some aluminium or PTFE tube like this:

[attachment 65336 IMG_4507.jpeg]

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Tha_Reaper

Exactly! I just discovered it 30 minutes later, and it turned into a bird's nest up there.

What's that part that you used? Can I buy that somewhere?

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nebbian

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Tha_Reaper

Exactly! I just discovered it 30 minutes later, and it turned into a bird's nest up there.

What's that part that you used? Can I buy that somewhere?

That part is called "Bit of aluminium tube I had lying around".

I've since replaced it with a part called "1 cm offcut of PTFE tubing, exactly the same stuff as is in your bowden tube". The easiest way to do this is to press the little button on your extruder and pop off the bowden tube. Cut off 1 cm and replace. Now put some tape around that offcut and screw it into the threaded hole. You might have to take some parts of the extruder off to do this, because the idler bearing gets in the way. Then trim the tubing so that it's just proud of the gear and idler bearing.

Alternatively if you're feeling brave you could disassemble the push fit connector and drill it out the same as the one on the hotend, which would allow you to push the bowden cable all the way through the hole in the extruder until it's almost touching the extruder gear and idler bearing.