A1 Mini Front Cover with Tripod Screw

Added a tripod mount screw intended to mount a Pro Mini Camera Mount for Raspberry Pi Zero with a Pi Zero 2W as a camera tool that's pointing directly down. We're planning to use this for autonomous 3D printer parameter optimization using visual feedback, where we use a Python API / G-code to manual move the printer head to allow us to image a single-layer 3D print (e.g., small square). More context on the usage at: https://github.com/AccelerationConsortium/ac-training-lab/issues/158 | #156 | #147 | #144

The 1/4"-20 UNC screw (standard for tripod screws) was imported from McMaster-Carr and then cropped to be ~15 mm tall. A bit shorter would have been better. I added a bit of extruded, filleted material where the screw and the cover meet to try to reduce the chance of breakage. However, this might keep the camera mount from sitting flush against the cover (I didn't check the hole diameter of the laser cut piece). In retrospect, I think I would make this the same diameter (i.e., flush with the screw threads).

You can tell the length was a bit overkill (two nuts added, but one would still be fine). Keep in mind the nut needs to be somewhat small in external diameter to have enough clearance relative to the Pi Zero 2W. I'd probably reduce it to 10 mm or 7.5 mm depending on the intended nut to be used (e.g., 7.5 mm if using the silver nut below, which I think is the one called out in the bill of materials).

The mechanical connection between the camera holder and the Zero 2W holder is not very strong, so it tends to wobble / not keep a perfect 90 degree angle. If taking images while the extruder head is stationary, maybe not a huge deal. However, with a slight modification inserting a thin shim on either side, the wobble is reduced significantly.

I set it in the following orientation to try to avoid having too many supports on the mechanically relevant pieces (i.e., the clips/hinges and the screw).

A tap would have been best for the threads, but a metal nut and some flush cutters can be used to try to get the threads to behave. In my case, it wasn't worth the extra hassle at this prototyping stage to get additional hardware (tap, trying to do heat-set insert, using metal rod instead and a nut on both sides with a countersunk design on the back, etc.). If I were to print it again, I think I'd increase the infill percent significantly (ideally, focused on the screw, but because everywhere is so thin anyway, setting it to a high infill percent across the entire part probably wouldn't be an issue).

Aside: Originally, I tried printing with PAHT-CF to get stronger threads, but the added difficulty of a good print wasn't worth it considering the redundancy already there (100% infill and the extra support material). It seems it may have warped/lifted a bit off the build plate (I'm using an X1E with 0.4 mm hardened steel). The print with PAHT-CF was quite poor as you can see from here, hence just using regular PLA above. Note, for this failed print I printed with 100% rectilinear infill to try to keep the screw stronger, but above it was the default 15% infill.


 

Design by AC Training Lab on MakerWorld (license: BY).