How does a 3D printer work?

Introduction

You want to use 3D printing, but don’t know how 3D printers work? Or maybe you are already using 3D printing but don’t really understand the way these impressive 3D machines work. That is why, today, we chose to focus on these amazing 3D printing systems.

How does a 3D printer work? Are there different types of 3D printers? Let’s go deeper into the 3D printing technology!

What is a 3D printer?

At first, 3D printing seem like a little bit of magic, we see that this amazing technology can help to build houses or any objects from our daily life. But how does it work?

First, let’s go back to the basics and see what a 3D printer is. From metal to plastic or even chocolate, additive manufacturing gives life to a lot of different projects. There isn’t just one type of 3D printer, there are a lot of existing machines, and a lot of different printing techniques.

Here is the basic 3D printing process: first, you need to get a 3D file. The 3D design is necessary while starting a 3D printing project, it the digital version of the project that you will 3D print.

Then, you will have to choose the 3D printing technology you need for your project. Each material has its own properties, your choice will totally depend on the nature of your project. Do you need a rapid prototype or an end-use product? Does your object have to be heat resistant, flexible or really resistant to stress? This choice is surely an important step in this process and it will define the quality and the coherence of your project.

After all of this, your 3D design will be sent to a 3D printer, to create a three-dimensional object, with a succession of layers. But, what are the different 3D printers on the market and how do they work?

Plastic 3D printers

Selective Laser Sintering (or SLS): This 3D printing technique is perfect to create complex forms or interlocking parts. How does an SLS printer work? This plastic 3D printing technique creates 3D printed objects by sintering the powder layer by layer. The powder bed is preheated, almost at its melting point, and then a laser sinters the powder according to the 3D file. The laser sinters the powder layer by layer, creating a solid object. Polyamide needs to be sintered at a temperature of 160°C to 200°C.

Fused Deposition Modeling (or FDM): This additive manufacturing technique is preferred by hobbyists and in education. Thanks to one or two print heads, the 3D machine allows the deposition of the 3D printing materials. This 3D printer works by the material being melted and extruded through a nozzle to 3D print a cross-section of an object each layer at a time.

Metal 3D printers

Direct Metal Laser Sintering or DMLS: 3D printers for the DMLS technology create parts additively by sintering fine metal powder particles, to fuse them together locally. It is quite similar to the SLS process we saw previously, the major difference is the sintering temperature. Indeed, polyamide needs to be sintered at a temperature of 160°C to 200°C, whereas metal melts at a temperature around between 1510°C and 1600°C meaning that a more high-wattage laser is needed to reach that temperature.

A roller will apply a layer of metal powder, then the laser will sinter the powder and the build platform will lower before applying a new layer of powder. The process is repeated until the desired 3D part is created! Once it’s finished, the 3D printed parts need to cool down.

Selective Laser Melting, SLM: This method creates parts additively by fusing metal powder particles together in a full melting process. With this SLM process, like for other additive manufacturing techniques, your metal part will be created layer by layer, according to your 3D model.

The build chamber of the 3D printer is filled with an inert gas (either argon or nitrogen at oxygen levels below 500 parts per million) in order to create the perfect conditions for the melting process. Indeed, unlike DMLS, SLM fully melts the powder, and therefore it needs to reach a higher temperature than this other metal 3D printing technique. This process allows the metal to form a homogeneous block with great resistance.

Binder Jetting: Binder Jetting is an additive manufacturing method that also creates metal parts additively. This process works with a binding agent. This liquid binding agent is deposited on the powder, according to the 3D file you want to have made. The powder is lightly cured for solidification between each layer. When the printing process is complete, the build box is removed from the printer and placed into an oven for curing.

When the process is over, the parts are extracted from the build box and the remaining powder is removed thanks to brushes and air blowers.

Resin 3D printers

The DLS technology: The DLS technology developed by Carbon works by projecting a continuous sequence of UV images, generated by a digital light projector, through an oxygen-permeable, UV-transparent window below a liquid resin bath.

The dead zone created above the window maintains a liquid interface below the part. Above the dead zone, the curing part is drawn out of the resin bath. Carbon 3D created two 3D printer machines: the M1 printer and the M2 printer for this technology.

Polyjet 3D printers: PolyJet 3D Printers spray layers of curable liquid photopolymer onto a build tray. During the pre-processing, the software automatically calculates the placement of photopolymers and support material from a 3D CAD file. During the printing, the resin 3D printer jets and instantly UV-cures tiny droplets of liquid photopolymer.

Multicolor 3D printers

Colorjet: One example of multicolor printers is the ZCorp 3D printer. This machine, like all other 3D machines, print out the object layer by layer. A rolling batch leaves a uniform layer of the sandstone-like powder. From there, two printing heads pass over the batch, coloring and adhering the object at the same time. The batch of powder then makes another pass, until the object is completed!

Which should you choose?

We hope that this blog post helped you to understand how 3D printers work and understand the different possibilities. There are obviously a lot of choices to 3D print your project, each 3D printing technique and 3D printer has its specificities. Check out our 3D printing catalog and choose your 3D printing technique! Upload your 3D file on our online 3D printing service and get your instant quote for your project!

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