3D Printing Materials: SLA Resins and SLS Nylon

Last updated September 27, 2026

OpusFab offers two polymer 3D printing processes, and each has its own material family. SLA printing cures liquid photopolymer resins under UV light, with three resins to choose from. SLS printing fuses nylon powder with a laser, offered in three colours. Metal 3D printing is a separate process covered in Metal 3D Printing (DMLS/SLM).

SLA resins

Every SLA resin produces the smoothest surface and finest detail of any polymer process on the platform. Layer lines are barely visible, and small features and embossed text come out crisp. The surface is perfectly smooth, the closest in feel to an injection moulded part.

The resin range:

  • Standard Resin (9400, white): the general-purpose photopolymer, suited to appearance models and light-duty functional parts. This is also the large-format option, printable up to 1700 x 800 x 600 mm.
  • Tough Resin (black): stronger and more heat resistant than Standard Resin, printable up to 800 x 600 x 600 mm.
  • Red Wax Resin (castable): for lost wax casting patterns and miniatures. Wax parts are typically small.

Shared characteristics:

  • Rigid but brittle compared to thermoplastics: they snap rather than bend
  • Properties can drift with long-term UV and moisture exposure
  • Standard tolerance shown at checkout: ±0.5mm
  • Finish: As Printed is the only option; no other finishes are currently available on printed parts

Typical uses: visual prototypes, fit-check models, presentation parts, casting patterns, and masters for moulding, anywhere appearance matters more than mechanical load. Check the quote editor for the current live material list. See What is SLA 3D Printing?.

SLS nylon

SLS fuses nylon powder layer by layer. Because the unsintered powder supports the part during printing, SLS needs no support structures, which frees up geometry: internal channels, interlocking parts, and complex assemblies can print in one go.

The nylon is offered in three colours, all with the same properties: Nylon (Black), Nylon (White), and Nylon (Grey).

Characteristics:

  • Durable and slightly flexible, with good impact and fatigue resistance
  • Near-isotropic strength, meaning similar properties in all directions
  • Handles heat better than SLA resin but softens above roughly 100°C
  • More textured than SLA: a slightly grainy, matte surface, but generally stronger parts
  • Standard tolerance shown at checkout: ±0.5mm
  • Finish: As Printed is the only option; no dyeing or other post-finishes are currently available on printed parts
  • Build volume: up to 450 x 300 x 300 mm

Typical uses: functional prototypes, snap fits, living hinges, brackets, housings, and end-use parts in low volumes. See What is SLS 3D Printing?.

Both processes have fixed print beds. Parts larger than the build volumes above can be split and bonded, or quoted for CNC machining.

When printed materials beat machined ones

  • Complex geometry: internal channels, lattices, undercuts, and consolidated assemblies that no cutting tool can reach
  • One-off or very low quantity parts where machining setup dominates the cost
  • Speed for form and fit checks during development
  • Weight-saving structures that would waste most of a solid metal or plastic block

When machined materials beat printed ones

  • Tolerances: CNC holds ±0.05mm standard, while printed parts (SLA, SLS, SLM) are ±0.5mm
  • Material performance: machined metals and engineering plastics outperform printed polymers in strength, heat resistance, and wear
  • Functional surfaces: a machined face beats any printed surface for sealing, bearing, or sliding contact
  • Larger parts and higher quantities, where per-unit machining cost drops below printing

Choosing between them

If the part is cosmetic or a quick fit check, an SLA resin gives the best-looking result; pick Tough Resin when the part also needs more strength and heat resistance. If the part needs to work mechanically in low volumes, SLS nylon is the practical printed option. If it carries real load, needs tight tolerances, or must survive heat and wear, machine it from metal or engineering plastic instead.

For a deeper design comparison, see CNC vs 3D Printing Design Rules and Choosing a Process.