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The design engineers guide to prototyping

clock 10.5 minutes | 15 Nov 2019

Design engineer designing model on computer

2018 saw the U.S. Patent and Trademark Office work its way through 597,141 patent applications, and a further 47,137 industrial design applications.

That’s a lot of big ideas. But how do you maximise the chances of getting your big – or small – idea off the ground? Prototyping. It’s the first stage of turning an idea into a working reality. In this article, we’ll talk you through the fundamentals of prototyping: what it is, why it’s important, and the different methodologies you can use to turn your idea into a product. We’ve also developed a step-by-step guide to the prototyping process that you can use to inform your own journey from idea to product.

Table of Contents:

What is the prototyping stage?

Types of prototype

  • Visual prototype
  • Functional prototype
  • Presentation prototype
  • A note on digital prototypes

Why is the prototyping stage important?

Advantages of prototyping

  • Brings design to life
  • Invites early feedback
  • Generates interest and excitement
  • Saves time and money

Step-by-step breakdown

  • Waterfall vs spiral model
  • Research and requirements
  • Reverse engineering
  • Concept sketch
  • Virtual prototype
  • Free resources
  • Materials / tools
  • Initial prototype
  • Professional prototype services
  • User evaluation
  • Refinements
  • Find a manufacturer


Metal prototype printed with 3D printer

What is the prototyping stage?

A prototype is a sample or mock-up of the product you want to build. It can be used to demonstrate:

  • Size
  • Appearance
  • Function
  • Layout
  • Design integrity

The kind of prototype (or prototypes) you choose to create will depend on why you need it, and what’s most important to your project.

Types of prototype

Visual prototype

Your priority at the prototyping stage may be to help stakeholders understand what the product will look like: its size, shape, colour and texture.

If you don’t need to replicate the functionality of the end product, you may prefer to opt for a purely visual prototype as a means of saving time and money.

This kind of prototype would also be suitable for simple products, such as an outdoor electrical box enclosure or plastic conduit junction boxes; they’re not complicated and there are limited moving parts.

If you do create a visual prototype as the first step in your product development journey, you’ll find that a functional prototype will probably follow.

Functional prototype

If you’re less concerned with appearances and more concerned with demonstrating that your product will actually do what it’s supposed to, a functional prototype is probably the place to start.

Functional prototypes are used to test a product in its development stages. You’ll use this kind of prototype to gather feedback, and you’ll make adjustments to the design based on those insights.

Most functional prototypes will go through multiple iterations as you refine the design. For that reason, these test pieces may well be created using cheaper materials and processes than you would use for the final product.

Presentation prototype

So you’ve started off with a visual or functional prototype; what’s likely to come next is a presentation quality prototype.

Presentation prototypes combine the appearance and functionality of the end product and are usually manufactured using production-grade materials and processes.

The presentation prototype is more expensive than a purely visual or functional prototype, so it almost always appears towards the end of your product development process. It’s something to invest in to generate excitement and impact for investors, manufacturers and potential customers.

A note on digital prototypes

It’s amazing what you can do with CAD software now. You may find that you don’t want to generate a physical prototype until later on in the development journey — a virtual concept model may suffice.

While digital prototypes may not have the same impact as physical products, they do offer a wealth of benefits, including:

  • Allowing you and your team to visualise your design
  • Showing the product in action, including within automated, manual and robotic workflows
  • Enabling you to adjust the design quickly and easily, with no added spend
  • Performing design validation testing to assess manufacturability and usability

Going to need to include a cam lock enclosure in your design? A T-handle latch or rubber handle grips? Now’s the time to check the tolerances with mathematical precision.

Why is the prototyping stage important?

A prototype is a tangible and precise representation of your product. Now’s the time for real-life testing in the environment in which the actual product will find itself. The prototype is also to ensure everyone’s buy-in within the business, from the head of design to board members.

Once interested parties have had the opportunity to see, touch and experience exactly what you’re proposing to create, they can feed back on functionality, commercial viability, and potential problems for both manufacturers and end users.

For instance, if you’re designing a rack mount cabinet, end users will want to examine the hinges for durability, the material for sturdiness, and the lock for security.

And you won’t always make the right choices first time. The prototyping stage of your project is your opportunity to get things wrong without investing too much time or money — and to fix problems before they have potentially expensive consequences.

Tweezers, small screws and Xacto knife removing CNC object for prototyping

Advantages of prototyping

✅ Brings design to life

✅ Invites early feedback

✅ Generates interest and excitement

✅ Saves time and money

✅ Helps commercialisation of product

✅ Helps bring design to life

You can visualise and explain it a hundred different ways, but there’s nothing like a prototype to bring your design to life.

Prototyping doesn’t just help you and your team understand the look and feel of your finished product — it clarifies how it works in real life, how it interacts with its environment, and how people can use it.

✅ Invites early feedback

When you’re caught up in a new idea, it’s easy to become so focused on what you’re doing that you miss crucial opportunities for improvement.

The prototyping stage is a great way to invite and gather constructive feedback from the people who matter — those involved in the design, manufacture, funding and promotion of your product — and the end users.

✅ Generates interest and excitement

It’s fair to say that the success of most commercial design projects is contingent on the buy-in of a wider team. Prototyping can be an effective way to generate and maintain interest and excitement in a product, and to convince stakeholders that it’s worth investing in.

After all, if you’ve heard the saying “a picture’s worth 1,000 words,” then ask yourself how valuable a prototype could be.

✅ Saves time and money

As we’ve pointed out above, the prototyping stage of product development is your chance to get things wrong before you’ve invested too much.

But what does that look like in reality?

  • Exploring a physical prototype gives you and stakeholders a clearer view of how the product works in real life. It’s easier and quicker to gather accurate and pertinent feedback than other methods.
  • Accurate, in-depth feedback at the preliminary stage means fewer meetings, less time wasted on misunderstandings and clarifications, and fewer product iterations needed.
  • Identifying and solving issues at the prototype stage minimises the money, resources and labour wasted on large batches of unusable products.

✅ Helps commercialisation of product

This is part of saving time and money. Commercialisation is a process that converts prototypes into viable products and production systems. (Not just prototypes, but ideas and research.) With Commercialisation, you’re looking for the functionality and design you want coupled with cost effective manufacturing and strategies for your supply chain.

A step-by-step break-down of prototyping

Now we’ve covered the basics of prototyping, it’s time to look at the prototyping process itself.

You may well decide to skip some of the stages we’ve outlined here, or to include extra steps as the project progresses. And that’s fine – these are just guidelines.

NOTE: Waterfall vs Spiral model

There are two ways of running through these steps, typically known as the Waterfall and Spiral models.

The Waterfall model (aka linear model) involves undertaking each step in turn and completing and signing off each step before moving on to the next.

The Waterfall Model

By contrast, the Spiral model involves working through stages a number of times, evolving your prototype during each iteration until you are satisfied with the result.

The Spiral Model

The best model for your project will depend entirely on your working methods, specification, lead-time and budget, so it’s worth looking into both approaches to see which seems more suitable.

1. Research and requirements

When it comes to prototyping, failing to prepare is definitely preparing to fail. Any prototyping project needs to begin with thorough research and requirement analysis. What is your product designed to do? Does it fulfill its brief? How? Make sure you gather information from your intended end users so you know what they expect from the finished product.

2. Reverse engineering

Is there something similar out there on the market? It’s a good idea to get a hold of competing or comparable products and disassemble them. Why? Because it’s the quickest way to understand how those products are put together, how they work, and how they — and their production methods — can be improved.

Competitor products can also be the starting point for your own design. Identified an issue with the kind of outdoor cable enclosure you normally use? Take it apart and do better. Unimpressed by a certain brand of weatherproof outdoor cabinet? Reverse engineer it to find new efficiencies.

3. Concept sketch

You’ve probably already sketched out your ideas on paper, but it’s time to get a little neater with a concept sketch. This will help you and others visualise the end product more clearly. As a design engineer, it’s worth keeping a sketchbook to hand when you’re gathering feedback, too, so you can update your concept sketches as you go.

Interestingly, hand-drawn sketches are important for the patenting process (which you may or may not want to undertake) and carry more weight than digital drawings if you’re ever called to protect or defend your design.

4. Virtual prototype

A virtual prototype will give your team — and your intended audience — a chance to see your proposed product in a neater format than a hand-drawn sketch.

CAD software enables you to rotate and manipulate your design and can give a clear indication of how the product fits with other products, or how it will function as part of a wider application or workflow — vital for things like HVAC components.

You can also protype using virtual reality and augmented reality, which can provide invaluable insight early in the design process. These agile practices can also speed up design processes and lower your development costs.

Virtual prototyping is also a good opportunity to make sure that the various components in your product function effectively and efficiently — everything from an enclosure door latch to snap rivets needs to be assessed.


Essentra offers a range of free CADs, which you can download and incorporate into your design, saving you time and money.

You can also order free technical drawings and free samples of our products, so that you can try before you buy to see how they’ll work on your end product.

5. Materials/tools

Now that you’ve got a clear idea of how your end product will be put together, it’s time to consider materials and tooling, both for your prototype and your end product.

You’ll need to weigh up things like production costs, production times, sustainability and functionality: heat resistance will be vital for things like industrial generator parts, while an outdoor utility cabinet will need anti-corrosion properties.

As you can see in the Types of Prototypes section above, your chosen prototype production methods will vary depending on the kind of prototype you’re creating. If you’re going to create more than one kind of prototype, be aware that your production methods and materials will most likely vary.

You can get an idea for your materials with these helpful guides:

Plastic mechanical gear prototypes

8. Build your initial prototype

Once you’ve created and finalised your virtual prototype, it’s time to move on to the physical prototyping phase. You may have the ability to build one in-house, or you may need to enlist some help.

Additive manufacturing, or 3D printing as it’s most commonly called, is a popular process for producing prototypes quickly and efficiently. Essentra frequently uses its own 3D printer to produce models and prototypes, and they can do the same for you.

When the first prototype is complete, you may find flaws that need correcting immediately. In this case, now’s the time to make those changes (via your virtual prototype, if necessary) before you show the prototype to your target audience.

NOTE: typically, the earlier in the process you are, the cheaper your materials and production methods should be. After all, you may need to build several prototypes before you get the results you want.

9. Professional prototype services

When you’re happy with your initial prototype, it’s time to see how the final product will fare during mass-production. You’ll want to partner with a reputable and experienced prototyping service or manufacturer who offers these services. Choose a company that:

  • Can work to your timeline and budget
  • Will give honest feedback on the product
  • Will sign a non-disclosure agreement (NDA)
  • Has expertise and experience
  • Has great reviews from other users

Presentation prototypes help to impress end users, shareholders and potential investors. Whether you’re designing a new kind of data cabinet or innovative HVAC system components, you need to be able to show they’re fit for purpose.

NOTE: Many manufacturers offer prototyping services, so you may want to consider finding a vendor you can use at both of these stages in your project.

10. User evaluation

It’s time to present your professionally made prototype to the people who matter. This step will help you to identify the strengths and weaknesses of your design and gather data from your potential customers that can be incorporated into the final product.

Maybe your data cabinet dimensions are slightly out. Or perhaps your electrical enclosure door hinges don’t open as widely as they should.

Better to find out now than after a production run of 1,000.

11. Refinements

There’s a good chance you’ll need to make adjustments to your design following the user evaluation stage — after all, it’s not often we get things right on the first attempt. Use the feedback you gathered to inform the changes to your design, then repeat the last few steps in order to present the user with an amended professional prototype.

12. Locate a manufacturer

When you and your end user are happy with the working prototype, it’s time to look for a suitable manufacturer. The right vendor for you will depend on the materials and tooling you decided on earlier in the process. You’ll also want to think about:

  • Costs and lead times
  • Customer care
  • Location (in relation to you and your target markets)
  • Integrated services (machining and assembly, for example)

Remember to contact multiple companies before deciding on your final choice. You may be able to get a better deal once you have several offers that can be used for leverage.


Prototyping is a vital part of product design and development. This important stage can bring your product to life, helping you to:

  • Clarify its purpose, function and appearance
  • Improve user experience and marketability
  • Explore its manufacturability and make-up
  • Solve problems before they occur

And while this exploratory stage of the product development process does take time, money and effort, you’ll find the return on investment well worth it in the end.

Let Essentra enhance your prototype

From initial concept to finished product, we can help make the journey easy and cost effective. Our range of technical design capabilities includes everything from 3D printing to sample generation.

Save time and money with our extensive portfolio of completely free CADs, which you can download and incorporate into your prototype.

We’re also happy to send you free technical drawings and samples of our products, giving your product the benefit of ready-to-use, professionally developed solutions.

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