Abstract: Internal vacuumization of thin-walled parts may cause circumferential or radial instability of the member and cause the member to be scrapped. This is a difficult problem for positive pressure quantitative leak detection of thin-walled parts. In this paper, a positive pressure-vacuum helium mass spectrometry leak detection method is proposed, which fills helium inside the thin-walled member and vacuumizes it outside. A quantitative leak detection tool with synchronous comparison of positive pressure standard leak holes is designed, which can be used for quantitative leak detection of positive pressure-vacuum helium mass spectrometry in the gauge pressure range of -0.1-0.1 MPa. Through the working condition pressure-vacuum helium mass spectrometry leak detection test on the stainless steel thin-wall neck parts with a wall thickness of 0.4 mm, the results show that the method has fast leak detection speed and high efficiency, and the leak detection sensitivity meets the requirements of minimum detectable rate, which can be well applied to the batch leak detection of thin-wall parts production line.

Key words: helium mass spectrometry, leak detection method, thin-walled component, positive pressure vacuum leak detection, minimum detectable leakage rate