The installation of vacuum clamp joints is a standardized mechanical action sequence, which essentially achieves micro deformation matching of the sealing interface through controllable clamping force. The first step is end face pretreatment: the two connecting flanges must be operated in a Class 100 ultra clean room, using a lint free cloth dipped in electronic grade isopropanol to wipe. There should be no visible particles visually, and a surface water contact angle of ≤ 5 ° indicates no organic pollution. The second step is to locate the sealing ring: The FFKM sealing ring must be placed at the center of the flange groove and must not be twisted or offset. The ratio of the rounded corner radius at the bottom of the groove to the circular arc radius of the sealing ring section should be controlled between 1.05-1.15 to ensure uniform stress distribution during compression. The third step is flange alignment: use an optical alignment instrument to calibrate the coaxiality of the two flange axes, with a deviation of ≤ 0.03 mm and end face parallelism of ≤ 0.02 mm/m. The fourth step is clamp assembly: align the clamp opening with the flange locating pin, manually screw in the initial thread, and then use a calibrated torque wrench to apply torque in three diagonal cross directions - the first time reaches the specified value of 30%, the second time reaches 70%, and finally reaches 100%. The torque value is checked according to the clamp specification in Appendix A of ISO 2852, with an error of ± 2.5%. The fifth step is sealing verification: immediately perform helium mass spectrometry rough inspection after installation, and only enter the system pumping process when the leakage rate is ≤ 1 × 10 ⁻⁹ Pa · m ³/s; After the system reaches 1 × 10 ⁻⁴ Pa, perform a pressure holding test. If the pressure rise rate within 1 hour is ≤ 5 × 10 ⁻⁴ Pa/h, it is considered qualified. All steps must be completed in a temperature and humidity controlled environment (20 ± 2 ℃, RH ≤ 40%), and operators should wear powder free nitrile gloves with a surface particle size of ≤ 3 particles per square inch (0.5 μ m or more).