Why do precision instruments choose low-expansion precision alloys for core assemblies?

Ordinary metals expand or shrink noticeably with temperature variation, leading to assembly gaps, lens offset and measurement data errors in precision instruments. Low-expansion precision alloys are optimized with nickel-iron matrix formulas to achieve an extremely low thermal expansion coefficient within common operating temperature ranges. Their component sizes barely change in cold storage, high-temperature workshops or outdoor fluctuating environments. They avoid structural deformation of optical lenses, measuring gauges and aviation precision fixtures, ensuring constant equipment precision all year round without repeated calibration.