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Compressed Air and Vacuum Requirements 7 Site Preparation 7-3 Compressed Air Requirements The i3070 uses compressed air to pressurize air cylinders that actuate fi xt ure pull-down towers. Pull-down towers are used to pu…
7-2 Site Preparation
7 Compressed Air and Vacuum Requirements
Introduction
Both compressed (or pressurized) air and vacuum are used in the testhead. Compressed air is used
primarily to secure the test fixture to the testhead. Vacuum is used primarily to actuate the test fixture:
that is, to make contact between the board under test and the probes in the fixture. Compressed air
is sometimes also used for air-assisted, solenoid-actuated valves used to switch the vacuum, and for
air-actuated test fixtures.
The site preparation requirements for compressed air and vacuum are different depending on the type
of testhead you are preparing the site for. This chapter describes those requirements.
For more about compressed air and vacuum principles and terminology, see the short Compressed
Air and Vacuum Primer on page 7-7.
Compressed Air and Vacuum Requirements 7
Site Preparation 7-3
Compressed Air Requirements
The i3070 uses compressed air to pressurize air cylinders that actuate fixture pull-down towers.
Pull-down towers are used to pull and hold a fixture down onto the testhead, enabling contact
between the pins on the fixture and the spring-loaded interface pins in the testhead.
• Connecting Air to the Testhead
• Compressed Air Specifications
• Air Quality
Connecting Air to the Testhead
Install compressed air lines using rigid line to a point near the testhead. An air cutoff valve is
recommended for situations when the air line must be disconnected.
When the system is installed, connect the air to the testhead with a flexible line that has a Hansen
Series 3000 Push-tite 1/4-inch female coupling or equivalent. The testhead air input connector is
shown in Figure 7-30.
Figure 7-30 Compressed air connection to the testhead
7-4 Site Preparation
7 Compressed Air and Vacuum Requirements
Compressed Air Specifications
Table 7-13 shows the compressed air specifications for the systems. The air flow rates when using
Performance Port are the maximum that could be needed. Some installations might require lower
volumes.
Air Quality
The compressed air must be oil-free and must meet the humidity specifications in Table 7-13. We
recommend that the air be filtered to remove contaminants such as oil and aerosols. The filter should
filter 0.3-micron particles.
Table 7-13 Compressed air specifications for the system
Description Measurement
Maximum Pressure for Testhead Only 1035 kPa (150 psi)
Minimum Pressure for Testhead with Performance Port 690 kPa (100 psi)
Minimum Pressure for Testhead Only 480 kPa (70 psi)
Minimum Flow Rate for Testhead Only 0.66 l/s at STP (1.4 SCFM)
Minimum Flow Rate for Testhead with Performance Port 7.1 l/s at STP (15 SCFM)
Relative Humidity allowed 70% for compressed air (150 psi) at 25°C
50% for compressed air (150 psi) at 40°C
Dew point must be not more than 5°C