LENA-R8 series - System integration manual
UBX-22015376 - R02
Handling and soldering
Page 100 of 116
C1-Public
Cooling phase
A controlled cooling avoids negative metallurgical effects (solder becomes more brittle) of the solder
and possible mechanical tensions in the products. Controlled cooling helps to achieve bright solder
fillets with a good shape and low contact angle.
•
Temperature fall rate: max 4 °C/s
☞
To avoid falling off, modules should be placed on the topside of the motherboard during soldering.
The soldering temperature profile chosen at the factory depends on additional external factors, such
as the choice of soldering paste, size, thickness and properties of the base board, etc.
⚠
Exceeding the maximum soldering temperature and the maximum liquidus time limit in the
recommended soldering profile may permanently damage the module.
Preheat
Heating
Cooling
[°C]
Peak Temp. 245°C
[°C]
##
##
Liquidus Temperature
217
217
##
##
40 - 60 s
End Temp.
max 4°C/s
150 - 200°C
150
150
max 3°C/s
60 - 120 s
100
Typical Leadfree
100
Soldering Profile
50
50
Elapsed time [s]
Figure 76: Recommended soldering profile
☞
LENA-R8 series modules must not be soldered with a damp heat process.
3.3.3
Optical inspection
After soldering the module, inspect it optically to verify that it is properly aligned and centered.
3.3.4
Cleaning
Cleaning the soldered modules is not recommended. Residues underneath the modules cannot be
easily removed with a washing process.
•
Cleaning with water will lead to capillary effects where water is absorbed in the gap between the
baseboard and the module. The combination of residues of soldering flux and encapsulated water
leads to short circuits or resistor-like interconnections between neighboring pads. Water will also
damage the sticker and the ink-jet printed text.
•
Cleaning with alcohol or other organic solvents can result in soldering flux residues flooding into
the two housings, areas that are not accessible for post-wash inspections. The solvent will also
damage the sticker and the ink-jet printed text.
•
Ultrasonic cleaning will permanently damage the module, in particular the quartz oscillators.
For best results, use a "no clean" soldering paste and eliminate the cleaning step after the soldering.
