Chocolate Haro — 3D Printed Master & Silicone Mold

For this assignment, I designed and fabricated a chocolate mold based on Haro, the robot mascot from the Gundam series. Haro’s simple spherical form made it a great subject for my first chocolate casting attempt, while the face lines and details provided opportunities to experiment with 3D sketching and surface shaping.

PLA filament (for 3D-printed master)

Makerspace FDM printer

Class silicone (AB silicone for soft mold)

Standard outer casing provided in class (Ø 38 mm × H 37 mm)

Fusion 360 (for design and parametric control)

Calipers, sketch tools, mixing cups, and stir sticks

I started with a quick reference sketch of Haro to plan out the circle base and face details. Since Haro is basically spherical, I aimed to simplify the form into a 30 mm diameter × 12 mm tall medallion.

Created a circle profile for Haro’s body (Ø 30 mm).

Added arcs and spline curves to define facial details.

Used extrude to cut grooves and add shallow features.

Final dimensions: 30 mm diameter, 12 mm height, flat base for molding.

Printed the Haro master on the UCSB Makerspace FDM printer in PLA.

Orientation: flat base down for stability.

Layer height: 0.1 mm for reasonable print time and smooth top details.

Removed strings and lightly cleaned surface before molding.

Placed the PLA master face-up, base down against the casing floor.

Mixed two-part AB silicone carefully to avoid bubbles.

Slowly poured silicone into the casing, covering the master.

Allow to fully cure before demolding and carefully removing the 3D printed Master.

Melted and tempered chocolate during class.

Poured into silicone mold cavity, tapped casing to remove air bubbles.

Cooled until hardened, then gently peeled silicone back to release.

The chocolate Haro came out stable and recognizable, with the grooves from the face lines transferring clearly. The size (30 × 12 mm) made it more like a candy piece than a full 3D sphere, which worked well for demolding.

The reading influenced how I approached both the design and fabrication of this mold. Section 4.2 on molding and casting emphasized that demolding should be planned at the design stage, which is why I kept Haro’s base flat and used only shallow cuts for facial details. Section 5.2 reminded me that designers rely on multiple partial representations: I started from a simple sketch, then moved to arcs and spline curves in Fusion, and finally tested proportions through the printed master before casting. Section 6.1 about parametric design helped me think about constraints such as diameter, height, and draft, and how these settings affect both machine behavior (layer height, extrusion quality) and material behavior (chocolate release from silicone). Next time, I would like to experiment with projecting details directly onto a curved surface so that Haro’s features follow the dome more naturally, creating a richer chocolate impression.