3D printing. Why and how?


For a long time, having a device that would allow us to create an object to our liking at the push of a button was the domain of science fiction. Well, as we are already used to, technology is already overtaking us on the right and some time ago technology came to light that allows even us mere mortals to really conjure up a real product in physical form from a digital record. Of course with certain limitations, but still relatively easy. But why would you really need to? So that we don't have to go to stores and print the products ourselves? Well, it hasn't happened in this form yet, but things have progressed quite a bit and let's see what we can really do. Everything is described below in a more layman's way, so I hope it will be understandable to everyone.



First of all, let's ask ourselves - why would we need this at all? In any case, the technology itself is quite fascinating, and it shows its practical value in applications where we need a unique product that cannot be obtained or bought and that we have created ourselves in a digital environment. So what can we create? It's probably not the first purpose to print toys for your kids, although people do that too. In the first phase, when the technology advanced to a useful level, this technology was seized mainly by engineers, designers and planners. Since the product printed on a 3D printer is a fairly accurate thing, it is very helpful when making prototypes or models. If we cite as an example the process of manufacturing an object, either for general use or strictly for a specific purpose: it is something completely different if, during the design phase, the shape and ergonomics of the product are observed on a computer screen, or if the same product is held in one's hands as a real object. In the latter way, it will be much easier to find out whether its shape is really ergonomic, fits well in our hand, fits into other objects, etc... Only when we are really satisfied with the shape can we go to the next step, making a tool for mass production. Sometimes prototypes were made from wood, which is imprecise and time-consuming manual work. 3D printing technology therefore allows us to save a lot of time and, of course, money. Any design errors can be corrected already on the model.

Also, 3D printing allows us to manufacture very complex, small-batch products and replacement parts, of course, where the technical specifications allow it. The latter is connected, of course, with the choice of materials in the printing process itself.



How does a 3D printer even work? Although we have a few different methods available, what they all have in common is that the product is created by applying material in layers. To caricature a little: imagine a pear cut into very thin slices. Each of these slices has a different shape, depending on where the cut is. So when we cut this pear into very thin slices, what we actually got from a 3D object is a collection of (almost) 2D objects that are stacked on top of each other to create an object in 3 dimensions, approximately the same way MRI works in medicine, where a strong magnet "cuts you " on the layer, and the computer assembles this set into a digital 3D image.

Recently, printers have become really accessible to practically anyone who would like to work in this field. There are currently two slightly different technologies available, which I will describe below.


Printing with filaments (thermoplastic)

The basic principle of this printer is the injection of molten plastic through a small hole (nozzle). For the system to work, this nozzle must be placed in a heated print head that moves in all three dimensions. In this heated head, the filament that the printer has wound in the form of a "string" on the reel melts and turns into a liquid state. The printer therefore injects a thin layer of plastic onto the work surface (in some professional printers, other materials can also be used, such as powdered metal, etc., but these are applications that, for the most part, at least in amateur use, we will not encounter for the time being). After the first layer is applied, the head moves up a few tenths of a millimeter and begins to apply the next layer, and so on until the final shape. Although printers of this type are relatively accurate, they enable very complex products, but they cannot be compared to resin printing technology in terms of detail.


Resin printing

These printers also print layer by layer using software that breaks the digital object into slices. However, here in the next phase it is a slightly different way, because the basic material is also different. With this printer, a special epoxy resin is poured into a special container. Here, too, we can choose from different resins - depending on what our needs are. Directly below this container, which has a transparent bottom, there is an LCD screen (it practically touches this transparent bottom). The screen emits UV light and shows the current layer being printed. Because the resin is sensitive to this type of light - it partially hardens. The system moves the working plate upwards via a worm screw, so that the layers are stacked on top of each other. In this case, the entire object moves up, which is fairly strongly glued to the work surface with the first layer (so that it does not fall into the container with resin). The object "grows" from top to bottom - exactly the opposite of filament printing, where the print head moves and the object is stationary. Resin printers are much more precise in terms of details and allow a resolution of up to 0.03 mm. Which is satisfactory for mechanical purposes, dental medicine, etc... They also have much less moving parts. The only disadvantage of this technology is that it is a little harder and dirtier work, because we have to wash all the containers and products with isopropyl alcohol at the end to remove the excess uncured resin. We also need to clean the rest of the tools and the container where the resin is left (which can be poured back into the packaging and stored). After cleaning, the product must be additionally and finally hardened with the help of a device that emits UV light.


With both technologies, we also have to count on support columns, because in certain shapes (especially negative ones) they support layers that are not yet completely solidified, so that they do not deform under their own weight. Most printing programs enable this automatically and we don't need to worry about where and how many of these supports are needed...

Both technologies are quite revolutionary and allow us to print products that we have drawn in one of the 3D modeling programs, or we have obtained or purchased the file of an already designed product online. All in all, it probably has a bright future, and with the current prices of printers, it has become accessible to just about everyone.


Tomaž Berčič


Here you can find links to the online store with printers and consumables:
3D printer ELEGOO MARS 3
Cleaner and UV hardener
Bad luck