Water is Cool.
NB: We use the term ‘water’ interchangeably with ‘coolant’ throughout this blog post and, indeed, the product description. ‘Well which is it!?’ we hear you cry. Well it’s both, in that we recommend using a water-based coolant with Titan Aqua and the E3D water-cooling kit. You could use plain water and it would work, but it would also go mouldy and lime-scaley and generally gross and gunked-up quite quickly. Water-based commercial coolants contain all the anti-fungal salts and distillation that the system needs. Plus they’re often UV-colour tinted, which looks much cooler than boring old transparent H2O.
The primary use-case for water-cooled HotEnds in 3D printers is when using heated chambers or passively-heated enclosures. Heated chambers use an active heating element and are necessary when printing with some engineering and high-performance filaments. Passively-heated enclosures simply use heat generated from the print bed to warm the air inside a 3D printer, the intention being to prevent materials like ABS and ASA from warping due to draughts and cool air. The method for this can be as simple as a plastic sheet placed over the front of the printer, a box placed around the printer, or a roast-chicken bag wrapped around the printer (don’t laugh, there is video evidence of Sanjay using this method in the early days of E3D).
These methods are actually very effective at warming the environment around the print, and allow users to print in materials including polycarbonate, Ultem, and PAEK, but create a number of perhaps unexpected problems. For one thing, cooling starts to be less effective when you try to cool a HotEnd with warm air. This creates a less-sharp thermal transition for the filament, and therefore less precise printing. Expect oozing, blobbing, and stringing. Even good-quality fans like the ones we use for V6 and Titan Aero also start to fail at around 45°C - 50°C, and motors (which generate their own internal heat) aren’t keen either. Conversely, the air moving around the heatsink fan creates pockets of turbulent, cooler air. This risks more warping of the printed plastic, negating the benefit of a heated chamber. Fans are also noisy and can vibrate at high speeds.
[caption id="attachment_501" align="aligncenter" width="600"] This is Rory, creator of Titan Aqua. Inventor, engineer, part-time giant.[/caption]
Technically, a fan still does the actual job of cooling for Titan Aqua, but it’s not situated bulkily on the print-head next to the part. Instead, we use a large and very effective fan mounted outside of the chamber. The fan is big so that it doesn’t have to spin as fast as a normal one, also making it much quieter. The job of water in the system is to transfer heat from the HotEnd to a radiator attached to the fan, where it can be dissipated. Now while water isn’t the best coolant in the world (ammonia, for example, has a higher specific heat capacity, but is rather unpleasant), it is many, many times better than air. A small amount of water can do the same job as litres and litres of air.
Our design is such that coolant circulates inside the metal body of Titan Aqua, keeping it cool by carrying heat away. The water-cooling channel is intentionally wide to remove metal and to reduce as much weight as possible while maximising water-flow and heat-transfer area. This body simply and reliably mounts onto the face-plate of the extruder motor. While it’s not often discussed, motors do create heat internally due to electrical power dissipation, and can fail at temperatures over 80°C. Chances are therefore good that they will fail sooner or later when run in a heated chamber. Aqua’s internal cooling keeps the motor running reliably at an optimal temperature, and maintains the same powerful extrusion you’d get with a standard Titan setup.
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Of course the relationship between electricity and water has long been a somewhat turbulent one, and the proximity of flowing water channels to an electrical motor might be quite reasonably prompting wariness in some of you. We would like to dispel any fears you might have on this count; we’ve made the Aqua very watertight indeed. By implementing a gasketing system with a custom-made, tightly-fitting seal, we’ve made Aqua to be as watertight as a vacuum-sealed raincoat.
[caption id="attachment_506" align="aligncenter" width="600"] Groovy.[/caption]
Another aspect that some of you may find disconcerting is that the Aqua body and guide are actually two separate parts fixed together. This design isn’t absolutely ideal, as thermal contact is therefore less than perfect. However, it offers a number of benefits, in that it allows us to create variants for different filament sizes, it makes it much easier to assemble other components, and it makes manufacturing much easier and therefore less costly. This minor issue is also offset by the design of the components themselves, which are made to maximise surface area contact. In addition the amount of heat that needs to be transferred away from the heatsink is not as great as you might imagine, so that as long is removed efficiently (as is the case with water-cooling), the HotEnd will work perfectly.
As well as including all the benefits of water-cooling, Titan Aqua also includes some benefits all of its own.
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Both Titan Aqua and its predecessor Titan Aero are based on our classic Titan Extruder (as their names might suggest). This means that they make use of the same tried-and-tested features like the idler mechanism, sharp-toothed custom-machined hobb, and 3:1 gearing ratio, all of which make the Titan extremely precise, tenacious, and easy to use. This also brings all the benefits of reliability and expertise. We have thousands of hours of experience printing with Titan extruders in-house, which means that we know every single one of their strengths and potential weaknesses.
We’ve also carried through everything we learned while designing Titan Aero: we’ve kept the all-metal design and the compact, rigid body, while adding a cantilevered hobb shaft. This lowers the axial load placed on the shaft and makes the design more open from the front. It’s basically a water-cooled Aero with an even sharper thermal transition to further increase flow accuracy and reduce risk of jamming. We’ve also changed up the mounting style, so that you can assemble it independently before mounting it on your printer. This is a godsend when tinkering with enclosed printers, which aren’t known for their internal roominess.
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Aqua is a complete, grown-up member of the E3D family. Being cut from the same cloth as Titan Aero, Aqua also maintains the same compatibility with V6 hot-side parts. The heat break, block, nozzle, etc can all be swapped with V6 parts and even Volcano parts, so you can upgrade with E3D’s specialist high-temperature performance parts. In particular, we recommend the following upgrades for super-heated synergy:
Titanium heat break
Plated copper block and nozzle
High-precision heater cartridge
PT 100 amplifier board
PT 100 temperature sensor
[caption id="attachment_498" align="aligncenter" width="600"]Plated copper comes with extra shine.[/caption]
This isn’t our first foray into water-cooling. The Kraken, our mighty feat of engineering, not only had four heads but was also fed on water. Our water-cooling system, however, was less impressive. It was of course perfectly functional, but definitely still had a more home-made scent about it. Quite literally in fact, as we often used takeaway containers as coolant reservoirs and 3D printed some parts of it. Of course if you prefer this kind of set-up and have the skill to keep it working reliably then that’s absolutely fine (not to mention quite impressive!) and Aqua integrate into it quite happily.
However, in the interests of user-friendliness we’ve invented our own, much-evolved water cooling kit. It isn’t complicated - in fact we’ve taken steps to simplify it as much as possible. All parts are off-the-shelf, standard versions that can be easily modified with the same pieces as you’d find in a PC water-cooling system. We’ve combined the reservoir and pump into a single, quiet, unit and done the same for the radiator and fan. That’s not to say that the system doesn’t work hard. The water being pumped around the system simultaneously cools the tubes through which it flows, the various couplers, and even the motor.
[caption id="attachment_507" align="aligncenter" width="600"]Totally cool.[/caption]
One unique addition is that of slim, flexible nylon tubing which attaches to the HotEnd itself via adaptors. This tubing has the same outer diameter as Bowden tubing, meaning that it can be easily routed through cable chains for organisation and assembly. Adaptors connect these slim tubes with standard 8mm silicone tubing, of the same standard material and diameter as you would find in water-cooling systems built for computers.
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