Manufacturing And Soldering - Quectel EC21 Series Hardware Design

8.2. Manufacturing and Soldering

Push the squeegee to apply the solder paste on the surface of stencil, thus making the paste fill the
stencil openings and then penetrate to the PCB. The force on the squeegee should be adjusted properly
so as to produce a clean stencil surface on a single pass. To ensure the module soldering quality, the
thickness of stencil for the module is recommended to be 0.18mm. For more details, please refer to
document [4].
It is suggested that the peak reflow temperature is from 235 to 245º C (for SnAg3.0Cu0.5 alloy). The
absolute maximum reflow temperature is 260º C. To avoid damage to the module caused by repeated
heating, it is suggested that the module should be mounted after reflow soldering for the other side of
PCB has been completed. Recommended reflow soldering thermal profile is shown below:
ºC
250
217
200
150
100
50
0
NOTE
During manufacturing and soldering, or any other processes that may contact the module directly, NEVER
wipe the module label with organic solvents, such as acetone, ethyl alcohol, isopropyl alcohol,
trichloroethylene, etc.
EC21_Hardware_Design
Preheat
Liquids Temperature
160ºC
Between 1~3ºC/s
50 150
100
Figure 45: Reflow Soldering Thermal Profile
Confidential / Released
Heating
200ºC
40s~60s
70s~120s
200 250
Time
LTE Module Series
EC21 Hardware Design
Cooling
300 s
86 / 94