3D Printing Technology

The process of producing three-dimensional, physical objects on the basis of a computer model. Initially, it was only one of the rapid prototyping methods used both for building molds and the prototypes themselves. Along with the advances in the accuracy of making objects by 3D printers, it has also become a method of making ready-made objects, machine elements and consumer devices.

3D printing is one of the methods of additive or incremental production, it is the production of items by adding building materials. A 3D printer is a digitally controlled machine that can recreate a digital model by shaping it piece by piece from some material. Only as much raw material as needed is used in 3D printing, so this technique can fundamentally change production in many industries or transfer it from the industrial world to our desks. A typical 3D printer consists of plastic structural parts, metal rods, bearings, motors and a control microcomputer. Only the former can be printed, the rest must be purchased, but they are standard, widely available components used in the industry. The function of the controlling microcomputer is usually performed by cheap and popular Atmel AVR processors.

In a nutshell, a 3D printer consists of the so-called the working platform, i.e. the table on which the 3D print is made (depending on the version, the platform is heated or not) and the head with the extruder, which is responsible for feeding the filament and heating it to such a temperature that it is liquid. Then, the head according to a specific movement (based on a spatial model), applies successively layer by layer until a ready model is created. The principle of operation of 3D printers is theoretically very simple. To create your first 3D print, we need:

• a program for spatial design + skills or a ready-made STL file

• 3D printer + necessary software

• filament - the material from which we print

At the beginning, however, you need to have an idea for the object, and this is often the most difficult step in 3D printing. Suppose we already have, in our imagination or on paper, an image of an object that we need. We need to use several tools to produce this item, as in any production method. 3D printers are digitally controlled machines, so the item must be described in a language they understand. You have to have a three-dimensional digital model of things. You can make it from scratch using almost any computer modeling program. The more artistic (Maya, Blender, 3ds Max) and the more engineering ones (SolidEdge, AutoCAD, Solidworks, FreeCAD, OpenSCAD) are suitable, the model can also be made from nature, using a 3D scanner. The three-dimensional digital model must then be simplified and converted into a list of instructions for the machine. This is done by programs called slicers (from the word slice - cut into slices), which first divide the block into thin parallel layers, and each layer divide each layer into tightly arranged plastic paths, and finally describe these paths in the language of CNC machines. The standard format understandable for all slicers is the STL file, any popular modeling tool can export in this format. The language of machines is g-code (GCODE), in which the next lines of text are the next commands: move the head to a given place at a given speed, heat the head, release so much and so much molten plastic. The ready list of instructions for the machine in the form of g-code must be given to the microprocessor controlling the printer. Some printers can read g-code from a memory card or USB flash drive, and even receive it via Wi-Fi. Others need to be controlled with a PC the whole time printing. The so-called host is used for control - a program that communicates with the printer via USB (most often emulating a serial port). The host sends the g-code line by line to the printer; in case of communication breakdown (e.g. computer hang-up), the printer will finish executing the last command and stop.

The plastic used in 3D printers is the same material as the one used to make Lego bricks. It has the form of a thin strip, melted in the nozzle and "spit out" as droplets with a diameter roughly corresponding to the thickness of the layer characteristic for a given device. You can print with almost any uniform material: plastics, polymer resins, glass, metals, wax, plaster. Many techniques allow small objects to be suspended in some type of carrier, which allows printing with a suspension of living tissue, composites of plastic with wood or metal, sugar, etc. Popular FDM printers use thermoplastics, i.e. polymers that become plastic when exposed to high temperatures and can be molded many times . The liquid, hot plastic ejected through the nozzle hardens instantly at room temperature. Thanks to this, you can put another layer on it after a while. 3D printing is a long-term process, at least compared to the time needed for printing, e.g. photos on an inkjet printer. In the case of home devices, it takes about 2 hours to produce an object the size of a smartphone housing. A 3D printer allows you to print and thus produce new things, such as jewelry, toys, machine and device elements and many other products. This is the key to simplifying the production of many technical components.