Additive Manufacturing (AM) is used to describe a set of technologies that create 3D objects by adding layer upon layer of material. Although the 3D printing materials vary from technology to technology, they require computers with specialized 3D modelling software. The printing process starts with the creation of Computer Aid Design (CAD) sketches.
The sketches are then read by AM devices to build a structure, layer by layer, using whichever printing material is available. Printing materials that lend themselves to 3D printing include plastic, powder filaments, sheets of paper, or liquid. Below are six popular types of 3D printing:
1. Stereo Lithography (SLA)
This 3D printing method is an additive manufacturing process used to implement projects that involve 3D printed objects. It’s the oldest in the history of 3D printing, although it’s still in use today. Stereolithography turns your models into real 3D printed objects. So, whether you’re a creative person who desires to make plastic prototypes of upcoming projects or a mechanical engineer who wants to verify if a component fits into their design, SLA is the way to go.
SLA Printing machines convert liquid plastic into real solid 3D objects that are hardened by rinsing into a solvent and then placing them in an ultraviolet oven for final processing. SLA was patented by Charles Hull in 1986.
2. Digital Light Processing (DLP)
DLP 3D printing is similar to stereolithography. These types of 3D printing were developed by Larry Hornbeck of Texas Instruments in 1987. After that, it became the most popular technology for projectors. DLP lays digital micromirrors onto a semiconductor chip. It’s ideal for cell phones, movie projectors, and 3D printing.
DLP works with photopolymers such as the SLA. However, these types of 3D printing use different light sources such as Arc lamps and a Liquid Crystal display panel. The light sources are applied onto the whole surface during a single run of DLP. These types of 3D printing are cost-effective and has the advantage of an excellent and robust resolution. It also has minimal wastage. Examples of DLP rinses include the MiiCraft High-Resolution 3D printer, the Envision Tec Ultra, and Lunavast XG2.
3. Selective Laser Sintering (SLS)
Selective Laser Sintering (SLS) utilizes laser as a power source to create solid 3D objects. SLS was developed in the 1980s by professor Joe Beaman and Carl Deckard, one of his students at Texas University. Although SLS and SLA are similar, SLA uses liquid resin. SLS, on the other hand, uses powdered material in the Vat and does not require support structures. This is because it’s always surrounded by unsintered powder.
SLS is popular in 3D printing of customized products due to its wide range of material options, which include ceramics, nylons, glass, silver, steel, and aluminum.
4. Fused Deposition Modeling (FDM)
FDM technology was initially developed and implemented in the 1980s by its inventor, Scott Crump. Over the years, other 3D printing companies have adopted similar technologies with different names. A well-known example is the MakerBot company that has a similar technology known as Fused Filament Fabrication (FFF). FDM allows you to print final end-use products and concept models other than just functional prototypes.
Its products can be utilized in engineering-grade thermoplastic and in high performance. It’s the only printing technology that builds parts with production-grade thermoplastics. Hence, final products are of excellent chemical, thermal, and mechanical qualities. FDM makes it possible to create objects with complex cavities and geometries.
FDM technology builds objects layer after layer in a bottom-up fashion by extruding and heating the thermoplastic filament to a melting point. It then extrudes it through a nozzle onto a built platform along a precisely calculated path. When the thin plastic layers come into contact with the previous layers, they cool down and harden. Objects can be painted, milled, or plated afterwards.
FDM Technology is considered environmentally friendly and easy to use. Hence. It’s widely spread across diverse industries such as automobile companies like BMW and Hyundai, to food companies like Dial and Nestle, not forgetting the medical industry where it’s used to package drugs.
5. Selective laser melting (SLM)
SLM uses a high-power laser beam that melts and fuses metallic powders to form 3D objects from 3D CAD data. SLM is not a subcategory of selective laser sintering (SLS). Unlike SLS, SLM fully melts the metal material into a solid 3D-dimensional part. SLM is a brainchild of a German research project conducted at the Fraunhofer Institute ILT in 1995. Like other 3D printing methods, a CAD file is processed by a special software featuring a standard .stl file format.
6. Electronic Beam Melting (EBM)
EBM is an additive manufacturing 3D printing for metal parts, developed initially by Arcam AB Inc. EBM and SLM are somewhat similar processes, the only difference being that the EBM 3D Printing method while utilizing a powder bed fusion technique, uses an electron beam as a power source. The SLM, on the other hand, uses a high-power laser beam as a power source.
Besides, EBM uses a metal powder that melts under extreme temperatures of up to 1000°C. It forms a 3D layer by layer part using a computer that controls the electron beam in a high vacuum. EBM technology applies mainly to aerospace and medical implants. Metals used in EBM include Inconel 718, Inconel 625, and pure Titanium.
The printing technology has rapidly evolved over the years. One segment that has seen tremendous growth is 3D printing. Depending on available printing material and the surface to be printed on, there’s always an array of 3D printing technologies to choose from.