I looked at various types of modular racks, but I had trouble finding a design that suited my needs. So, I designed this one myself.
Most designs had the following problems, which I needed to address.

1️⃣ Inefficient printing workflow
To print just a single module, I had to do three separate prints — one for the base and one for each side wall.
Personally, I wanted to print multiple modules at once, ideally leaving the printer running overnight.
The original design wasn’t optimized for batch printing.

2️⃣ No wall contact = less stability
Most of the designs were fully symmetrical, the spools stuck out slightly from the back.
This meant the shelf couldn’t sit flush against a wall, which felt unsafe — especially if I wanted to stack the shelves higher.
I prefer to have racks that can lean slightly against the wall, both for space efficiency and stability.

3️⃣ Inefficient horizontal expansion
Each module had its own left and right walls.
So when expanding horizontally, walls were duplicated between modules — wasting both time and filament.
In my design, adjacent modules share side walls, eliminating this duplication.
This not only reduces material use and printing time but also makes the whole structure stronger, since the modules lock directly together without relying on extra coupler parts.

With these three problems in mind, I created a new modular rack design that’s:

• Easier to print (multiple modules in a single print batch)

  

• Safer and more stable (flush against the wall)

  

• Stronger and more efficient when expanded (shared walls and direct locking)

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• Printable using A1-mini

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If you want to fit the shelf to the width of the desired placement location, you can use the Parametric Model to print the shelf base length to your desired size.

The default value is 220mm, and you can shorten or lengthen the length.

Please adjust to an appropriate length, as making it excessively long may result in it being unable to withstand the weight of the filament.

Some pictures to help assemble. (Only Foot has Front & Back… But it's important)

There are two types of walls, and if you are building higher than 3 floors, using the strong wall type is recommended.

The tolerances are very tight to ensure a sturdy assembly. I assembled it without any tools, but depending on the print quality, assembly may require considerable force. In this case, use a rubber mallet or similar tool.