FDM vs SLS vs SLA: Which 3D Printing Technology Is Right for Your Project?

The Short Version

Choose FDM when you need affordable functional parts or rapid concept models and surface finish is not critical. Choose SLS when you need strong, durable parts with complex geometry and no support structures. Choose SLA when you need fine detail, smooth surfaces, and dimensional accuracy for visual prototypes or dental and medical applications.

FDM — Fused Deposition Modelling

FDM 3D printing works by melting a thermoplastic filament and depositing it layer by layer through a heated nozzle. It is the most widely used 3D printing technology in the world — fast, affordable, and compatible with a wide range of engineering-grade materials.

When to Choose FDM

FDM is your go-to technology for functional parts that need to be strong and affordable but do not require a perfectly smooth surface. It is the best choice for concept models, early-stage prototyping, and custom jigs, fixtures, and production tooling — the kind of parts that engineering and industrial teams use every day on the factory floor.

FDM Materials

We offer six FDM materials: PLA for concept models, PETG for functional parts with chemical resistance, ABS for heat-resistant automotive and electronics prototyping, ASA for UV-resistant outdoor applications, Nylon PA for high-strength mechanical parts, and TPU for flexible gaskets, seals, and grips.

What to Expect

Layer heights range from 0.1 to 0.3 mm with visible layer lines. Parts are anisotropic — stronger along the print plane than between layers. Build volumes go up to 500 x 500 x 500 mm, making FDM the best choice for large parts. Standard orders ship in 3 to 5 business days, with express available within 24 hours.

SLS — Selective Laser Sintering

SLS 3D printing uses a laser to selectively fuse powdered nylon material layer by layer inside a heated build chamber. Because the unfused powder supports the part during printing, SLS requires no support structures — enabling complex geometries like interlocking parts, internal channels, and lattice structures.

When to Choose SLS

SLS is the workhorse of professional 3D printing. It excels at functional, durable parts for mechanical stress, chemical exposure, or repeated use. Widely used for end-use production parts, spare parts for legacy equipment, robotic end-of-arm tooling, and small batch manufacturing. Our case study on replacing a legacy valve housing in Stuttgart demonstrates SLS nylon delivered in 4 days, performing identically to the original machined part.

SLS Materials

Nylon PA 12 is the industry standard — excellent mechanical properties, chemical resistance, and thermal stability up to 170°C. Parts are isotropic with consistent strength in all directions.

SLA — Stereolithography

SLA 3D printing uses an ultraviolet laser to cure liquid resin one layer at a time with incredible precision. Layer heights as low as 25 microns produce the smoothest surfaces and finest details of any 3D printing technology.

When to Choose SLA

SLA excels at visual prototypes, dental and medical applications with biocompatible resins, and architecture competition models where fine detail matters. Our Copenhagen urban development model combined SLA building details with FDM terrain, helping the firm win second place internationally.

SLA Materials

Standard Resin for smooth, rigid visual prototypes and Tough Resin for functional prototypes needing impact resistance.

Head-to-Head Comparison

Accuracy: FDM ± 0.3 mm | SLS ± 0.2 mm | SLA ± 0.1 mm

Surface finish: FDM has visible layer lines | SLS is matte and slightly grainy | SLA is smooth and near-injection quality

Strength: FDM is good but anisotropic | SLS is excellent and isotropic | SLA is moderate but can be brittle

Complex geometry: FDM needs supports | SLS needs no supports | SLA needs supports

Max part size: FDM 500 x 500 x 500 mm | SLS 380 x 284 x 380 mm | SLA 145 x 145 x 175 mm

Relative cost: FDM lowest | SLS medium | SLA medium-high

Lead time: FDM from 24 hours | SLS from 48 hours | SLA from 48 hours

How to Decide

If it needs to be strong and functional with surface finish secondary, go with FDM. Widest material choice, largest build volume, lowest cost.

If it needs to be mechanically durable with complex geometry or you need multiple identical parts, go with SLS. No supports means design freedom, and Nylon PA 12 handles real-world use.

If it needs to look great or be dimensionally precise — presentations, dental, architecture — go with SLA. Nothing matches its surface quality.

Many projects benefit from combining technologies. A product prototype might use FDM for the internal chassis and SLA for the external housing. We help customers choose every day — get in touch for a free consultation.

Next Steps

Ready to get your part printed? Upload your STEP, STL, OBJ, 3MF, or IGES file and request a free quote. Standard delivery across Europe is 3 to 5 business days. Have questions? Contact us — our team helps customers make this decision every day.