Water cooled all metal hotend

@Xabbax

I like your water cooled extruder!

I don't see a hose clamp on the coolant hose.
Plastic creeps over time, the coolant hose could separate, and leak water.
To be safe add a hose clamp to the flexible tubing.
If your microcontroler is located under the build table it could short if your system develops a leak.

If you're worried about the additional weight of the hose clamps, drill cross holes into the nuts, and holes into the end effector plates.

If possible, I would push the water up to the extruder. When the power is turned off, the water will drain back to the reservoir. Add a few shots of alcohol to the water to stop the algae from growing.

Thank you all for the positive comments and the links.

Reasons for copper water cooled hotend

1. I want to use a heated chamber for ABS and possible PET printing and water cooling was a nice solution to get rid of the heat on the stainless steel tube - no pumping used only convection.
I tried pumping cold air from a peltier cooled element but I found it a bit to cumbersome.

2. Use copper rather than aluminium for better heat transfer(http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html) from the heater element to the meltzone and it is easier to silversolder than aluminium.

2. lighter and shorter hotend than with a copper or aluminium heatsink - I use it on a delta printer.

3. I want to print with .75 mm and bigger size nozzles with higher speeds and for that will need higher temperatures than the traditional 245 C

Shortcomings and things that I want to improve in the immediate future -

1. Replace the bottom brass bolt with a copper bolt for better heat transfer(if I can find one - otherwise will have to improvise)

2. Shorten the section between the copper water pipe and the upper brass bolt - no need for an open space here. The water pipe can be horizontal - the side that gets the most heat will automatically transfer the warm water to the top.

3. A shorter thermal break - do not know if this will be possible but will try it out.

4. Definately improve on the heat retention capabilities of the hotend with more thermal insulation
(thank you cozmicray )
Would love to get hold of some aerogel.(http://en.wikipedia.org/wiki/Aerogel) Mean time will have to do with cuttlefish bone and will also try out glass microballoons(http://en.wikipedia.org/wiki/Microballoons) mixed in high temperature silicone made in a mould to cover the hotend.

A2 Wrote:
-------------------------------------------------------
> @Xabbax
>
> I like your water cooled extruder!
>
> I don't see a hose clamp on the coolant hose.
> Plastic creeps over time, the coolant hose could
> separate, and leak water.
> To be safe add a hose clamp to the flexible
> tubing.
> If your microcontroler is located under the build
> table it could short if your system develops a
> leak.
>
> If you're worried about the additional weight of
> the hose clamps, drill cross holes into the nuts,
> and holes into the end effector plates.
>
> If possible, I would push the water up to the
> extruder. When the power is turned off, the water
> will drain back to the reservoir. Add a few shots
> of alcohol to the water to stop the algae from
> growing.

Thank you for the tips - will keep it in mind - a water leak can make a mess.
My electronics and motors are in the top section of my new delta. Was at the bottom on my old delta.

Edited 1 time(s). Last edit at 10/06/2013 02:15PM by Xabbax.

So when you refer to the bottom brass bolt, that would be the brass 'acorn' nut on the end with the orfice?

I'm not sure replacing it with aluminium would alter much, I suspect there is very little heat flow anywhere in that area. The plastic is already at its hottest temp, the nut is just acting as a physical channel. It could probably be made of any material that can handle the heat and wear.

Wrapping it in any insulation is bound to improve things, anything past the heater block is leaking heat away.

I hope we will get the chance to see this all set up!

---

Yvan

Singularity Machine

Xabbax Wrote:

> 1. I want to use a heated chamber for ABS and
> possible PET printing and water cooling was a nice
> solution to get rid of the heat on the stainless
> steel tube - no pumping used only convection.
> I tried pumping cold air from a peltier cooled
> element but I found it a bit to cumbersome.
I am using a heated chamber (@50°C) for ABS printing and i don't need any cooling for the nozzle.
Maybe check again if it is really neccesary for you.

>
> 3. I want to print with .75 mm and bigger size
> nozzles with higher speeds and for that will
> need higher temperatures than the traditional 245
> C
I tried 0.75-1mm nozzles usccessfully, the thing that was neccesary was a powerfull heater cartridge, the temperature stays the same, you need a larger amount of heat, not a higher temperature.

Hope this helps
Björn

... Wrote:
-------------------------------------------------------
> ok so not sure if this has been said, but the mk7
> hot end is actively cooled, just like a water
> cooled hot end. [...]

Lets just make clear what "active cooling" is. I think it is related to a consumption of system power for controllable tweaking some aspect like to improve heat transfer purposes.

Therefore existence of a fan does equate to "actively" cooled.

However the phrase "water cooled", or existence of a liquid to transfer heat, does NOT imply "active" cooling. For example the whole point of using liquid is that it allows one to play around with the size and placement of system components, and these can easily be dimensioned in such way so it can be realized with only *natural convection*, both in liquid circulation and heat exchanger, and that is NOT "active" cooling, that would be passive by all means since natural convection does not equal active.

What would make it "active" would be a circulation pump or a fan on top of a heat exchanger, or any other device that actively consumes power from the system. The mk7 is much lesser in that regard as it has no chance of being tweaked to work only as passive in that configuration. In the meantime, the OP system could be passive very easily, and probably it is so, unless there is a fan or circulation pump involved. Just ensure natural liquid circulation and on top of printer put a good water-to-air exchanger (radiator) with no fan and that is passive. So OP system could be entirely passive and more than that i think it is so, because the tube soldering position presents an intended slope which would hint to a natural liquid flow.

well I guess you could technically have the mk7 be actively cooled by having it intake cold air, but yes there are two types of cooling then, passive, meaning being cooled down by the environment, even if it is accelerated by the fan or water pump. then active which would mean being refrigerated, where energy is being actively transferred out of the system, being able to go below the environments temperature.

The fact that heat moves through liquid means nothing. If we put an alumina radiator on top of a heat source, heat would move through solid, e.g. metal, but would still move through a preferential path. Or such a radiator could have a liquid filled core. So either if heat is moving through a solid or a liquid, this information alone says nothing about if the system is active or passive.

"Active" means there is involved a device that is "active", hence consumes power from the system. That could be fan, circulation pump, peltier module, etc. If no such system exists, and no power is actively drawn from supply for cooling, then cooling is passive.

The exact word to use for an element of any new field is usualy in flux until decided by formal or informal consensus. For myself, I prefer to think of cooling enhanced by a prime mover to be forced cooling - this was the use even back in the days of thermionic valves, if it's got a fan it is force cooled. Again for myself, I think of active cooling as being where the cooling is controlled. A simple convection cooler with bimetallic valves or shutters would be active, but unforced - sometimes seen on early gas engines.

Of course, it does depend on where you inherited your terminology.

Mike

I consider an extruder HOTEND and COOLEND (mechanical pusher)

My take is heating / cooling of the HOTEND.

So a HOTEND with just a heater has NO active "cooling"

Putting a fan or other heat extraction device is COOLING the HOTEND or a section of the HOTEND
to either control the melt volume or prevent heat leakage to other components.
Putting energy into HOTEND to heat it, and using more energy to extract heat and cool it or some portion of it
is ACTIVE cooling

Isolation / insulation (prevent heat flow out) can / should be applied to a HOTEND,
to prevent heating components that don't like it, and keeping energy in the HOTEND
to stabilize temperature and perhaps prevent burning flesh.

Getting filament to pass smoothly thru a good insulator on the way to the hot zone
seems to be the real task PTFE used many times to provide a slick route.

Even a bowden extruder may require cooling to keep it from melting it's mount
or control melt area.

Just my point of view

Yvan Wrote:
-------------------------------------------------------
> So when you refer to the bottom brass bolt, that
> would be the brass 'acorn' nut on the end with the
> orfice?

I want to replace the brass bolt with a copper bolt - the brass acorn nut will not be replaced.

Okay, I see what you mean now. If you can't find copper threaded rod or bolts, how about threading a short section yourself? If you are soldering some parts, maybe just silver soldering it to the heater block and then just threading the end where it meets the acorn nut...

It would be nice to calculate the heat flow into the threaded rod past the heater block, maybe brass is all that is needed?

---

Yvan

Singularity Machine

Srek Wrote:
-------------------------------------------------------

> I am using a heated chamber (@50°C) for ABS
> printing and i don't need any cooling for the
> nozzle.
> Maybe check again if it is really neccesary for
> you.

Thank you for the chamber temperature info - will keep it in the back of my mind.

Update on the upgrades to the hotend



I used a nozzle from the welding industry to replace the bottom brass with copper

Cool! (No pun intended.) Maybe you have seen this already, but your use of a welding nozzle reminded me of North90s hot end.

MattMoses Wrote:
-------------------------------------------------------
> Cool! (No pun intended.) Maybe you have seen this
> already, but your use of a welding nozzle reminded
> me of
> [url=http://reprap.org/wiki/North90%27s_hot-end_V2
> ]North90s hot end[/url].

I guess that wildseyed has used it much earlier. So using welding nozzles has a long tradition.

---

Detlef

[url=http://reprap.org/wiki/Excalibur_Hotend]Excalibur Hotend[/url]

reprapclean32.png

[url=http://reprapzone.blogspot.de/]reprapzone.blogspot.de[/url]

Cool, thanks for the additional info, theodleif. The link is here for those interested: Wildseyed Simple Hot End.

My intention was not to start a contest of "who invented it first". Rather, I thought Xabbax (and other people) would be interested in North90's trick of inserting a small stainless steel tube into the tip of the copper welding nozzle in order to reduce the hole diameter. I should have made that more clear in my original post.

I think we are all interested in ALL developments, and this thread has some great info about the state of liquid cool. I call it liquid cool since I use automotive antifreeze in mine. It is normal for people to refer to previous things that may or may not be similar, it does not detract from anything you have done. We want to know what you have discovered also. I used to use modified welding tips for nozzles when I started, they worked fantastic. The only reason I switched was 0.7mm is about as small as you can reasonably do. I seen where one guy was compressing the tip, then redrilling it, I found that this was very time consuming, not very reliable, and redrilling copper is not something pleasant to do. I machined some from copper billet, still not a very practical thing to do. I found that aluminum nozzles worked very well, but then when people started printing more with nylon, I had several requests for brass nozzles, apparently aluminum reacts with nylon. Since brass works fine for all materials, all my nozzles are now brass. Brass is not quite as easy to machine as aluminum, but with a little practice it is not bad, way better than machining copper.

Good luck to ALL, and keep posting your discoveries, even if some one has done it, they probably didn't do things exactly the way you are doing them.

www.vanguardinnovations.us

MattMoses Wrote:
-------------------------------------------------------
> Cool, thanks for the additional info, theodleif.
> The link is here for those interested:
> [url=http://reprap.org/wiki/Wildseyed_Simple_Hot_E
> nd]Wildseyed Simple Hot End[/url].

Thank you for the interesting links. Such a wealth of info on this forum.
I replaced the bottom brass bolt with a welding tip and still use the brass dome nut for the nozzle.
For me it is easier to drill (already a pilot hole) and solder a welding tip than to cut threads in copper.
And it was cheaper to buy a welding tip than a 6 mm brass bolt in my local hardware shops.


Edited 1 time(s). Last edit at 10/29/2013 08:19AM by Xabbax.

---

You only learn when you change your mind.
[url]http://www.deltaprinter.co.za[/url]

I made a watercooled attachment with thermistor for about my hotend, but have yet to test. There was an interesting seller on ebay that had good documentation on water cooled hotends (albeit, ones that he was selling) .
But the more I read and work with injection molding, the more watercooling I am integrating into my 3d printer.





Why are you using antifreeze ? Just wondering. I hope your printer isnt getting down to -40c



knowbusiness Wrote:
-------------------------------------------------------
> I think we are all interested in ALL
> developments, and this thread has some great info
> about the state of liquid cool. I call it liquid
> cool since I use automotive antifreeze in mine.
> >
> www.vanguardinnovations.us

edit; I see it was you selling the watercooled hotends. Ive been working off your notes. The watercooler, I made to look closely to yours, very nice work.

Edited 1 time(s). Last edit at 10/30/2013 08:34PM by cakeslob.

Pure ethylene glycol/antifreeze does not conduct electricity very well, it does conduct heat too well. You can have a problem with too much cooling, actually if you are following the Europa design(eBay), that is not a problem. The new Mercury can cool way too much, it is the only issue we are working on. Some materials, PLA, like the extra cooling, but PC does not like as cool as the Mercury runs. It has been cured on the final version. The new Mercury, known as MV3, will be available soon. Be the first on your block to have one. For any further info, you can PM me, I doubt I will have much to say on forums in the future.

knowbusiness Wrote:
-------------------------------------------------------
> Pure ethylene glycol/antifreeze does not conduct
> electricity very well, it does conduct heat too
> well. You can have a problem with too much
> cooling, actually if you are following the Europa
> design(eBay), that is not a problem. The new
> Mercury can cool way too much, it is the only
> issue we are working on.

Thank you for this tip.
Do you need special plastic tubing or not for the antifreeze? I thought of using acetone - more like a heatpipe sort of setup but ran into the problem of flexible tubing that can withstand the acetone and vapors.

The reason for using antifreeze is that it is a corrosion inhibitor. The hot end described in this thread uses mixed metals. And that is without any mention of the radiator. While it is possible to get brass radiators, most are aluminium, which will make things even worse.

The long and the short of it is that if you're using mixed metals in a water cooling loop, you need a corrosion inhibitor, and antifreeze works.

Ah, the things you learn from PC water cooling.

Edited 1 time(s). Last edit at 10/31/2013 06:07PM by Annirak.

Annirak Wrote:
-------------------------------------------------------
> The reason for using antifreeze is that it is a
> corrosion inhibitor. The hot end described in this
> thread uses mixed metals. And that is without any
> mention of the radiator. While it is possible to
> get brass radiators, most are aluminium, which
> will make things even worse.
>
> The long and the short of it is that if you're
> using mixed metals in a water coming loop, you
> need a corrosion inhibitor, and antifreeze works.
>
> Ah, the things you learn from PC water cooling.

So much to learn - so little time - life is to short.

Quote
Jasper1984
Drilling a 0.5mm hole in that domed nut sounds hard..(well through the M6 nuts too) Yet i havent seen anyone describe it. Suppose is just a matter of getting a tiny drill and a stable drill stand?

It is pretty easy in a lathe. Little secret about doing it.
Hold the drill very short in the pin chuck (jewelers chuck)
If drilling a dome nut, mount it on a short piece of thread held in the lathe chuck with a lock nut to keep it tight.
Peck the drill, don't try and push it, you will break the drill. (pecking is just touching and pull away, touch again and pull away)
You must get the drill to start in dead centre (Australian spelling) or it will wander off and then break.
Use a piece of emery paper to clean up the dome nut end before you start so that it is uniform.

I have done many like this before going to CNC.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci