SLS vs Resin: Functional Complexity or Fine Detail?
Comparing Selective Laser Sintering in PA12 nylon with mSLA resin printing to help you choose the right technology for precision applications.
Two Paths to High-Precision Printing
SLS and mSLA both produce parts with higher precision than FDM, but they achieve it through completely different mechanisms and serve different application domains. SLS fuses PA12 nylon powder with a laser, producing strong, chemically resistant parts with complex geometries and no support structures. mSLA cures liquid resin with UV light through an LCD mask, achieving the finest surface detail and dimensional accuracy available in desktop-to-industrial printing.
SLS produces functional parts (48 MPa tensile, 175°C HDT, high chemical resistance) at ±0.10 mm tolerance. mSLA produces visually perfect parts at ±0.05 mm tolerance with 0.025 mm layer resolution. Understanding the tradeoff between functional performance and surface quality is key to choosing between them.
Head-to-Head Comparison
| SLS (PA12) | mSLA (Resin) | |
|---|---|---|
| Dimensional Tolerance | ±0.10 mm | ±0.05 mm |
| Cost per Part | Medium — batch-optimized | Medium — resin + post-processing |
| Typical Lead Time | 3-5 days (cooldown required) | 3-5 days (wash + cure required) |
| Material Properties | PA12: 48 MPa, 175°C HDT, chemical resistant | Resin: 40 MPa, 60°C HDT, detail-optimized |
| Surface Finish | Slightly grainy, uniform texture | Near-smooth, glass-like finish |
When to Choose SLS vs Resin
Choose SLS when your parts must function under mechanical load, resist chemicals, or survive elevated temperatures. PA12 nylon's 175°C HDT and high chemical resistance make it suitable for under-hood automotive parts, industrial tooling, and functional assemblies. SLS requires no supports, enabling internal channels, living hinges, and interlocking geometries impossible with other technologies. Choose mSLA when visual quality and micro-detail matter most — jewelry casting masters, dental arches, miniatures, and presentation models where the 0.025 mm layer resolution makes a visible difference.
Making Your Decision
SLS is the choice for functional, complex parts that need real-world durability. mSLA is the choice for visual perfection and micron-level detail. SLS excels in batch production (powder bed nesting), while mSLA excels in one-off visual models. For applications requiring both strength and appearance, SLS parts can be dyed, bead-blasted, or painted to improve their visual quality.
Frequently Asked Questions
Can SLS parts match the surface quality of resin?
Not without post-processing. Raw SLS parts have a slightly grainy, sandpaper-like texture. Bead blasting, dyeing, and vapor smoothing can significantly improve appearance, but mSLA will always produce a smoother native surface.
Which is more cost-effective for batch production?
SLS wins for batches. The powder bed can be packed with multiple parts in a single job, sharing the build cost. mSLA builds parts one build plate at a time, making it less efficient for high quantities.
Are SLS parts waterproof?
Raw SLS PA12 parts are slightly porous. For waterproof applications, parts can be sealed with infiltration or coating. Resin parts are inherently non-porous and watertight as printed.
Which technology works for dental applications?
mSLA is the standard for dental models, surgical guides, and orthodontic aligners due to its ±0.05 mm accuracy and smooth surface. SLS is used for dental tooling but not patient-facing models.
Can I dye SLS parts to specific colors?
Yes. SLS PA12 parts accept dye baths well, producing uniform coloring throughout the surface. This is a common post-processing step for consumer-facing SLS parts.
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