Comparison of SLA and FDM/FFF technologies in industrial 3D printing

3D printing technology from thermoplastics in the form of a filament – FDM / FFF, is the most popular and cheapest three-dimensional printing method. In turn, SLA – historically the first additive technique, although more expensive to use and therefore less popular among users, offers incomparably better quality of finished parts. However, this does not mean that it is “better” than FDM / FFF, just “different”. In this article, we describe the key differences between both manufacturing techniques, based on the experience of Technology Applied – the largest 3D printing house in Poland, which uses all the most important additive methods in everyday work.

SLA, or stereolithography, uses UV light to harden photopolymerized resins layer by layer. This method is known for its very high accuracy and finish quality, allowing the creation of complex, precise details. In contrast, FDM (Fused Deposition Modeling) or FFF (Fused Filament Fabrication) involves the gradual application of layers of molten material, usually thermoplastic, to build an object. Although FDM/FFF is more available and less expensive, it has lower accuracy and poorer surface quality compared to SLA.

One of the key aspects that differs SLA from FDM is the way in which support structures are generated. In SLA, these structures are often necessary to support the 3D print during the resin curing process and must be manually removed after printing is complete. This process can be time-consuming and requires additional work. In FDM/FFF, support structures can be used, but their removal is usually easier. Additionally, using two-head 3D printers, it is possible to build support structures from material soluble in water or chemical compounds. This makes it much easier, but it makes the whole process longer.

The finishing process using SLA technology is more complicated and “dirty”. It requires rinsing prints in isopropyl alcohol to remove excess resin, and the tools used in the process must be additionally cleaned. After finishing work, 3D prints should also be illuminated with UV light in dedicated post-processing stations. Meanwhile, FDM / FFF is a relatively cleaner process because it does not require additional activities apart from removing any supports (the exception is the dissolution of support structures printed from a different material).

The differences in consumables between the two technologies are also significant. SLA uses a variety of light-cured resins that can offer various properties, including flexibility, strength and transparency. FDM/FFF involves the use of thermoplastic filaments such as ABS, PLA or PETG, which are cheaper and easier to handle, but offer limited properties compared to SLA resins.

In summary, SLA and FDM/FFF are technologies that have their own unique advantages and limitations. SLA, used by companies such as Technology Applied, ensures higher quality and accuracy, which is crucial in many professional applications. FDM/FFF, on the other hand, offers simplicity, accessibility and greater ease of use, making it more suitable for hobbyists and smaller projects. The choice of appropriate technology depends on the specific project requirements, budget and desired properties of the printed object.

Photo: www.ta.parts