Rapid Prototyping: Accelerating Design Development
Definition
Rapid Prototyping
Rapid prototyping is the use of 3D printing and other additive techniques to quickly create physical models from CAD designs, allowing fast testing and feedback.
- It is often referred too as 3D printing, especially in schools and industry, but technically, 3D printing is just one part of rapid prototyping.
- Rapid prototyping focuses on speed, iteration, and development, not just the printing itself.
- All 3D printing methods (FDM, SLS and SLA) can be used for rapid prototyping, depending on the detail, speed, and material needed.
Why Designers Use Rapid Prototyping
- Produces prototypes quickly from CAD
- Enables frequent iteration and fast feedback
- Ideal for complex or customised designs
- No tooling or moulds required
Key Rapid Prototyping Techniques
Stereolithography (SLA)
- Stereolithography (SLA) uses a laser to cure liquid resin into solid layers, building a 3D model.
- Produces very high-detail and smooth surface finishes, ideal for aesthetic models.
- Commonly used for small, intricate parts like dental models, jewellery, or concept casings.
- Requires post-processing, such as washing and UV curing, after printing.
| Advantages | Disadvantages |
|---|---|
| High precision and detail | Weaker mechanical properties - more brittle than FDM or SLS |
| Wide range of resins available | Post-processing required - messy and time-consuming |
| Excellent surface finish | Higher cost per part - maintenance and resin is expensive |
Fused Deposition Modelling (FDM)
- FDM involves extruding thermoplastic filament through a heated nozzle, building the model layer by layer.
- Common in schools and hobbyist settings due to low cost and simplicity.
- Works best for basic prototypes, functional parts, and enclosures.
- Requires support structures for overhangs, which must be removed after printing.
- Common filament materials include ABS and PLA.
| Advantages | Disadvantages |
|---|---|
| Low cost & widely available | Visible layer lines may lead to poor surface finish |
| Good for functional parts | Limited detail on small features |
| Easy setup & operation | May have weaker points along the layer lines, affecting structural integrity |
Selective Laser Sintering (SLS)
- SLS uses a laser to fuse powdered material (such as nylon or metal) into solid layers, creating a 3D model.
- Ideal for complex parts, including internal features and moving mechanisms.
- No need for support structures, surrounding powder holds the print in place.
- Often used in engineering, medical, and industrial design contexts.
| Advantages | Disadvantages |
|---|---|
| Strong and durable prototypes | High equipment and material cost |
| No support structures needed | Requires post-processing (depowdering) |
| Prints complex shapes with ease | Surface can be slightly grainy |
Analogy
- Think of SLS like building a sandcastle.
- The laser acts like a sculptor, fusing the grains of sand (powder) into a solid structure, while the surrounding sand supports the shape until it's complete.
Note
- Rapid prototyping is not limited to physical models.
- It can also include digital simulations and virtual reality environments, enabling early and efficient testing of design functionality, usability, and user interaction.
Example question
An architecture studio uses stereolithography (SLA) to produce a detailed scale model of a new building, layer by layer cured in photopolymer resin.
Which best states the manufacturing process used to create this scale model?
- Subtractive
- Additive
- Joining
- Finishing
Solution
Award 1 mark for the correct answer: b - additive
