AppNote180907 - Soldering LED/wires to VirEnce MCPCB
Several things to consider when soldering LED/wires on VirEnce MCPCB. Due to it's unusually low thermal resistance, manual soldering can be challenging. Please follow below steps carefully.
LED reflow soldering:
The biggest problem for beginner is to keep the ultra thin solder mask layer intact.
Slowly heat the MCPCB at no more than 2°C/second pace.
Avoid hard and sharp object on the solder mask especially at high temperature.
Avoid using too much soldering flux. Some aggressive flux will discolor the solder mask, some will make it bubbled.
Slowly cool the MCPCB at no more than 2°C/second pace. I use thick rock wool as the base insulator to make a slow air cooling. Putting the hot MCPCB on a cold thick metal after reflow soldering will make it cools too fast. The solder mask will delaminate or cracking.
Wire terminal soldering:
Slowly preheat the MCPCB or the entire host to at least 70% the temperature of the melting point of the solder paste/wire used. Example: 130°C for Sn63Pb37 solder. Check if the components attached to the host are resistant to the preheat temperature.
In most cases, 60 watt solder with big blunt tip is the minimum for easy soldering (25° - 30°C room temperature). Small soldering iron tip doesn't have the required mass to recover from fast heat loss once it touched the MCPCB.
Use the supplied intermediate FR-4 PCB for easy wire soldering.
Consider to use slave wire (wire soldered to the MCPCB first) when it's not possible to heat the entire MCPCB's host. Temporary insulation between the MCPCB base and the heatsink (host) also works very well.
Consider to use low melt temperature solders such as Sn42Bi58 (138°C) and/or In100 (157°C).