Medical Applications

Your masterclass in product design and development


Protolabs’ Insight video series

Our Insight video series will help you master digital manufacturing.

Every Friday we’ll post a new video – each one giving you a deeper Insight into how to design better parts. We’ll cover specific topics such as choosing the right 3D printing material, optimising your design for CNC machining, surface finishes for moulded parts, and much more besides.

So join us and don’t miss out.


Insight: Medical Applications


Hello and welcome to this week’s insight. 

If you’ve been watching this series you’ll know that one of the great advantages provided by digital manufacturing techniques is their ability to quickly and easily develop designs and whip up new prototypes. This ability to rapidly cycle through new ideas and make quick tweaks is great news for plenty of different sectors, but it’s particularly powerful when you’re developing parts and devices for the medical industry.

Designing these devices can be a truly challenging, high-stakes process where both speed and accuracy are utterly vital to success. The development process is all about successfully passing through the gates set up by industry regulators as fast as possible – getting bogged down in these can easily cost huge amounts of time. Being able to rapidly turn around parts that accommodate the tweaks and revisions needed to keep the regulator happy can really help to keep things on track.

With this in mind, before you even start up a project to create a new medical device, whether it’s a stent or a blood pressure cuff, you need to get two things lined up: the right manufacturer to partner with, and the right manufacturing process to use.

When it comes to manufacturers, you’re looking for a company that can provide both quality and speed. Getting through regulatory gates requires the parts you’re providing to be top-notch, so being able to rely on your prototypes is vital, as is being able to supply them in a timely manner. You should be looking to get hold of new designs in a few days, not a few months.

On top of this, look for manufacturers that provide immediate design feedback when the quote is delivered. This drastically accelerates the process, results in better and easier-to-manufacture products and can help you spot defects before anything is produced.

You’re also going to be looking for experience with the three options we’ll be weighing up for rapid prototyping: injection moulding, CNC machining and 3D printing.

Now, injection moulding is an incredibly common production method in plenty of sectors and that’s no different for medical parts and devices. It has some great advantages, like being able to provide production parts made from plastic, metal, and much more besides, as early as possible, which comes in handy during the regulatory gating process. On top if this it’s a nice, robust process that provides repeatable, reliable and consistent results – all good things.

There are a handful of disadvantages to the process, however. The upfront tool cost can be pretty high, especially when it’s spread over a low number of parts, and making design changes after a tool is made can be costly.

There are also a handful of common shortcomings of injection moulded parts. If you’ve handled enough of them you’ll know that some flash, parting lines, weld lines, and ejector pin marks can crop up on the final part, while challenging or poorly designed injection moulded parts can cause real problems further down the line.

What is the best way around this? Just sticking to standards and practices. It’s not exciting advice, but it works.

Next up on our list we have CNC machining. This particular method often plays a big role in the early and end-of-life stages of development because there is no tooling expense at all, and different products can be supplied quickly and relatively inexpensively.

This is a big advantage because it’s a practical way to test multiple different designs all in parallel. This is great because device developers can’t merely pivot if they fail to pass a gate – they need to start from the beginning again. Testing these multiple design options at each gate provides a greater chance that one of them will be successful.

Machining is also important for testing parts and devices with engineering-grade materials, as they usually provide the same feel and weight as the final product for any hands-on tests by doctors. This is especially relevant for metal prototypes, where you want to be testing the product’s strength and weight.

Our final process is 3D printing, or additive manufacturing to give it its proper title.

Simply put, this is an excellent way to quickly evaluate new product designs. You can produce parts without making compromises due to complex part geometries, it has a low cost compared to tooling, and it’s incredibly easy to make changes.

There are a couple of disadvantages, however. 3D printing can have higher costs per part, you have pretty limited colour and texture choices, and – in certain instances – the materials you’re printing with might differ from those you’re using in full-scale manufacturing. Sometimes this isn’t a problem, but sometimes it is.

For these reasons, developers will typically use 3D printing to identify design flaws in their early designs, make changes and then make second-generation parts using one of the other methods.

Right that’s it for this week. I look forward to seeing you again next Friday.


With special thanks to Natalie Constable.


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