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Hello,
I’m trying to bring prototype production in house.
I took delivery of a batch reflow oven, old surplus not a toaster oven, two days ago and set about my first ham fisted attempt at it.
I got a 5 mil thick polyimide stencil to match my roughly 11x8 mini panel of 20 boards, a tube of Kester NP560 SnAgCu paste, put paste on half of the boards, spent I don’t know how long placing components while awaiting a call back from Kester tech support for advice on profileing, and then went about repeatedly failing to reflow having never received my call back, until after thoroughly cooking all my components and paste to death.
So now I’m mostly resigned to accepting how foolish it was to jump in to the deep end with both feet.
I should have started with 1 board at a time,I should have started with tin/lead solder paste, and I should have run a bare board with a thermocouple soldered to it with high temp. solder to create a base profile before cooking components. (It’s kind of hard to believe I couldn’t find a youtube video suggesting this route to begin with. In the heat of the moment, pun intended, I was able to find a video from an oven manufacturer showing them doing this in their oven with included external thermocouple ports and software. This let me at least get an idea of how far board temps lag behind air temps. With observations of how things went in their oven and a couple multimeter attached thermocouples which only halfway melted stuck in as best as could hastily be arranged in my oven I was able to determine things tracked pretty much the same in my oven as theirs up to 220C.). On a ”positive” note I can now use my loaded junk PCBAs complete with their massive 1510 inductors instead of bare boards to dial in profiles before trying to reflow anything else.
Anyway, I’m ordering a new stencil for individual boards and would like to get some opinions on thickness. .004-.008 is the standard range right?
I can get .005 in polyimide. I can get .006 or .008 if I go with stainless. My smallest components are an SOT23F package voltage regulator and a couple 0402 capacitors. I feel like more goo would be more better assuming it doesn’t lift off the board in the “smaller apertures.”. Anyone have an educated opinion? I’m planning on going with the EP256 goo from the stencil manufacturer this time.
I’m trying to bring prototype production in house.
I took delivery of a batch reflow oven, old surplus not a toaster oven, two days ago and set about my first ham fisted attempt at it.
I got a 5 mil thick polyimide stencil to match my roughly 11x8 mini panel of 20 boards, a tube of Kester NP560 SnAgCu paste, put paste on half of the boards, spent I don’t know how long placing components while awaiting a call back from Kester tech support for advice on profileing, and then went about repeatedly failing to reflow having never received my call back, until after thoroughly cooking all my components and paste to death.
So now I’m mostly resigned to accepting how foolish it was to jump in to the deep end with both feet.
I should have started with 1 board at a time,I should have started with tin/lead solder paste, and I should have run a bare board with a thermocouple soldered to it with high temp. solder to create a base profile before cooking components. (It’s kind of hard to believe I couldn’t find a youtube video suggesting this route to begin with. In the heat of the moment, pun intended, I was able to find a video from an oven manufacturer showing them doing this in their oven with included external thermocouple ports and software. This let me at least get an idea of how far board temps lag behind air temps. With observations of how things went in their oven and a couple multimeter attached thermocouples which only halfway melted stuck in as best as could hastily be arranged in my oven I was able to determine things tracked pretty much the same in my oven as theirs up to 220C.). On a ”positive” note I can now use my loaded junk PCBAs complete with their massive 1510 inductors instead of bare boards to dial in profiles before trying to reflow anything else.
Anyway, I’m ordering a new stencil for individual boards and would like to get some opinions on thickness. .004-.008 is the standard range right?
I can get .005 in polyimide. I can get .006 or .008 if I go with stainless. My smallest components are an SOT23F package voltage regulator and a couple 0402 capacitors. I feel like more goo would be more better assuming it doesn’t lift off the board in the “smaller apertures.”. Anyone have an educated opinion? I’m planning on going with the EP256 goo from the stencil manufacturer this time.
