The installation and commissioning stage is the main part of the leak detection of the vacuum coating machine. If the airtightness of the equipment welds has been ensured through the leak detection at the processing stage, the key of leak detection is to check and ensure the tightness of the connecting parts during the installation and commissioning of the equipment. Including the flange connection and dynamic seal between various pipes and components and other key suspicious parts. If leak detection is conducted on the weld and the connecting part at the same time, the workload and difficulty of leak detection will increase. For large and complex vacuum equipment, it is better to use sectional leak detection. Once a component is installed, the connection part and weld joint will be tested once, and then the next component will be installed after meeting the requirements. Because it is not only suspected that there are too many parts, but also possible that multiple leak holes leak at the same time, which brings great difficulties to the overall leak detection. The leak detection steps during the installation and commissioning of vacuum equipment are as follows:

1. Understand the structure composition and assembly process of the equipment to be inspected. Master the requirements of the equipment and find out the key and suspicious parts requiring leak detection.
2. According to the specified maximum allowable leakage rate and whether the specific location of the leakage hole needs to be found, and based on the principles of economy, speed and reliability, properly select the leak detection method or instrument, prepare the auxiliary equipment required for leak detection, and then formulate a practical leak detection procedure.
3. The inspected parts shall be cleaned, and the welding slag and oil dirt shall be removed, and then cleaned and dried according to the vacuum sanitation conditions. Small devices with high requirements. After cleaning, it can be baked in a vacuum drying box. After cleaning, it can not only prevent the leakage hole from being blocked by dirt, oil, organic solution, etc., but also protect the leak detector.
4. Calibrate the leak detection sensitivity of the selected leak detection method and leak detection equipment, and determine the leak detection time of the leak detection system.
5. If the vacuum leak detection method is used, in order to improve the sensitivity of the instrument, the tested piece should be pumped to a higher vacuum as far as possible.
6. If allowed, the more economical and on-site leak detection methods shall be preferred as far as possible.
7. When helium mass spectrometer leak detection equipment is used for leak detection, for the parts to be inspected that require low leak detection or have large leakage, try to use helium with low concentration at the beginning of leak detection, and then conduct leak detection for small leakage holes to save helium.
8. The detected large leak shall be repaired and blocked in time, and then the small leak shall be detected.
9. Recheck the leakage holes detected and repaired to ensure that the leakage detection results meet the requirements.
The leak detection of vacuum coating machine is a necessary step in every link from design, manufacturing, commissioning and use.