Acrylic Stencils Help With Component Placement For SMD Assembly

Surface mount is where the action is in the world of DIY PCBs, and deservedly so. SMDs are so much smaller than through-hole components, and fewer holes to drill make surface-mount PCBs easier to manufacture. Reflow soldering is even a snap now thanks to DIY ovens and solder stencils you can get when you order your boards.

So what’s the point of adding another stencil to the surface-mount process? These component placement stencils are [James Bowman]’s solution for speeding up assembly of boards in production runs too small to justify a pick and place robot. [James] finds that placing small components like discrete resistors and caps easy, but struggles with the placement of the larger components, like QFN packaged microcontrollers. Getting such packages lined up exactly is hard when the leads are underneath, and he found repositioning led to smeared solder paste. His acrylic stencils, which are laser-cut from SVGs derived directly from the Eagle files with a script he provides, sandwich the prepped board and let him just drop the big packages into their holes. The acrylic pops off after placement, leaving the components stuck to the solder paste and ready for their trip to the Easy Bake.

[James] claims it really speeds up hand placement in his biggish runs, and it’s a whole lot cheaper than a dedicated robot. But as slick as we think this idea is, a DIY pick and place is still really sweet.