SLS vs FDM 3D Printing: Complete Comparison Guide
Choosing between Selective Laser Sintering (SLS) and Fused Deposition Modeling (FDM)? This comprehensive guide compares both technologies across performance, cost, materials, and applications to help you make the right decision.
Technology Overview
SLS (Selective Laser Sintering)
SLS uses a high-powered laser to selectively fuse powdered material layer by layer. The entire build chamber is heated to just below the material's melting point, and the laser adds the energy needed to fuse particles together. Unsintered powder supports the part during printing, eliminating the need for support structures.
Parts have isotropic properties (equal strength in all directions) and excellent mechanical characteristics. SLS is ideal for functional prototypes, low-volume production, and complex geometries.
FDM (Fused Deposition Modeling)
FDM extrudes melted thermoplastic filament through a heated nozzle, depositing material layer by layer. Each layer bonds to the previous one as it cools. Support structures are required for overhangs and complex geometries, which must be removed post-printing.
Parts have anisotropic properties (weaker layer adhesion in Z-direction) and visible layer lines. FDM is cost-effective for concept models, visual prototypes, and simple geometries.
Head-to-Head Comparison
| Feature | SLS | FDM |
|---|---|---|
| Part Strength | Isotropic, 48 MPa tensile | Anisotropic, 20-40 MPa |
| Support Structures | Not required | Required, manual removal |
| Surface Finish | Matte, uniform, no layer lines | Visible layers, requires post |
| Complex Geometries | Excellent, assemblies possible | Limited by supports |
| Materials | PA12, PA11, TPU, composites | PLA, ABS, PETG, Nylon |
| Machine Cost | $30,000-50,000 (desktop) | $300-5,000 |
| Part Cost | $5-50 per part | $1-10 per part |
| Build Time | Height-dependent only | Volume-dependent |
| Post-Processing | Minimal, bead blast optional | Support removal, finishing |
| Best For | Functional parts, production | Visual models, fixtures |
When to Choose SLS
- Functional prototypes requiring mechanical testing
- End-use parts for production or low-volume manufacturing
- Complex geometries with overhangs or internal channels
- Assemblies or interlocking parts in a single build
- Parts requiring chemical resistance or heat resistance
- Batch production of multiple parts simultaneously
When to Choose FDM
- Concept models and visual prototypes (non-functional)
- Budget-conscious projects with minimal strength requirements
- Simple geometries without overhangs or complex features
- Rapid iteration during early design phases
- Educational or hobbyist applications
- Jigs, fixtures, and tooling aids with low stress
Cost Analysis
While FDM printers have lower upfront costs, the total cost of ownership tells a different story for professional applications:
SLS Total Cost
- Machine: $30,000-50,000
- Material: $60-80/kg (90% reusable)
- Maintenance: $2,000-3,000/year
- Labor: Minimal (automated)
- Post-processing: 10 min/part
- Part cost: $5-50 depending on size
FDM Total Cost
- Machine: $300-5,000
- Material: $20-50/kg (not reusable)
- Maintenance: $500-1,000/year
- Labor: High (supervision, support removal)
- Post-processing: 30-60 min/part
- Part cost: $1-10 + significant labor
For production volumes above 20-30 parts per month, SLS becomes cost-competitive despite higher initial investment due to lower labor requirements and superior part quality reducing rework.
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See how SinterX industrial SLS printer delivers functional parts with mechanical properties that FDM can't match.