日本語
Hi I am building some pcbs but have trouble with the connectors melting.
I could use some tips how to protect these smd connectors against the heat of the reflow process.
The connectors are smd type and should withstand reflow according to the datasheet but they don't.
It is leaded solder so temps are not going >220oC and I stick to the standard reflow curve.
Mounting afterwards is a PITA due to the "wingpads", the mechanically solderpads on the sides.
thanks,
- Comments(1)
A****min
Apr 26.2019, 09:29:30
IR and convection reflow use two different heating and cooling mechanisms. In IR reflow the heating and cooling mechanisms are radiative because the air is static, whereas in convection refow the heating and cooling mechanisms are convective and rely on the movement of a heat through a conducting fluid such as air.
In IR reflow you have to put radiative heat energy in to heat up metal conductors and that heat is distributed throughout the metal whereas for insulating materials like plastics the same heat energy goes in but stays there because there is no conductive mechasism to get the heat back out, apart from the connector pins. So heat insulators like plastic connectors will get hotter than heat conductors like pcb tracks and components. In convection reflow you have a moving heat conducting fluid, air in this case, that puts heat energy in but also takes the heat out.
Not the best scientific explanation, but imagine the air as being a heatsink. IR reflow just puts heat in whereas convection puts heatn in and takes it back out.
