Dell WD-15 USB-C dock with 120mm Fan

Design Goal

With working from home, I’m at my desk a lot more than usual. I also am swapping between my work laptop (a Dell Latitude 7390) and my personal laptop (a Dell XPS 13 9370). I’ve used a Dell WD-15 for years, but with sitting around at home more I’ve moved things around, got a new monitor (…then another), relaid out my desk, etc. Since moving into my apartment here in Las Vegas I’ve a basic laptop cooling pad since the desk is fairly warmer compared to the rest of the apartment, but I couldn’t really fit it anymore with an Ultrawide (21:9) monitor. I thought through my options and landed on this. Worth noting, I didn’t really like the Ultrawide I got so I switched back to 16:9, but the idea seemed really good (and space saving) so I stuck with it.

The design goal was fairly simple: Minimize the foot print of the dock and laptop while still providing cooling to the laptop’s bottom. I usually leave my laptop closed while docked so, if I stand everything up it should be fairly easy to keep the foot print down significantly.

By standing the WD-15 dock on it’s side, with the USB-C cable running up and back, I can put the laptop with it’s back facing the other direction, feed the USB-C cable thru the front, and have a fan blowing against the bottom of the laptop.

Design wise it’s really quite simple. The “left” slot is for the WD-15 dock, there’s a slot on the middle separator to feed the USB-C cable thru, and the laptop rests on the right. The cutout for the fan is for a standard 120mm computer fan (I have a few laying around). It includes cutouts for nut on the “inside,” but using more traditional case fan self-tapping screws should work. Even standard M4 screws are held in place without nuts somewhat securely (depending on your printer’s tolerances that may or may not be true for you). There’s a little cubby under the fan with a cutout to route the fan’s cable. There’s a little cutout where the WD-15’s power button is as well so you can still hit it (albeit with a bit more difficulty).

Included the Fusion 360 file for modification. It fits both my XPS 13 9370 and my work Latitude 7390, although the XPS 13 is a bit thinner so it wobbles around a bit more than the Latitude. The dock side itself could be a bit smaller for a tighter fit, but I prefer it a bit loose so if I have to move things around I can easily pop it out.

Part of the idea is also that the weight of the dock should provide enough counter balance so the laptop doesn’t tilt the whole thing around. I tested it out and it seems good, but to stop the weight of the cables plugged into the dock pulling it back I used some Command Strips on the bottom of the dock holder to keep it in place.

Bill of Materials

Required:

• 3D printer and filament (inb4 someone points it out in the comments)
• 120mm 3 or 4 pin fan
• 3/4pin fan to USB (for providing power)
• 4 screws M4/case fan tap screws for mounting fan

Optional:

• 120mm case fan dust filter
• 4 screws for mounting dust filter (if using above)
• 4 to 8 M4 nuts (4 if using M4 screws to mount fan, 8 if using M4 screws to mount fan and filter)

Note on the 3/4pin fan to USB power adapter:

I used the following from Frys.com:
https://www.frys.com/product/9085057?site=sr:SEARCH:MAIN_RSLT_PG

It’s cheap, easy, has a long cable, and chief for me: A power adjustment knob. Absolutely not a required feature, but a nice to have. You can easily wire up something yourself, look for a similar product elsewhere, etc., just pointing out the option I went with it and linking it for easier consumption.

How to use it

The STL is already oriented for printing. In case your slicer imports it wrong, the “back” side should be on the print bed. This will mean the shortest separator is on the left, the longest (with the fan cut out) on the right. Obviously, rotate how you will and the left/right won’t be accurate anymore, but live your life. If your printer has solid cooling you can print without supports. I used PrusaSlicer support enforcers to get a cleaner top of the fan hole cutout, but otherwise nothing.

Mount the fan as you wish. I used M4 16mm screws and M4 nuts because I have bunch laying around. I also mounted a case fan filter to the fan itself with more of the same screws and nuts.

Put the WD-15 dock on the left, standing up so the the side opposite the USB-C cable is facing the bottom. Feed the USB-C cable thru the back side of the cable route so it comes out the front of the printed part.

You’re basically done. Drop your laptop on the right with the underside of the laptop facing the fan, back (where the hinge is) facing the bottom of the part, and plug your USB-C cable in.

Optional, but I used some Command Strips to mount the dock in place on my desk. Some rubber feet or something would probably help, too. I suggest the command strips or similar products to “fasten” the dock in place so the weight of the cables that plug into the dock don’t tilt it around too much.