u-blox NEO-5 Series, Руководство по интеграции оборудования

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NEO-5 - Hardware Integration Manual Preliminary Product Handling
GPS.G5-MS5-08003-A2 u-blox proprietary Page 31
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3.3.3 Reflow Soldering
A convection type-soldering oven is strongly recommended over the infrared type radiation oven.
Convection heated ovens allow precise control of the temperature and all parts will be heated up evenly,
regardless of material properties, thickness of components and surface color.
Consider the "IPC-7530 Guidelines for temperature profiling for mass soldering (reflow and wave) processes,
published 2001".
Preheat Phase
Initial heating of component leads and balls. Residual humidity will be dried out. Please note that this preheat
phase will not replace prior baking procedures.
•
Temperature rise rate: 1 - 4°C/s If the temperature rise is too rapid in the preheat phase it may cause
excessive slumping.
•
Time: 60 – 120 seconds If the preheat is insufficient, rather large solder balls tend to be
generated. Conversely, if performed excessively, fine balls and large
balls will be generated in clusters.
•
End Temperature: 150 - 200°C If the temperature is too low, non-melting tends to be caused in
areas containing large heat capacity.
Heating/ Reflow Phase
The temperature rises above the liquidus temperature of 216 - 221°C. Avoid a sudden rise in temperature as the
slump of the paste could become worse.
•
Limit time above 220°C liquidus temperature: 20 - 40s
•
Peak reflow temperature: 230 - 250°C
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 3°C / s
To avoid falling off, the u-blox 5 GPS/GALILEO module should be placed on the topside of the
motherboard during soldering.
The final soldering temperature 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 in the recommended soldering profile may permanently damage the module.