S.P.O.T.T.

Hello Sean,

We are currently using a Pin in Paste process to mount some through hole relays. This particular board has 72 relays per. We have cut the stencil to overprint the hole. By putting a small amount of solder in the hole to flux the lead, the overprinted solder gets drawn into the hole through capillary action. We are only soldering one pin of the relay to tack it in place. (We use a Mydata and place the component by machine) The component is soldered at the wave process. This allows us to place the component, reflow and handle the PCB without losing the components. We used a formula to determine the apperture required in the stencil. Basically, you calculate the volume of solder required for the solder joint. You will need that volume of solder paste times two. We have had great luck with this process so far (knock on wood). We are using Alpha WS619 paste with a .006" stencil

Hope This Helps

Good Luck

Christopher

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Sean, Have you contacted Speedline Technologies applications enegineers? They have a lot of knowledge about SPOTT working with customers over the years to develop the process. I myself have experience doing SPOTT. I used Fuji GSP2 printers with oversized apertures on the stencil and did hand insertion of the connector before reflow. I used Multicore MP100 paste. I had a little issue getting our customer to accept the visual appearance of the solder joints. They will not have a fillet that looks like what you get with wave, selective or hand soldering. When inserting the connector the pin displaces solderpaste so after reflow there was a small solder ball on the tip of the pin. Also, the bottom side fillet did not completely wet down the pin. The fillet came down just to fill the barrel. The joints were compliant w/ IPC-610 rev. C, as I showed the customer and they were happy with the cost savings of the SPOTT process.

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