Differences between FDM / FFF and SLS 3D printing technology

The most popular 3D printing technology is FDM / FFF, which is successfully developing both in the industrial and amateur worlds – at home. In the latter case, this is due to very cheap, but still functional 3D printers provided by companies such as PRUSA Research, Creality3D or UltiMaker. In turn, SLS technology based on PA12 polymers is dominant only in the large industry sector, serving as a complementary production tool for low series of end-use parts. Each of the mentioned methods has its own unique features and applications. Although both techniques are used to create three-dimensional objects, they differ in fundamental aspects of the manufacturing process, materials, and resulting quality.

FDM/FFF involves the extrusion of a thermoplastic material through a heated nozzle, which arranges the molten material layer by layer to form an object. In contrast, the SLS method uses a laser to selectively sinter thin layers of polymer powder, such as PA12, layer by layer, creating the structure of the object.

FDM/FFF mainly uses thermoplastic filaments such as PLA, ABS, or PETG and this method is often limited to relatively simple geometries and may show visible layering. SLS is based on polyamide PA12 and, recently, also flexible TPU and high-performance PP (polypropylene), which allows the creation of more complex geometries with higher accuracy and better surface quality, thanks to the uniform sintering of the powder.

The FDM/FFF technique often requires the use of support structures to hold the parts during 3D printing, especially with complex geometries where there are overhangs. In SLS, the unsintered powder acts as a natural support, enabling the creation of complex and delicate structures without building additional supports.

FDM/FFF printed objects usually require additional surface finishing to achieve smoothness. SLS offers better surface finish and higher quality of details. Moreover, objects made of PA12 using SLS technology are characterized by better mechanical properties, including strength and flexibility.

While both FDM/FFF and SLS are popular 3D printing methods, they differ significantly in terms of production process, material options and quality of the final product. SLS with PA12 offers greater precision, better surface quality and the ability to create more complex geometries, making it the preferred method for applications requiring higher accuracy and durability. Technology Applied – the largest Polish company providing 3D printing services, offers both additive methods, so if you want to test them at the level of the final application, it is worth consulting them and ordering test prints.

Photos: www.ta.parts