Lights DFMA

Owned by Connor Hawkins
Last updated: Jul 04, 2021
3 min read

Several aspects of the lights have now been designed, including the lights PCBs, positions on the vehicle, aesthetics, and rough enclosure concepts. Next, a manufacturing plan needs to be finalized for each component. This will involve modifying the existing enclosure designs, creating new enclosure designs for some lights, modifications to any other parts as needed for manufacturing, designing any required molds, selecting materials for each component, and creating a formal assembly procedure.

 

Figure 1: An exploded view of the headlight assembly.

 

Take the headlight for example, as these are the most complicated lights. The current design seen in Figure 1 consists of an outer lens that conforms to the aerobody, then a few aesthetic components, an enclosure to hold the lights PCBs, and then the PCBs themselves.

  1. Starting with the lens, this will be thermoformed out of 1/8” clear polycarbonate (or similar thermoplastic) which will require a mold to be designed.

  2. At some point in time, the lens will be glued to the flanges on the hood and side panel, but this will create an ugly glue joint that will be visible from the outside of the car (due to the transparency of the lens). The way car companies hide this joint on windows is by painting a black border around the inside of the the transparent panel to cover the flange. Thus the 1st aesthetic component will be a layer of black spray paint around the border of the headlight. There will also be portion in the middle of the lens that will either be spray painted black or tinted since the lens is quite large compared to the lighting elements. This will require a stencil to control where the paint lands on the lens and possibly some research into how to apply window tint properly (avoid air bubbles, etc).

  3. The next aesthetic elements are optically diffusing elements. These are pieces of plastic that diffuse and soften the light from the LEDs. Manufacturing will be probably be straightforward (gluing small pieces of plastic to the enclosures, maybe some minor thermoforming involved or maybe 3D printing to get the shape right?), but the materials, colours, and dimensions still need to be finalized.

  4. The enclosures will likely be 3D printed due to how intricate they are and because that’s already how the hardware team makes board mounts and enclosures. The enclosures still need mounting points for the PCBs, they need to be logically split into smaller parts so that they fit in a 3D printer, and they may need some modifications to make printing easier.

  5. To my knowledge, the PCBs are finished.

 

After every part is completed, they need to be assembled. The order will probably follow something like

  1. Paint and tint the outer lens.

  2. Assemble and glue the enclosure parts together.

  3. Add heat-set inserts to the enclosure mounting holes.

  4. Glue diffusers to the enclosure.

  5. Glue the enclosure to the lens.

  6. Glue the lens to the aerobody.

  7. Attach the PCBs with screws.

 

A similar process must then be repeated for the side turn indicators, high-mounted brake light, rear brake lights, and rear turn indicators. These will be simpler though because they will not require thermoforming molds, won’t need painting, and will have smaller enclosures with fewer PCBs. Further work beyond this outline could include adding a cover to the back of the headlights to protect them from dust and moisture coming through the wheel wells and maybe adding reflective elements to help maximize the brightness of the lights?