Prototyping is an essential part of designing and refining a product's specifications.
You get to turn a concept into something tangible that you can test and tweak until you're happy.
Historically, creating a prototype wasn't always easy – it was a huge and expensive process.
But with rapid prototyping, things have changed.
What Is Rapid Prototyping?
Rapid prototyping is a fast and inexpensive way of creating prototypes. With computer-aided design (CAD) software and additive manufacturing technology, engineers and designers can speed up their turnaround time when designing a product. With rapid prototyping, iterations can happen in much shorter time frames, sometimes even 24 hours or less.
Rapid prototyping technology is used in various fields, including design, technology, and engineering.
This article will focus on the rapid prototyping processes of engineers and designers, and the 3D printers they use.
The Role Of Rapid Prototypes In Manufacturing
Rapid prototyping combines techniques to quickly fabricate a physical part or component from a three-dimensional design.
It allows designers and engineers to create a better final product through iterative improvements.
While prototypes were traditionally made from sheet metal, injection moulds, or CNC machining, 3D printing allows engineers to create prototype parts and products in a much more cost-effective way.
When a model is very similar in function and appearance to the end product, it is called a high-fidelity prototype. Conversely, low-fidelity prototypes serve only to test a function of a product.
Rapid prototypes are intended to improve and quicken the communication between the parties involved in the design and manufacture of a product, enabling product developers to test and tweak a product until they believe it is ready for production.
The Rapid Prototyping Process
The process of rapid prototyping has only three steps, but these are repeated as often as necessary.
Each time a prototype is updated, it's sent to the relevant parties for approval and feedback and, if necessary, the prototype will be modified and tweaked, and the process will be iterated.
The three steps in rapid prototyping are the following:
- Prototype: Design and create a physical part.
- Review: The designer shares the prototype with the stakeholders, users, manufacturers, and other relevant parties. Each one gives feedback based on what the focus is.
- Refine: Once feedback has been received, the designer can refine and modify the prototype.
The Rapid Prototyping Workflow
The typical rapid prototype workflow works on a 24-hour design cycle.
- The designer or engineer uses computer-aided (CAD) software to create a 3D model. This should be done during work hours.
- The 3D printer prints the prototype parts overnight.
- In the morning, the designers or engineers clean the prototype and then measure, test, and create assemblies. Through this process, they will collect feedback to adjust to the next prototype.
In the case of manufacturing, rapid prototypes become more complex with each iteration of digital designs.
Different Applications For Rapid Prototyping
Rapid prototyping using additive manufacturing has a host of applications. The following are a few examples:
- Proof-of-concept models. These help product designers validate their ideas.
- Looks-like prototypes. These prototypes allow designers to evaluate the design.
- Works-like prototypes. Works-like prototypes are an accurate representation of the finished product. They are designed to validate the functionality of a design.
- Engineering prototypes. These prototypes are also known as pre-production validation parts. They are designed to simulate the final product and validate manufacturability.
The Advantages Of Rapid Prototyping
The biggest advantage of rapid prototyping is that comparing concepts side by side has become faster, easier, and more cost-effective.
Designers and engineers can move beyond virtual visualisation when designing a part, allowing them to create and thoroughly validate functional prototypes by checking the part's usability and manufacturability before sending it to production.
Rapid prototyping also helps to avoid expensive corrections in mass production. For example, sometimes design flaws only come to light when production has started, and then they must be corrected.
A company that can afford an in-house 3D printer can further speed up the rapid prototyping process and improve communication with colleagues and clients who give actionable user feedback.
The Disadvantages of Rapid Prototyping
Rapid prototyping has some disadvantages, but only a few.
For instance, it's not a useful tool for complex products like engines with lots of moving parts.
Cost-wise, rapid prototyping will cost you more upfront. The outlay of buying a 3D printer and making lots of prototypes to test will make the product development process more expensive. However, over time it will save you money.
Although great as proof of a concept, a rapid prototype won't always give you a sense of the final product's colour, strength, or surface finish.
What Type Of 3D Printers Do Engineers Use For Rapid Prototyping?
The three most popular additive manufacturing solutions for rapid prototyping are SLA, SLS and FDM printers.
SLA 3D printers use Stereolithography technology, where a laser cures liquid resin into hardened moulded plastic.
These printers print precise details with high resolution, accuracy, and a smooth finish. As a result, they are ideal for high-fidelity prototypes that require detail, tight tolerances, and smooth surfaces which are perfect for concept models and functional parts.
SLA 3D printers can print with a variety of resins which result in different properties for the finished prototypes.
For example, draft resins can be used for early prototypes, and standard resins are ideal for transparent or highly detailed models. Engineering resins can be used for prototypes that need to be durable, heat-resistant, extremely stiff, or flexible.
Selective Laser Sintering (SLS)
Selective laser sintering uses a high-powered laser to fuse small particles of polymer powder together into the layers of the final prototype. As the laser fuses the particles, the unfused powder supports the prototype.
SLS 3D printers are ideal for creating prototypes with complex geometries such as interior features, thin walls, undercuts, and negative features.
In addition, prototypes built with an SLS 3D printer have remarkable mechanical characteristics and a strength comparable to injection-moulded parts.
These printers are popular among engineers for functional prototyping because of their high productivity and low cost per part.
Fused Deposition Modelling (FDM)
A Fused Deposition Modelling printer heats a filament to its melting point, pushing the molten filament material through extruders and onto the print bed to print a prototype layer by layer, from the bottom up.
FDM printers are the most common type of 3D printer for hobbyists and small firms, allowing engineers to create a low-fidelity prototype that can be used to validate early concepts.
Entry-level FDM printers are available as desktop machines and can be useful in gaining design or user feedback at the early stages of the product development process.
Rapid prototyping techniques have revolutionised the manufacturing process.
It speeds up the design process and is relatively cheap to create a prototype using a 3D printer.
Each iteration of the rapid prototyping workflow takes about 24 hours, but the number of iterations is not set. Finally, when the final prototype has been approved, production can begin.