FDM (Fused Deposition Modeling) is the most cost effective way technology for producing custom thermoplastic parts and prototypes. It has the shortest lead times and ensures fast deliveries.
A spool of filament is loaded into the printer and then fed to the extrusion head, which is equipped with a heated nozzle. Once the nozzle reaches the desired temperature, a motor drives the filament through it, melting it. The printer moves the extrusion head, laying down melted material at precise locations, where it cools and solidifies (like a very precise hot-glue gun). When a layer is finished, the build platform moves down and the process repeats until the part is complete.
After printing, the part is usually ready to use but it might require some post-processing, such as removal of the support structures or surface smoothing. Any 3D printing technology that requires support to produce parts accurately needs support removal as the first stage of post-processing. A support can be either standard or dissolvable. For 3D printed enclosures that need to accept screws, threaded bass inserts are great way to add longevity.
As of 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.
Image Courtesy: 3DHubs.com