Fused deposition modelling (FDM), also known as the material extrusion additive manufacturing technique, utilizes polymers as the raw material (filament). The filament is usually heated to a molten state and then extruded through the nozzle of the machine (3D printer). The nozzle head can move in three degrees of freedom (DoF) to deposit the extruded polymer on the build plate as per the G-code instructions. As shown, the filament is continuously fed through the extruder and nozzle of the machine via the two rollers rotating in opposite directions. The material is deposited on the build plate layer-by-layer until the required product shape and size are achieved. During the layering, the printer nozzle navigates back and forth as per the spatial coordinates of the original CAD model in the G-code files until the desired size and shape of the component is produced. In some FDM systems (3D printers), multiple extrusion nozzles can be used to deposit the polymer constituents especially in cases where components of compositional gradients are required. Usually, the resolution and effectiveness of the extrusion largely depend on the properties of the thermoplastic filament and as such, different 3D printers are designed for specific filament materials. In fact, most of the low-cost FDM 3D printers can process only one type of thermoplastic and polylactic acid (PLA) is the most common material. The components are usually layered onto the build plate (platform), which after printing can be removed by snapping off or soaking in a detergent depending on the type of the thermoplastic. Then, the printed components may be surface cleaned, sanded, painted or milled to enhance both their surface appearance and functionality.
In certain FDM systems, multiple extrusion nozzles may be utilized, particularly for applications requiring components with compositional gradients. The quality and precision of the extrusion process significantly rely on the characteristics of the thermoplastic filament. Consequently, various 3D printers are tailored to accommodate specific filament materials. Many budget-friendly FDM 3D printers are restricted to processing a single type of thermoplastic, with polylactic acid (PLA) being the most prevalent material.
Following printing, the components are typically adhered to the build plate, which can be detached by either snapping off or soaking in detergent, depending on the type of thermoplastic used. Subsequently, the printed components may undergo surface cleaning, sanding, painting, or milling to improve both their appearance and functionality.
