Electronic – How are through-hole boards mass-produced

pcb-assemblyproductionthrough-hole

I'm familiar with the manufacturing process of surface mount boards. Chips come on reels (very high volume smaller parts), trays, or tubes. They are loaded into pick-n-place machines. The PCB, with solder paste applied, is put into the machine as well, and the pick-n-place (PnP) will populate the board.

I was wondering how this used to be done/is still done with through hole components. Our classic ¼W resistors and such come with their leads sticking out on a form of tape. How are these put on PCBs in a mass production environment? Is this all manual labour, or are there machines for this as well? I've never seen or heard of machines for this, and I can see their round shape causing headaches for the suction cups on the PnP.

We like to say that "through-hole is dead" and "everything is SMT nowadays", but open up most cheap power supplies or even many audio amplifiers (which often have a handful higher power resistors, transistors, …) and you have plenty of through-hole parts! Hence I was wondering, just how are these populated in high-volume production?

Best Answer

Mass production THT parts are either done with cheap people, or with axial insertion machines. You can find lots of videos on youtube:

https://www.youtube.com/watch?v=CCBST-qk2t8

https://www.youtube.com/watch?v=P17J5RzbsgQ

They pull the part off the bandolier, cut the leads, bend the leads, insert the part, and bend the leads on the opposite side in one stroke.