IP ratings are a measure of the resistance to dust and water ingress of a consumer electronics device, but the enclosure depends on the integrity of its seals. The silicone gaskets and parts used to make those seals is what often makes the difference between a product passing the IP67 or IP68 rating, or failing in the field.
This guide presents practical sealing strategies that are applicable in the real consumer electronics market, including smart phones, smart watches, fitness trackers and outdoor applications, and identifies the most common sealing pitfalls that lead to product leakage and test failures. . When done right, you can design better IP-rated silicone parts for consumer electronics that deliver reliable protection without adding unnecessary cost or complexity.
What IP Ratings Mean for Consumer Electronics
The international standard IEC 60529 defines IP ratings that specify protection from solid particles (first digit) and liquids (second digit). For consumer electronics, these ratings directly affect the durability of the product, user safety, and the warranty.
- IP54: Limited dust protection and resistance to water spray—suitable for basic indoor devices.
- IP66: Dust-tight and resistant to powerful water jets, typically used for robust outdoor products.
- IP67: Dust-tight and can take temporary immersion (up to 1 meter for 30 minutes) – perfect for most mobile devices and wearable electronics.
- IP68: Dust-tight and continuous immersion rated as per the manufacturer under the specified conditions—For high-end diving watches or special purpose underwater equipment.
The majority of consumer products are aimed at IP67 as it offers a good compromise in performance, price, and manufacturability. If you’re looking for a device with a full IP rating of IP68, few devices need it beyond very extreme conditions such as prolonged submersion.
Common IP Ratings for Smartphones, Wearables, and Outdoor Electronics
If you like to take a dip in the pool or brave heavy rain, you can expect your athletic smartwatch to have IP67 ratings. Smartphones tend to have internal sealing as well as IP67 or 68 protection. Robust silicone sealing ensures outdoor Bluetooth speakers, action cameras, and fitness trackers continue to perform in damp or dusty conditions. It’s typical that laptops and projectors remain within the IP5X range and generally more concerned about dust than water. Identifying these goals early in the process allows engineers to design a silicone gasket that will meet the correct targets.
Sealing Strategy #1 – Closed-Cell Silicone for Water Resistance
Closed-cell silicone stands as the gold standard for water-resistant seals in consumer electronics. Unlike open-cell foams that absorb moisture like sponges, closed-cell structures trap air in isolated pockets, preventing water from migrating through the material itself.
This construction is essential for consistent IP67 and IP68 performance. Water simply cannot penetrate the gasket body, even under prolonged exposure or pressure changes.
Why Closed-Cell Is Essential for IP67/IP68 Ratings
Closed-cell silicone is the preferred material for water resistant sealing at consumer electronics. Closed cell foams trap air in isolated cells, as opposed to open cell foams that absorb moisture like a sponge, which allows water to seep through the foam.
Sealing Strategy #2 – Seamless Gaskets Over Joined or Glued Strips
Seams are the weakest links in any sealing system. Whether die-cut from sheet or directly molded, seamless gaskets eliminate these vulnerabilities and offer protection all the way around.
Glued or spliced strips result in joints that can fail over time, particularly during thermal cycling or flexing, as often occurs in consumer electronics.
Die-Cut vs Molded Gaskets for Electronics Sealing
The precision of die-cut gaskets are ideal for flat or simple geometries and suitable for high-volume smartphone and wearable manufacturing. Molded gaskets are more precisely manufactured and can be made with more complicated features such as embedded ribs or varying thicknesses. Both methods provide smooth construction for IP-rated performance. Do not use glued assemblies wherever possible as they are the main lines of leakage during pressure or impact testing.
Sealing Strategy #3 – Proper Groove Design and Compression (25–40%)
The best silicone material will not work without proper and constant compression from the groove design. The designers of most consumer electronics designs aim for 25-40% compression, to ensure a reliable seal without overstressing the material.
This range has been designed to provide the proper sealing force while avoiding the problems of long-term compression set and loss of elasticity throughout the product’s service life.
Groove Dimensions and Compression Percentages for IP67/IP68
The width and depth of the grooves should be determined to obtain an even squeeze of 25-40% when the enclosure is completed. If there is not enough compression, then gaps will exist, and if there is too much compression, the gasket may extrude or become unresponsive. For wearable devices, for example, plastic housings that are subject to lip-and-groove designs need to consider tolerances and thermal expansion of the materials to ensure this compression window is kept.
Ensuring Even Clamping Force Across the Gasket Surface
The percentage is equally important, and just as important is a uniform clamping force throughout the length of the gasket. If the pressure is not consistent, water can pass the seal at underscrewed areas which can occur due to uneven torque on the screws, warped housings or poor tolerance stack-up. Designing for even loading is verified through finite element analysis (FEA), and physical pressure mapping during prototyping.
Sealing Strategy #4 – Silicone Gaskets Form Continuous Barrier on Imperfect Surfaces
Silicone’s biggest benefit is that it can conform to the imperfect mating surfaces. There are many small parts associated with consumer electronics housings that rigid seals can’t tolerate, such as minor parting lines, texture variations and assembly tolerances.
The flexibility and resilience of silicone enable it to fill these micro gaps and remain continuous even when subjected to vibration, thermal cycling and mechanical shock.
Why Silicone’s Flexibility Enables Sealing on Imperfect Surfaces
Outdoor electronics and fitness trackers rely on silicone gaskets for their versatility in fitting onto uneven surfaces, ability to withstand UV exposure, and durability in a variety of temperatures. The forgiving nature means that the need for ultra-precise (and costly) machining of plastic or metal parts is reduced, which makes high IP ratings more realisable in cost-sensitive consumer products.
Common Pitfall #1 – Poor Compression (<25% or >40%)
Too little compression will not form the seal and too much will permanently crush the gasket, thereby decreasing its compression ability. These are often causes of an IP test failure.
How to Avoid Under-Compression and Over-Compression
Communicate with your silicone supplier at a young stage to test and confirm the groove dimensions with prototypes. Always stay in the 25-40% range and don’t over tighten fasteners. For example, in smartwatch designs, they have to account for the travel of buttons and flex of the case to ensure localized over-compression does not affect the main seal.
Common Pitfall #2 – Seams and Joined Gaskets Creating Leak Points
Glued or spliced gaskets create discontinuities which can become leak paths during drop testing or when subjected to a pressure differential.
Why Seams Cause IP Rating Failures
Even a good glue can deteriorate over time because of exposure to chemical solvents used for cleaning or environmental stresses. Seamless molded or die-cut products offer a no-risk approach and provide more reliable performance in sealed consumer gadgets, like smartphones and wearables.
Common Pitfall #3 – Open-Cell Foams Acting Like Sponges
While open cell foams may appear soft and comfortable, they absorb water quickly, and fail the water ingress test.
How Open-Cell Foams Fail IP Ratings
Water flowing into the cells will remain trapped and have the potential to travel to vulnerable electronics. Closed-cell silicone will totally eliminate this and will be the reliable choice for any IP67 or IP68 application.
Common Pitfall #4 – Inconsistent Clamping Force Across Gasket
Even when you have the correct compression targets, poor clamping of the material will create opportunities for water to flow through the less loaded sections.
How to Ensure Uniform Compression in Enclosure Design
Confirm uniform pressure distribution using FEA simulation, tolerance analysis and physical testing. Care must be taken to ensure wall thickness and ribbing in plastic cases not be too thin, or flexing will cause a leak in the design.
Design Guidance – Groove Dimensions, Material Selection, and Testing
When designing parts that need to be rated for IP, consider the following practical list:
- Use closed cell silicone compounds that have a suitable durometer (usually 30-60 Shore A for consumer electronics).
- Create grooves that compress 25 – 40%, use appropriate fill ratio.
- Identify gaskets to be die-cut or molded for seamlessness.
- Check for uniformity of clamping with simulation and prototyping.
- Do IP testing (water jets, submersion) on the final assemblies (after drop and thermal cycling).
UL and NEMA Compliance for Regulated Industries
When products pass into regulated areas, select materials that are UL 94 flame rated, UL 50 enclosure rated or NEMA rated. Well experienced manufacturers are able to provide certified compounds and assist with documentation.
Summary – Sealing Strategies and Pitfalls for IP-Rated Electronics
Four essential sealing techniques are important to the successful performance of IP-rated consumer electronics; these are the use of closed-cell silicone for inherent water resistance, seamless gasket construction, 25-40% compression in well-designed grooves and the ability for the material to create continuous barriers on imperfect surfaces. The ability to avoid the common problems of poor compression, seams, open cell foams and inconsistencies in clamping force provides for a dramatically higher first-pass success in IP testing.
These principles can be used early in the design process to ensure that engineers can design and develop silicone components for consumer electronics that are reliable, affordable and IP rated for real-world conditions. Our engineering team has successfully provided custom gasket solutions, in-house tooling, and quality control for many consumer electronics projects, which have helped brands achieve their desired IP ratings in an efficient and robust manner.
