DfM - Considering Device Manufacture

I’ve had some excellent feedback on my recent articles. I appreciate the subject is a huge one and I have only covered a very limited part of it. Thank you to everyone for your feedback as this will help with future articles.

One popular subject was mentioned numerous times, so I thought it worth covering that quickly. The subject which seems to be a hot one is design for manufacture or DfM.

HD’s background is from manufacturing so considering how the devices and products we create can be manufactured, is ingrained from the start. I will use this knowledge to provide some key pointers for ensuring there are no sudden surprises when your manufacturing team finally see the amazing new device heading their way! I think a lack of understanding some elements of DfM is why some pharma device teams opt for a CDMO approach, rather than undertake the work themselves. However, if you want to ensure all of the IPR and know how belongs to your company, then it is perfectly feasible to do your own design for manufacture. Also, I believe ultimate responsibility when launching a combination device belongs to the pharma companies, so understanding the manufacturing process is essential.

In very simple terms – if manufacturing and tooling experience is limited within your team – get potential suppliers involved from the start!

As soon as there are some broad-brush ideas for a new device, then speak to suppliers or subject experts and get their advice. Most are eager to provide input, to advise on new processes, materials and what to avoid in a design or key component.

There are numerous levels of design for manufacture to suit the development stage of a device. In the early stages then 3D printing will be required. Despite all of the stories and news about 3D printing – it does have limitations. Accuracy, finishes and materials are progressing rapidly, but we often struggle with resolution and tolerance capability of this process - not just materials and their mechanical properties compared to final mouldings. This means that prototype designs need to be properly engineered for the 3D printing and vac casting processes. With 3D printing there is no need to consider draft on components but if vac casting is to be used then this cannot be ignored.

The best way to reduce time here is to build good relationships with companies which supply both prototyping and tooling. They will advise on the various processes and materials suitable for the prototypes and provide manufacturing tolerances for the processes too. The design can then be engineered to suit. Far too often we see people designing without considering the tolerance capability of the manufacturing process, suitable for the development stage, so components can’t be assembled or don’t function as intended. Using a prototype and tooling company means they will also advise at the early prototyping stage, of how the components can be tooled and manufactured in volume.

Once 3D printed prototypes have been tested and reviewed, then the design will need amending/refining/optimising to suit manufacture in higher volumes. For high volume devices it is usual to make aluminium tools to obtain prototype parts which are as close to the final device as possible. This enables Human factors and further design robustness/engineering design work to take place and design optimisation to take place. Using aluminium tooling allows assessment of the components and device in the intended production materials. However, it is still important to consider aluminium tooling may have limitations on draft and manufacturing tolerances so further work may be required before progressing to hard steel tools. Again, the manufacturers and suppliers, if engaged early enough, can be invaluable in advising the most time and cost effective route for tooling of the device.

Developing long term relationships with companies in the prototyping, tooling and manufacturing chain will ensure device designs aren’t presented to them which cannot be made. Done correctly this will strip away unnecessary iterative loops of the design process, reducing development time and costs.

I hope these articles have been useful, it is a broad and complex subject but hopefully there have been one or two pieces of advice which help you reduce development times and costs. If you need any help in this area, please get in touch.