This model allows you to insert two Thunderbolt 4 (USB-C) cables which will be properly aligned so that you can connect and disconnect them both at the same time from a MacBook Pro. It essentially turns them into a single plug.
I use my laptop with its lid closed and with two external monitors connected. I designed this to make it easy for me to plug it in to work on those two monitors, or to unplug it to take it elsewhere.
This is designed in three pieces: a two-part inner clamshell, intended to be printed in TPU, and a rigid outer shell, designed to be printed in a rigid plastic (PLA, PETG, ASA, take your pick). When printed properly, the inner clamshell will be a tight friction fit in the outer shell, which will compress the TPU to firmly grip the cable connectors. I did try printing the inner clamshell from PETG when I was prototyping, and I think it might be a viable option but the TPU works so well that I didn't pursue it.
For the model in the photos, I used Polymaker Polyflex TPU95 (blue) and Prusament PETG in “Anthracite Grey”. I would stick with a high-durometer TPU like this so that the cables will be held in the proper position to align with the ports.
Because different Thunderbolt cables have different dimensions for the plugs, I've supplied a parametric Fusion 360 model that will allow you to customize the fit for the cables you actually have. I've also supplied a 3MF file for a version that fits two of Apple's 1m Thunderbolt 4 cables. (Note that Apple's longer cables have a longer plug, so they won't work with the supplied 3MF; you'll need to use the Fusion model).
You can see that the version in my photos was made to fit two different cables. The small one is the Apple 1m. The larger one is a no-name cable that came with my LG monitor. This is a good example of using the parametric model. The two connectors had different width, height, length, and corner radius. The Fusion 360 file is set to the dimensions for my two cables as shown in the photos, because I think that helps to understand which parameters do what.
The model works well for most connectors that are essentially a simple extrusion of a cross section. Some non-Apple cables have a fancy over-molded strain relief or curvy shapes, and those are not likely to work well.
The length of the model auto-sizes based on the sizes of your connectors, and the slot in the back shell through which the cables pass auto-sizes based on the height (thickness) of the plugs.
Note: as designed, this will block access to the MagSafe port. Not an issue for my use case, since my monitors supply power. If you need to use the MagSafe as well, you'll need to revise the model a bit. I think that may be as simple as changing the Outer_shell_width variable to 33mm instead of 35. I didn't do this because I wanted to leave the TPU thicker on the sides for easier printing, but I bet it would work. Please comment or post a make if you try this and it works!
I did model the MagSafe in the Fusion 360 file, so you'll have that as a reference. The MagSafe body (in the Tools folder) is oversized slightly to represent some clearance. The MagSafe sketch has an inner perimeter that is the measured size, and an outer perimeter to create that clearance.
Tips for Using the Parametric Model
“Connector 1” or “C1” is the connector closest to the back of the laptop (next to the MagSafe).
You'll want to carefully measure the length (along the axis of the cable), width, height, and corner radius of the connectors on your two cables. If using TPU, err a tiny bit on the small side so that the TPU will be a tight fit. I printed this handy radius gauge which worked perfectly for me to measure the corners on my connectors.
You also need to measure the diameter of the strain relief (if present) or of the cable itself if there's no strain relief. Note that the strain relief diameter is often highest right at the connector. The model will automatically add a little extra space around this diameter so that the cables aren't squeezed excessively.
The model is set up to print with a 1° draft so that the outer shell will squeeze progressively tighter as you slide it on. This will produce a few steps in the TPU, but that's fine. I did try printing a version with no draft, but it's definitely more challenging to get the shell on.
The model is set up to have a 0.1mm gap between the outer shell and the inner clamshell. That produced a perfect snug fit for me on my printers. Adjusting this parameter will adjust the thickness of the outer shell. So, if you print a version and find that it's slightly too tight or too loose, you can adjust this parameter and just re-print the outer shell, which is a lot quicker than re-printing the TPU.
You should not need to adjust the USB port spacing value. The two “Max” parameters are computed and shouldn't need to be modified.
Printing Tips
I printed the TPU with 15% infill and 0.20mm layer height. Outer shell was also printed at 0.2mm layer height, and it's thin enough that there's no infill.
If using the F360 model, after adjusting parameters, export to 3MF.
Open the 3MF file in Prusa Slicer, and when it asks you if it should be opened as a single object with multiple parts, say no.
Printing orientation for the TPU parts should be obvious. Printing orientation for the outer shell will work best if printed with the back side (where the cables pass through) on the bed.
The author marked this model as their own original creation.