3D Printing - Heart Chocolate Mold

For this making assignment, I designed and fabricated a heart-shaped chocolate mold using Fusion 360 and a 3D printer.

1. Fusion 360
2. 3D Printer (PLA filament from Library Makerspace)
3. Silicone
4. Chocolate
5. Casing

I went with a heart-shaped form because even though it is pretty simple, it is a good test case for working with spline curves, symmetry through mirroring, and decorative features.

I began sketching the final heart shape that I wanted to design and then drew it in 3D form to mimic the final extruded chocolate mold. I noted the maximum width to be 30 mm and the height to be 30 mm. These dimensions ensured that my final mold will fit into the casing.

Since the form needed a flat base and a minimum 3° draft angle, I extruded the heart profile upward by 30 mm with a positive taper of 4°. This positive draft ensured that the chocolate can be easily extracted from the mold.

Besides extruding and tapering, I added one more complex 3D operation by adding a raised ridge heart on the top face using a fillet method. I projected the outline of the heart onto a new sketch. Then I offset the outline inward by 2 mm to create a smaller inner heart. I, then, extruded the area between the two hearts upward by 2 mm to form the ridge while making sure the draft angle for taper is also 4°. Finally, I filleted the top edge slightly to smooth the ridge.

I exported the design from Fusion 360, sliced it, and sent it to the 3D printing queue from Library Makerspace. I oriented the print flat on its base to minimize supports and ensure a clean surface finish on the heart. I made sure all the printing parameters were correct and double-checked the dimension of my form. Finally, I sent my form to the queue for it to be printed.

The mold was successfully printed and picked up and is ready for the casting. The pink PLA was a plus; my final form turned out to be what I wanted!

First, I used Gorilla Spray Adhesive to spray the bottom (the wider base) of my chocolate form. Then, I attached it to a circular base of the casing and attached the cylinder casing around my chocolate form. I made sure that the cylinder was attached properly so the container can be airtight for later casting of silicone.

Next, I mixed the two-part silicone according to the manufacturer's ratio (1:1 by volume), stirring slowly for 4 minutes to avoid air bubbles. I then carefully poured the silicone mixture into my cylinder casing, letting it flow over my heart mold. Once the silicone reached a bit above my mold, I stopped pouring and tapped the sides of my casing to reduce trapped air.

Finally, we let the silicone sit for about 3 - 5 hours, then we will disassemble the casing and remove my 3D print, leaving behind a silicone mold ready for chocolate casting.

The silicone mold turned out great. It was somewhat difficult for me to remove my 3D-printed mold out of the silicone, so I had to use a spoon to carefully scoop it out. Then, I poured the melted chocolate into my silicone mold and tapped on the sides to make sure the chocolate is evenly distributed in the mold. After that, I put it into the freezer for about 2 hours. The final chocolate form looks good!

The reading for this week had an influence on how I created my heart-shaped chocolate mold. The reading pointed out that while digital fabrication was originally considered to be totally democratizing, in practice, successful products remain significantly dependent upon material knowledge, machine setup, and workflow optimization. This struck a chord with me as I experimented with handling the requirements of draft angles, form limits, and surface detail. I realized that even the simplest form/design, such as my chocolate mold, still requires accuracy in geometry and the facts of manufacturing—just as it was with the Coral Cup and Other Vessels from the reading—with toolpaths and casting. The fact that designers typically work from incomplete or even ambiguous representations also had an impact on my design thoughts; my heart sketch, though simple, was built up step by step rather than being perfect right at the start. Ultimately, the emphasis on parametric design also reminded me that geometry by itself is not enough-- draft angles, offsets, and surface design are just as important in the design workspace to create a polished form.