Manufacturing And Soldering - Quectel SC20-WL Hardware Design

8.2. Manufacturing and Soldering

Push the squeegee blade to apply the solder paste on the surface of stencil, making the paste fill the
stencil apertures and then letting it penetrate to the PCB. Downward squeegee pressure should be
adjusted properly to ensure that the stencil is wiped clean without damaging the stencil. To ensure the
module soldering quality, the recommended stencil thickness is 0.18mm~0.20 mm. As for LGA pads, less
soldering paste volume is recommended to avoid short circuits. For more details, please refer to
document [2].
It is suggested that the peak reflow temperature ranges from 240 to 245° C (for SnAg3.0Cu0.5 alloy). The
absolute maximum reflow temperature is 245° C. To avoid damage to the module caused by repeated
heating, remounting the module after finishing the reflow soldering of the first side of PCB is highly
recommended. The recommended reflow soldering thermal profile is illustrated as follows.
Temp. (° C)
245
240
220
200
Soak Zone
150
100
Max slope: 1~3° C/
Figure 42: Recommended Reflow Soldering Thermal Profile
Table 36: Recommended Thermal Profile Parameters
Factor
Soak Zone
Max slope
Soak time (between A and B: 150° C and 200° C)
Reflow Zone
SC20-WL_Hardware_Design
A
sec
Smart Wi-Fi Module Series
SC20-WL Hardware Design
Cooling
Reflow Zone
down slope:
Max slope:
1~4° C/sec
C
2~3° C/sec
B
D
Recommendation
1 to 3° C/sec
60 to 120 sec
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