IP67/IP68 Waterproof Sealing for Electronics: Materials & Design Guide 2026
Author: Site Editor Publish Time: 2026-05-25 Origin:
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Understanding IP Ratings
| IP Rating | What It Means | Typical Applications |
|---|
| IP54 | Dust protected, splashing water from any direction | Outdoor sensors, workshop tools |
| IP65 | Dust tight, protected against water jets | Outdoor lighting, marine electronics |
| IP67 | Dust tight, immersion in water up to 1m for 30 min | Smartphones, wearables, outdoor sensors |
| IP68 | Dust tight, continuous immersion beyond 1m (manufacturer-defined) | Smartwatches, underwater equipment, marine GPS |
Key Seal Materials for Electronics
| Material | IP Performance | Temp Range | Best For |
|---|
| LSR Silicone | IP68 | −60 to +230°C | Smartwatches, wearable devices |
| EPDM (hardness 70A) | IP67-IP68 | −45 to +150°C | Industrial enclosures, automotive ECUs |
| TPU (Thermoplastic PU) | IP65-IP67 | −40 to +120°C | Budget electronics, cable glands |
| FKM (Viton®) | IP67 | −26 to +205°C | High-temp electronics, oil-exposed enclosures |
Sealing Design Principles
1. Compression Seal (Static)
The most reliable method for electronics enclosures. A silicone or EPDM gasket is compressed between two housing halves using screws or clips. Key parameters:
- Compression: 15-30% of gasket cross-section height
- Gasket groove: Width = gasket diameter × 1.1 (to allow fillet)
- Groove depth: Calculated to achieve target compression when assembled
- Seal height: Should be 0.2-0.3mm above flush when uncompressed
2. Snap-Fit Seal
- Elastomer overmolded or snap-in seal ring
- Lower assembly cost — no screws needed
- Less reliable at high pressure — suitable for IP67, not IP68
3. Lip Seal (Dynamic — for cables/buttons)
- Radial lip seal for cable penetrations
- Actuator button seal (silicon membrane with integral lips)
- USB/connector port weatherproofing — silicone flap seal
Design Mistakes That Cause IP Failure
- Insufficient compression: Gasket not compressed enough creates gaps — target 20% minimum
- Stress concentration at corners: Gasket corner geometry must be radiused (R0.5mm minimum)
- Sharp edges on housing: Will cut through the seal during assembly
- Uneven compression: Screw preload variation causes local gaps
- Thermal mismatch: Different housing materials expand at different rates — design tolerance accordingly
Testing IP Rating: What Manufacturers Must Do
- IP67: Immersion in 1m water for 30 minutes — test at multiple orientations
- IP68: Per manufacturer spec (often 2m for 1 hour or deeper)
- Thermal cycling: −40°C to +85°C for consumer, (−40°C to +125°C for automotive)
- Humidity test: 85% RH at 85°C for 1000 hours (accelerated aging)
- Salt spray: For marine applications — minimum 96h per ASTM B117
LSR Overmolding for Electronics
LSR overmolding onto plastic or metal substrates is the premium approach for waterproof electronics. The silicone bonds directly to the housing during molding, eliminating any gap between seal and housing. Best for:
- Smartwatches and fitness trackers (IP68 at depth)
- Underwater cameras (IP68 for diving)
- Industrial sensors in harsh environments
- Automotive ECUs under-hood sealing
Anlintech offers LSR overmolding and compression-molded silicone seals for waterproof electronics. Contact us to discuss your IP rating requirements.
