In order to ensure that the pvd coating machine has good sealing performance, it is necessary to cut off the cause of possible leakage at the source. Therefore, it is not enough to find the location of the leakage only after the installation of the equipment. Vacuum leak detection must be carried out when setting the vacuum coating machine design. The following is a summary of the vacuum coating precautions that everyone needs to check for leaks at the design stage:

1. Determine the total maximum allowable leakage rate of the pvd coating machine according to the process requirements of the equipment, and determine the maximum allowable leakage rate of each component according to this total leakage rate.
2. According to the maximum allowable leakage rate of the equipment and other indicators, the leakage detection method to be used will be preliminarily determined in the design stage, and it will be taken as one of the basic principles guiding the commissioning acceptance.
3. According to the maximum allowable leakage rate index of equipment or components, determine the sealing, connection mode and overall processing accuracy of equipment, as well as which dynamic sealing form can meet the requirements. For example, the flange adopts metal seal or rubber seal.
4. When designing the structural strength of the vessel, consider the pressure resistance and structural strength of the tested parts if the pressurization method is used to detect leakage.
5. When selecting the structural materials of parts, consider whether the materials that may be damaged by the working medium and leakage indicating gas are used.
6. During structural design, necessary spare interfaces of leak detection instruments shall be reserved on vessels or systems for leak detection during equipment assembly and commissioning. Especially for large and complex pipeline systems, sectional leakage detection method is usually required, so sectional isolation valves shall be set on the pipeline, and leakage detection instrument interfaces shall be reserved on each isolation section.
7. During the structural design of parts, the design scheme that may interfere with leak detection shall be avoided as far as possible. For example, the screw hole in the vacuum chamber cannot be a blind hole, because the gas in the remaining space inside the screw hole can only escape through the thread gap after installing the screw, forming a virtual leak. This will prolong the pumping time of the system and interfere with the normal leak detection. As shown in the figure, there should be no structure in vacuum leak detection.
8. Similarly, continuous double-sided welds and multi-layer sealing ring structures are not allowed in the structural design, because this will form a "parasitic product" in the middle of the gas will form a virtual leak; However, when the internal and external welds or sealing rings leak at the same time, the "parasitic volume" makes the response time of the leakage indicating gas passing through the double-layer welds too long, which makes it impossible to detect the leakage normally.
9. During the design of welding structure, the welds that cannot be detected after the final assembly shall be minimized.
The leak detection of the pvd coating machine needs to be carried out at any time in the design, manufacturing, commissioning and use of various related links. However, in order to reduce the aggravation of the leak detection in the later stage, the source design link must be taken into account, and the leak detection work should be emphasized to ensure the reduction of the leak detection link in the later stage of the pvd coating machine.