Headlight Design Log

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

Winter 2021

After doing some work with the rough headlight enclosure model, it became clear that some modifications will be needed so that it fits with the surrounding panels (Hood Panel - Updated - 2020-07-24 and DriverSidePanel), as can be seen in Figure 1. With the model I received, there are 2 problems. First, the top edge of the enclosure seems to be based off of a different headlight shape and does not follow the edge of the hood well. Second, there was not enough room left for the hood flange, so the enclosure currently overlaps the flange. This flange issue is also slightly complicated because the hood flange indent is not normal to the surface. I think this is intentional to avoid having overhangs on the mold, thus simplifying the machining process so this is something that will have to be worked around.

 

Figure 1: Arrangement of the hood panel, side panel, and headlight enclosure.

 

The headlight enclosure was remade to follow the top edge of Headlight Lens Driver - Updated - 2020-07-24. I should also mention that the walls were thickened to a minimum of 2 mm thick. This was to make them a little sturdier based on 3D printing advice from Micah Black. I wanted to make this change early since it will impact how much volume the enclosure takes up and might impact how the parts fit together.

 

Figure 2: Arrangement of the hood panel, side panel, and new headlight enclosure.

 

The top portion of the enclosure now fits the hood panel better. Next, the enclosure needs to be shifted downwards to allow more room for the hood flange and evaluate any effect this has on the aesthetics. Min and I have agreed to remove the core reinforcement on the hood panel flange to allow more room.

It was also around this time that I realized there is a considerable gap between the lens and the flanges. The lens has been modelled as 1/8” thick but the flanges were made assuming 1/4” thickness. The hood panel flange can be modified in CAD right now, but the side panel flange will need to be thickened with extra carbon fiber layers after the panel layup (Another option might be to add a thickener to the adhesive, depending on the final gap width).

 

Figure 3: Cross-section of the headlight and surrounding panels to show the gap between the lens and the hood panel flange.

 

Thus I’m proposing 2 changes to the hood panel:

  1. Reducing the flange depth from 1/4” to 1/8”.

  2. Cut the flange normal to the surface, rather than normal to a single plane. Not sure if this explanation makes sense on its own. The flange was previously being cut perpendicular to a specific plane to avoid having overhangs in the mold. This works for most of the flange, except for the curved section at the front of the headlight lens. In this region, there is less space for the headlight lens. Cutting the flange normal to the surface maintains more consistent space for the headlight lens. My trick was to fill in any overhangs afterwards so that the mold can be machined easily.

The result of the changes up to this point are presented in Figure 4. This new version of the hood panel is called Hood Panel - Updated - 2021-04-17 on GrabCAD. I think these changes allow the headlights to fit with the other panels, so now the PCB mounting points can be added.

 

Figure 4: New headlight enclosure.

 

Spring 2021

The PCBs were positioned relative to the headlight enclosure so that none of the components are overlapping in space. Some modifications to the enclosure walls were made to conform better to the rectangular shape of the PCBs.


 

Then the position of these boards was used to create mounting points for the heat-set inserts that the boards will be screwed into. Tabs were also created on 3 sides of each board to help align them during installation. These tabs were offset 0.2 mm from the board to allow some room for variation, movement, or errors, although this offset value was arbitrarily chosen.

 

Unfortunately, these features create overhangs from the anticipated printing direction so 45 degree chamfers were added to each of these features with the hope that this would help them be printed with minimal need for additional supports.

A flange was added for the turn signal diffuser. This was to help guide the shape of the diffuser (since the manufacturing plan for this component is not finalized but cold bending may be an option?) and to increase the surface area for gluing.

 

 

That covers all the current design changes to the enclosure. In order to 3D print the enclosure though, it must be broken into parts that fit within a 180 mm cube (the size of our 3D printer). The best location for a split was thought to be between the 2 DRL lights. The split line was shaped with a trapezoidal (?) protrusion to align the 2 components vertically.

 

 

After separating the inner and outer components, the front 3 mm of the trapezoidal protrusion was removed to create a sort of alignment feature in the z-axis. This explanation might not have been very clear but the CAD models can be consulted for a better understanding of the physical structure. The intent is that the components are aligned in 3 dimensions during gluing after printing. Finally, some 0.5 and 0.25 mm fillets were added to most corners on the model. Corners that are not currently filleted are those that contribute to the aesthetics, inner corners near PCBs edges or diffuser edges (places where an external rectangular edge will be in contact with an concave corner on the enclosure), gluing surfaces, and edges where SolidWorks ran into errors while trying to fillet them. The final headlight enclosure can be seen in Figure 9. The components can be found on GrabCAD in the aerobody lights folder (Development → Aerobody → Lights) with the file names HeadlightEnclosureUpdated - Shifted9mm, InnerHeadlightEnclosure, and OuterHeadlightEnclosure.