Summary

I designed this piggy bank for my son who is a big Minecraft fan. My goal was to come up with a sturdy solution that prints without supports, needs no post-processing and assembles without requiring additional hardware or small parts. The head slides in from the top using a dovetail-like sliding joint and provides easy access to the inside compartment.

I'm relatively new to 3D-modelling and 3D-printing, and many aspects of this model took considerable tuning and experimentation. It's actually the first design that I was able to get out of the prototype stage and proud enough of to publish it. I hope you like it!

Print Settings

Printer Brand:

Creality

Printer:

CR-20

Rafts:

No

Supports:

No

Resolution:

0.2mm

Infill:

20%

Filament: Real Filament PLA Fluorescent Pink

Notes:

I scaled the model to 60%. I used 4 perimeters for the walls and 6 top and bottom layers, since the material I used was slightly translucent and otherwise would've showed the infill prominently. For aesthetic purposes, I used a 'grid' infill pattern with a 90 degree fill angle. For the pig's face, I used a concentric top fill pattern, but hadn't calibrated Linear Advance sufficiently, so that looks slightly over-extruded in the pictures. For the left and right part of the body, I used the ironing feature of Supermerill's awesome fork of PrusaSlicer (called Slic3r++) to make the mating surfaces as flat as possible (thank you Supermerill!). Tested with both PrusaSlicer and Slic3r++.

Post-Printing

Frontside

Tailside

Shown with open compartment. Note: a previous version of the head is shown.

How I Designed This

I designed this Thing to be entirely printable without supports.
The tolerances I used should work for any well-tuned FFF-printer.
The head is printed face upwards.
The two halves of the body print on their sides.
The body is not designed to be easily disassembled again.
The STL files are not rotated in printing orientation, please do so yourself.

NOTE: I took an overengineering approach to designing the snap-fit joints of the body shell and made them very stiff and strong. Therefore, the snap-fit hooks themselves lack springiness and instead use the entire shell itself to implement the required spring effect.

For assembly, it's best to start with hooking in both top joints, close the bottom snap-fit, while at the same time carefully closing the front snap-fit (which is the most delicate, so be careful). The trick is to lightly press the shell near the hooks inward and lightly pull the opposite sides outward, to give the snap-fits more room to snap and not break. If you take it slow and don't use excessive force snapping the halves together, you'll be fine.

Build plate orientation

Since the STL parts have not been generated in an orientation in which they print without supports, and user brittalicious had a question about this, I'm providing the image below as an example of how to arrange and rotate the parts on the build plate so that the model prints without supports.

Note that I suspect that user KateWantsCake has printed the head in the default orientation and used supports for the pig's nose, which produced a very clean result as well.

Suggestion for the orientation of the parts on the build plate.

Minecraft Piggy Bank

Minecraft Piggy Bank

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