3D Model for Chocolate Casting

This project displays how to create a 3D Printed Flower Model using a Prusa MK4 3D printer. This flower mold was formed with the idea of chocolate casting after creating a mold with silicon. Additionally, the look/design of the flower was based on a light that hangs in my living room, with the round edges in mind.

This project used a Prusa-12 MK4 3D Printer, 0.4mm Blue PLA, Food-Safe Silicon, Gorilla Glue, Popsicle Sticks and Dark, Tempered Chocolate heated on a portable stove.

First step, as it goes in the design process, was to sketch out the design of the flower. Due to certain parameters for this assignment, based on the casing size needed, the flower must be within a diameter of 38mm and height 37mm fitting with 4mm clearance from the outer edge of the casing and with the height being 7mm shorter than the top of the casing (max height 30mm). This meant that I was gonna design a pretty small flower and I wanted it to be good size for chocolate bites.

To design this flower on Fusion 360, I started with a pre-made file of the casing with the correct dimensions. I then began a sketch on the bottom of the casing and first drew a construction circle using the parameter of 30mm to ensure there was clearance on all sides. I used the 'spline' tool to create a petal curve from the center of the flower to the edge of it and extruded the sketch to 6mm with a 3 degree draft angle to ensure it fit inside the height requirement. After extrusion, I used the circular pattern feature to copy and replicate the petal around the vertical axis to create 6 evenly spaced petals. To then round out the edges of the flower, I used the fillet tool and set it to 1.00mm. This created the perfect mold however, the draft angle should've been negative 3 to further prevent the mess-up when gluing the flower to the casing.

Once the file was saved from Fusion, I exported it to the 3DPrinterOS page and submitted it to a printer. The makerspace was able to finish it for me and take off any supports used to provide the final PLA printed form.

After all forms were printed, we glued each down to the casing bottom with Gorilla Glue Adhesive spray and let it dry to create a strong seal for the mold. It was important to glue the 'flat' side down on the bottom of the casing however the first attempt at gluing it I glued the other side. When I re-glued it, it then became quite messy and the adhesive beaded on the top of the flower, therefore adding interesting texture to the overall mold. We then mixed the food-safe silicon for 3-5 minutes, being careful not to create air bubbles in the mixture, and poured it into our casings. After tapping all the bubbles out of the casing, we let it sit overnight until the silicon hardened.

The final step of this process was the Chocolate Casting into the silicon mold. After the Silicon had set, I removed the outside casing and was able to pop the 3D printed flower out, revealing the silicon mold of the flower. Next, the chocolate was slowly stirred over boiling water to temper it and then was slowly poured into the molds and a popsicle stick was used to smooth over the top of the flower. This was a bit of a messy challenge to ensure the chocolate was smoothed over, however after we set them in a ice-chest to harden the chocolate. After an hour, the chocolate was hardened and was able to be popped out of the mold revealing a clean chocolate flower.

After reading Nothing Like Compilation: How Professional Digital Fabrication Workflows Go Beyond Extruding, Milling, and Machines by Hirsch, et.al. it changed the way I approach my own design and fabrication process. In Section 4.2, the discussion of molding and casting helped me realize how much of the final outcome depends on trial and error and learning through the materials themselves. I connected to the idea from Section 5.2 that designers often rely on multiple, partial, and open ended design sketches and I’ve noticed in my own projects that sketches, prototypes, and small tests all guide my decisions more than a single finalized model ever could, its more about the journey. Section 6.1 on parametric design also resonated with me, more specifically the idea that design isn’t just about shaping geometry but also about experimenting with the machine settings itself, the material your using and other outside factors. It reminded me to view fabrication as an exploration, where unexpected results can lead to solutions and to continue to think outside the box.