Can there be such a thing as TOO MUCH cooling in the heatbreak?

Topics around mechanical design, controller and electronics. Mods & hacks welcome.
EL Cuajinais
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Joined: Wed Apr 06, 2016 8:48 pm

Can there be such a thing as TOO MUCH cooling in the heatbreak?

Postby EL Cuajinais » Tue May 03, 2016 2:17 am

I ask because I just has my biggest clog up to date and it was with the V2 hotend and a new fan shroud I was testing for it. You see, the original fan shroud has two things I don't like:

1. It requires that silly cover to be placed every time you are printing with something other than PLA.
I found that it proximity to the hotend basically softened it to the point where inevitable it would fall. Yes, incredibly, factory-supplied ones were made from PLA in the first batches, but I think I read somewhere that they are now supplying ABS ones in the new printers. In any case, I don't need ANY model cooling from this fan since I have a single hotend version of the N2 which comes supplied with its own g-code controllable model blower.

2. The V2 hotened is 2mm longer and has an extra fin in the heatsink, but the original shroud was designed for the smaller heat break with 6 fins. So the opening on the original shroud is too small to allow the air to hit the additional fin on the V2 nozzle.

With these two things in mind I designed a new shroud that did not diver any air to the nozzle, and had an increased hole to account for the extra fin on the V2. It just seemed like the right thing to do. Well on the maiden test of this new shroud I got the worst clog I've had with this printer so far. I left an overnight print, which completed fine. But when I went to change the filament, I realized there was a huge clog in the heat break section. I had to disassemble and torch the heat break to get the clog out. I must say, props on the material selection for that heat break section, I don't know which metal that is, but it sure a is a very good insulator (for a metal). I tried applying heat with the thermocouple directly and with a soldering iron and it just would not conduct enough heat to melt the ABS plug inside. I had to torch it.

Do you think it was coincidence that my first clog on the heat break occurred right after completing my first print with a fan should that presumably provides better cooling?

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Vicky@Raise3D
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Re: Can there be such a thing as TOO MUCH cooling in the heatbreak?

Postby Vicky@Raise3D » Tue May 03, 2016 2:52 am

EL Cuajinais wrote:I ask because I just has my biggest clog up to date and it was with the V2 hotend and a new fan shroud I was testing for it. You see, the original fan shroud has two things I don't like:

1. It requires that silly cover to be placed every time you are printing with something other than PLA.
I found that it proximity to the hotend basically softened it to the point where inevitable it would fall. Yes, incredibly, factory-supplied ones were made from PLA in the first batches, but I think I read somewhere that they are now supplying ABS ones in the new printers. In any case, I don't need ANY model cooling from this fan since I have a single hotend version of the N2 which comes supplied with its own g-code controllable model blower.

2. The V2 hotened is 2mm longer and has an extra fin in the heatsink, but the original shroud was designed for the smaller heat break with 6 fins. So the opening on the original shroud is too small to allow the air to hit the additional fin on the V2 nozzle.

With these two things in mind I designed a new shroud that did not diver any air to the nozzle, and had an increased hole to account for the extra fin on the V2. It just seemed like the right thing to do. Well on the maiden test of this new shroud I got the worst clog I've had with this printer so far. I left an overnight print, which completed fine. But when I went to change the filament, I realized there was a huge clog in the heat break section. I had to disassemble and torch the heat break to get the clog out. I must say, props on the material selection for that heat break section, I don't know which metal that is, but it sure a is a very good insulator (for a metal). I tried applying heat with the thermocouple directly and with a soldering iron and it just would not conduct enough heat to melt the ABS plug inside. I had to torch it.

Do you think it was coincidence that my first clog on the heat break occurred right after completing my first print with a fan should that presumably provides better cooling?


Improper cooling will cause the filament become soft before get into the nozzle.

Anyway, thanks for your feedback. Notes taken.

We are trying to design a new fan shroud as well. Still on testing now. Will pass your advise to our engineer.

EL Cuajinais
Posts: 221
Joined: Wed Apr 06, 2016 8:48 pm

Re: Can there be such a thing as TOO MUCH cooling in the heatbreak?

Postby EL Cuajinais » Tue May 03, 2016 2:58 am

Yes, having the filament go soft before going into the nozzle is a bad thing. But is the result of TOO LITTLE cooling. What I'm asking about is if it is possible to have TOO MUCH cooling. I usually share my designs and I intend to share this one as well. But the thing is I like to test everything before releasing it into the wild. Last thing I want is to cause other users problems. I'm wondering if there is such a thing as TOO MUCH cooling because my design intent was to increase cooling at the V2 heatbreak.

Andy Cohen
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Re: Can there be such a thing as TOO MUCH cooling in the heatbreak?

Postby Andy Cohen » Tue May 03, 2016 3:52 am

EL Cuajinais wrote:Yes, having the filament go soft before going into the nozzle is a bad thing. But is the result of TOO LITTLE cooling. What I'm asking about is if it is possible to have TOO MUCH cooling. I usually share my designs and I intend to share this one as well. But the thing is I like to test everything before releasing it into the wild. Last thing I want is to cause other users problems. I'm wondering if there is such a thing as TOO MUCH cooling because my design intent was to increase cooling at the V2 heatbreak.

I cannot see how too much cooling (unless it is actually COLD) would make a difference. IMO it sounds like it was a coincidence. Slightly ovalized filament can still get stuck and then left unattended for awhile would jam it up more.
I try another long print with it, but change to a different filament spool and check it regularly.

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dhylands
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Re: Can there be such a thing as TOO MUCH cooling in the heatbreak?

Postby dhylands » Tue May 03, 2016 4:51 am

I was also wondering if it makes sense to have the extruder cooling go from front-to-back instead of from side to side.

It seems to me, that at least with dual extruders, having the fans blowing towards each other will have some of the cooling effect cancel each other out?

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Vicky@Raise3D
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Re: Can there be such a thing as TOO MUCH cooling in the heatbreak?

Postby Vicky@Raise3D » Tue May 03, 2016 6:22 am

EL Cuajinais wrote:Yes, having the filament go soft before going into the nozzle is a bad thing. But is the result of TOO LITTLE cooling. What I'm asking about is if it is possible to have TOO MUCH cooling. I usually share my designs and I intend to share this one as well. But the thing is I like to test everything before releasing it into the wild. Last thing I want is to cause other users problems. I'm wondering if there is such a thing as TOO MUCH cooling because my design intent was to increase cooling at the V2 heatbreak.


Did the clog happen when unloading or the clog was there during printing?

EL Cuajinais
Posts: 221
Joined: Wed Apr 06, 2016 8:48 pm

Re: Can there be such a thing as TOO MUCH cooling in the heatbreak?

Postby EL Cuajinais » Tue May 03, 2016 11:14 am

Vicky@Raise3D wrote:Did the clog happen when unloading or the clog was there during printing?

That's a good question. I guess it must have been during unloading since the overnight print had completed successfully. OR, during the printer cooldown right after it completed the print in the wee hours of the night.

Here are some pictures to show the difference in where the hole on the original shroud prevents the air from hitting the last fin of the heatsink directly.

Original:
IMG_7574.JPG


Shroud I'm testing:
IMG_7583.JPG

IMG_7581.JPG

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Vicky@Raise3D
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Re: Can there be such a thing as TOO MUCH cooling in the heatbreak?

Postby Vicky@Raise3D » Wed May 04, 2016 3:42 am

EL Cuajinais wrote:
Vicky@Raise3D wrote:Did the clog happen when unloading or the clog was there during printing?

That's a good question. I guess it must have been during unloading since the overnight print had completed successfully. OR, during the printer cooldown right after it completed the print in the wee hours of the night.

Here are some pictures to show the difference in where the hole on the original shroud prevents the air from hitting the last fin of the heatsink directly.

Original:
IMG_7574.JPG


Shroud I'm testing:
IMG_7583.JPG

IMG_7581.JPG


Since your print completed with no problem, I think the fan shroud is not the main cause.
In my opinion, the clog happened most likely when unloading. Suggest you can try to load some filament first, then unload. Then the melt over-night section of filament can be extruded from nozzle, the unload part will have low possibility to clog in hotend.

firesped
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Location: Tucson, AZ

Re: Can there be such a thing as TOO MUCH cooling in the heatbreak?

Postby firesped » Wed May 04, 2016 7:42 pm

I'd like to note, that everything I tried that was different from Raise3D's original design caused failure of prints. you need the downward print cooling provided on the sides. I was able to insulate my hotend and I reprinted a fan mod based on their design in PLA and I haven't had it melt at all yet, though I have not tried to print ABS/ePC yet with it. I haven't posted it up yet because I need to make a change to it.
RL name: Michael Nolen
printers:
raise3D N2 kickstarter Early Bird
Trinus Deluxe (running smoothieware on Azteeg X5 GT board)
Monoprice Maker Select v2


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