Processes - Additive Manufacturing
Fused Deposition Modeling (FDM)
Fused Deposition Modeling (FDM) was developed by Stratasys in Eden Prairie, Minnesota. In this process, a plastic or wax material is extruded through a nozzle that traces the part's cross sectional geometry layer by layer. The build material is usually supplied in filament form, but some setups utilize plastic pellets fed from a hopper instead. The nozzle contains resistive heaters that keep the plastic at a temperature just above its melting point so that it flows easily through the nozzle and forms the layer. The plastic hardens immediately after flowing from the nozzle and bonds to the layer below. Once a layer is built, the platform lowers, and the extrusion nozzle deposits another layer.
The layer thickness and vertical dimensional accuracy is determined by the extruder die diameter, which ranges from 0.08 to 0.4mm (0.003” to 0.016”). In the X-Y plane, 0.05mm (0.0019”) resolution is achievable for high precision FDM printers. A range of materials are available including Polylactic acid (PLA), polyethylene terephthalate glycol (PETG), acrylonitrile butadiene styrene (ABS), Nylon, Polycarbonate (PC), Acrylonitrile Styrene Acrylate (ASA), thermoplastic polyurethane (TPU)
Advantages
Low Cost
FDM stands out as one of the most cost-effective additive manufacturing technologies, offering exceptional value through its affordability and broad material compatibility. It supports a wide selection of thermoplastic filaments available in various colors and properties, many of which are economical and readily accessible.
Speed
FDM is also highly efficient in terms of production speed. Parts can be printed within minutes to a few hours, significantly reducing lead times and accelerating the prototyping cycle. This makes it ideal for rapid design iterations and time-sensitive manufacturing needs.
Scalability
The modular and adaptable design of FDM systems enables the production of larger components with a favorable cost-to-size ratio, making it a practical solution for both small-scale and large-format printing applications.
Disadvantages
Low Resolution
FDM typically produces thicker layer heights and coarser surface finishes, making it less ideal for printing intricate details or high-precision components. Even with the ability to adjust nozzle size and layer thickness, the minimum feature size achievable—typically around 0.4 mm—falls short when compared to the finer detail possible with technologies.
Surface Quality
Since FDM utilizes the layer-by-layer printing process, while foundational to its functionality, also introduces issues related to surface quality and structural integrity. Prints often display visible layer lines and a rough texture, which may require additional post-processing—such as vapor smoothing, sanding, gap filling, or epoxy coating—to achieve a refined finish.
Failure along the layering direction
FDM-printed parts exhibit anisotropic mechanical properties, meaning their strength varies depending on the direction of applied force. This is because the bond between layers is typically weaker than within a single layer. As a result, FDM parts are prone to failure under stress applied parallel to the layering direction. While adjusting the print orientation or alternating print axes can improve strength, the structural limitations still make FDM less suitable for load-bearing or highly durable parts.
Capabilities
Disclaimer: All process specifications reflect the approximate range of a process's capabilities and should be viewed only as a guide. Actual capabilities are dependent upon the manufacturer, equipment, material, and part requirements.