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How Does 3D Printing Work?

Bindu swetha
Until a couple of years ago, the 3D printing technology was unheard of, except among some geeky tech circles. Recently, it has started gaining momentum with the NASA opting to invest in 3D food-printing technology. Know what is this technology exactly and how does it function.

Did You Know?

Even James Bond uses a 3D-printed car! The Aston Martin used in the 2012's movie Skyfall was made in a 3D printer.
3D printing is the process of making a three-dimensional object from a digital file. This object is a three-dimensional version of the file created using a computer software. Charles Hull is the inventor of the 3D printer. The first 3D model was created in 1981 by Hideo Kodama of Nagoya Municipal Industrial Research Institute.
3D printing is the member of the additive manufacturing (AM) family. Additive manufacturing is the process in which the object that needs to be printed is created by adding material to the object, layer by layer. This means that if a doll has to be created, the plastic material is added in limited quantities to create different layers.
The material is added till the final product is created. This technology has started to grow in various fields, like medicine, aerospace, automotive industry, toy manufacturing, fashion, etc. With the advancement in its technology, 3D household printers are also available.
There are many online printing services too, which require people to upload their 3D designs. Here is the step-by-step method of 3D printing.

3D Printing Process

The printing process can be broadly explained in three phases:
(i) pre-processing;
(ii) production;
(iii) post-processing.

First, let us take a look at these phases.
This phase is the one where the blueprint of the object is created. A digital model of the object needs to be created using computer-aided design (CAD) software, or any animation software. This file is fed to the printer in an .stl format.
In this stage, the printing process takes place. Suitable material are added to the printer, and the printer deposits layers of these material to create the object. Once the object is created, it is removed from the printer and taken to the post-production process.
In this phase, the additional material deposits on the object are cleared. Thus, the final 3D printed object is created.

Step-by-step Process of 3D Printing

There are a lot of steps involved in creating the 3D object. Here's a detailed explanation of the intermediate steps in the printing process.

Step 1: Prepare the 3D Model

The first and the foremost step in the process is to create the CAD file. This 3D model will give the designer an idea about the look of the final product. This digital file is the blueprint for the object to be created. Also, CAD offers a huge library of different material.
The designer can select any material and check the behavior of the 3D model under different conditions. Most 3D printers need an .stl file to start the process. So, using one of the many software available, convert the CAD file to .stl file. This conversion can be done using software, like RedEye, Stratasys, AutoCAD commands, SolidWorks, etc.

Step 2: Send the STL format file

After converting the CAD file to STL format, the file is sent to the machine. Upon selecting the "Print" option, the file is automatically transferred. Here, the size and the orientation of the page (landscape or portrait) is selected. This option is similar to the one available in 2D printers.

Step 3: Setup of the Machine

The material that is to be used needs to be fed to the machine.
Apart from this material, a support material also needs to be fed. This support material will hold the product until it is completely developed. The material cartridges are inserted. A suitable base is inserted, and the printing job is selected.

Step 4: Machine Performs the Printing Function

Once, the material cartridges are loaded in the machine, the internal machine process starts. The printer block moves to the "start" position and creates a thin layer.
The machine itself mixes the material in varying quantities to create various textures and flexibility regions on the object body. The support material is used to create this initial/foundation layer.
Now, the extrusion head moves in the XY direction to fill more layers of the object material. Once, the motion in this direction is completed, the gantry moves in the Z direction and fills it with the object material. UV light or other modeling techniques are induced to print the layers on top of one another.
The movement in the Z direction of the gantry depends on the desired thickness of the object. Printing in this direction is achieved by lowering the base/tray that holds the part.
Support material is sprayed, and this creates the base for printing.
Machine prints continuously in X and Y direction in high speed.
Now, the machine prints in the Z direction. This is the step that differentiates 2D and 3D printing.

Step 5: Taking Out the Part

Once, the printing process is completed, the printer displays the "Complete" command. The lid of the printer is opened, and the tray is taken out. The part is removed from the tray, and its post-processing phase begins.

Step 6: Cleaning the Object

To support the part material while it is still in the production stage, support material is used. This excess support material needs to be separated from the object. But this removal process needs to be done carefully. This excess material is removed by spraying water with high force on the object.
Also, the part can be put into a tank where soluble material are used to remove the excess material. The part can also be manually cleaned by breaking or twisting the undesired material.

Step 7: Additional Steps

These steps are optional ones. The part can be used once it is cleaned.

The part sans the support material can be dipped in a special glue to make it stronger. The glue-coated part is subjected to heating, so that the glue sticks evenly to the part.
Even after removing the excess material, the surfaces of the part can be rough. They can be smoothened by manual processes. The part can also be painted to give it an enhanced look.
With the help of 3D printing, many useful products can be created, like fossil replicas, toys, human tissues, etc. Thus, with the advancements in this technology, we can look forward to creating many new products within no time.