Installation and commissioning stage is the main part of leak detection of pvd coating machine. If the airtightness of equipment welds has been ensured through leak detection in the processing stage, the key point of leak detection is to check and ensure the tightness of connection parts during equipment installation and commissioning. It includes the flange connection between pipes and components, dynamic seals and other key suspicious parts. If the leakage detection is conducted on the weld and connection parts at the same time, the workload and difficulty of leakage detection will be increased. For large and complex vacuum equipment, it is better to use sectional leak detection. Each component is installed, its connection and weld joint shall be leak detected once, and the next component shall be installed after meeting the requirements. Because the leakage detection is conducted after all components are fully assembled, it is not only suspected that there are too many parts, but also that multiple leakage holes may leak at the same time, which brings great difficulties to the overall leakage detection. The leakage detection steps during the installation and commissioning of vacuum equipment are as follows:

1. Understand the structure and assembly process of the equipment to be inspected. Master the requirements of the equipment and find out the key suspicious parts that need leak detection.
2. According to the specified maximum allowable leakage rate and whether it is necessary to find the specific location of the leakage hole and other requirements, and based on the principles of economy, speed and reliability, the leakage detection method or instrument shall be correctly selected, and the practical leakage detection procedure shall be formulated after the auxiliary equipment required for leakage detection is prepared.
3. The inspected parts shall be cleaned, and the welding slag and oil dirt shall be taken out and then cleaned according to the vacuum sanitary conditions, and dried. Small devices with high requirements. After cleaning, it can be baked in a vacuum drying oven. After cleaning, it can not only prevent the leak 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 equipment, and determine the leak detection time of the leak detection system.
5. If vacuum leak detection method is adopted, the tested part shall be pumped to a higher vacuum as far as possible to improve the sensitivity of the instrument.
6. If allowed, more economical leak detection methods and on-site conditions 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 detected that require low leakage detection or have large leakage, helium with low concentration shall be used for leak detection at the initial stage of leak detection, and then leak detection shall be conducted for small leakage holes to save helium.
8. The detected large leak shall be repaired and blocked in time before the small leak shall be detected.
9. The leak detected and repaired shall be rechecked once to ensure that the leak detection results meet the requirements.
The leak detection link of pvd coating machine is a necessary step from design, manufacturing, commissioning, use, etc.