What is 3D Printing?

3D Printing, also known as additive manufacturing is a process by which 3D digital files are transformed into three dimensional solid objects. The objects are built up by laying down successive layers of material on the building surface/platform.

Whilst there are a number of different technologies in the 3D printing space; the fundamentals are basically the same. Every 3D print starts as a digital 3D design file – like a blueprint – for a physical object. This design file is then sliced into thin layers which are then sent to the 3D printer.

This is the most popular type of 3D printing in the market and also the most common technology used in desktop 3D printers. It is ideal for quick and low-cost prototyping. In these printers, the ink is a string of solid material called the “Filament”. This Filament is melted as it passes through a heated nozzle before it is then laid down onto a surface (sometimes heated) called a “Print Bed”. As soon as the Filament is laid down, it is cooled and solidifies. The nozzle guides the melted Filament onto the desired path in the X and Y directions. Once the layer is complete, the print bed is slowly lowered in the Z direction layer by layer to allow the nozzle to print new layers. Eventually the three dimensional object is complete, after being built from the bottom up. FDM is currently limited to thermoplastic materials; however recent innovations are opening up the prospect of printing in metal.

These technologies work on the principle that special photosensitive liquid resins solidify when exposed to a light source. In these printers, the build platform is at the top and the resin tank is at the bottom. The build platform is submerged into the resin tank; then the light source quickly moves back and forth in the X and Y directions to map the desired pattern and the resin begins to solidify. The building platform then moves up the Z direction by the thickness of a single layer, and the light source begins to harden the next layer. The difference is that SLA uses a UV laser as the light source whilst DLP employs a projector. SLA & DLP 3D printers produce highly accurate parts with smooth surface finishes and are commonly used for highly detailed sculptures, jewelry molds, and prototypes. 3D Printer Technologies

 This technology uses a laser to melt and solidify layers of powdered material into finished objects. The print bed is a layer of powder; and the laser is mapped to melt or sinter the powder in the desired pattern. The print bed then moves down by one layer and is topped up with a fresh layer of powder and once again the laser melts the new powder layer; the process repeats itself eventually building up the final object.

Material Jetting (Stratasys PolyJet and 3D Systems MultiJet Modeling) technologies are similar to inkjet printing, but instead of jetting drops of ink onto paper, these 3D printers jet layers of liquid photopolymer onto a build tray and cure them instantly using UV light. The build process begins when the printer jets the liquid material onto the build tray. These jets are followed by UV light, which instantly cures the tiny droplets of liquid photopolymer. As the process is repeated, these thin layers accumulate on the build tray to create a precise object.

Selective Laser Melting and Electron Beam Melting (SLM and EBM) are two of the most common metal 3D printing technologies. Just like SLS, these processes create objects from thin layers of powdered material by selectively melting it using a heat source. Due to the higher melting point of metals they require much more power – a high power laser in the case of SLM or an electron beam for EBM. During the printing process, the machine distributes a layer of metal powder onto a build platform, which is melted by a laser/electron beam. The build platform is then lowered, coated with new layer of metal powder and the process is repeated until the object is fully formed.