Watercooling the Printhead

[Simon2.4]

22 minutes ago, smirk said:

 Did it self-destruction after you read it?

nah, it somehow ended up posted online, on some obscure 3d printing forum hopefully avoiding others the wasted time...

[Todd]

So what Stratasys is basically telling us all is they don't want our business. Either that or you requested the part to be made from Sterling Silver or Unobtanium. Love the 'waterhead' name though. Maybe that's the guy who priced this one

 

[smirk]

Or they think these 3D printing sorts are all gullible rubes, or zillionaires with  many PI.......

[Todd]

When Craftcloud3D can do it for under $40 that tells us all where the respect for the community is and where the elitist dreams are harbored

 

[Todd]

And now back to our regular show already in progress.....

Been thinking about water cooling the V2.4 amid this thread and looking at other opinions and articles and for me it comes down to a couple of factors that are weighing on my decision. Cost, which isn't that much. We've seen that Aluminum heatsinks can be sourced for <$40USD and the mods to the print head parts are a no-cost add. The larger question is ...... Why? My answer to that lies in the enclosure heater I designed and am now running, which can bring the enclosure up to whatever I need it to be - from 40 - 80C. At the higher temperatures I am starting to experience a couple of nozzle jams that slicer settings won't cure, they're related to the fact that the filament is just plain getting soft at the upper end of the enclosure temperature and conventional air-cooled fans blowing around hot air do nothing to alleviate that. So here we are....water-cooled. This approach contains the area traditionally served by the heat break/heatsink combination and puts the heat removal duties on the heat exchanger and cooling system. Using a minor concentration of ethylene glycol (~10%) will keel the heat transfer efficiency up while inhibiting corrosion in the aluminum. Just found an 80 x 80 mm "radiator" designed for PC cooling systems on Amazon for <$20 USD including a 12vdc fan and a 12vdc high-torque gear drive motor to couple with a peristaltic pump I designed in Fusion 360 for <$15 USD. All in, I'm looking at $75 USD plus whatever cost you want to assign to self-designed and printed parts. Hey, it's all about the innovation and experience, right?

[Simon2.4]

22 minutes ago, Todd said:

And now back to our regular show already in progress.....

I'm using a 360mm x 120mm radiator that cost about 20usd it's pretty nice for the price and won't need any fans. For the pump, I got a chinese 24v circulating pump capable of maintaining about 1 to 2 psi, which I need because of my long tubes. I opened it up and sealed the ferrite rotor with a thin coat of silicone adhesive to slow down nasty ion release. the pump was also about 20$

For coolant, I'm using EKWB pre mixed coolant, which is designed exactly for this kind of use. It's what I trust with my watercooled RTX3080's

Add to this the silicone tubing and misc supplies it costs around 100usd in materials to make this.

 

30 minutes ago, Todd said:

At the higher temperatures I am starting to experience a couple of nozzle jams

That is the exact reason I want to try this.

BTW Peristaltic pumps have a very low flow and very low durability. They are intended for precision dosing, not endurance. the tube inside needs to be replaced regularly.

 

[Simon2.4]

For now, this thread has mostly covered the heatsink design and fabrication but the biggest challenge for me is the routing of the hoses

I'm going to follow the cable chains since there is really no other way for me to do this. I'm using these clips to fix the tubes on the chains and in order to accomodate the bending radius of the tubes, I need to redesign a few parts.

[Todd]

1 hour ago, Simon2.4 said:

BTW Peristaltic pumps have a very low flow and very low durability. They are intended for precision dosing, not endurance. the tube inside needs to be replaced regularly. 

The reason I went with the peristaltic design was total elimination of leak potential. I've had success over the years with Tygon tubing in them. Trying silicone tubing on this iteration. Also using 625-2RS bearings on three lobes in the pump.

[Simon2.4]

LGX lite extruder chain post

X axis chain post

[Todd]

My understanding of EK Cryo is that it's a silicone-based product. Not saying that is bad, but past motor work I've done in automotive has shown that silicone-based coolants form air pockets more readily, which lead to cavitation. Besides, EK recommends changing fluid every 6 months and they mention very little about conditioning.

 

Hey, we're not talking drag racing motors here, so the possibilities are certainly open. Good to hear other views. 

[Todd]

I have pretty much settled on the Bondtech BMG extruder. Have a new set of gears that just arrived at home for installation in the new SB when I get back. I like the post designs though.

[Todd]

Started the extruder upgrade to Bondtech back on my first Prusa Mini and have never been disappointed.

[Simon2.4]

4 minutes ago, Todd said:

My understanding of EK Cryo is that it's a silicone-based product. Not saying that is bad, but past motor work I've done in automotive has shown that silicone-based coolants form air pockets more readily, which lead to cavitation. Besides, EK recommends changing fluid every 6 months and they mention very little about conditioning.

Hey, we're not talking drag racing motors here, so the possibilities are certainly open. Good to hear other views. 

I'm a bit of an EK fan boy...  ; )  I have a loop with clear cryo that's been going 24/7 for a year and it look as pristine as the day I filled it so I trust the stuff.

You peaked my curiosity as to what it contains... not much:

https://www.ekwb.com/shop/EK-IM/EK-IM-3831109813256.pdf

[Simon2.4]

7 minutes ago, Todd said:

I like the post designs though.

I'll post the whole design when it's all proven to work.

[Todd]

I stand corrected on my earlier "silicone-based" understanding. Looks like it's basically a sodium salt akin to the acetate solutions we saw in ground-sourced heat pumps for years. Relatively mild. If you're happy with it stick with it.

Edited September 3, 2022 by Todd

[Simon2.4]

13 minutes ago, Todd said:

I stand corrected on my earlier "silicone-based" understanding. Looks like it's basically a sodium salt akin to the acetate solutions we saw in ground-sourced heat pumps for years. Relatively mild. If you're happy with it stick with it.

It's my understanding that the stabilizing agents form a layer on the metals akin to how cold blueing metal works. Do you know this?

[Simon2.4]

Pump and radiator mounting

To be fixed on the rear of the machine on a vertical extrusion, the base is a small container that will catch leaks in case of problems. The most likely area to have a leak should be the pump head or failure of the cheapo radiator.

Also, there is plenty of reserve volume in the pipes and rad , combined with the flexibility of silicone tubes, I opted not to include a tank.

[Todd]

You shouldn't need a tank. The radiator will serve the same purpose in its own top tank. With the 360mm height you should have plenty of heat rejection. Just finished designing a set of bulkhead connectors for 1/4" silicone tubing. You may find these helpful. There is also a TPU "D"-ring that can be substituted with an o-ring of the same diameter. One word of note on the fittings though, they are sized for 1/4" (6mm) thick top cover. If they are used with 1/8" (3mm) the extra space will need to be taken up with an equal thickness washer or gasket. Print them laying down and use supports to prevent them from snapping off.

Topside Fitting.stl Inside Fitting.stl TPU Seal Ring.stl

[Todd]

[Todd]

The seal ring should be printed laying down, and out of TPU.

 

[Todd]

@Simon, I didn't think it was possible but I received a quote more absurd than the one you shared with us. Check this one from Fathom out...

[claudermilk]

  That's definitely the "go away, we don't want the deal with this" price.

[Todd]

There's a mantra in business that says "ignore your customers, they'll go away soon enough". 

Edited September 7, 2022 by Todd

[Simon2.4]

On 9/4/2022 at 11:10 AM, Todd said:

You shouldn't need a tank. The radiator will serve the same purpose in its own top tank. With the 360mm height you should have plenty of heat rejection. Just finished designing a set of bulkhead connectors for 1/4" silicone tubing. You may find these helpful. There is also a TPU "D"-ring that can be substituted with an o-ring of the same diameter. One word of note on the fittings though, they are sized for 1/4" (6mm) thick top cover. If they are used with 1/8" (3mm) the extra space will need to be taken up with an equal thickness washer or gasket. Print them laying down and use supports to prevent them from snapping off.

Topside Fitting.stl 702.13 kB · 0 downloads Inside Fitting.stl 831.14 kB · 0 downloads TPU Seal Ring.stl 68.05 kB · 0 downloads

Looks good; have you printed and tested these?

Though I have never tried myself, from what i've seen on youtube, I don't trust FDM for making water tight parts. I suppose it would be easy to silicone the inside. I'm just buying the fittings I need, which I just need 2 anyway:

Good old SharkBite PEX fittings for the pump and all the pipes are sealed with adjusted pressure rings:

 

And this is what it looks like with the raised cable chains. It takes about 200mm of extra wire length to get the bigger radius and max chain travel:

[Simon2.4]

To slip tight rings on silicone tubes, lubricate by keeping it drenched with isopropyl alcohol.