8 considerations for your water tight seal design

Reliable sealing plays a crucial role in the performance and life span of today’s portable devices, especially those exposed to harsh environments.

For this reason, the sealing component should be considered in the early stages of product design to ensure the optimum product is specified for the job.

When using a foam component to act as the seal, product teams should select a material to meet the fluid ingress resistance and mechanical requirements of the application.

We’ve put together some key considerations to assist in choosing the right material in your water tight seal design:

1. What environment/conditions will the device be exposed to?
   Will the seal need to resist UV, oil, dust, debris, chemical contamination and temperature extremes?
2. Will these conditions be occasional or constant?
   This will determine the performance requirements of the product.
3. Will the finished product be IP tested or need to meet an IP rating?
   This provides an indication of the conditions the seal will be exposed to e.g. whether it needs to be water repellent, waterproof or submersible.
4. Will the product need re-working, requiring the seal to be opened and closed?
   If yes, the sealing product should have good memory.
5. Will the product be subject to changes in temperature?
   The material you specify should meet the temperature needs of the application. An appropriate vent should also be incorporated to avoid seal failure from pressure and moisture build-up. Read our venting design considerations post to learn more.
6. Will you require an adhesive backed foam to bond as well as seal?
   There are a variety of single sided and double sided foam tapes to choose from. A foam tape also offers damping, cushioning and gap filling functionality.
7. What substrates will you bond to?
   When sealing with an adhesive backed product, the substrates will determine the adhesive type, for example one suited to a low or high surface energy substrate.
8. Has material compression been considered in the enclosure’s design?
   The foam component will require compression to achieve an effective seal. We recommend a compression rate of the original product thickness of at least 25%.

Understanding the above factors will assist in specifying the right material for your sealing component.

You should also consider a material’s conformability, thickness and firmness, as well as its cell structure. In general, a closed-cell foam is most effective in waterproof seals, however, some open-cell products do offer a good level of sealing, such as Poron® foam and some VHB™ tapes.

For over 45 years, ADDEV Parafix has designed and manufactured custom sealing solutions for a range of portable devices, including mobile phones, military communications equipment and handheld measuring and sensing devices. Our experienced team can advise the optimum material for your application and our rapid prototyping service allows for testing the effectiveness of your designs.

Get in touch today to discuss your device sealing needs.