Ublox SARA-R422 User Manual

SARA-R4 series - System integration manual
UBX-16029218 - R20 Handling and soldering Page 104 of 128
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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 like
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]
250 250
Liquidus Temperature
217 217
200 200
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 69: Recommended soldering profile
☞ The 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 correctly aligned and centered.
3.3.4 Cleaning
Cleaning the 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.

Ublox SARA-R422 Specifications

General

Brand	Ublox
Model	SARA-R422
Category	Control Unit
Language	English