UPDATE: v2 has been redesigned to ALSO fit the SKR E3 Turbo!

The pictures are of both versions - slotted front grill is v1, hex front grill is v2.

This is a new design to replace the stock Ender 3 Pro motherboard case, which will fit both the form-identical 4.2.7 silent motherboard or the Bigtreetech SKR Mini E3 v2.0, as well as mount a buck converter for a fan upgrade. It also features a full-size SD card slot in the front in case you're tired of fiddling with the teeny tiny ones.

If you find yourself needing to access the motherboard compartment on your Ender 3 Pro more than one time after you buy it, for example to...

• replace the board
• install a BLTouch
• replace the fan
• stare at the inside

...you'll curse the fact that you not only have to flip the whole machine over but also access screws on both sides. There is simply no convenient way to work in that compartment in the stock location.

Same Location

If you have already moved your PSU to the back of the unit, perhaps under the Y axis to make room for a dual Z upgrade, you no longer have that location open for the motherboard chassis unless you want to move the PSU again. And if you've already chosen or created a control box for your raspberry pi - perhaps under the LCD - then you don't really need a full electronics box in the rear anyway. This thing keeps the motherboard in the original area.

The stock cables on the Ender 3 Pro are extremely tight. There is negligible allowance to move the motherboard mount location any further forward from the base than it is when it's mounted in the factory location. This mount keeps it in the same relative location, and shouldn't require any longer aftermarket cables to be run. At least, it didn't on the unit it was originally built for.

Room for more

Unable to find a CAD model for the 4.2.7 board, this case was literally built around the Bigtreetech SKR Mini E3 v2.0 model. The mounting holes are identical between that and the Creality 4.2.7 silent board, which is what I have installed in the first 'final' print.

The stock 4010 fan fits upright screwlessly in a mount that holds it to the side of the case, and a buck converter can be mounted in the front just behind the grill in case you want to upgrade to something that isn't 24v. The stock fan is actually 10.5mm thick, so any 4010 that thick or thinner should fit fine.

Due to the motherboard location not allowing access to the front ports, this inspired a slot in the front to mount a micro SD to regular SD converter ribbon cable. If you're using a raspberry pi that needs to connect to the motherboard, the cable will enter the box through the same hole your LCD ribbon cable does, but you'll still have full access to the SD card without opening the box.

Requirements

All are "optional" if you want to be pedantic about it.

• 5x M3 6mm screws for the motherboard, if you want it secure in the case
• 2x M3 screws, 6mm or so, plus T-nuts for the sides, if you want it to sit between the extrusions instead of falling on whatever surface supports your printer
• Micro SD to SD Card Extension Cable Adapter, if you want access to the SD reader without opening the lid
• 2x M3 6mm screws for a buck converter, if you want to install an aftermarket fan that is less than 24v
• Upgraded 4010 fan, if you want less / different noise in your life

2021-07-08 Update v2

• Moved fan to front of case to accommodate Turbo board
• Changed intake and exhaust grill design

There should be no need to install the previous version. The original boards fit in the remodel and I believe the new fan location is better for cooling the stepper motor drivers.

If you're using one of the smaller boards for which it was designed, have no intention to upgrade, and like the design better for your own reasons, the file is still included here.