In addition to knowing how a 3D printer works and the different techniques covered by additive manufacturing, it is necessary to understand the different preparatory stages that precede the manufacturing phase.
3D printing begins with a digital file called a 3D file, without which it is impossible to print an object. This file, which corresponds to the virtual model of the part, and the software, the tool that allows you to draw it in three dimensions, are essential elements in converting a 2D image into a 3D object.
There are several ways to get a 3D model
The first is to download 3D printable files from specialized sites. When you don’t have the means or the technical skills, the simplest method is to retrieve your file directly from a dedicated platform. Many websites are offering this kind of 3D model for free or not.
Thingiverse, the famous sharing platform of the American Makerbot, is undoubtedly the most popular among makers. But also 3D Warehouse, the well-known image bank of Sketchup Google, a kind of Amazon of 3D printing. Finally, let’s also mention Cubify, a platform created by the American manufacturer 3D Systems. In this more elitist and qualitative system, designers selected in advance for the quality of their creations offer their 3D models.
3D modeling software
To print an object, except for rare exceptions, having a 3D file is a must. This can be created using 3D modeling software, retrieved directly from a specialized site, or via a 3D scan. To design a part in 3D, the first solution is to model it, i.e., draw it in three dimensions. To do this, there is a wide range of free or paid design software on the market, which can be divided into four main groups:
1. Volumetric modelers
These modelers allow you to work with simple and primitive shapes: cylindrical, cubic, rectangular, spherical, etc. You design the part by adding, subtracting, or assembling forms like a sculptor. They are widely used for the manufacture of mechanical parts.
2. Surface modelers
Surface modelers that mathematically define the object’s surface are generally used in the artistic field for design, digital sculpture, and organic forms.
3. Parametric modelers
These modelers are primarily intended for professionals such as engineers or architects. With this tool, you do not model by drawing but by programming. Thanks to equations, you can parameterize as you wish. A parametric modeler allows you to create mechanical parts and objects with organic shapes (gears, jewelry, etc.). OpenSCAD and Rhinoceros 3D (via the Python functionality) are the best known. Besides, Python is easy to learn. Of course, coding is not so bright and easy, especially at the beginning, but you can always get assistance and programming assignments help from professional developers online.
Whatever the modeler, in addition to being able to work on complex geometric shapes, it also allows playing with colors, textures, and brightness. The modeler’s choice will depend on the nature of the object, its applications (sculpture, mechanical part, architecture, etc.), the budget, and the user’s skills in this field.
4. 3D sculpture software
The software in this category allows you to model your model as if it were clay. In addition to the usual 3D modeling features, other tools will enable you to grasp, pull, press, smooth and pinch your ball of material until you obtain the final shape. This digital sculpting technique is particularly well suited to modeling organic figures such as figurines or jewelry. The number 1 software in this field is the famous ZBrush from Pixologic. Its very high level of detail and its hyperrealistic results make it a modeling tool widely used in animation and cinema.
The 3D scan
The second method consists of digitizing the object you wish to print with a 3D scanner. Among the many models on the market, there are three leading families:
1. The scanners called structured light emit different types of radiation: x-ray, laser, light, etc., which are projected on the object while a camera analyzes the deformation of the projection.
2. Laser scanners work similarly to laser rangefinders used to measure distances. Thousands of laser points are projected onto the target object, each corresponding to a spatial coordinate. Some of the best-known are the Faro model and NextEngine.
3. Stereoscopic scanners work with two video camera systems pointing at the same object. The principle is the same as human stereoscopic vision. When we look at something, our right eye and our left eye each send their information to the brain, which will reconstitute the image from the two images received.
4. The Kinect is the cheapest method on the market, even if it is not the most accurate. This is a peripheral of the Xbox game console. It is a small camera that detects movements and images. This technique has been diverted from its initial use to play the role of a scanner by coupling it to different software such as Scenect, Skanect, or ReconstructMe.
Calling on a 3D designer
While 3D printing is becoming increasingly easy and accessible for the general public, creating a 3D model is still a complicated process and is mainly reserved for professionals. So when you want to make your part, especially in very complex shapes, it is necessary to call on the services of a 3D designer (also called a modeler or 3D designer).
The STL format
Whatever the method for recovering the file, it must be exported in a specific format, the standard format being the STL (Standard Tessellation Language). Invented by 3D Systems, this format describes the surface geometry of your object. The exported file is a mesh composed of several triangles that determine the volume of your object in space. It is essential to ensure that this mesh is well closed so that it is considered solid, and its quality is crucial because it affects the final result of your print. Even if all the software does not export in STL format, often it is enough to modify the extension to avoid the problem.
Among other export formats, OBJ is used in particular cases. Developed by Wavefront Technologies, it is mainly used for printing multicolored materials. Its simple structure also makes it easy to handle with programming languages.
Let’s also mention the 3MF, a format imagined by Microsoft. It is wealthier than its predecessors, STL or OBJ, because it includes more parameters (textures, colors, meshes, etc.) but is also more flexible to adapt to the different 3D printing processes. Born from a world consortium of the same name, this universal format aims to solve the problems of interoperability and functionality that the current designs have.
Preparation of the STL file
Before launching the printing, there is a last operation. The software will have to cut this STL file into several slices, each representing a portion of the model to be printed. The lower the resolution, the more pieces are needed and the longer it will take.
In general, each 3D printer has its integrated slicing software. Among the most common is the famous Cura, MakerWare, Lychee Slicer 4.1, KiSSlicer, Slic3r, or ReplicatorG. The sliced file will be exclusively in G-code format, an almost universal command language for machine tools.
A support for your object
For FDM 3D printing (fused deposition), the addition of a manufacturing grid called raft (below the part) or brim (around the part) is sometimes recommended to support your object. This support prevents the part from coming off the tray (a phenomenon called warping), especially if the base is small.
The layer-by-layer deposit will be made on this base to prevent the piece from collapsing. This type of support is most often used for ABS or nylon-type filaments whose edges tend to come off due to the shrinkage of the plastic when it cools down, especially if the 3D printer does not have a heated plate.
For plumbed objects such as figurines or a rocket, a support structure (a kind of scaffolding) will be needed to support the part during printing. The slicing software determines the location of these supports and the quantity of material to be deposited according to an exact grid to remove it more quickly once the printing is finished.
Exporting the file
There are several ways to export a 3D file. It all depends on the type of 3D printer used – its brand and model. The export can be done via a USB cable, Wi-Fi, or an SD card. For most 3D printers on the market today, the transfer of the 3D file can be done via all these options, with the addition of Wi-Fi.
There’s no ideal way to create files for 3D printing, so try different methods and use whatever is best for you. We hope that this article was helpful and exciting for you.