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]
Page
8
sur
83
Wetting force
Knowing Fr we can extract the wetting force Fw from the measurement by adding the
Archimedean push.
Fw = Fr +Fa
From LAPLACE’s law,
Fw =
LV
l
cos
And
Fa =
v
g
Hence
Fr =
LV
l
cos
-
v
g
Fr
➔
resultant force measured (mN)
Fw
➔
wetting force (mN)
8
➔
wetting angle
LV
➔
liquid-vapour surface tension alloy/flux (mN/mm)
l
➔
sample perimeter in the meniscus area (mm)
➔
Specific volume of the molten alloy (g/mm3
v
➔
immersed sample volume (mm)
g
➔
gravitational field (9.81 m/s2)
The other parameters are data fixed in accordance with the testing conditions.
If the value of the surface tension
LV
, is unknown, operator shall start by determining it as
this value is mandatory for wetting angle and standard limit calculations, for more details see
section
“Video recording”
.
Wetting angle
The wetting angle gives a direct and absolute answer by a simple reading of the value. It is
difficult in case of complex shape to extract the wetting angle.
The software uses dedicated formulas following the shape and the entry angle to extract the
correct wetting angle.
In the
general case (component fully wettable, regular shape on “z” axis),