can you overcool an e3d v6?

So I have two genuine e3d v6 hot ends, both bought direct from e3d. One about 5 months old - has performed without fault throughout.

The other is about 1 month old. Both assembled exactly as per e3d's website and the same as I have assembled countless clone hot ends before I bought some real ones (minus the fixes needed for clones).

The newest one jams if I look at it in the wrong way. Jammed with PLA possibly due to fan being off. Cleared it easily, I've got a version of the new silicone cover, this version does not cover the nozzle but sits around it and the hot end. I wonder since the silicone cover only exposes the top of the heater block if aside from insulating it, actually encourages more heat to rise from the heater block than without a cover.

Then swapped from ABS to PETG - instant jam. Very difficult to clear but managed it - without scratching the inside of the heatbreak. I am using a fan cowl based around e3d's but with two layer fans on the side. Same airflow as the e3d fan cowl.

So I installed a serious fan but still an hour into printing a jam with ABS. The heatbreak temperature at the fin nearest the heater block is 38 Deg C measured with a k-type thermocouple. It pushes serious air through at 8v but I'm only running it at 3.5v where it still moves much more air than the supplied fan (with a lot more noise to go with it). Will over-cooling it encourage filament to jam?

I am a bit out of ideas except maybe I got a duff hot end from e3d which would be disappointing as I bought genuine to be rid of the issues with the clone units, but spent 5 times more on the hot end - you expect less hassle.

Edited 1 time(s). Last edit at 10/21/2016 10:34AM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Not sure to be honest... it would partly depend on what size of heater cartridge you are using, 20W or 40W.

A 20W would be easier to overcool, but I guess if your cooling is doing more work than the heater cartridge, you could theoretically overcool any hot end.

Edited 1 time(s). Last edit at 10/21/2016 11:39AM by DragonFire.

If you were overcooling I would expect to see the hotend struggle to reach the set temp, this would get worse at higher temperatures.

I've never seen my v6 jam because of over cooling. I would look for other problems, starting with a foreign object in the nozzle, even if you've cleaned it there might be something left, try a new nozzle if you have one.

Moriquendi

Rebuilt it for the 5th time in a month and it just made it through a 2 hour print so maybe I'm there? It failed the same print after 45 minutes yesterday.

It's a 30w heater.

Good point about the hot end not being able to get up to temperature.

Edited 1 time(s). Last edit at 10/21/2016 01:33PM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

M303 command might do the trick - it does a series of tests on the hotend and returns optimal P, I, D values to enter into config.h file, for THAT paricular combination of hotend, heater cartridge, and cooling system.

It's a great feature on Marlin, not supported by some firmware types.

Edited 1 time(s). Last edit at 10/21/2016 02:22PM by DragonFire.

As others have said, check the temperature readings. I did have problems with the layer cooling fan (in an Eclips3D) blasting extra air onto my E3D and the temperatire dropping as a result. I fix this by limiting the max fan percent in the slicer settings, and by wrapping ceramic tape round the heater block. I later replaced this by an E3D sock - these are awesome, BTW.

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See my blog at [moosteria.blogspot.com].

Thanks for the suggestions. My hot end temp I've checked with the thermocouple and its within 5 deg of the set temperature.
(I find putting some AG Gold heatsink compound between the heater cartridge and the heater block (spec'd for 300 Deg C) seems to help with temperature stability.)

My layer fans do not blow air onto the heater block, and I have an early version of the E3D silicone sock installed which was supplied by e3d with the hot end kit, I will get the later version with just the nozzle tip sticking out soon, but I'm waiting for the volcano one to be available also, as E3D's postage is expensive for small orders.

To be honest its working now I am nearly to the end of another 2 hour print, but its annoying I cannot see what was doing it as I assembled it the same this time as the previous 4 times.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I know what you mean, it can be infuriating not being able to find the root problem even if you've managed to fix it.

One other thing I thought of, what are your retraction settings. If your retraction distance is too long you might pull hot plastic far enough into the heatbreak to cool and solidify it, that's something that might be exacerbated by overcooling of the heatsink.

Moriquendi

How did this work out DjDemonD?

Did you manage to finish the print? What is the status here?
How is the situation above the hot end? Long bowden? That would impact retraction, which could cause issues like Moriquendi pointed out.

Since you switched filaments it is not an issue with a duff filament.

Could it be a slightly misaligned heat break?

Lykle

Managed to finish the print so for now fixed. No reason I can see for what the problem was.

It's a flying extruder so only 15cm bowden tube. Retraction is just 1.4mm. Both the abs and petg were well used rolls which were printing fine on the other two printers, that's the frustration theres nothing seemingly to blame.

Thanks for help guys for now whilst it's working it'll have to remain an unsolved mystery.

Edited 1 time(s). Last edit at 10/22/2016 08:48AM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions