We Are Learning 3D Printing Through Our Personal Experience…
The 3D printer we are using, namely the MakerBot Replicator 2 is equipped with a 0.4 mm nozzle for extruding the molten thermoplastic and this does provide a decent speed/quality options. However various 3D printers do use different nozzles that have varying hole diameter, so we wanted to play a bit with that and to try replacing the 0.4 mm default one with different size. Our first try was with a nozzle that had double the size of the hole for extruding the thermoplastic material as compared to the standard one, so 0.8 mm instead of the 0.4 mm one. We have created the nozzle ourselves by carefully enlarging the hole of a standard 0.4 mm nozzle with a precise 0.8 mm drill bit, an operation done slowly and by hand and not with a rotary tool. The idea to use a nozzle with a larger hole was to try printing with rougher detail level at a faster speed, but also to see if it is possible to print finer details with good enough quality as with the smaller nozzle.
To test we have used a small simple house 3D model that looks like an easy to print thing, but is actually a more complex and demanding than you may think while still fast to print even at small layer sizes. We have test printed the simple house with both the 0.4 mm standard and the larger 0.8 mm nozzles with three different layer heights – a very fine one at 0.1 mm, rougher details at 0.4 mm and very rough details at 0.8 mm layer height. There are some rules for the settings when you are printing in the form of ratios such as the one between the layer height and the extrusion width depending on the nozzle diameter you use in order to get the best possible results. In general however printing with a layer height over the diameter of the nozzle you use is not recommended as it does not produce so good results.
Printing with the standard 0.4 mm diameter nozzle took about 22 minutes at 0.1 mm layer height, 7 minutes at 0.4 mm layer height and 4 minutes at 0.8 mm layer height. The resulting quality at 0.1 mm was great, at 0.4 mm was pretty good and at 0.8 mm was awful and pretty much unusable at standard printing speeds. We have tried lowering the extrusion speed at 0.4 mm and 0.8 mm to allow for easier printing and hoping for a bit better quality, but that did not help.
Replacing the nozzle to the modified 0.8 mm one took us about 16 minutes for printing at 0.1 mm layer height, 5 minutes for the 0.4 mm layer height and just 2 minutes at 0.8 mm layer height at the standard speed settings. The fact that we have larger hole on the nozzle allows us to extrude more material for the same amount of time than with a smaller nozzle diameter and as a result we could increase the speed. But even without increasing the printing speed we got faster print times with the default extrusion speed of the Replicator 2. The quality of the 0.4 mm print was comparable to that of the print with the smaller nozzle and that of the 0.8 mm was as expected better even though at that layer height the number of fewer layers used made the object seem rougher. At the setting using thicker layers we could further increase the printing speed at up to about 50% over the standard one for the 3D printer and get the same quality results. With the highest quality 0.1 mm layer resolution however we’ve had to lower the speed a bit in order to get good results, at up to about 25% lower extrusion speed the print result was actually surprisingly good.
Do note however that while the layer resolution with the larger 0.8 mm nozzle could go in a wider range as compared to the standard 0.4 mm nozzle there are some drawbacks. As you will probably see on the photo above the corners of the house that are supposed to be 90 degree ones are a bit rounder on the prints done with the larger nozzle. Also there are some tweaks to the print settings that you need to consider when printing with a larger nozzle, you can for example reduce the number of outline/perimeter shells, especially when you get to use smaller layer height as the layer width will actually be twice the one of the 0.4 mm nozzle. So instead of two outline shells you can go with just a single one and that is especially important when you are printing smaller objects where the use of two perimeter shells might actually cause you trouble printing properly.
In the end if you need to print larger models where the level of detail is not so important, but the speed of the printing process is more important you might want to play with nozzles that have larger diameter than the standard ones used for your printer. Next up we are going to be trying out with twice the smaller diameter nozzle, namely 0.2 mm as this is pretty much the smallest one you can currently find available.