9018-18076.pdf.pdf - 第62页
7-4 Site Preparation 7 Compressed Air and Vacuum Requirements Compressed Air Specifications Ta b l e 7 - 1 3 shows the compressed air specifications fo r the systems. The air flow rates when using Performance Port are th…
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
Compressed Air and Vacuum Requirements 7
Site Preparation 7-5
Vacuum Requirements
The i3070 uses vacuum (with vacuum-actuated test fixtures) to pull the board under test down onto
test probes. Because of the different sizes of test systems, test fixtures, and the variety of boards that
can be tested, vacuum requirements can vary significantly.
Keysight recommends that you work with a qualified vendor of vacuum pumps who can give you
advice based on your requirements.
• Vacuum Recommendations and Guidelines
• Connecting Vacuum to the Testhead
Vacuum Recommendations and Guidelines
Table 7-14 shows the vacuum recommendations for a typical system.
Vacuum Guidelines
Keep these additional guidelines in mind as you design your system:
• Use the largest diameter of pipe practical from the vacuum pump to the testhead area. This
diminishes vacuum loss due to friction in the piping (especially at bends), and provides a demand
reservoir.
• Keysight also recommends that a filter be installed between the vacuum supply and the testhead
to prevent dirt or contaminants from being sucked through the test fixture into the vacuum
supply.
• Pressure meters, flow meter, and filters are optional but recommended.
• If the vacuum manifold is used, a 2-inch vacuum hose should be used. If vacuum ports are
connected individually, a 1-inch vacuum hose must be used.
Table 7-14 Vacuum recommendations for the system
Description Measurement
Recommended Flow Rate of Pump 18.9 l/s at STP (40 SCFM) Use this value as a guideline.
Vacuum specification is dependent on the fixture, not the
testhead. Keysight has found this specification will pull down
most fixtures.
Pressure Performance 50 kPa (7.2 psi)
Vacuum Control Ports available for controlling
external vacuum valves
4 vacuum control ports: switched 24 volts DC, 750 milliamps
maximum per port
Vacuum pumps installed for the tester should be installed outside or vented outside in
order to prevent the vacuum pump from exhausting oil-bearing air or carbon
fragments in areas where there are people.