We Are Learning 3D Printing Through Our Personal Experience…
If you have wondered how the extruder of a 3D printer looks like in terms of operating temperature this thermal image can give you some idea about that. It is of the extruder of MakerBot Replicator 2 3D printer, but the situation is similar with other devices that are based on the same technology using thermoplastic material. Pretty much the heating block is the hottest thing and the rest of the extruder remains with a relatively low temperature, but if you have trouble with the extruder working properly one of the things that may be causing this is other components getting hotter than they should be.
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.
We were looking for a while at alternatives to using various kinds of tapes to cover the build plate of a 3D printer that can provide good adhesion, easy removal and most of all to be more durable, so that we won’t have to replace it often. One such solution that we have found out about is the BuidTak 3D printing surface that is essentially a specially developed thin plastic sheet that you stick on top of your build plate. This 3D printing surface is supposed to provide an optimal printing surface for 3D objects to adhere to for the duration of a print, while allowing for a clean, easy removal of completed builds. It is heat-resistant, so that you should be able to use it for ABS printing as well if you have a 3D printer with a heated build platform and not only PLA.
A single sheet of BuildTak should be more durable than any kind of tape and the price is affordable enough if the surface proves to be durable enough for making a lot of prints before having to replace it. The surface is available in multiple pre-cut sizes including rectangle, square and circle shapes that should fit on most FFF/FDM 3D printers available and if the size you need is not available you can go for a larger one and then cut the extra. We got two sheets with size of 292×165 mm (6.5″ x 11.5″) at $12 USD per sheet, this is the size needed for the build plate of the MakerBot Replicator 2 3D printer that use use with just a bit needed to be cut at one of the sides after applying the surface to the build platform.
Sticking the BuildTak 3D printing surface to the build plate of the 3D printer is a bit tricky, it is a lot like when installing a screen protector on a mobile phone or a tablet. You need to be careful and to remove air bubbles while sticking the surface and not trying to remove them after that as it will be very hard or impossible. Our first installation was less than perfect and we’ve had a few air bubbles left, good thing that we have ordered a spare sheet. Do note that after applying the BuildTak you will need to re-level the build plate as the height of the new 3D printing surface is probably going to be a little more than that of the tape that you have used before. Make sure you level the build plate properly by doing a test print, we have found out that printing a SIM card adapter does a great job for testing the proper leveling and is quick to print and uses little filament.
After applying the BuildTak 3D printing surface we have started printing using different filaments. No problems when using PLA – the printed part sticks well and is easy to remove, not that we expected otherwise, so we have moved to other more problematic filaments. Going for ABS on our 3D printer without a heated build platform we have observed the expected warping of the base of the printed part resulting in the object not being able to adhere to the build surface for long. We have then tried Bendlay filament, something that we had trouble printing on our Replicator 2 using the 3M ScotchBlue tape – we had trouble having the material to stick no matter what settings we have tried. With the BuildTak installed however we had no trouble printing using Bendlay filament, it was sticking quite well with very minor warping that we have observed at the very edges of the test prints – something that can easily be overlooked as the prints were fine in general. Next up was the T-glase filament that we also had trouble printing with on the standard blue painters tape, however the situation was not as good as with Bendlay here. It certainly was better than with the painters tape before, but still not good enough adhesion – we may have to play some more to find the best settings for printing T-Glase on the BuildTak.
We are going to continue playing with the BuildTak 3D printing surface printing with different filaments, but so far we are already seeing better results than when using various tapes for covering the build plate. Another good thing that we have also observed when using the BuildTak surface is that the bottom of the 3D printed parts is that it is smoother to the touch and a bit better looking as compared to when using painters tape.