For almost four decades now countless groups of super smart people have been advancing the technology that we simply call 3D printing. The more technical and accurate description of the process and technology is additive manufacturing but the concept is pretty straightforward. A 3D model image is sliced into tool paths and then sent to a 3D printer that lays down molten plastic (FDM/FFF), laser sinters a resin (SLA) or powder (SLS), or jets melted materials a single layer at a time and repeats this process to recreate the digital 3D model.
Now that we are done with the history lesson let's talk about how you choose the 3D printing process and material that is right for you? One of the important things to consider during the rapid prototyping process is the intended end use of the prototype or model. Will it be functional? Just it simply need to look good for demo or presentation purposes? Are you using it for an injection mold or jewelry mold? These are all common scenarios that you need to discuss before committing to a 3D printing format.
Below are the four most common additive manufacturing options available today.
Example of FDM 3D printing
Fused Filament Fabrication, also known under the trademarked term Fused Deposition Mdeling (FDM), is a 3D printing process that uses a continuous filament of a thermoplastic material. Filament is fed from a large coil through a moving, heated printer extruder head, and is deposited on the growing work. The print head is moved under computer control to define the printed shape. Usually the head moves in two dimensions to deposit one horizontal plane, or layer, at a time; the work or the print head is then moved vertically by a small amount to begin a new layer. The speed of the extruder head may also be controlled to stop and start deposition and form an interrupted plane without stringing or dribbling between sections.
Pros: cost-effective, fast, accurate, low odor during print process.
Cons: low resolution compared to SLA and SLS, limited to plastics for material type.
Stereolithography (SLA; also known as stereolithography apparatus, optical fabrication, photo-solidification, or resin printing) is a form of 3D printing used for creating models, prototypes, patterns, and production parts in a layer by layer fashion using photochemical processes by which light causes chemical monomers to link together to form polymers.
SLA can be used to create things such as prototypes for products in development, medical models, and computer hardware, as well as in many other applications.
Pros: Can be fast and can produce almost any design
Cons: Can be expensive and has a higher failure rate than PLA or ABS.
Material Jetting (MJ) is an additive manufacturing process that operates in a similar fashion to 2D printers. In material jetting, a printhead (similar to the printheads used for standard inkjet printing) dispenses droplets of a photosensitive material that solidifies under ultraviolet (UV) light, building a part layer-by-layer. The materials used in MJ are thermoset photopolymers (acrylics) that come in a liquid form.
Multi Jetting creates parts of high dimensional accuracy with a very smooth surface finish. Multi-material printing and a wide range of materials (such as ABS-like, rubber-like and fully transparent materials) are available in Material Jetting. These characteristics make MJ a very attractive option for both visual prototypes and tooling manufacturing.
Pros: Smooth surface, high-def detail
Cons: Brittle, expensive, and slow