In box-type optical evaporation coating, factories often encounter issues such as pinholes, fogging, spectral drift, and poor batch-to-batch repeatability. Despite repeated adjustments to evaporation sources, substrate temperatures, and process gases, the problems persist; the root cause often lies in **residual water vapor** within the vacuum chamber.
Optical lenses, filters, and infrared components demand rigorous vacuum environments, typically requiring a base vacuum level of 10⁻⁴ Pa. Even with high-capacity molecular or diffusion pump systems, the partial pressure of water vapor remains high due to continuous outgassing from plastic fixtures, workpieces, and chamber walls. During evaporation, water vapor reacts with the coating material, directly causing film defects and leading to massive rework or scrap rates.
Traditional methods—such as prolonged baking or extended pumping times—lengthen production cycles and reduce equipment throughput. Installing an ultra-low-temperature water vapor cryopump (cold trap) is a proven industry solution. By utilizing a cryogenic surface cooled to between -120°C and -145°C, it directly condenses and captures water molecules within the chamber, rapidly lowering the water vapor partial pressure without requiring modifications to the main vacuum pumping system.
The WVCP series water vapor cryopump from Guangzhou Xieyi Automation is specifically designed for optical box-type coaters. It is compatible with mainstream domestic and international coating systems and supports both new equipment integration and retrofitting of existing machines. The unit offers stable cooling performance capable of handling long-term continuous production loads, effectively shortening base vacuum pump-down times while improving film density and optical consistency.
Many optical factories report that integrating a water vapor cryopump reduces vacuum pump-down times by 20–35% and significantly lowers defect rates. It is important to note that a cold trap is not merely a simple accessory; it must be properly matched to the chamber size, baking conditions, and refrigerant system. Blindly purchasing low-cost equipment often leads to issues such as failure to reach target temperatures, frequent alarms, and defrosting malfunctions. When selecting equipment, prioritize suppliers with comprehensive experience in cryogenic vacuum engineering to ensure stable, coordinated operation with your existing coating system.
Post time: 2026-09-05 14:26:30