7-6 Site Preparation
7 Compressed Air and Vacuum Requirements
Compressed Air and Vacuum Primer
There are two key concepts involved in understanding the compressed air and
vacuum requirements for the i3070. The first is pressure and the second is flow rate.
Pressure is the force per unit area that a gas exerts on a surface. If zero is used as a
reference, the measurement of pressure is called “absolute”; if the local
atmospheric pressure is used as a reference, the measurement is called “gage.”
Although atmospheric pressure varies with altitude and weather, gage pressure is
typically used for engineering measurements, so it is used in this manual. A
pressure value below zero gage is considered a vacuum.
Common units for measuring pressure are kilopascals (kPa), pounds per square inch
(psi), and atmospheres (atm).
Flow rate is the quantity of a gas moving through a given area per unit of time. Since
air is compressible, you must know both the speed and pressure of the air when
measuring the flow rate. To reduce confusion, the industry has agreed on a
standard set of conditions for flow rate measurements called “standard
temperature and pressure” (STP). The standard temperature is 0°C (32°F), and the
standard pressure is one atmosphere (101.3 kPa or 14.7 psi).
Common units for measuring flow rate are liters per second (l/s) and cubic feet per
minute (CFM). When using standard conditions, the units are written as “l/s at STP”
or “SCFM” (standard cubic feet per minute).
Compressed Air
The i3070 uses compressed air to activate both the fixture pull-down towers and
the vacuum valves. The system also provides an outlet for supplying air to
accessory equipment such as handlers and air assisted fixtures.
The minimum pressure needed is 480 kPa (70 psi). The system has an internal
regulator to restrict the maximum pressure inside the system to 550 kPa (80 psi).
The flow rate needed is dependent on how often fixtures are changed, but is
generally much less than what is available in most production areas. Additional air
(flow rate) may be needed to supply the outlet for custom fixtures or presses
depending on their requirements.
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