Additive manufacturing by definition is a process of adding material (solid filaments or powdered particles or liquid resins) together layer by layer to form a three dimensional object. The entire process is computer controlled and the object formed is a perfect replica of the corresponding 3D CAD model designed earlier in a relevant CAD software.
Additive manufacturing, or most commonly known as 3D printing, is a revolutionary manufacturing process and touted as the first manufacturing revolution of the 21st century. The name clearly explains the process where material is added layer by layer and fused together to form the object.
Additive manufacturing also has significant advantages over the traditional manufacturing processes or subtractive manufacturing processes.
Subtractive manufacturing, as the name suggests, is a process wherein a solid block of material is cut in subsequent stages to form the final part. This process has inherent drawback of wastage of material as bulk of the raw material is cut away. Secondly, it also involves a series of different operations like turning, milling, drilling, etc., to remove material and this increases the production time and manual intervention leading to larger lead times and wastage of resources.
Subtractive manufacturing is most suitable for mass production as it relies on economies of scale and short batch productions are relatively costly.
Additive manufacturing eliminates most of the limitations of subtractive manufacturing. Since the object if built layer by layer by adding material, it saves a lot of material which otherwise would have been wasted. It eliminates the need to perform numerous cutting operations and builds the object in a single operation. The manual intervention is eliminated and a dimensionally accurate replica of the CAD model is built (printed). Complex geometries which were previously not possible can be easily and efficiently 3D printed without the need of assembly.
Additive manufacturing is not a mass production technique, at least as of now but research is moving towards finding a solution for the same issue. It is now a great alternative to short batch production requirements.
Additive manufacturing process starts from a CAD file designed in any relevant CAD software (PTC Creo, Solidworks, Fusion360, etc.). This 3D CAD file saved in relevant formats (most common being .STL & .OBJ) is loaded into a printer compatible slicing software and the CAD model is sliced and converted into a Geometric code (G-Code) which the 3D printer can understand. This G-Code file is then traced used by the 3D printer to subsequent layers on above the other to form the final object.
The final part may or may not require post-processing depending on the design, orientation and technology used.
Additive manufacturing technique is used in numerous processes and multiple technologies have emerged over the years.
Below is the list of some of the most common additive manufacturing technologies:
FDM/FFF: FDM/FFF is the cheapest form of 3D printing technology accessible to everyone. It uses polymer materials in a filament form which are melted by a heater and then extruded onto the build platform in subsequent layers to form the printed part.
SLA/DLP: SLA/DLP printers use a UV laser/UV light source which is flashed on the resin contained in a tank. On exposure to UV light, the resin hardens (or cures). The hardened resin is built up layer by layer to form the final object.
SLS/DMLS: SLS is a powder bed fusion 3D printing technology wherein the material is in a fine powdered form. This powdered material is melted at a particle level with a CO2 laser to fuse with the adjacent particles to trace out a layer. The object is built layer by layer to form the final object.
The major difference between SLS & DMLS is the use of metal materials in DMLS.
Binder Jetting: Binder jetting is similar to inkjet printers, but binder jetting uses two materials, a binding agent & powdered material, unlike regular inkjet printers. The liquid binder acts as a binding agent to the powdered layers of the material. The print head moves horizontally along the X-Y direction depositing the binder while the bed which holds the powdered material moves in Z-direction. After successive layers, the object is completely printed and is supported by the surrounding powder.
Will Additive Manufacturing replace Traditional Manufacturing?
Researchers and scientists have debated a lot on the revolutionary capability of additive manufacturing and its potential to shape the future world. While some believe traditional manufacturing has no replacement while others feel that soon additive manufacturing will replace the subtractive manufacturing process. While the debate may go on for years, currently, both the technologies, additive and subtractive complement each other and can easily sustain by leveraging their own potential.
Complete replacement of subtractive is a distant possibility but not a guarantee as yet.