Unitek MICROPULL IV MP4/115 Operation And Maintenance Manual page 20

CHAPTER 1: SYSTEM DESCRIPTION
End-Of-Test Conditions – When the HOOK RETURN switch is set to AUTO, the hook
automatically slews to the Downstop in the event any of the following end-of-test conditions occur:
1 A bond failure.
2 The PRESET FORCE is reached and the HOLD TIME expires.
3 The Beam hit the Upstop.4
and the force reaches 100% of full scale.
FT SW (Footswitch) ENABLE Switch – This momentary-action, spring-loaded switch returns control
of the MP4 to the operator in the absence of a completed test, as defined by one of the four End-Of-Test
Conditions.
ILLUMINATION Control – This control changes the intensity of the test site lighting.
RS-232C Mode (PRINTER/CMPTR) Switch (figure 1-7)– This switch selects communications with a
PRINTER (out) or the CMPTR (computer) (in).
PULL RATE Adjustment – This control adjusts the pull rate from 0.0115 inch/sec. to 0.115
inch/sec,.±20%. This is equivalent to 5% to 57% of the full-scale force per second. The upward speed
of the beam cannot exceed the preset MAX PULL RATE. When the force on the wire bond approaches
95% of the PRESET FORCE, the PULL RATE is automatically reduced to 5% of full-scale-per-second
in order to minimize, and in most cases, eliminate overshoot. The beam moves down at a fixed rate of
0.5 inches/second. Movement in either direction may be inhibited by use of the Control Lever unless
one of the four End Of Test Conditions, described above, occurred. The repeatability of the PULL
RATE is ±2%.
HOLD TIME Adjustment – Hold time is the length of time for which the PRESET FORCE is applied
to the wire bond. This control is used to adjust that time, when operating in the Non-Destruct Mode,
from 0.1 to 3 seconds, ±20%. Although this feature is active in both the Automatic and Manual Hook
Return Mode, its meaning is insignificant in the Manual Mode as the operator manually returns the
hook. A wire bond failure during the hold time is indicated by a unique message which can be recorded
using the optional RS-232C interface. Repeatability is ±2%. HOLD TIME is useful when performing
peel tests. It should be set to MIN for all other tests.
ZERO Mode Switch - In the MAN (manual) position (out), positive tare is displayed at the beginning
of each test. In the AUTO position (in), any positive tare is automatically subtracted from all readings.
The MP4 does not recognize negative inputs and, therefore, cannot compensate for them. The ZERO
switch should not be set for AUTO (in) when the HOOK RETURN switch (above) is set to the
MANUAL position.
UNITS Switch – The UNITS switch selects the unit of measurement as grams-force (gmf) (in) or
newtons (N) (out) (for the 1000gf beam) or millinewtons (for the 10 and 100gf beams). The selected
unit of measurement is displayed to the right of the PEAK FORCE indicator (above) reading.
1-12
The MP4 MODE switch is in the NON-DESTRUCT position
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MICROPULL IV WIRE BOND PULL TESTER
990-180