Solder Wave

Our PC board assembly center exists for one reason. To feed boards into the Solder Wave. The Solder Wave is a machine that is enclosed in it's own building on our floor. The size of the Solder Wave is about two buses long and it's somewhat narrow. Usually it only takes one guy per shift to operate the whole thing which is impressive. It's a complex machine that takes the racked boards with loose parts installed from Royonics and solders every joint in the board in one shot. The Royonics operators take their loaded boards and carefully place them on slow moving chain driven conveyors. The conveyors trail into the front of the Solder Wave room and it runs the boards just slightly above the solder pot. In this manner you get thousands of perfect solder joints made in just seconds. It's actually quite cool to watch. The solder pot must have more than a gallon of liquid metal solder in it, and it looks like the shiniest chrome you've ever seen. As a racked board passes over the solder pot you can see shiny liquid metal wick up the parts legs and into all of the component's through holes.

After a board has hit the solder pot, it continues down the conveyor for a brief cool down period. Then, just like in an amusement park log ride, the boards disappear into a cave. Inside the closed portion of the Solder Wave machine a couple more things happen. The boards are rinsed in a warm water bath which not only cleans the boards but it also removes the hard vinyl substance we put on the back side of each PC board to mask certain areas so solder doesn't adhere to it. The solder masking goop we apply using those robots in my production area is water soluable. After the water bath they continue on through a drying stage and then get spit out back in the Racking area. The Rackers then de-rack the boards, put them back in black ESD boxes, and ship them out to an auto test area or the boards go back out to the hand load lines. This is why the Rackers always have to bust ass all shift long. They are taking new boards from my area and racking them, and de-racking boards all night long as they come out of the Solder Wave. Those folks really have to keep an eye on things or it can get out of control fast.

Here's why the solder masking process I work on is so important. Many, if not all of the PC boards have to get wiring or oversized components installed like large capacitors. Sometimes they even get additional hardware added like heatsinks. Without the solder mask those through holes that accomodate these kinds of parts would be filled up with solder from the Solder Wave and blocked up. So the masking keeps those holes clean and free. Also it's necessary to add some of these components and wiring after the Solder Wave opeartion anyway because they might extrude too far from the surface of the board and get caught in the machine. Or the parts might be sensitive to heat or moisture so they have to be added after Solder Wave is finished. When it's done right, and everything is running smoothly we can really crank out a high volume of PC boards.