Our top priority was a concept to develop a universal and reliable, wear-resistant nozzle with high hardness, but with the best possible thermal conductivity and the lowest possible coefficient of expansion at a reasonable price. Also, we didn't want to use inlays, instead we wanted to design a nozzle from solid material.
Why didn't we use steel for production?
Hardened steel has good mechanical properties, but (depending on the alloy) with its thermal conductivity of 21 to 31 W / mK and a relatively low density it is completely inferior to tungsten in this respect. Calibrating the temperature while printing with a nozzle made of such alloys can cause significant fluctuations, which can affect the quality of prints when using temperature-sensitive polymers.
Why didn't we use brass with a ruby/sapphire inlay?
Ruby nozzles are undoubtedly the top shelf. They are much harder than tungsten, but also much more expensive. The concept itself, which is based on embedding a ruby in the brass body of the nozzle, can be quite unreliable in some respects. Brass is a great heat conductor, but not particularly temperature-resistant. It is therefore not suitable for applications where high-temperature polymers have to be used, as changes in the metal structure can cause the corundum to loose from the brass body. For this reason, there are special versions of the ruby nozzle that are only intended for high-temperature printing - but they are almost twice as expensive as their brass counterparts.
Tungsten carbide? The non-plus-ultra?
In the early stages of our nozzle development, we took a very thorough and serious look at tungsten carbide. In our opinion, it has excellent properties, but the hardness that tungsten carbide offers would simply be an "overkill" in terms of abrasion resistance to current applications of 3D printing - at least as long as someone does not let diamond reinforced filament through the nozzle. As with the ruby, it would not be economical in this case.
Based on certain knowledge in the field of plastic extrusion, we, therefore, decided on a material that does the job just as well but is thermally more reliable. The last point is also the price - for tungsten carbide, corundum, and its processing relatively higher than for tungsten. Since we wanted our product to reach the majority of customers with desktop 3D printers, we found this factor also crucial.
Today we agree that we have managed to develop a 3D printer nozzle that combines our top 3 priorities:
1. Has an enormous hardness, thus offers an extremely high wear resistance in contrast to brass nozzles. Also, it offers high-temperature resistance so that materials can be printed at 400° and more without any problems.
2. Has excellent thermal conductivity, so the print layers are always constant, which affects the print quality. As there are no temperature fluctuations, you can in most cases print without calibration, with your usual print settings.
3. Relatively economical to manufacture, so we can pass the price advantage on to you as the end customer.
Below we are presenting the material comparison of Tungsten and the most popular 3D-printing nozzle materials currently on the market.