CORE One Mini - Had to bend over backwards this time :)

One of the biggest challenges in this iteration turned out to be the back panel. What looks like a simple flat part at first quickly became one of the most constrained areas of the entire build.

Because of the overall size reduction and the tighter frame geometry, the space behind the printer is extremely limited. At the same time, the back panel has to accommodate multiple requirements at once - fan openings, structural rigidity, cable pass-throughs, connectors, and clean routing for everything from the heatbed and chamber fans to thermistors, LEDs, and sensors. So it quickly became a matter of “adding holes in the right places” while still having enough space for cable management, the PSU, and the xBuddy box. Hiding everything cleanly while keeping it serviceable required a different approach.

The solution was to completely redesign the back panel and everything attached to it.

The approach was to shave material off the universal and rear profiles to make the panel wider - and to introduce a double 45° angled section below the CoreXY plate to gain additional space for cable management. This angled section also improves stiffness and makes the panel more forgiving, since a few original mounting points had to be sacrificed.

Inside this cavity, cables are guided vertically, similar to the CORE One - so the assembly process does not really differ, the part just looks a bit different. Due to the tight space constraints, many components (especially inside the printer) had to be adjusted to work with this new geometry.

A custom fan grid with inset cable tie points is required so it does not collide with the part cooling fan. The original part cooling duct on the toolhead will be replaced with the one from the CORE One L - which has a slightly different angle and is a bit shorter, providing additional clearance. An additional pass-through was added on the left side for the heatbed wiring, since the Prusa MINI heatbed is mirrored.

Because of the bend in the back panel, the Z-rod guide also had to be redesigned. The CORE One mounts this guide on the CoreXY plate - but that geometry is no longer present and would collide with the toolhead. Instead, the guide was redesigned in the style of the CORE One L - but using square nuts so the original CORE One hardware can still be reused.

The result is a surprisingly clean layout in a very tight space - no cables pressed against frame profiles, no collisions with fans, belts, or moving parts, and a much cleaner assembly with easier maintenance than in my earlier CAD models, where there was virtually no space for cable management.

This redesign also made it possible to standardize cable lengths better and avoid sharp bends or improvised fixes. What started as a space limitation ended up driving a more structured and modular solution than originally planned - helped significantly by the release of the CORE One L CAD files under the OCL.

As with many parts of this project, the back panel evolved from a “simple scaled-down plate” into a custom-designed, multifunctional structural and organizational component. It’s a good reminder that tight constraints often lead to better designs - if you let the problem guide the solution instead of fighting it. And in this case, since the part needs to be custom-made anyway, it does not compromise the original goal of the project.

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If you want to learn more about the project, make sure to checkout the main post "CORE One Mini - The Rocky Road to a Prototype." for the complete background and FAQ.

If you intend to buy a Prusa machine, you can use the referral code "@suit" at checkout in the Prusa online shop. This will give you some Prusameter points and me as well (which I can use for some free filament). Or you can just download, like and make some of my models here on Printables and even consider to become a member in my Printables club.

I've also set up a GoFundMe campaign to tackle the costs. Thanks to everybody who has donated a few euros already - that means a lot and helps me cover the expenses.