Selecting a style of
vacuum suction cup is
determined primarily by the product to be lifted.
Flat Vacuum Suction
Cups (listed
below) are typically designed to handle flat or slightly curved
surfaces. They offer fast attach/release times due to their small internal volume and are
good for handling heavy, horizontal loads. Flat vacuum suction cups with cleated bottoms to prevent
puckering are useful for handling flat, flexible loads such as cardboard and sheet metal.
Single (1.5)
Bellows Vacuum Suction Cups are ideal for
handling loads with uneven surfaces and irregular shapes. The bellows design compensates
for product irregularities and varied heights. They have longer attach/release times than
flat cups and are less suitable for lifting vertical loads.
Double (2.5)
Bellows Vacuum Suction Cups can be used in the
same applications as single bellows cups, but can accommodate greater product
irregularities and height variations. Double bellows cups are recommended only for
horizontal lifting of loads.
Flat
Vacuum Suction Cups Flat vacuum suction cups attach quickly due to the small volume
of air to be evacuated. They feature patterned knobs on the bottom to maximize capacity
and are excellent for holding flat, flexible materials without deformation. Relatively
stiff, the cup bodies retain their shape well in production applications. They are
excellent for use on fast cycle transfer systems. Use on flat or slightly curved surfaces,
and for horizontal or vertical lifting.
Vacuum Cup Materials:
The
standard materials are Nitrile (NBR) and Translucent Silicone (SIT).
For more information on the
materials, Click Here.
The cup capacities shown
above ( *
) are
theoretical capacities based on 24"Hg at sea level with a safety factor of two (2)
and a
±
5% margin of error. This is
the US ANSI ASME Standard B30.20 for vacuum lifter specifications and is commonly used in North America
as a design capacity for vacuum components. When used in vertical
applications, take these values
and divide again by 2 to obtain a 4 to 1 safety factor per the ANSI
specifications. These are realistic working capacities when designing
equipment.
Other manufacturers use a pull-off
figure at 27"Hg to show a high capacity value for their cups. This is
accurate, but requires users to do all the math themselves to build in safety
factors. The
values are basically the same, but it is necessary to calculate the working
capacities with a safety factor via the following formula at sea
level:
Pull-off
value
(at
27"Hg) = ANVER's Listed Capacity x 2 x 1.125 (at 24"Hg)
For example:
ANVER vacuum cup number F52 has a rated capacity of 15.10 lb at
24"Hg. The pull-off capacity at 27"Hg for this cup would be
15.10 x 2 x 1.125 = 33.98 lbs. From this point, it is necessary to
calculate the safety factor based
on the vacuum level being used, and the altitude.
To
ensure safety, 80% of actual overall diameter is used when determining Load
Capacity.
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