OnRobot VGC10, Руководство пользователя, Страница: 177 / 213

Hardware Specification
177
Vacuum
Vacuum is defined as the percentage of absolute vacuum achieved relative to atmospheric pressure, i.e.:
The vacuum in kPa setting is the target vacuum. The pump will run at full speed until the target vacuum
is achieved, and then run at a lower speed necessary to maintain the target vacuum.
The pressure in the atmosphere varies with weather, temperature and altitude. The VG g rippers
automatically compensate for altitudes up to 2km, where the pressure is about 80% of sea level.
Air flow
Air flow is the amount of air that must be pumped to maintain the target vacuum. A completely tight
system will not have any air flow, whereas real life applications have some smaller air leakages from two
different sources:
•
Leaking vacuum cup lips
•
Leaking workpieces
The smallest leak under a vacuum cup can be hard to find (see picture below).
Leaking workpieces can be even harder to identify. Things that look completely tight might not be tight at
all. A typical example is coarse cardboard boxes. The thin outer layer is often requiring a lot of air flow to
create a pressure difference over it (see figure below).
Therefore, the users must be aware of the following:
•
VG grippers are not suitable for most uncoated, coarse cardboard boxes.
% vacuum Bar kPa inHg Typically used for
0%
0.00rel.
1.01 abs. 0.00rel.
101.3 abs. 0.0rel.
29.9 abs.
No vacuum / No lifting capacity
20%
0.20rel.
0.81 abs. 20.3rel.
81.1 abs. 6.0rel.
23.9 abs.
Cardboard and thin plastics
40%
0.41rel.
0.61 abs. 40.5rel.
60.8 abs. 12.0rel.
18.0 abs.
Light workpieces and long suction cup life span
60%
0.61rel.
0.41 abs. 60.8rel.
40.5 abs. 18.0rel.
12.0 abs.
Heavy workpieces and strongly secured grips
80%
0.81rel.
0.20 abs. 81.1rel.
20.3 abs 23.9rel.
6.0 abs.
Max. vacuum. Not recommended