#video of #gomezgimenez #manufacturing a solder-paste stencil for #electronics #hardware from an aluminum can. The cotton gloves for handling the aluminum are a good idea. He anneals it with a clothes iron on the high setting on a corkboard for 20 minutes, then removes the paint with acetone. First he tries photolithography with photoresist film. For a photomask he prints out three identical transparencies on a Brother laser printer and cyanoacrylate-glues them together. His UV source for exposing the photosensitive film is one of those nail-salon UV caves. 2% washing soda removes the unexposed film. Then he etches the aluminum with a commercial etchant of HCl and sodium persulfate (‽). To remove the exposed photoresist film and the inner epoxy liner of the Coca-Cola can he uses acetone. This produces somewhat uneven and rounded holes. Second, he tries milling with a “CNC 1419” desktop milling machine, using a 100μm conical milling cutter with a 30° included angle. His workholding is supergluing painter’s tape on the back of the aluminum to painter’s tape on a plywood spoilboard. (Stackup: plywood, stickum, paint backing, superglue, paint backing, stickum, aluminum can, air.) The calculated kerf is 207μm from the sum of the 100μm tip, the 200μm surface penetration, and the 30° included angle. FlatCAM ingests the Gerber and runs the mill. His cutting fluid is 3-in-1 oil. This one seems to be cut more precisely, though not quite as precisely as PCBWay’s laser-cut stainless stencil.
on 02024-05-09#video by #gomezgimenez on #manufacturing a digital clock that works by illuminating falling sand at 10Hz, all initially controlled by an Arduino (maybe a Mega, not sure), though later he got his own board fabbed with an onboard micro, looks like a PIC18F4550 actually, then soldered the parts down with a solder-paste stencil and hotplate reflow. Demonstrates some interesting #manufacturing techniques, such as CNC-routing a PCB with a D-bit with auto-bed-leveling sensed by conduction to the (coppper-clad) workpiece. Standard captive-nut technique for screwing together FDM 3-D prints and PCBs. Not sure why each digit requires 4 pixel columns of sand instead of 3. Because he’s modulating the timing of the sand release with the (16!) solenoids rather than the timing of the light flashes, he doesn’t have to worry about leakage of light between columns. Unfortunately you’d need a higher refresh rate than 10Hz for this to be practical; a 10Hz flicker is maximally distracting. Also the sand runs out in two minutes. #electronics #hardware
on 02024-05-09