Design Progress | Week 6

Dates: 09/24/25 - 09/30/25

This week, progress was made on both the hardware and design aspects of the NAVI project. The USB-C charging module and 12 mm push button switches were modeled in CAD and integrated into the main enclosure, with port locations reassigned after the original placements proved unfeasible. Work also began on the strap housing that will connect the enclosure to the head strap, which will be 3D printed in TPU to provide both flexibility and durability. In addition, two 12 mm push buttons (momentary and latching) were ordered for testing; however, shipping delays due to tariffs may extend their arrival time, so comparable alternatives will be sourced from local electrical supply stores for preliminary testing if unable to find an adequate substitution in the open lab.

The faceplate design went through several iterations this week. A reprint in ASA using revised print settings was mostly successful, but the center wall proved too thin, leading to cracks under light pressure. To address this, the faceplate was redesigned with thicker walls and reinforced structures in CAD. M-series hole inserts were also incorporated to allow solder-press brass fittings, greatly improving durability, usability, and fastening strength. Testing confirmed that the brass fittings securely combine the faceplate with the supporting brim, and after several attempts with adjusted print settings and environmental conditions, a functional ASA faceplate was successfully produced, though further refinements remain.

The majority of the issues discovered with the ASA filament stem from the fact that ASA is highly sensitive to both temperature and humidity, which makes it more challenging to work with compared to materials like PLA. Because it requires high extrusion and bed temperatures, ASA is prone to warping, cracking, and delamination. One of the other discoveries this week is that ASA is hygroscopic and readily absorbs moisture from the air, which can lead to bubbling, stringing, weak layer adhesion, and overall brittleness when printed. To achieve reliable results, ASA filament should be thoroughly dried before printing, stored in a sealed container with desiccant, and printed under controlled thermal conditions to ensure both dimensional accuracy and durability.

Beyond structural work, a prototype frame was printed to support preliminary system testing, troubleshooting, and software development..