Fabricating Structures - Offset-official/Nautilus-One GitHub Wiki

This page details the creation of the various parts in Nautilus.

3D Printed Parts

All part designs were created using SolidWorks, which is preferred for its parametric modeling capabilities, comprehensive simulation tools, and excellent assembly management that allows for precise fit testing before manufacturing.

We used:

  • Formlabs Form 3 SLA printer (expensive)
  • Bambu Labs Carbon X1 with 100% infill

Our 3D printed components include:

  • Bucket for manipulator: Container designed to pickup and drop golf balls during underwater missions STL file
  • Connector for manipulator: Interface component connecting the manipulator to the AUV frame STL file
  • Kill Switch: Emergency cutoff mechanism for quickly disabling the AUV STL file
  • Resin filled underwater Connector: Waterproof electrical connection housing STL file
  • Spacer for clamps: Component ensuring correct spacing between clamped elements STL file
  • Battery holders: Component ensuring battery is held firmly inside the enclosures STL file
  • TPU electronics tray holder: Component made from TPU so that it can flexible and also act as suspension for electronics tray STL file

Laser Cut Parts

We export DXF files directly from SolidWorks sketches for our laser cutting needs. Our laser cut components include:

  • Weight plates: 8mm thickness, providing ballast and structural support DXF file
  • Electronics plate: 3mm thickness (could have been 5mm), serving as the mounting surface for electronic components DXF file
  • Camera mounts: 3mm thickness. For mounting the low light cameras on the electronics tray. DXF file

Printing Stickers

To ensure proper handling during transportation and assembly, we created several types of stickers:

  • Fragile stickers: Applied to the AUV transport case to alert handlers about delicate contents
  • Orientation stickers: Used to mark correct clamp positions and AUV orientation for assembly
  • Branding stickers: Offset printed for team identity

General Tips

Small Holes and Threading

3D printers struggle with small holes due to limited resolution and material behavior. Holes typically print undersized, requiring post-processing for proper fit.

For simple bolt-through applications, printed holes work adequately when drilled to final size. However, for threaded connections that require repeated assembly/disassembly, printed threads wear out quickly and fail prematurely.

For reliable threaded connections, we use heat set inserts. These metal threaded bushings:

  • Provide strong metal threads in plastic parts
  • Allow multiple assembly/disassembly cycles without degradation
  • Distribute load better than plastic threads

Installing Heat Set Inserts:

  1. Design holes 0.1-0.2mm larger than insert diameter
  2. Heat soldering iron to 170-215°C
  3. Place insert on hole (knurled edge down)
  4. Apply gentle pressure with iron until flush
  5. Allow 10-15 seconds cooling time

Ensure at least 1-2mm wall thickness around inserts for structural integrity.

Print Orientation

Part orientation impacts strength and support requirements:

  • Align print layers parallel to applied forces
  • Choose orientations minimizing support structures for easier post-processing