FDM is the most cost-effective way of producing custom thermoplastic parts and prototypes. It also has the shortest lead times – as fast as next-day delivery – due to the high availability of the technology. A wide range of thermoplastic materials is available for FDM, suitable for both prototyping and some functional applications.
As for limitations, FDM has the lowest dimensional accuracy and resolution compared to the other 3D printing technologies. FDM parts are likely to have visible layer lines, so post-processing is often required for a smooth surface finish. Additionally, the layer adhesion mechanism makes FDM parts inherently anisotropic. This means that they will be weaker in one direction and are generally unsuitable for critical applications.
SLA can produce parts with very high dimensional accuracy, intricate details, and a very smooth surface finish ideal that are ideal for visual prototypes. A large range of specialty materials, such as clear, flexible, castable, and biocompatible resins, or materials tailored for specific industrial applications, are also available.
Generally, SLA/DLP parts are more brittle than FDM parts, so they are not best suited for functional prototypes. Also, SLA parts must not be used outdoors, as their mechanical properties and color degrade when they are exposed to UV radiation from the sun. Support structures are always required in SLA/DLP which may leave small blemishes in the surfaces they come in contact with that need extra post-processing to remove.
SLS parts have very good, almost-isotropic mechanical properties, so they are ideal for functional parts and prototypes. Since no support structures are required (the unsintered powder acts as support), designs with very complex geometries can be easily manufactured. SLS is also excellent for small-to-medium batch production (up to 100 parts), since the bin can be filled throughout its volume and multiple parts can be printed at a single production run.
SLS printers are usually high-end industrial systems. This limits the availability of the technology and increases its cost and turn-around times (compared to FDM or SLA, for example). SLS parts have a naturally grainy surface and some internal porosity. If a smooth surface or water tightness is required, additional post-processing steps are needed. Beware that large flat surfaces and small holes need special attention, as they are susceptible to thermal warping and overwintering.
Direct Energy Deposition (DED) is a series of several similar metal 3D printing technologies that creates parts by melting and fusing material as it is deposited. While it can be used to manufacture new parts, DED is typically used for repairing and rebuilding damaged components. One of the main metal 3D printing technologies, DED is already utilized in key industries like aerospace & defense, oil & gas, as well as the marine industry.
A thin layer of powder is first spread over the build platform where it is heated to a near-sintering temperature. A carriage with inkjet nozzles (which are similar to the nozzles used in desktop 2D printers) passes over the bed, depositing a fusing agent on the powder. At the same time, a detailing agent that inhibits sintering is printed near the edge of the part. A high-power IR energy source then passes over the build bed and sinters the areas where the fusing agent was dispensed while leaving the rest of the powder unaltered. The process repeats until all parts are complete.
Composites typically comprise a core polymer material and a reinforcing material, like chopped or continuous fiber. The composite material offers higher strength and stiffness compared to non-reinforced polymers. In some cases, it can even replace metals like aluminum.
These enhanced material properties make composites sought-after materials for tooling and end-use applications in a range of industries, like aerospace, automotive, industrial goods plus oil, and gas.
Atomic Diffusion Additive Manufacturing (ADAM) is a proprietary 3D printing process developed by Markforged. It is a metal 3D printing process built on the foundation of metal injection molding, a metalworking process that uses a mold, powdered metal, and binding agents to create three-dimensional models.