Cover glass adhesives for dash cams
High-temperature elastic adhesives hold the protective lens cover of dash cams firmly in place, with no delamination even when the car is parked in the sun for hours and cabin temperatures exceed 85°C.
Dash cams are mounted right against the windshield, exposed to direct solar radiation, continuous vibration while driving and large temperature swings between day and night. A protective lens cover that comes loose or opens at the edges lets dust and moisture in, blurring the image right when an incident needs to be recorded.
Vietnam's hot and humid tropical climate makes this challenge even tougher: a car parked under the midday sun and then caught in an afternoon downpour goes through a thermal shock cycle almost every day during the summer.
Challenges of bonding dash cam lens covers
- Glass and plastic housings have very different coefficients of thermal expansion.
- Low-frequency vibration from the road over many years.
- UV radiation that ages low-quality adhesives.
- The requirement for clean glass surfaces with no adhesive marks in the field of view.
Suitable adhesive types
Moisture-cure silicone adhesives
High elasticity, heat resistance up to 200°C and excellent UV resistance. The drawback is a long full cure time of 24–72 hours depending on thickness.
MS polymer or polyurethane adhesives
Good adhesion to plastic and glass, moderate elasticity and faster curing than silicone. Suitable when painting is required after bonding.
Elastic UV adhesives
Cure in seconds, suitable for high volumes. Choose grades with elongation above 100% and heat resistance of at least 120°C.
Recommended bonding process
- Clean the glass and housing with IPA, and plasma-treat hard-to-bond plastics.
- Dispense adhesive with a metering machine in a continuous, uninterrupted bead.
- Place the glass using a locating fixture and press lightly to spread the adhesive evenly.
- Cure as recommended and check for squeeze-out with a camera.
- Run thermal cycling from -30°C to 85°C and vibration tests per automotive standards.
Besides liquid adhesives, some designs use double-sided acrylic foam tape for flat glass, enabling fast assembly while also creating a dust-tight seal. The choice between liquid adhesive and tape depends on the glass shape and waterproofing requirements.
Periodic inspection in production
In mass production, samples should be taken every shift to test glass push-out force with a force gauge, with values recorded and plotted on a control chart. When push-out force trends downward, immediately check the adhesive shelf life, shop floor humidity and surface cleaning quality. Early detection helps avoid widespread lens cover detachment once products are in users' hands during the hot season.
AMS is ready to advise on and supply suitable adhesive samples for dash cams. Contact AMS Vietnam.
