Rapid Prototyping for every stage of product development

By Protolabs

Time to market is vital for your competitive advantage. Yet a decision to skip prototyping is a huge risk that could cost you in manufacturing costs, or loss of revenue and reputation if you get your product wrong. Here we take a brief look at the different rapid prototyping options available and when each might be suitable for your next development project.

Exactly which prototyping technology you will choose will depend on where you are in the product development cycle. At the beginning you may need a prototype to simply represent an idea for initial approval, but as you move through the development process you need to consider its form, function, how it will perform and how easily it is manufactured when it comes to production.

Smart manufacturers will always have an eye on the end product. Rapid prototyping aims to refine the design, its functionality, test it in action and for regulatory compliance. Sometimes you may even want to test market the new product before committing to final manufacture; at this point the lines between low volume production and prototyping start to become blurred.

Clearly there are many reasons to prototype and often it will involve a number of iterations and different technologies as you move through the development phases. The main thing is that over the years rapid prototyping has evolved and become more rapid.

Choosing the right technology at the right time

Many people think of 3D printing when it comes to rapid prototyping and it is a technology often used. In fact, it has evolved to the point where it is also used for low volume production. But it is not the only process used for prototyping.

At Protolabs for example we use:

• MultiJet Fusion (MJF)
• Selective laser sintering (SLS)
• Stereolithography
• Direct metal laser sintering
• Polyjet
• CNC machining
• Injection moulding.


The first five process are additive manufacturing technologies and we are always seeking to add to this list; while the second two are clearly different manufacturing processes – but both offer different options for the rapid prototyping process.

The early stages of a project typically include concept development, initial design and product validation and some testing for aesthetic appeal and functionality. Here speed of delivery is vital and 3D printing may well be your chosen option – but it is not a definitive choice. Even within the additive manufacturing world there are different technologies all offering different options at different price points. Ultimately, it pays to work with a supplier that offers you a wide choice and good advice.

Usually, you will need between one and five parts for initial concept prototyping so 3D printing or CNC machining would be the obvious choice. If your needs move into the hundreds then you may also consider rapid injection moulding as a process.

Each of the manufacturing technologies will be a compromise and you need toInjection Moulding think about the speed, cost and level of information you need in the initial stages. You may for example need to prototype a part using 3D printing, but you need to be aware of how it will be manufactured. This may require a change in technology later on for preproduction prototypes to use the same material and manufacturing process.

Later stage prototyping

Once you have validated prototypes for fit, form, function and aesthetics you need to optimise manufacturability. At this point you will move onto a form of the final manufacturing process.

For injection moulding you might want to tweak prototype designs so that you can produce moulding tooling more quickly or cost effectively. Equally you will want to achieve optimum mouldability. A good example is to change a mould’s draft angle which can deliver significant improvements in part ejection to improve surface finish and strike rate.

In practice, a supplier will help you with the design of a mould and suggest alterations to either make it possible or improve its design. At Protolabs we have automated this process so that when you upload your CAD for injection moulding you will receive a quote and a design for manufacturability analysis within a few hours.

But beyond this it is also useful to prototype using the same process as the final manufacturing. And if you are using injection moulding, you don’t need to wait the usual 10 -12 weeks for steel moulds. Using aluminium moulds this process becomes “rapid” and can deliver parts in just a few days.

Better yet if you design your mould carefully, you can alter it to tweak your production parts – it’s best to talk to your supplier for advice at this point.

Link to production

Another benefit of using rapid injection moulding is that it can ease you from prototyping into low volume production. If you only need up to 50,000 parts then you may be able to stop there. Alternatively, it can act as a bridge into mass production providing you with parts until your final steel tooling is ready.

And finally rapid injection moulding allows you to test market and if necessary, reiterate your design before you commit.

But most importantly this phase of prototyping, or low volume production, helps validate the production process quickly and cost effectively; which is also something that you can achieve with prototypes using CNC machining or one of the different additive manufacturing processes.

There are no hard and fast rules for prototyping in product development, other than I would suggest not skipping it. Exactly what you need and when will depend on your individual needs. It’s best to speak to a supplier that offers a wide range of technologies who can help you through the entire process and if needed onto initial production.