Behaviour and impact of leakage in vacuum gripping systems

Leakage in a vacuum system causes the pressure to rise if it is not compensated like in case the supply energy carriers fail. This leads to the workpiece to be dropped. So in order to design vacuum gripping systems that can withstand a failure of the supply energy carriers over a predefined amount of time, it is crucial to know the influences and effects of leakage. In previous examinations the behavior of leakage has been examined on the basis of a closed fluidic reservoir with a hole in its wall. But the only impacts taken into account here are the volume of the reservoir, the diameter of the hole and the pressure difference. Whereas when it comes to vacuum gripping systems, the leakage has significantly more influencing factors as it is neither a single component nor a closed system. In vacuum gripping systems leakage mostly occurs at the interface between the suction cups and the workpiece. So in this contribution the focus is on the impact of the properties of those components, and how the variation of these properties affects leakage. To achieve this, a theoretical description is done based on the aforementioned research, which is expanded in order to the relevant characteristics of a vacuum gripping system. After that the description is evaluated on a test bench. The goal is to be able to make a statement about the leakage rate for a vacuum gripping system composed of standard components. This can then be used in the design process of such gripping systems, which have to fulfil the requirement of compensating leakage in case the energy supply fails.