Additive Manufacturing
Additive Manufacturing (AM), commonly known as 3D printing, refers to processes used to synthesize three-dimensional objects in which successive layers of material are formed under computer control to create an object. These objects are produced from digital 3D model data, typically originating from CAD (Computer-Aided Design) software or 3D scanning technologies.
History
The roots of additive manufacturing can be traced back to the 1980s:
- In 1984, Charles Hull invented the first form of AM, known as Stereolithography (SLA), and was granted a patent for it in 1986. This process used a laser to cure photopolymer resin layer by layer to form solid objects [1].
- In the same year, Carl Deckard developed Selective Laser Sintering (SLS) at the University of Texas, which uses a laser to fuse together small particles of plastic, metal, ceramic, or glass powders into a 3D shape [2].
- By the early 1990s, AM technologies started to become more widespread with the introduction of Fused Deposition Modeling (FDM) by S. Scott Crump, which extrudes melted material through a nozzle to build layers [3].
Technologies and Materials
AM encompasses various technologies:
- Stereolithography (SLA): Uses a laser to cure liquid photopolymer resin into a solid.
- Selective Laser Sintering (SLS): Uses a laser to sinter powdered material.
- Fused Deposition Modeling (FDM): Extrudes melted plastic through a nozzle.
- Direct Metal Laser Sintering (DMLS): Similar to SLS but specifically for metal powders.
- Electron Beam Melting (EBM): Uses an electron beam to melt metal powder in a vacuum.
The materials used in AM have expanded from plastics to metals, ceramics, and composites. The choice of material depends on the desired properties of the final product, like strength, flexibility, or heat resistance.
Applications
Additive manufacturing has applications in:
- Prototyping: Rapid prototyping allows for quick testing and iteration of designs.
- Custom Manufacturing: Producing unique or custom parts, particularly in medical applications like dental implants or prosthetics.
- Production: Used for small batch production or to create complex geometries that are difficult or impossible with traditional manufacturing.
- Repair: Rebuilding parts with complex shapes or internal structures.
Challenges and Future Directions
While AM offers numerous advantages, it also faces challenges:
- Material Limitations: Not all materials can be easily used in AM processes.
- Cost: Initial setup costs for high-quality AM machines can be high.
- Post-Processing: Often, AM parts require significant post-processing to achieve the desired finish and accuracy.
- Standards and Quality Control: Establishing standards for AM parts to ensure reliability and safety.
The future of AM looks promising with advancements in:
- Hybrid manufacturing systems combining AM with traditional subtractive methods.
- Multi-material and multi-process printing.
- Development of sustainable and eco-friendly materials and processes.
Sources
[1] Charles W. Hull, "Apparatus for production of three-dimensional objects by stereolithography," U.S. Patent 4,575,330, March 11, 1986.
[2] Carl R. Deckard, "Method and apparatus for producing parts by selective sintering," U.S. Patent 4,863,538, September 5, 1989.
[3] Stratasys, "FDM Technology," accessed [date].