Component weight with SMT assembly on both sides
Particularly in the case of printed circuit boards equipped with SMT on both sides, the weight of the components must be taken into account. The decisive factor is the component weight per component connection area = component limit weight.
Components with a high component weight limit must not be processed in the first soldering process with this method - otherwise there is a risk of dropping during the second overhead soldering process.
All heavy components should therefore only be placed on one side of the PCB (TOP or BOT).
Clues for the identification of heavy/large SMT components:
- component height > 4 mm
- RM > 1.27 mm
- body volume > 50 mm3/connection
- strongly asymmetrical housings with regard to the connections
The formula also offers an approximation:
max. component weight < L * b * 0,05 * n
- L = length of the component connection (minimum value)
- b = width of the part connection (minimum value)
- 0.05 = component weight 0.05 g/mm2
- n = number of connections
NOTE: If the limit weight cannot be complied with, affected components can be fixed using a separate adhesive dispenser. The manufacturer of the assembly must be consulted in advance.
Further tips and tricks from 30 years of experience in electronics production can be found in our EMS Design Guide. Our practical little helper is already published in 3rd edition.
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