How do you generate pick-and-place files for through hole components in KiCad? The default exporter omits through-hole components. Well, here’s the rationale for doing so. Through-hole pick-and-place is a lot more expensive than surface-mount pick-and-place because all the pins need to be properly aligned before insertion. Surface-mount is more forgiving, and therefore cheaper.
Also, wondering why KiCad’s mounting holes are plated rather than non-plated? Two reasons. First of all, it’s typically cheaper for the manufacturer. Second, the plating helps protect the hole against wear and tear from the screw.
20200724/DuckDuckGo kicad pick and place through hole
20200724/https://electronics.stackexchange.com/questions/456671/kicad-no-footprint-for-automated-placement
20200724/https://forum.kicad.info/t/create-a-mounting-hole/6737
Again, I reiterate, because this is important! Through-hole automated assembly is fully possible. With the correct machines, through-hole components can be placed on the board. Provided that the components can handle the temperature range, solder paste and reflow soldering is also fully possible with through-hole components, by stuffing the holes with solder paste before stuffing the components onto the board. For temperature-sensitive components, wave soldering will need to be used instead.
So, that being said, how does through-hole reflow handle in practice when I do it? It actually handles pretty well! The main notes I have to take into consideration from my experience. In the digrams, the thickness of solder paste above and below the through hole is about the same as in the case of surface-mount components. I’ve found out from some first-hand working experience, this is not enough. You want to make sure the amount of solder paste above/below the the hole is a little bit rounded off, thicker than only of that of surface-mount solder paste pads. Otherwise, there won’t be enough solder to form a nice fillet join after reflow, instead the solder will be only between the pin and the ring on the inside of the hole.
Finally, of course, sometimes it is difficult to fully fill up a hole with solder paste. It may be that you cannot see through the hole because there is solder paste covering the top and the bottom of the hole, but how full is the hole itself? Try really hard to make sure that the hole is absolutely full, otherwise you’re not going to get good results, of course. In particular, although the pin and the ring may be electrically connected by solder, there may be some holes where you can see light shine through, the through-hole not being completely covered on the inner surface.