Matching Process to Specification
No single 3D printing process dominates all applications. Choosing between Fused Deposition Modeling (FDM), Stereolithography (SLA), and Selective Laser Sintering (SLS) comes down to surface finish requirements, mechanical loading, and batch economics.
1. Fused Deposition Modeling (FDM)
Mechanism: Thermoplastic filament extruded layer by layer through a heated nozzle.
Strengths: Wide array of true production engineering polymers (ABS, ASA, PETG, Nylon, PC, PEI), huge build volumes (up to 300-500 mm), and lowest material cost per kilogram.
Limitations: Visible layer lines and anisotropic strength (weaker along Z-axis).
2. Stereolithography & Resin (SLA / MSLA)
Mechanism: UV laser or LCD photopolymerization of liquid resin vat.
Strengths: Microscopic feature resolution (25-50 microns), injection-mold-like smooth surface finish, water-tight isotropic solid parts.
Limitations: Photopolymers can be brittle and degrade under prolonged sunlight unless treated with UV-protective clear coats. Build volumes are typically smaller.
3. Selective Laser Sintering (SLS)
Mechanism: CO2 or fiber laser sintering powdered nylon (PA11 / PA12) bed layer by layer.
Strengths: Completely support-free printing. Complex internal channels, nested assemblies, and fully isotropic mechanical properties. Ideal for batches of 50 to 500 functional parts.
Limitations: Grainy matte surface finish, higher initial setup cost, and post-processing powder evacuation requirement.
