This project started as a gift idea. I wanted to create a 3D printed, all-in-one charging solution for an iPhone and Apple Watch. See its evolution below. This project had me deal with DFM/DFA as the tolerances needed to be tweaked as parts that appeared to work in CAD did not translate into the real world, requiring significant changes.
The first version of the phone and watch charging stand being printed.
The design used an off the shelf, 50 mm wide, Qi charging coil and an Apple Watch charger. Cables for both chargers were routed close together for easy management. This design went through a few iterations in order to correctly position the relatively small Qi coil so that the both a smaller iPhone X and a larger Pixel 4 XL could charge with no readjustment by the user.
The first version of the phone-only stand was simply an edit to remove the Apple Watch section. Additionally, I added pins and mating holes in the Qi Board Cover and the main body with an interference fit for more permanent assembly. As I printed a few more of these units in different materials, I was running into issues with unit to unit variation in tolerances. The dovetail slots and rails were occasionally differed enough that I was unable to slide the Coil Cover onto the stand. This issue occurred consistently in certain material, requiring tweaks to the design. This, along with further changes to how the Board Cover mated to the stand, were made in the V2.
Version 2 of the stand is where I changed the slot and rails for the coil cover from a dovetail to an asymmetric shape. This still keeps the the cover from shifting laterally while also allowing me to include a lager tolerance between the parts. Additionally, I tapered the leading edge of the coil cover rails to prevent binding that occurred if the parts were not perfectly parallel when first being assembled.
I added a draft to the Qi board cover pegs so the friction fit between them and the stand did not engage until the cover is nearly flush with the surface of the stand base. These are all minor changes, as shown by the end result looking very similar but, these details are what makes a good idea a great product.
