CC Connection Port

Intro

The side of the catamaran cover will have a port that houses the connectors we need such as USB-C for phone charging and CAN debug outputs. @Renzo Villanoy originally designed a port housing and cover to be 3D printed but the design for the hinge had some issues that needed to be improved upon. The goal of this mini project was to find a redesign for the port cover and housing that is able to meet all the requirements and is easy to use.

Requirements:

Outer dimensions do not change
Must be 3D printable, the simpler the better, the less parts the better
Easily accessible
Robust when closed, shouldn't swing open from the vibrations of the car
Cover should have range of motion of at least 90 degrees from closed position
Cover should completely enclose connectors

Original Design

This design had some issues with assembling the hinge, as well as the hinge interfering/getting in the way of the lid’s movement. The hinge was also visible when the lid was closed, which was unideal in terms of interior aesthetics.

Redesign Ideas

There were mainly 2 options that were considered for the redesign. Either continue with the hinge design, improving the hinge, or recreating a sliding cover that could slide to open/close the housing. Some quick thoughts about each option were brainstormed.

Cover with Hinge

Hinge should ideally be inside the cover, concealed when closed
Needs lock mechanism, ensure doesn't open/close/bounce due to vibrations
Needs a way to assemble the cover and housing, or to print both pieces together in place

Sliding door

Can stay open while ports are in use, without needing to be held up manually
Does not take up “horizontal” space when opened, simply slides to side
Might be harder to 3d print / assemble

Water Soluble Support Material Research

As I have never worked with water soluble support material before, I compiled some research about printing with water soluble filaments into this doc:

https://docs.google.com/document/d/10QN38Uj_W4yAm_tFNQ_ntweiMHvqF4Rbda2itpTB8dU/edit?usp=sharing

Hinge Research

Living hinges
- Basically having one solid hinge that physically bends
- Cool idea for hinges, not designed for durability though, mainly used for prototyping or for uses where the durability of the hinge is not important
Parametric Hinge
- Your typical hinge
- Need to consider how to remove support material inside hinges if printing all together
- Inspiration for possible hinge designs
  - https://www.thingiverse.com/thing:2187167
  - https://www.thingiverse.com/thing:1551631
  - https://www.thingiverse.com/thing:1396038
  - https://www.instructables.com/Parametric-Print-in-Place-Hinge/
  - - One in place print hinge design, looks interesting
    - Would probably try this design for the hinge

Sliding door

Not much (or any) designs found for a sliding door, but the concept is pretty simple
- Have “tracks” on top and bottom of the housing, and “rails” on the inside of the cover that can run along the tracks when the cover is pushed/pulled
Some thoughts considered when designing the sliding door
- Need to see how much space there is
- How to 3d print and assemble?
  - Need to get the “rails” onto the tracks, while having a stopper to limit the cover’s movement so that it doesn’t just slide off the housing entirely
- Should the cover slide open sideways or upwards?
Ended up deciding on designing a sliding door, as with all considerations, it seemed reasonable to create, and seemed to be the better option in terms of using it in the car.

A (super sketch) sketch about what the sliding cover would look like. An idea to snap the rails in place from the front was an idea, however, the 3D print material would probably not be flexible enough.

Upon deciding on the sliding door, I just went into Solidworks to try to work something out. I took the original model that Renzo made, and cut off the hinges, and designed the basic “track rail” system for the sliding cover.

Took base design that Renzo created, and removed hinges
Designed sliding door

Added rails for sliding on top and bottom of case
Trimmed case so that the overall dimensions of the housing remains the same as before

Added stops
- Limits movement of case, ensuring doesn’t slide off

“Soft lock” , basically way to make the cover stay in place when closed
- There is an extra 0.25 mm clearance on the top and bottom sides, and the hump is 0.5 mm tall. When the cover is pushed over the hump, it should go over the hump and sort of lock itself when closed.
  - Only on the top rail, bottom rail is fully smooth

Random design that I added for fun
- Can be changed or removed
- Included grooves to enable opening the cover by pulling on the design
Main concerns after first design:
- The design had the cover and housing printed together, as I had not thought of an idea on how to assemble the cover with the housing. The stops prevented the cover from being simple slid onto the rails.
- The idea was to print the cover and housing offset from each other, to minimize the amount of support material printed between rails and tracks, which could be dissolved later.

The cover should slide open to the right. The Catamaran cover has a curve on the left that might interfere.

Some more clearance should be added on either side of the rail, around 0.5mm on both sides.

This fillet radius should be increased because the 3D printer may not be as precise.

It might be better to print as 2 separate pieces, cause right now there’s no way of getting the cover on the rails. I could design another separate piece that we can just super glue on after to stop the cover from sliding out.

Idea was to put the glued on piece this back part, so that it would be theoretically concealed and never actually seen

Cut out a part to insert from back once the cover is on the rails

After the cover is slid on, this piece can be slid in from top, super glued, and will act as a stopper, preventing the cover from sliding off
Technically cannot be seen when opening / closing the cover when it is set in the car

In total, will be 3d printing 3 separate pieces
Rest of the issues such as clearance and fillet size were updated as well

Wanted to keep a well to collect superglue so that excess superglue is directed away from other parts
Kept slant of the “lock”, while simplifying the lock shape

After the fifth update, the port housing and cover design seemed to be finished, and was uploaded to GrabCAD. It’ll then be prototyped by Renzo to check if any further changes are required, or if it is good to go.

Final Design Images

Prototype 1 (Renzo)

The 3 components were 3D-printed using PLA to test dimensions and ease of assembly.

Total print time: 6hrs 30 min

Port housing and cover printed with brim and support structures. Support structures were easy to remove.

The cover and housing experienced warping and poor bed adhesion at one corner due to my amateur printing skills but could still be assembled.

The cover fit tighter than expected due to the warping, had to use some force to fully close it. The glue-on piece fit well, with adequate room around all sides. The significance of the warping can be seen with the piece in position.

Changes for final print

Increase tolerance around all sides of rail system by 0.5mm for smoother travel
Increase diameter of soft lock humps by 2mm
Add handle protrusion (most likely a separate piece that will be glued on to cover)
Fillet outside edge of cover face to eliminate sharp edges