The design of O-rings in metal button switches

The design of O-rings in metal button switches—directly dictates their long-term waterproof performance, as these components form the critical barrier against moisture ingress.

Material selection is foundational. Nitrile rubber O-rings excel in oil-rich industrial environments, resisting degradation from lubricants that could compromise seals in metal push button switches. Silicone O-rings, meanwhile, thrive in high-temperature settings, making them ideal for LED metal push button switches where heat from the diode might accelerate material breakdown. Fluorocarbon rubbers, though costlier, offer superior chemical resistance, a must for round metal switches in corrosive environments like chemical processing plants. Using mismatched materials—such as nitrile in high-heat LED switches—leads to premature hardening or cracking, destroying waterproofing over time.

Size and dimensional precision are equally vital. An O-ring that is undersized for its groove in a round metal switch leaves gaps when compressed, allowing water to seep through during repeated actuation. Oversized O-rings, common in poorly calibrated metal push button switches, suffer excessive compression, causing permanent deformation and loss of elasticity. For LED metal push button switches, where internal electronics are highly sensitive to moisture, even minor size discrepancies can lead to catastrophic failures, as water ingress shorts out LED circuits.

Hardness, measured in durometer, balances seal tightness and durability. O-rings with low hardness (60-70 Shore A) conform better to irregularities in groove surfaces, enhancing initial waterproofing in round metal switches. However, they wear faster under frequent use, a drawback in high-cycle metal push button switches. Higher hardness (80-90 Shore A) O-rings resist deformation in LED metal push button switches but require precise groove design to ensure sufficient compression—otherwise, they fail to seal gaps, undermining long-term performance.

In a word, O-ring design—material, size, and hardness—must align with the specific demands of each switch type to maintain reliable waterproofing over time.