USER MANUAL
SOLDERABILITY TESTER
METRONELEC
V2.0
–
10/2021
6 Avenue Eiffel - 78420 Carrières-sur-Seine
Tél : 01 30 15 20 00
Web :
http://www.metronelec.com| Mail : [email protected]
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p is the “wettable “perimeter only, the distance where the wetting will occur, this
perimeter is defined following the type used.
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Θ, theta is the wetting angle, the angle between the coupon and the meniscus at the
point where the three phases are present. Only theta is changing during the test, the
other terms are fixed and constant during the test.
•
V is the Archimedean volume, known from the type used, this force could be great in
comparison to the wetting force, we always try to have a low value of this force to
have the better ratio Fwetting / Fbuoyancy.
•
ρ rho is the alloy density at the test temperature.
•
g is the acceleration field fixed at 9.81 m/s² in normal condition.
So the result expressed in mN is the balance between the wetting force and the buoyancy
force, hence a result sign depending on the value of these forces. So no panic is the result is
negative, this is fully possible if the wetting is partial (one side board) or if the buoyancy
force is great.
When you define the standard to use, if you choose IEC or IPC or MIL specification, you will
obtain a green horizontal line representing the 2/3 of the maximum force or another value if
you define by yourself in Option Other Spec, another value for the “coefficient”. 2/3 is t
he
general value defined in the specification but you can use other values with this option.
This pass/fail green line can be negative due to the balance between the wetting force and
the buoyancy force
Here is below an example : section of coupon wettable only on one side, so the wetting
force is the green area and the buoyancy force is the red area (buoyancy from the
inversed meniscus).
As the red area is greater than the green one, it is fully clear than in this case the result will
be negative ! but the test result is Ok.