Rapid Prototyping: Development Stages

In the previous article, we introduced the basics of rapid prototyping. Now, we take a step further into the “hows” of the prototyping process. This article overviews how developers close the gap between design and manufacturing and manage their workflows …

Alejandro Auerbach

November 22, 2021

In the previous article, we introduced the basics of rapid prototyping. Now, we take a step further into the “hows” of the prototyping process. This article overviews how developers close the gap between design and manufacturing and manage their workflows throughout distinct stages.

The Difficulties of Product Development

Taking a product to market has its many hurdles, and bad decisions can cost the entire project’s success. Therefore, testing and refining must be constant, and it should take all the time and effort as necessary. Above all, a solid framework is key for success.

Among the many requirements needed to manage a product development project, designers must deal with recurring costs estimations, compliance and supply chain documentation, manufacturability, certification standards and voice-of-customer (VOC).


A validation process is essential to ensure that the status of the design meets the right set of requirements at every stage. Transitioning through every phase with clear exit criteria ensures optimal decision making and use of resources.

Requesting Help

Due to the heavy nature of product development, leveraging a partnership with experienced consulting services is a typical approach. By effectively defining their project in sections, developers can choose external help for a specific stage or aspect of their work.

Several consultors specialising in design, manufacturing, prototyping, and quality assurance are available to assist small entrepreneurs and big companies alike.

Now, with our purpose in mind, let’s start with the prototyping phases. Segmenting the developing process has many approaches. In this case, we’ll review it from the alpha-beta perspective.

Alpha Phase: Testing Features

An Alpha Prototype is devised to test the fundamental features of a product design. The need to construct several alpha prototypes emerges from assessing the risks involved when proceeding with the design in its early development.

This stage also holds another purpose. Concept models and mockups also sell the idea to internal and external stakeholders (Upper management, investors, potential users). Assuring resources from early stages with sales models and getting feedback from a customer base to enhance engineering requirements is vital.

Before working on a prototype, designers must pose the following questions:

According to your inquiry, a proof of concept (POC) prototype and/or a visual model is the way to go.

Proof of Concept: Will the Product Work?

A proof of concept (POC), or proof of principle, strictly focuses on the functionality of specific features of a product. The aim is to verify and demonstrate the feasibility of a concept for practical uses. To achieve this, a succession of testing under controlled settings take place to check assumptions, identify failures, and verify if there’s real market potential.

This prototype is often referred to as a benchtop model due to its reduced scale, incomplete assembly and the commonplace use of off-the-shelf components and open-source tools to save costs. Among some examples:

  • Parts made of cardboard, tape, foam and wood
  • Motors, pumps, pulleys, belts to reproduce mechanical functionality
  • Arduino, Raspberry Pi, cables, switches, protoboards for electronic functionality
  • Parts from disassembled products after the end of their life. It is not only a valuable source of materials for prototyping but a way to learn from previous design processes

Apart from physical prototypes, mathematical simulations like FEA is also an option.

As design moves forward, the need for customised parts increases and rapid prototyping becomes the ideal tool to achieve better insights.

Visual Models: How Will It Look and Feel?

These models are made to validate the aesthetics, ergonomics, interfaces and user experience of a product. Moreover, this prototype simulates usability and ease of use through a static model without working features.

At this stage, industrial designers attempt to balance the use of viable materials and inexpensive materials since prototypes can become prohibitively expensive compared to mass-produced products.

Typical materials used to achieve these requirements are foam (XPS, EPS, PU), cardboard, MDF, wood, wax, clay, sheet metal and paint. Furthermore, you can also simulate the visuals of a 3D model through a photorealistic rendering or rapid prototyping.

For a more hands-free and streamlined process, rapid prototyping enables more accuracy and freedom in design. CNC machines can cut most foams, metals and woods, while 3D printed techniques enable fast and hassle-free prototyping cycles.

Every 3D printing technology has application in look-alike modelling. Nevertheless, photopolymerisation technologies like SLA are the best option regarding surface finishes and geometrical complexity.  

Print high quality, mechanically strong parts with the Ultimaker S3.

Beta Phase: Functional Prototypes

With enough confidence in component functionality, visuals and ergonomics, designers can proceed with a more comprehensive prototype, closer to the final product. Beta prototypes are the first attempts to create a fully functional product to refine its final features before submitting it to subsequent manufacturing. First, many details must be considered: costs, materials, manufacturability, tolerances, v&v, user experience, serviceability and assembly planning.

The central purpose here is to have a system to test against operational environments and the PRD (Product Requirements Document). To achieve these objectives, developers must invest in testing hardware and a select group of lead users

Functional prototypes certainly require high levels of customisation and end-use quality, so it is no surprise that functionality, precision, and durability performance requirements increase in difficulty. Although reaching this point of product development, a major challenge emerges.

Costs of Functional Prototypes

With a beta prototype, you don’t get the benefits of mass production tooling, but you still need to create an end-use quality product. As a result, creating only one of these prototypes can be prohibitively expensive. Many developers would want to skip this issue. Still, an early investment can mitigate even greater losses from mistakes that could potentially appear during production.

To illustrate this, traditional manufacturing processes like injection moulding require considerable investments and lead times to set up tooling and parameters. Also, if you don’t get it right, you must spend large quantities of time and money to do it all over again.

Rapid Prototyping Solutions

Thankfully, numerous rapid prototyping techniques that can meet end-use and tooling requirements have been increasingly emerging in the latest years.

Engineering thermoplastics like nylon (PAs) have ideal end-use properties, and you can produce a part in toolless and cost-effective cycles. SLS is the go-to technology for this purpose since it can replicate isotropic parts quickly and with utmost accuracy. Check how the Formlabs Fuse 1 can deliver quality results at reasonable prices from your benchtop to see what this technology can do.

Formlabs Fuse 1 functional prototyping

Although not as precise, fast and isotropic as SLS, FDM offers an immense variety of material options (including nylon) and potential multi-material printing. One such example is Markforged‘s Continuous Fiber Reinforcement (CFR) system which can significantly enhance the mechanical properties of nylon parts.

CNC machining, although a costlier and harder-to-run process, can deliver quality metal parts. Fortunately, CNC machining companies like Pocket NC have been developing more affordable and compact desktop solutions in the latest years.

Electronic components also transition to further customisation requirements, so making PCBs is often necessary at this stage. However, the big drawback of making these boards is outsourcing. Most PCBs designs are sent to East Asia for manufacturing, significantly increasing lead times due to extensive shipping and potential IP endangerment. Are there rapid prototyping solutions to this? Yes. Companies like Nano Dimension offer fast and in-house PCB prototyping solutions.

Final Stages: Pilot Production

Contrary to general belief, prototyping does not end once the product reaches its final version. Now the issue is how to scale manufacturing effectively. Fabrication lines and tools must also be tested for validation, so a soft launch or pilot production must occur first. During this stage, manufacturers must verify production performance and set reviews for certification.

Among the many aspects that must be secured for optimum efficiency during production is gauging daily yield, adequate quality assurance systems, operation practices, assembly, supply chain logistics, packaging and complete integration within enterprise systems. Once everything is in place, the product will be ready for commercial deployment.

So, how do we leverage rapid prototyping at this stage? For pre-production, it is better to create short-run rather than final quality tooling, in other words, bridge tooling. One such example is, again, injection moulding. Long run quality moulds are commonly made of steel, which is costly and hard to process. Instead, more affordable and faster to get machined aluminium, 3D printed, or silicone moulding techniques can be applied for pilot production.

Once enough pilot trials are made, and the approvals are in place, we’re finally ready to ramp up production.

Solid Print is here to help you get the best rapid prototyping tools on the market to secure seamless bridging between development and production. For more information, please call SolidPrint at 01926 333 777 or email info@solidprint3d.co.uk.

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