The primary case for 3D printing with a water-cooled HotEnd like the new Titan Aqua from E3D is related to the use of 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, in order to prevent materials like ABS and ASA from warping due differences in air temperature.
Simple covers are actually very effective at warming the environment around the print and allow users to print in materials including polycarbonate, ULTEM, and PAEK family polymers, 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 E3D 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.
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, E3D 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 many liters of air.
E3D’s 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 running 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. The Aqua is also very watertight indeed. By implementing a gasketing system with a custom-made, tightly-fitting seal, the Titan Aqua is as watertight as a vacuum-sealed raincoat.
Both Titan Aqua and its predecessor Titan Aero are based on E3D’s classic Titan Extruder. 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.
Read more about the Titan Aqua on E3D’s blog by clicking here.