Suction Cup Performance
Turning atmospheric pressure into precise, reliable grip
Suction cup performance depends on the pressure differential between atmospheric pressure and the vacuum level inside the cup.
For porous materials, vacuum levels between 30% and 55% maintain required flow to compensate for leakage. For airtight surfaces, 55% to 80% vacuum provides higher holding force, allowing smaller suction cup sizing and improved efficiency.
VACUUM HANDLING PHASES
1 - Approach
For shock-free contact with the surface to be gripped, and to conform to its shape, the suction cup in this instance has 1.5 bellows.
2 - Gripping
Vacuum is then applied to the suction cup, which lifts the object pushed by atmospheric pressure.
The suction cup and object then remain bound together throughout the entire process (transfer, packaging, etc).
3 - Release
At the end of the suction process, the vacuum is interrupted to release the object.
Most often, an air blow-off will help this process and avoid sticking. This also helps to quickly move to the next cycle.
VACUUM LEVELS AND SUCTION CUP SIZING
In practice, the majority of surfaces requiring suction are not airtight. If the material is porous or the surface is rough, it is inevitable that air will escape into the vacuum through the material or under the edges of the suction cup.
In this situation, a high flow of vacuum must be maintained to compensate for air leaks and to maintain gripping. This can be done economically and efficiently at a low level of vacuum.
Within the recommended vacuum range of 30% to 80%, two distinct zones must be distinguished, depending on the nature of the object to be gripped..
1. Porous materials
The 30 to 55% vacuum zone is both economical and efficient, given the amount of vacuum flow required. The suction cups should be sized appropriately to obtain the required holding force.
2. Airtight surfaces
In this case, the 55 to 80% zone gives excellent results. The holding force is greater (curves opposite), so that smaller suction cups may be used.