Additive Manufacturing
Additive Manufacturing
Additive manufacturing involves techniques that build objects by adding material layer by layer.
The most common form of additive manufacturing is 3D printing, used to produce prototypes, tools, and even end-use parts.
Common 3D Printing Techniques
- Laminated Object Manufacturing (LOM)
- Fused Deposition Modelling (FDM)
- Stereolithography (SLA)
- Selective Laser Sintering (SLS)
Laminated Object Manufacturing (LOM)
Laminated Object Manufacturing (LOM)
LOM is a system that slices a 3D CAD model into thin layers, then cuts each layer from material using a laser or plotter cutter. The layers are glued together in order to form a 3D model.
How it works:
- Material Layering: Sheets of material (usually paper, plastic, or metal) are layered one on top of the other.
- Bonding: Each layer is bonded to the previous one using heat and pressure.
- Cutting: A laser or blade cuts the desired shape from each layer.
- Stacking: The process repeats until the object is complete.
| Advantages | Limitations |
|---|---|
| Cost-Effective: Uses inexpensive materials like paper. | Surface Finish: Rougher compared to other methods. |
| Large-Scale Production: Suitable for creating large objects. | Material Limitations: Limited to sheet-based materials. |
| Minimal Waste: Excess material can often be reused. | Complexity: Less suitable for intricate designs. |
LOM is often used for prototyping and architectural models, where cost and speed are prioritised over surface finish.
Fused Deposition Modelling (FDM)
Fused Deposition Modelling (FDM)
FDM (Fused Deposition Modeling) is a 3D printing method that builds models by depositing melted material in layers onto a bed.
How it works:
- Material Extrusion: A spool of thermoplastic filament is fed into a heated nozzle.
- Layer Deposition: The nozzle moves along the X, Y, and Z axes, depositing material in precise layers.
- Cooling and Solidification: The material cools and solidifies, forming the object.
| Advantages | Limitations |
|---|---|
| Wide Material Range: Supports materials like PLA, ABS, and PETG. | Surface Finish: Visible layer lines may require post-processing. |
| Accessibility: Widely available and affordable for hobbyists and professionals. | Strength: Layer adhesion can be a weak point in some designs. |
| Versatility: Suitable for prototyping, functional parts, and educational purposes. | Speed: Slower compared to other methods for complex geometries. |
When using FDM, consider the orientation of the object to optimise strength and surface quality.
Stereolithography (SLA)
Stereolithography (SLA)
SLA is an additive manufacturing technique that builds 3D models layer by layer by hardening a photosensitive liquid polymer using a laser beam.
How it works:
- Resin Vat: The object is built in a vat (tank) of liquid photopolymer resin.
- Laser Curing: A UV laser traces the design, curing the resin layer by layer.
- Layer Building: The build platform lowers, and the process repeats until the object is complete.
| Advantages | Limitations |
|---|---|
| High Precision: Produces smooth surfaces and intricate details. | Cost: More expensive than FDM due to resin and equipment costs. |
| Material Variety: Offers resins with diverse properties (e.g., flexible, rigid, biocompatible). | Post-Processing: Requires cleaning and curing of printed parts. |
| Applications: Ideal for dental models, jewelry, and high-detail prototypes. | Material Constraints: Limited to photopolymer resins. |
- Think of SLA as sculpting with light.
- The laser acts like a chisel, carving out the design from a pool of liquid resin.
Selective Laser Sintering (SLS)
Selective Laser Sintering (SLS)
SLS is an additive manufacturing technique that uses a laser to fuse small particles of material into a solid 3D shape for rapid prototyping.
| Advantages | Limitations |
|---|---|
| No support structures needed - the surrounding unsintered powder acts as a support, allowing for complex geometries and overhangs. | Rough surface finish - parts often come out with a grainy texture and may require post-processing (e.g., sanding or polishing). |
| High mechanical strength - produces durable, functional parts. | High equipment cost - SLS printers are expensive and require specialised environments. |
| Efficient material use - unused powder can often be recycled and reused. | Limited to specific materials - primarily used with nylon and polymer powders. |
Emerging 3D Printing Techniques
- Digital Light Processing (DLP): Similar to SLA but uses a digital light projector for faster curing.
- Multi-Material Printing: Combines different materials in a single print, enabling functional and aesthetic versatility.
Applications of Additive Manufacturing
- Prototyping: Rapid iteration and testing of designs.
- Healthcare: Custom prosthetics, dental models, and surgical guides.
- Aerospace: Lightweight components and complex geometries.
- Consumer Products: Customizable goods and on-demand manufacturing.
In the aerospace industry, companies like Airbus use additive manufacturing to produce lightweight components, reducing fuel consumption and emissions.
