Vacuum technology / Coval - Vacuum managers

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How to choose a suction cup

A suction cup is a gripper which can be used to handle all sorts of objects of different weights, surfaces, shapes and dimensions.
For this reason we feel it would be helpful to explain all the parameters to be taken into consideration, in order to choose the right suction cup.    

Parameters

You will find the most comprehensive list possible of parameters to be taken into consideration when choosing a suction cup, on the following page.

Parameters

The shapes

The shapes

· Flat suction cups without cleats
Used for handling flat or slightly rounded, rigid, smooth objects. They withstand lateral forces and can be used for vertical handling.

· Flat suction cups with cleats
Used for handling thin, flexible, deformable objects. They increase resistance to lateral forces and horizontal handling.

· Suction cups with bellows
Used to handle spherical, cylindrical or egg-shaped objects. The effect of the technical characteristics increases with the number of bellows. They can be used for gripping objects with height differences, for a ball-joint effect, to lift and to grip corners or edges.

Suction cups force calculation

The force of a suction cup is proportional to its surface under vacuum and also depends on its shape, flexibility, material and especially on the level of vacuum attained inside the suction cup.

Theoretical force
F(DaN) = S (cm2) x V (%) x 0,01013
S = Surface of the suction cup (cm2)
V = Vacuum level (%)

Actual force
As its name implies, this force represents the actual force of the suction cup when in use. In general this is 50% less than the calculated theoretical force.
This difference is explained by the distortion of the suction cup during handling (which reduces the gripping surface), and by the condition of the surface of the object being handled.

The safety factor
All holding forces are listed in the data tables for each range of suction cup. These are actual values at 65% vacuum, calculated with a safety factor of:

. 2 for horizontal gripping,
. 4 for vertical gripping,
For applications involving high acceleration, the safety factor will be calculated accordingly.

Suction cup technical data

Diameters
The force of the suction cup and the product's available gripping surface depend on this parameter. COVAL offers standard suction cups of 1 to 600mm in diameter over all its ranges.

Minimum bend radius
This indicates the minimum radius of a product to be reliably gripped by the suction cup.

Internal volume
This corresponds to the volume which must be evacuated during a vacuum cycle. It must accounted for in the total volume of the gripping system and thus in the suction time calculation.

Stroke
This corresponds to the compression of the suction cup during the vacuum cycle.

COVAL materials

To meet the constraints of industrial applications, COVAL has a wide range of both standard and specific materials. COVAL can also study new materials based on specific requirements of your applications.

Properties of the materials

Properties of the materials