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Reflow pcb3/16/2023 ![]() I works very well, I probably won't use my toaster oven again. The frypan has a heat adjust knob to set it's preheat temperature and the heat gun air heat is controlled by how close you put it over the top of the PCBs. With the good lighting and top access you can get your face right over it and easily see the melt flow occur after a few seconds (maybe 10 seconds to get to melt point?), then a few seconds after melt just turn the heat gun off. Then use a fan heat gun or hair dryer (reduce fan air flow if needed with restrictions so it doesn't blow stuff around) to heat the top of the boards. This dries moisture and reduces thermal shock. Then you use the frypan for the preheat, usually 120'c or so for a minute (see temperature charts on google etc) so the whole PCB is hot but well below melt point. This evens out all the hot spots and gives a constant "plate temperature" to sit the PCB on. You can also put a piece of thermal mass in there like a 6" square ceramic tile or piece of flat metal. Industries have been using reflow soldering for many years to manufacture PCB assemblies. On top of that, it is very easy to control and monitor. It provides consistent soldering for the large variety of required components and pad sizes. If you use an electric frypan it has a lot of metal mass that gets a pretty even temperature, and access, lighting and visibility is very good. Reflow soldering is widely used for manufacturing PCB assemblies. There is also the hassle of visibility as it's all inside a dark metal box, and hassle to open/close doors etc. But the trouble is the "hot spots" near elements and cooler areas elsewhere (normally the element is like a square loop). One reflow oven I saw only had a heating element on the top side in the reflow section, this would keep the bottom a little cooler and perhaps not go to reflow.Ĭlick to expand.I used to use a toaster oven and still have my little oven in the workshop. I've never had a part heavy enough to fall off, but if they do then those would get glued down. Small parts get held in place by the surface tension of the solder. Just put the parts in with the side already reflowed down, and reflow the top. Now the thing about double sided boards is. We have lots of ceramic substrates lying about so I use them, but even a bare PC board would do. Generally you place parts on a "boat," some sort of solid surface to keep them off the belt. You put parts in one end and they come out the other. My preferred method is a chain belt reflow oven. Of course it is useless for double sided boards as it will wipe off all the parts on the "other side." So I use it for one side, then use a heat gun for the other. You place a part before an arm and it is swept through the 3 zones and gets left on the formica all nicely reflowed. I have here a small desktop "spinner" as I call it, 6 arms that rotate, half the base is formica and the other half is three sections of "hot plates," pre-heat, reflow, cool-down. The second way was made necessary when my company shipped my beautiful reflow over an 8 hour drive away. ![]()
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