Our goal originally was "To place top 3 in MakerWorld × TRYX Open-frame Case Design Contest."

We never made the entry deadline……, but the design was still finished, and Marmalade was born. So yes, it got very messy and sticky - not fun. Anyway lets get into the design.

Our brief was to make a 3D printed open frame pc case that makes the AIO the hero of the build.

Before I touched CAD, Blueberry Jam and I ideated with cardboard. To understand just how big this PC would be—would it be standing, lying flat, or sitting? I also needed to experiment with how to arrange the components. What the cardboard made apparent was that the radiator was really just a giant metal beam. Building it physically helped me start thinking about forms and gave me a real starting point; this is where the use of the AIO as a structural spine stemmed from.

Flavour profile

Inspired by brutalist architecture and 80s "office beige," Marmalade is an exercise in design honesty. Open-frame cases are inherently raw; the people who build these are enthusiasts about PCs and 3D printers, so I played into that. I leaned into the industrial vibe by making a feature out of parting lines, exposed bolts, and highly visible part numbers to create a unique case that would be fun for makers to own and build.

The Radiator as Backbone

The 360mm radiator is the "hero," but it’s also the structural spine. The core frame of Marmalade bolts directly to the radiator’s metal casing. By using the AIO as a beam, I could reduce snap-fits and glue, using strong hardware connections between the print and the AIO block. This enables a large-scale chassis that stays rigid with minimal 3D-printed mass.

DFM & Assembly

Like any good artist, I stole—I borrowed Corsair’s nut-and-bolt assembly system. It’s a clean alternative to threaded inserts and works perfectly for a frame of this scale.

The model is optimized specifically for a 0.8mm nozzle:

• Efficiency: A single 0.8mm wall provides the structural "thick-look" I wanted with a fraction of the print time.

• Tolerances: I kept the tolerances generous for high-flow printing. If you’re using a 0.4mm nozzle, the joints will be loose; I recommend a bit of superglue on the non-bolted sections to keep things snug.

• Infill: Aesthetic parts use lightning infill to save weight; load-bearing components use adaptive cubic for strength where it matters.

The assembly guide is currently in the kitchen; Blueberry Jam is perfecting the recipe as we speak. Thank you for reading this and checking out our site. For a while there, I hated Marmalade, but now I’m feeling like Paddington.

— Strawberry Jam