Correct option is D
3D printing techniques, also known as additive manufacturing (AM), encompass a variety of methods to create objects layer-by-layer from digital models. Below is a concise overview of the most common techniques:
1. Fused Deposition Modeling (FDM)
Process: Extrudes thermoplastic filament (e.g., PLA, ABS) through a heated nozzle.
Pros: Low cost, wide material selection.
Cons: Lower resolution, visible layer lines.
Applications: Prototyping, hobbyist projects, functional parts.
2. Stereolithography (SLA)
Process: Uses UV laser to cure liquid resin into solid layers.
Pros: High resolution, smooth surface finish.
Cons: Brittle materials, post-processing required.
Applications: Dental molds, jewelry, detailed prototypes.
3. Selective Laser Sintering (SLS)
Process: Laser sinters powdered material (nylon, metals) into solid layers.
Pros: No support structures needed, strong functional parts.
Cons: Expensive, rough surface finish.
Applications: Aerospace, automotive, complex geometries.
4. Direct Metal Laser Sintering (DMLS)
Process: Similar to SLS but for metals (e.g., titanium, aluminum).
Pros: High-strength metal parts, complex designs.
Cons: High cost, requires post-processing.
Applications: Medical implants, aerospace components.
5. Binder Jetting
Process: Binds powder particles (metal, sand) using liquid binder.
Pros: Fast, multi-material printing.
Cons: Lower strength, requires infiltration.
Applications: Full-color prototypes, sand casting molds.
6. PolyJet Printing
Process: Jets photopolymer droplets cured by UV light.
Pros: Multi-material/color printing, high detail.
Cons: Expensive, limited material strength.
Applications: Medical models, multi-texture prototypes.
7. Electron Beam Melting (EBM)
Process: Uses electron beam to melt metal powder in a vacuum.
Pros: High-density metal parts, reduced residual stress.
Cons: Limited material options, high energy use.
Applications: Orthopedic implants, turbine blades.
