Reflow soldering on a custom PCB

I recently had some through hole custom PCBs made by

Everything worked great. Now I am thinking that the next project I do will use surface mount components. What I am wondering is, is there enough solder on those custom PCBs to do reflow soldering? I don't see anywhere on that web site where it talks about that although they do talk about a tin/silver plating. Another prototype surface mount adapter board I got didn't look like there was any solder to reflow but it did work fine. I just don't want to spend the money on a custom PCB till I know for sure it will have enough solder on there to do reflow soldering of surface mount chips.

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Chris W

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Chris,

AFAIK the plating on the PCB is never used for reflow. That's to say, not on its own. In the reflow proces a fine grained solder and flux mixture is used that is put on the PCB by screen print. Then the components are placed and the PCB is heated by infrared to "reflow" the solder.

petrus bitbyter

As stated, the short answer is no, there is insufficient solder from the plating process.

That said, I have had surface mount boards soldered by hand. The difference is simply the amount of solder used. The person I use has successfully dealt with 0.5mm pitch ICs and 0201 passives. The one area you'll really need reflow is BGAs.

If you want a proper reflow, then you'll need to have a stencil made, as John noted. This is a standard cost item when producing surface mount boards using a contract manufacturer.

Cheers

PeteS

No, there is not enough solder on the boards to solder on parts. The solder there is basically tinning so additional solder will wet the pads cleanly.

Since I only do a few boards at a time, I solder surface mount boards manually without paste, masks, glue, stencils or other production methods or devices. I use a small tip Weller iron and 20mil wire solder. On the board, I flow a dab of solder on one of the component pads for each device to be mounted. Holding the device in position with a pair of tweezers, I reflow the solder dab sticking the part to the board by one pin. After aligning the part so that all of the pins are in the proper position, I apply solder to another pin on its pad. I push the component to the board and reflow this second pad insuring that the component seats onto the board and is aligned properly. I then solder all of the other pins to their pads in the normal manner. When solder accidentally bridges more than one pin, which happens occasionally in .5mm parts, I use solder wick to sop up the excess which leaves a clean joint. My eyes aren't to good so I work under a microscope, some people can do it with the naked eye. For small quantities, there is no need for paste, Infrared reflow equipment and the rest. Bob

These new QFN packages are not much fun either..