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What is Rapid Prototyping?

What is Rapid Prototyping?

New to rapid prototyping? Consider this.

According to Engineering Product Design:

Rapid prototype or rapid prototyping is a relatively new term and in its simplest form, the process of creating prototypes quickly to visually and functionally evaluate an engineering product design.

Careful consideration of the 5 key factors, viz. purpose, quality, quantity, complexity and cost would have a major impact on the prototyping success.

In an engineering product design context, a prototype is a preliminary version of the end-product and used to evaluate the design, test the technology or analyse the working principle which in turn provides product specification for a real working system.

Prototypes are an integral part of engineering product design and more importantly in an overall new product development process. Rapid prototyping can be used at any stage of the product development cycle or for any component or sub-component and can be repeated numerous times along the new product design process.

Although the term prototype is used in other contexts such as software programming, semantics, and application development etc, the purpose is the same.

Types of prototypes in product design

Prototypes can be categorised depending on the degree of accuracy required i.e. “Fidelity” or where in the product development stage it is used.

Fidelity types

Prototypes don’t necessarily need to look like final products and can vary depending on what the product designer is trying to achieve from the prototype. Rapid prototypes can be classified in terms of accuracy or “Fidelity” and the degree of prototype accuracy can vary from basic low-fidelity to high-fidelity in its functionality, appearance, user interface and size.

Low-fidelity prototype – Very simple and produced very quickly to test the broader concept. e.g. Paper sketches to cardboard mock-ups

High-fidelity prototype – These prototypes appear and function as similar and closer to the final product

NPD stage types

In modern-day engineering product design, the prototyping process of the build, review and refine, fits into all four major stages of the design process (product planning, conceptual design, embodiment design and detailed design).

  • Proof of concept prototypes
  • Demonstration or presentation model prototypes
  • Functional prototypes
  • Aesthetic or industrial design prototypes
  • Final factory sample
  • Alpha & beta build prototypes

Is rapid prototyping the same as 3D printing?

The simple answer is “No”. In the modern-day product development process, rapid prototyping is commonly used alongside terms like “3D printing” and “additive manufacturing” mainly because 3D printing first came into prominence as a way of making prototypes quickly (Read more on the history of 3D printing). But the 7 types of additive manufacturing technologies have moved along and have made giant strides towards the production of quality parts and might not be the preferred choice for some prototypes due to higher costs.
So, what is the difference between rapid prototyping and 3D printing? 3D printing or additive manufacturing is a manufacturing process while prototyping is the end result or the end product. Furthermore, 3D printing on its own or in combination with other processes could be used to create rapid prototyping.

Why is rapid prototyping important?

In this fast-moving modern-day consumer market, companies need to develop and introduce new products faster to remain competitive. Since faster product development and technology innovation are key to a company’s success, rapid prototyping becomes the most important element of new product development. The following objectives are achieved through rapid prototyping.

  • Faster new product development – Prototyping plays a vital role in the process of creating successful products because it speeds up the new product development process
  • Early-stage design/concept validation of the form, fit, and function of the design
  • Final stage product verification against the technical requirement and business objectives
  • It allows functionality testing to test the objectives of the concept and to finalise the specification
  • The prototype gives the end-user, client, customer, user participants hands-on user experience to get feedback

Types of rapid prototyping techniques

Choosing the right rapid prototyping technology is critical to the success of a prototype. Each rapid prototyping technique has its own compromise in terms of cost, speed, material compatibility of the feature, fidelity level and development stage.

Rapid prototyping doesn’t need to be limited to one process, one can use more than one manufacturing technique to assemble a prototype.

Following are the types of rapid prototyping technology available for engineering product designers:

  • Additive manufacturing
    • Stereolithography (SLA)
    • Selective laser sintering (SLS)
    • Direct metal laser sintering(DMLS)
    • Fused Deposition Modelling (FDM)
    • Binder jetting
    • Poly jetting
  • Other techniques
    • CNC Machining Prototyping
    • Vacuum casting
    • Investment casting

Advantages and Disadvantages of Rapid Prototyping

Like any manufacturing process or design stage, prototyping and rapid prototyping have their own pros and cons.

Advantages of rapid prototyping

  • Reduced design & development time
  • Reduced overall product development cost
  • Elimination or reduction of risk
  • Allows functionality testing
  • Improved and increased user involvement
  • Ability to evaluate human factors and ergonomics

Disadvantages of rapid prototyping

  • Lack of accuracy
  • Added initial costs
  • Some rapid prototyping processes are still expensive and not economical
  • Material properties like surface finish and strength cannot be matched
  • Requires skilled labour
  • The range of materials that can be used is limited
  • Overlooking some key features because they cannot be prototyped
  • End-user confusion, customers mistaking it for the finished project/developer misunderstanding of user objectives

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