3D printing, also known as additive manufacturing, has transformed how products are designed, developed, and manufactured. 3D printing has the potential to transform a wide range of industries, from simple prototypes to complex end-use parts. Not all 3D printing technologies, however, are created equal. In fact, the ASTM group “ASTM F42 – Additive Manufacturing” classified Additive Manufacturing technology into seven types in 2010.
These technologies have distinct capabilities and are well suited to a variety of applications. In this article, we will look at the seven different types of additive manufacturing technologies, as well as their advantages and disadvantages. Understanding the various 3D printing technologies available can help you choose the best one for your specific needs, whether you are a designer, engineer, or manufacturer.
7 Types of Additive Manufacturing Technologies
Material Extrusion
Fused deposition modelling (FDM) is one of the most common and widely used material extrusion type of 3D printing technology. FDM was trademarked by Stratasys Inc., one of the largest 3D printing companies in the world. The technology is also known as Fused Filament Fabrication (FFF), a name popularised during the RepRap movement of 2004 to avoid infringement issues.
In this method, material in a filament form is drawn through a nozzle, is heated and then extruded and deposited onto the build platform in a layer-by-layer process to form a 3D printed object. The affordability of these FDM printers, smaller sizes and ease of use are some of the main factors that has led the era of democratisation of 3D printing. These printers can start from as low as $200 and thus are mostly preferred by students, enthusiasts and makers. But do not consider this technology to be only for beginners or for low value items. Industrial FDM or material extrusion printers have proven advantages and are widely used for industrial and engineering prototypes, manufacturing aids and even for end-use application parts. Such printers are quite costly as they provide superior print quality, reliability, consistency of prints and even operate with engineering-grade materials like Carbon fibre, PEEK, and others.
FFF 3D Printers are most commonly cartesian type where the nozzle moves in X & Y-direction whereas the build platform moves in the Z-direction. However these printers can also be delta, polar and scara types.
The main challenge in using these printers is that it has a maximum resolution of around 100 microns and thus gives a rough surface finish. Entry-level printers require a lot of trial and error and produce inconsistent results which is not ideal for industrial usage.
Vat Photopolymerisation
Vat Photopolymerisation is a type of 3D printing technology that uses a vat of liquid photosensitive polymer resin which is cured using a light source. This curing process is carried out in a layer-by-layer form to ultimately build a 3D printed object. As the technology uses resin material, it is also referred to as resin 3D printing.
A layer of liquid resin is spread across a build platform in the vat photopolymerization process, and a UV light source is used to selectively cure the resin, solidifying it into the desired shape. The build platform is then lowered by one layer’s thickness, and the process is repeated layer by layer until the final object is finished. As vat photopolymerization technology is well-suited to producing objects with high detail and precision, it is widely used in fields such as dentistry, jewellery making, and product design.
Vat photopolymerization is not a single technology and has evolved over the years. You can read more on the evolution of resin 3D printing to know how the technology went from SLA to DLP to MSLA.
The resins are polymer compound with additives for specific applications like Tough, Flexible, Dental, etc. These processes impart high quality surface finish to the object. Most common process in this category are Stereolithography (SLA), Digital Light Processing (DLP) and Masked Stereolithography (MSLA).
Powder Bed Fusion
Powder-bed fusion (PBF) is an additive manufacturing technology which fuses powdered material to additively build 3D objects. Other technologies which operate on this principle are Selective Laser Sintering (SLS), Direct Metal Laser Sintering (DMLS), Selective Laser Melting (SLM), Electron Beam Melting (EBM), and Selective Heat Sintering (SHS).
Powder Bed Fusion (PBF) is a 3D printing technology that involves selectively fusing or melting layers of powdered material, usually metal or plastic, with the help of a heat source such as a laser or electron beam. A thin layer of powder is spread across a build platform in this process, and the heat source selectively melts or sinters the powder particles together, layer by layer, until the final object is complete.
PBF is popular in industries such as aerospace, automotive, and medical devices because it is highly precise and can produce complex, intricate shapes with excellent mechanical properties. However, the process can be time-consuming, and post-processing may be necessary to remove excess powder and smooth the printed object’s surface.
Material Jetting
Material Jetting process operates in a similar way a regular two-dimensional inkjet printer works. In this technology, the material, typically in liquid or viscous form, is deposited in tiny droplets that are precisely placed using computer-aided design (CAD) data. A UV light source is then used to cure or solidify the droplets, resulting in a solid layer that adheres to the previous layer. Layer by layer, this process is repeated until the final object is complete. Material Jetting can create high-resolution, highly detailed parts out of a variety of materials such as plastics, ceramics, and metals. Moulds, prototypes, and functional parts are frequently created using this technology in a variety of industries, including healthcare, aerospace, and automotive.
This additive manufacturing technology is used to create parts with precise dimensions and a smooth surface finish. Parts can be printed with equal accuracy in both glossy and matte finishes. It is a multi-material printing technology that allows for full-color printing. Drop-on-Demand (DOD) technology is also used to create wax-like parts, and it employs printheads that dispense liquid material. It is primarily used to generate investment casting patterns.
Binder Jetting
Binder Jetting is a 3D printing technology that selectively bonds layers of powdered material, typically metal, sand, or ceramics, using a liquid binding agent. A thin layer of powder is spread across a build platform, and a precise pattern of liquid binder is jetted onto the powder, binding the powder particles together. Layer by layer, the process is repeated until the final object is complete.
Binder Jetting technology is popular in industries such as architecture, automotive, and jewellery because it is quick and inexpensive. Parts made with Binder Jetting technology, on the other hand, may require post-processing to achieve the desired strength and finish. Furthermore, the process may not be as precise as other 3D printing technologies, limiting its application in some cases.
Binder Jetting 3D Printing technology is similar to material jetting but it uses two materials in place of one. The two materials include a powdered base material and a binder material. The binder is dispensed on to the powdered material in the build chamber and acts as the binding agent for adhesion of individual layers.
This process is relatively fast but BJ parts are not recommended for use in structural applications. The unused powder acts as a support to the object and it as such does not need any support structure.
Sheet Lamination
The Sheet Lamination process encompasses two types of manufacturing techniques. Ultrasonic Additive Manufacturing (UAM) and Laminated Object Manufacturing (LOM) are two examples.
Ultrasonic welding is used in UAM to join metal sheets or ribbons without the need for additional machining or material removal. This process can be used to join various metals such as aluminium, copper, steel, and titanium, allowing for greater flexibility in the final part’s strength requirements. Because the metals are not melted, UAM uses less energy than other processes.
Laminated Object Manufacturing (LOM), on the other hand, constructs objects out of paper sheets and adhesive. During the printing process, a laser is used to trace the object’s cross-section, and a cross-hatch method is used to make the completed part easy to remove. However, LOM objects are not suitable for structural purposes and are primarily used for aesthetic purposes.
Directed Energy Deposition
Directed Energy Deposition (DED) is a 3D printing technology that is commonly used for metal and alloy additive manufacturing, but it can also be used for polymers, glass, and ceramics, though this is less common. In DED, a feed material in the form of wire is held in a nozzle that moves across multiple axes with an electron beam projector. The electron beam projector melts the feed material as it follows the object geometry to create the desired shape. Because it melts with a laser, the DED method is also known as Laser Engineered Net Shaping, 3D Laser Cladding, Directed Light Fabrication, or Direct Metal Deposition.
As the machines use 4 to 5 axis, the nozzle that supplies the material can be moved at various angles, making it a versatile method for building new objects as well as adding materials to existing models for repairs.
Titanium, cobalt chrome, and tantalum, a rare metal, are common materials used in DED technology. It is commonly used in the aerospace and automotive industries, but it also has applications in biomedical engineering and the military.
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