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3D Printing SLS: functional parts, no supports.
Professional SLS 3D printing service. PA12 nylon powder sintered with CO₂ laser. Isotropic isotropic, parts with complex geometries in one piece and properties equivalent to injection moulding.
±0,3 mmTolerance
0 supportsComplex geom.
5 working daysProduction from
SLS · SinteritChamber 175 °C · CO₂ Laser
Layer 412/1240 · 100 µm
PA12
175 °CChamber
CO₂ 30WLaser
100 µmLayer
No supportsFREE GEOMETRIES
100% isotropyUNIFORM STRENGTH
Short runs viableUP TO 500 PCS NO MOULD
Industrial qualityEQUIV. INJECTION MOULDING
WHAT IS SLS 3D PRINTING
Selective laser sintering: thermoplastic powder fusion.
SLS SLS 3D printing (Selective Laser Sintering) is an industrial additive manufacturing technology. It works by selectively fusing polymer powder particles (nylon PA12) using a high-power CO₂ laser that scans the powder bed layer by layer.
The key advantage: the unsintered powder bed acts as a natural support. This enables printing highly complex geometries, one-piece assemblies, internal channels and lattice structures that would be impossible with FDM or SLA. Up to 80% of unused powder is recycled in the next batch.
The resulting parts have a density close to 100%, son isotropic (equally strong in all directions), with mechanical properties comparable to injection moulding.
QUICK TECH SPECS
Physical principleLaser sintering
Base materialPA12 / PA12+GF
Build volume40×40×40 cm
Grain size40 – 90 µm
Typical layer100 – 200 µm
Tolerance±0,3 mm / 100 mm
SupportsNot required
Imprimakers lead timeFrom 5 working days
HOW SLS 3D PRINTING WORKS
The SLS 3D printing process, step by step.
SLS is the most complex and most industrial of the three technologies. The full process (heating, printing, cooling and cleaning) can take several days per batch, but it fits many parts in one run.
STEP 01 · NESTING
Part nesting in the batch
With no supports required, we optimise the 3D volume by nesting all order parts in the build chamber. More efficiency, lower cost per part.
STEP 02 · PREHEATING
Chamber at 170–175 °C
The powder is preheated to just below its melting point (≈ 175 °C for PA12). This means the laser only needs to supply the extra energy required to sinter.
STEP 03 · SINTERING
CO₂ laser fuses the powder
A laser scans the current layer at high speed, sintering only the part areas, layer by layer. Then a roller spreads a new layer of powder on top.
STEP 04 · CLEANING
Cooling + depowdering
The batch cools slowly to avoid warping. We then extract the parts from the powder block, clean with compressed air and deliver.
ADVANTAGES & LIMITATIONS
Why choose SLS... and when it's not worth it.
SLS is the most versatile technology for functional parts, but also the highest-cost entry point. It makes sense when geometry or quantity justifies it.
Advantages Pros
- Unrestricted geometriesInternal channels, lattices, pre-assembled assemblies, living hinges, working joints straight from the printer. No supports.
- Mechanical properties equiv. to injection mouldingDensity >95%, isotropic. Better impact, fatigue and chemical resistance than FDM or SLA. For real end-use parts.
- Cost-effective short runsBy nesting parts in the batch, cost per unit drops with quantity. Competitive against injection moulding below 500–1,000 units.
- Uniform, professional finishUniform matte surface, technical feel. Ready for end-use without mandatory post-processing. Dyeing and smoothing optional.
- Chemical and thermal stabilityPA12 nylon resists oils, petrol, solvents and temperatures up to 170 °C. Ideal for engine, chemical or industrial parts.
- Powder reuseUp to 80% of unsintered powder is blended with fresh material and returned to the next cycle. Less waste, more sustainable.
Limitations Cons
- Higher entry costMore expensive per gram than FDM. Only worth it when geometry is complex or you need several units.
- Matte and porous finishParts come out with a slightly sandy and porous feel. For a smooth or transparent finish, post-processing is needed (chemical smoothing, sealing).
- Longer lead timeThe full cycle includes preheating, printing, cooling and cleaning. Standard lead time is 5 working days.
- Limited material catalogueWe work with PA12 and PA12+GF. For other needs, check our FDM or SLA services.
- Less detail than SLATypical layer is 100–200 µm. For text <1 mm or very fine textures, SLA gives better results.
- Natural colour: dark greySLS nylon comes out dark grey. For specific colours, dyeing after printing is required (Smooth Coloring or DyeMansion process).
TECHNICAL SPECIFICATIONS
Capabilities of our SLS service.
Default parameters applied in our SLS fleet. We work with Sinterit printers for functional production of PA12 and PA12+GF nylon parts.
LAYER HEIGHT100 – 200 µmStandard SLS layer. Not adjustable as in FDM/SLA.
TOLERANCE±0,3 mmper 100 mm of dimension.
MINIMUM WALL1,0 mmThin walls possible from 0.7 mm in small parts.
MINIMUM DETAIL0,3 mmEmbossed text readable from 0.8 mm height.
PART DENSITY95 – 99 %Near-solid. Properties equivalent to injection-moulded plastic.
COLOURSDark greyNatural colour. RAL dyeing available on request.
FILE FORMATSSTL · STEP · OBJAlso STP, IGES, IGS, ZIP. Up to 200 MB per file.
LEAD TIME5 working daysIncludes preheating, printing, cooling and cleaning.
AVAILABLE POWDERS
Materials for 3D printing SLS.
We work with nylon PA12 and glass fibre-reinforced PA12. These materials offer the best combination of mechanical strength, durability and part quality for functional production.
SLS · STANDARD
Nylon PA12
The SLS industry standard. Excellent balance of strength / durability / cost. Resistant to chemicals, oils and solvents. Skin-contact safe and biocompatible.
- Dark grey
- Up to 170 °C service temperature
- Excellent chemical resistance
SLS · STIFFNESS
PA12 + glass fibre (PA12+GF)
Glass microsphere reinforcement. Higher stiffness, thermal resistance and dimensional stability. For structural parts, technical tooling and high-load applications.
- Higher elastic modulus
- Up to 170 °C service temperature
- Greater dimensional stability
APPLICATIONS BY SECTOR
Applications of SLS.
SLS is the technology of choice when final-part quality is required. Particularly strong in automotive, aerospace, healthcare and consumer products. Replaces injection moulds for medium runs.
Automotive
Functional brackets, intake manifolds, electrical housings, end-use parts in low-volume vehicles. PA12 resistance to oils and temperature is ideal.
- Technical brackets
- Ducts and manifolds
- Vehicle customisation
Aerospace and drones
Lightweight and strong parts, topologically optimised lattice structures, cable supports, electronic housings for UAVs.
- Lattice structures
- UAV housings
- Lightweight supports
Consumer products
Short runs of eyewear, sports accessories, appliances, tools. Replaces injection moulding below 500–1,000 units, with no tooling cost.
- Runs of 10–500 units
- Eyewear and accessories
- Custom parts
Healthcare and orthotics
Custom insoles, personalised prosthetics, ergonomic splints, orthopaedic supports. PA12 is biocompatible and sterilisable, suitable for prolonged skin contact.
- Custom insoles
- Splints and prosthetics
- Custom orthoses
Industry and tooling
Assembly jigs, inspection fixtures, welding jigs, machining guides. On-demand spare parts for discontinued machinery.
- Functional tooling
- Industrial spare parts
- Inspection jigs
Robotics and mechanics
Functional gears, robotic arms, complex pre-assembled joints. PA12 nylon density and wear resistance make it ideal.
- Functional gears
- Joints and hinges
- Integrated mechanisms
SLS VS FDM VS SLA
Is SLS the right technology for your project?
SLS is the optimal choice for functional production, short runs and geometries other technologies cannot achieve. For large low-cost parts, FDM; for fine visual detail, SLA.
| Parameter | FDM | SLA | SLS |
|---|---|---|---|
| Material | Thermoplastic filament PLA, ABS, PETG, NYLON, PC, TPU… | Liquid photopolymer resin Standard, Tough, Castable, Flex, High-Temp… | PA12 / PA12+GF Sintered nylon powder |
| Relative cost | € · Most affordable | €€ · Mid-range | €€€ · More expensive per gram |
| Surface finish | Visible layers, stair-step effect 0.1 to 0.3 mm between layers | Smooth, near-polished Layers 25 to 100 µm | Uniform matte, slightly porous |
| Minimum detail | 0,4 mm | 0,025 mm (25 µm) | 0,3 mm |
| Mechanical strength | Good · anisotropic Weaker on Z axis | Medium · more brittle parts Tough resin improves it significantly | Excellent, isotropic Injection-equivalent |
| Max. volume | 500×500×500 mm | 220×220×220 mm | 40×40×40 cm |
| Supports | Yes · break-away or soluble | Yes · point contact | NO supports required |
| Best for | Prototypes · tooling · large low-cost parts | Fine detail · jewellery · visual prototypes | Functional production · short runs · complex geometries |
FINISHES AND POST-PROCESSING
Available finishes for SLS.
SLS parts come out with a uniform finish ready for end use. If you need colour, gloss or waterproofing, we offer several levels of specialist finishing.
STANDARD · INCLUDED
Depowdering
Residual powder cleaning with compressed air and fine bead blasting. Matte finish, natural powder colour. Suitable as end product.
Cost: included
+ DYEING
Dyeing (Smooth Coloring)
Immersion in thermally activated dye. Colour penetrates 0.3–0.5 mm into the part and does not peel. Colours: black, grey, blue, red, green.
Cost: contact us
+ PAINTING
Primer and paint
Filler primer + acrylic paint to your spec. RAL chart. For specific finishes not available with dyeing.
Cost: contact us
FREQUENTLY ASKED QUESTIONS
FAQ about SLS 3D printing.
The most common questions we receive about our SLS 3D printing service. If your question is not here, write to us directly.
Still have questions?
info@imprimakers.com →
When should I choose SLS instead of FDM or SLA?
Choose SLS when: (a) you need mechanical strength equivalent to injection moulding, (b) your part has complex geometry (cavities, lattices, integrated assemblies) that would need many supports in FDM/SLA, or (c) you want to produce a short run (10–500 units) without investing in a mould. For simple low-cost parts, FDM. For extreme visual detail, SLA.
What strength do SLS parts have?
SLS PA12 nylon has tensile strength ~48 MPa and elongation at break ~20%: comparable a piezas inyectadas. Resiste aceites, gasolina, disolventes habituales y temperaturas hasta 170 °C. Es isotropic (equal in all directions), unlike FDM, which is weaker between layers.
Why does SLS not need supports?
Because the unsintered powder bed itself acts as support. La pieza se construye dentro de un bloque de polvo: las capas que están "en el aire" en realidad reposan sobre polvo que no ha sido sinterizado. Cuando termina la impresión, simplemente sacudimos el polvo sobrante. Esto permite imprimir cavidades, ensamblajes pre-ensamblados (bisagras, articulaciones) y geometrías complejas sin restricciones de orientación.
Are SLS parts watertight? Can they be used with liquids?
SLS parts have inherent microporosity (density 95–99%). They work for low-pressure liquid use, but may seep slowly under pressure or with thin liquids. If sealing is critical, we offer epoxy resin sealing or VaporSmooth chemical smoothing, que cierra los poros y deja la pieza estanca al 100 %.
What colour are SLS parts?
The natural colour is dark grey in PA12. Para otros colores, ofrecemos immersion dyeing (Smooth Coloring): el tinte penetra 0,3–0,5 mm en la pieza, no se descascarilla y resiste roces. Cualquier RAL disponible bajo consulta.
How long does SLS printing take?
The complete SLS cycle is longer than FDM or SLA because it includes preheating, printing, slow cooling and depowdering. Nuestro plazo estándar es 5 working days from order confirmation. The advantage: dozens of parts fit in the same batch, making SLS very efficient for short runs.
Do you produce short SLS production runs?
Yes, it is our favourite use case for SLS. Trabajamos series de 10 a 500 unidades sin coste de molde, con descuentos por volumen significativos. Para tiradas mayores de 500–1.000 ud. evaluamos contigo si tiene más sentido inyección de plástico tradicional.
What files do you accept for SLS printing?
We accept STL, STEP, STP, IGES, IGS, OBJ, ZIP up to 200 MB per file. Models must be closed (manifold) with no holes in the mesh. If you need help with CAD preparation, we offer modelling and repair from 25 €/h.
Is SLS eco-friendly? Is the powder reused?
Yes, partially. Up to 80% of the unsintered powder is mixed with new material and goes back into the next cycle. It generates far less waste than FDM with supports, and virtually no liquid waste (unlike SLA).
Start your SLS today.
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