Selective Laser Sintering at Indus3D, on an EOS P396 — the widest material range in the powder category, including flame-retardant grades.
SLS is the oldest and most proven process for producing functional plastic parts additively. A laser scans a layer of nylon powder and fuses it exactly where the part is, layer after layer, while the surrounding powder acts as natural support.
What that means in practice: any geometry can be printed, with no supports to design and none to remove afterwards. Parts can also be stacked through the full height of the chamber, which is what makes SLS economical on series.
How SLS works
The build chamber is pre-heated to just below the melting point of the powder. A roller spreads a thin layer, and a CO2 laser scans it, supplying exactly the missing energy for the particles to fuse — a process called sintering. The platform drops by one layer thickness, a new layer is spread, and it repeats.
At the end of the build the whole chamber is a block of powder with the parts hidden inside it. It then goes through slow, controlled cooling — a critical stage that prevents warping — and only then are the parts extracted and bead blasted.
The difference from MJF
Both are powder processes without supports, and the parts are similar in character. The difference is the heat source: SLS traces point by point with a laser, while MJF heats a whole layer at once with an infrared lamp. In practice MJF is faster with a full chamber, while SLS offers a wider material range — and above all the flame-retardant grades, which have no MJF equivalent.
The system we run
| System | Build volume | Why it matters |
|---|---|---|
| EOS P396 | 340 × 340 × 600 mm | Unusual height — long parts, or a deep stack of many parts in one build |
SLS materials
| Material | Character | Typical use |
|---|---|---|
| PA2200 (PA12) | Standard nylon, the most widely used | The default — functional parts, housings, fixtures |
| PA11 | More ductile, better impact resistance | Parts that take a knock or flex repeatedly |
| PA 2210 FR | Flame-retardant nylon | Aerospace, defence systems, electrical enclosures |
| PrimePart FR | Additional flame-retardant grade | Applications that must meet fire standards |
| Glass-filled nylon | High stiffness and dimensional stability | Parts needing rigidity and better temperature resistance |
| Alumide | Aluminium-filled nylon | Metallic appearance, high stiffness, thermal conductivity |
| TPU | Flexible elastomer | Seals, flexible components, dampers |
| PP | Chemical resistance, low density | Chemical handling, lightweight parts |
This material range is the main reason to choose SLS over other powder processes. Full technical data and manufacturer datasheets are on our SLS materials pages.
When SLS is the right choice
- A flame-retardant material is required — this is the strongest reason to choose SLS here
- Long or tall parts — 600 mm of build height is room the other powder processes do not have
- Complex geometry — internal channels, lattices, enclosed cavities, part consolidation
- Small and medium series of functional parts
- Defence and aerospace applications
And when something else is better
- Large series where every machine hour counts — MJF is usually faster
- Transparency, colour accuracy or a very smooth surface — PolyJet or resin printing
- Very high temperature resistance, or ULTEM specifically — FDM
- A metal part — metal printing
Accuracy, finish and what to expect
An SLS surface is matte and slightly grainy — a characteristic texture that comes from the powder particle size. It is a perfectly normal finish for functional parts, and can be improved by polishing, smoothing or dyeing.
Dimensional accuracy depends on part size, geometry, position in the build chamber and cooling rate, so we confirm tolerances against your drawing before printing rather than promising a blanket figure. Where a specific feature needs a tighter tolerance, we print with excess stock and machine that feature on a CNC.
Finishing options
- Dip dyeing for an even colour
- Polishing and smoothing to improve texture
- Oven painting and coatings
- Heat-set metal inserts
Frequently asked questions
What is the difference between SLS and MJF?
Both are powder processes without supports and the parts are similar in character. In SLS a laser melts point by point; in MJF an infrared lamp heats a whole layer. MJF is faster with a full chamber, while SLS gives a wider material range — above all the flame-retardant grades. We run both and choose by requirement, not by what happens to be free.
Do you have a flame-retardant material?
Yes. We print PA 2210 FR and PrimePart FR on the EOS system. This matters particularly for aerospace, defence systems and electrical enclosures. It is worth stating the standard you need to meet in your first enquiry, so we can match both the material and the documentation.
Do SLS parts last?
Yes. PA12 is a long-proven engineering material, resistant to oils and many chemicals, with stable mechanical properties. It does absorb moisture from the air, which slightly affects dimensions and flexibility — on sensitive parts we account for that in design or seal it with a coating.
What is the maximum size you can print?
The build chamber is 340 × 340 × 600 mm. Larger parts can be split and bonded, or moved to a large-format process.
What does it cost?
SLS pricing is driven mainly by material volume and how much of the build chamber the part occupies — so printing several parts together is always cheaper per part. Send a file and we will come back with a quote.
Have a file? We will tell you whether SLS is the right choice
Send a STEP or STL and we will come back with a recommendation on technology, material and price for the quantity you need — including if the answer is that another process suits you better. If you need to meet a fire or aerospace standard, tell us up front.
Indus3D is an additive manufacturing bureau in Israel, an approved supplier to the Israeli Ministry of Defense, AS9100D and ISO 9001 certified. We run a range of printing technologies under one roof and support projects from file to finished part.