Custom Chocolate Cookies, Using Silicon, 3D Printing, Fusion 360 and Chocolate

Greetings!

I'm Jay Harvey, a Makerspace Assistant at the College of San Mateo Library's Makerspace. For my job, I serve as a helping hand for people's various projects, and I host scheduled workshops teaching individuals Makerspace skills.

For this instructable, I'm showing off a project I did with my club at CSM. This project runs through the basics of 3D printing, Fusion 360, and feeding yourself (yay! life skills obtained!). It also has a sweet end-product.

Over the last few weeks, members of STEM club designed customized silicon molds. The molds produce chocolate that goes well on PetitBeurre cookies. The idea for this project came to me while I was munching on some delicious PetitEcolier Cookies. I noticed the impressions on the chocolate and wanted to figure out whether I could replicate the taste but with my own charm.

As you'll see later on, making this possible was a team effort, so thanks for your help STEM club!

Supplies

General Materials:

• 3D Printer capable of printing at 0.08mm height (I used Bambu Lab P1P)
• PLA filament
• Fusion 360
• Freezer for cooling down chocolate

Silicon Mold:

• SmoothSil Food-Grade 940 Silicon Mix
• NON-silicon mixing tool
• Disposable Measuring Container for 1:10 ratio (linked below)
• 3D printed Molds

Chocolate Cookies:

• Double Boiler set up with heat source
• Guittard Milk Chocolate Baking Chips
• French Petit Beurre Biscuits (ingredients listed later in instructable)

Step 1: Design

Notes on Choosing Images:

There are few constraints on what cookies can be created. For example, because the molds are 3D printed, there is a limit to how detailed the mold can get. Be aware of letters and small details that could ultimately not show up.

Complicated is fine, however, try to keep details as large as possible. For this project, all cookies are 6.4 cm in diameter, which is big enough for a wide variety of designs.

Searching for Image:

Each individual will need to find an image of what they would like turned into a cookie and have it in a .png, .jpg, or .tif format. You can source an image from the internet, a drawing, or even someone's t-shirt. image size does not matter as everything can be scaled in Fusion 360 later.

Step 2: CAD in Fusion 360

Here is documentation on how I created the Base Mold design for the Chocolate Cookies.

Sketching 2D profile of Mold:

First, sketch the shape of the desired chocolate onto a floor plane (6.4CM diameter for this circle). Following this, add the shape of the wall (a Hexagon 4 CM away from the origin). Offset this wall to the desired thickness. I opted to make them 0.16 cm thick so that breaking the silicon out of the print would be easier. (a 0.4mm printer nozzle means that the walls will only be 4 layers thick)

Extruding the profiles:

First, extruded the walls 1.5 cm high. Next, establish the floor, 0.1 cm high, leaving out the cookie profile. Afterward, you can decide on the height of your chocolate. I chose to make them 0.6 cm Tall. This model is now ready to have designs added to it!

TIP: Hexagons Mesh well with each other and minimize space. If you were to make these chocolates in bulk, arranging them all next to each other expedites your process and reduces mess.

Attached below is the .f360 file I gave to my Club Members.

Step 3: Add Decal and Sketch

The video above shows the process of importing an image into Fusion 360 so that you can trace over the image using the spline tool.

When aligning a decal, align the images from the top-facing view cube. Try to maintain an orthographic viewpoint while tracing the design as well.

The Spline Tool is great for tracing any kind of design, all you have to do is place points along the edges of your design. If a line doesn't perfectly line up with your design, just use the green handles to adjust the curvature!

Image 1: Club Presentation on CADing the molds.

Image 2: My design with a traced-over sketch.

The next step will cover extruding the 3D design

Step 4: Extrude Settings

I've found that 1.6 mm or 0.8 mm is the best height for the designs because making the imprint too tall increases the chance that it breaks off when removing the chocolate.

The printer used can print layers of 0.08 mm. So when extruding, Multiples of 0.08 constitute layers. 1. 6mm = 20 layers. For complicated images like my Happy New Year example cookie, I have to make small deviations in layer height to show off the different letters.

Technical Tip: To make my life easier, I created an F360 parameter called Lowered for the layer deviation I wanted. (0.016mm). For each letter, left to right, I set the extrude height to the ({Previous Letter dimension}-Lowered) parameter. In this way, if I want to adjust the height deviation from element to element, all I need to do is change the Lowered Parameter.

Some students used this method for more complicated designs such as the Firefox logo, while others with simpler logos (like NASA) were able to make the entire design one height.

Step 5: 3D Print Molds

Over two weeks, I received everyone's Mold designs and printed them out on my personal Bambu Lab P1P. The makerspace has a 3D printer, but my P1P just had better overall reliability and precision. Here are some of the results!

Step 6: Bonus: Hot Chocolate Fish Concept

I had this spontaneous idea to make a Hot Cocoa Bomb in the shape of a fish, so you're essentially putting a fish into a cup of hot water... and you'll soon have hot cocoa! Here is the 3D-printed Mold.

Stay tuned to the end to see how this turned out!

Step 7: Mix Silicon

The first image is SmoothSil 940 Food-grade Silicon, it's a two-part 1:10 mixture meaning you need to add one part of the Liquid activater to 10 parts of uncured silicon.

Mixing:

For preparation, I 3D Printed this measuring cup and scaled it, estimating the volume of silicon I was going to make. All that mattered to me was the measuring markers counting up to 10. I ended up making it too big so we made a half-batch. First, we poured the activator to a roughly half mark (1/20th) and added uncured silicon up to the 5 mark. We used a screwdriver to mix the two agents :D

Image 4 shows a group of students collecting uncured silicon with a makeshift scooper?? ...It's a paper towel roll wrapped in duct tape. Good to be in a maker space when you don't bring a disposable mixing utensil.

Step 8: Pour Silicon

Pouring the Silicon:

This step is pretty self-explanatory, but there are a few tips worth knowing.

First off, Bubbles can easily become trapped in the mold, and if one of those bubbles is against the plastic, the resulting mold will have deformities. I've seen people online use a Vaccum chamber to "de-bubble-ize" the silicon. The alternative is to pour the silicon from as high a place as possible and as thin a stream as possible, reducing the chance bubbles get trapped. (Air will float to the top)

When pouring the silicon, always pull up the pitcher before the silicon reaches the top of the mold, since there is still falling silicon yet to make it in.

After the silicon was in the mold, each member tapped the mold on the ground to help the bubbles make their way up the mold.

Step 9: Finished Molds

Here we have several finished molds laid out next to each other in a grid.

The molds are dishwasher and microwave-safe, please wash the molds before putting any food into them.

Step 10: Temper Chocolate

Tempering Chocolate is a tedious process: You have to aim to keep the chocolate around 90F+, but you can't let the chocolate reach an internal temperature over 110F otherwise certain chocolate crystals will break down... which is bad. Additionally, never let chocolate touch water.

1. Properly tempered chocolate makes a snapping sound (the result of intact chocolate crystals in chocolate) and has a signature gleam/shine.
2. Not properly tempered chocolate is soft and mushy. It tastes just fine, but the texture is less optimal.

Here is my process for getting tempered chocolate. In all honesty, it took me several tries to master it. ill try my best to explain the steps below:

Materials used:

• Food Thermometer
• Silicon Spatula
• Silicon Mini Spatula
• Parchment Paper

How to heat the chocolate:

1. Heat the Double Boiler to around 100F, mine did not go that low, so instead I had to rotate between turning it on and turning it off.
2. Add half the bag of chocolate, leaving the rest as "reserve" chocolate. Don't worry about trying to melt the chocolate fast, because slow is better. Keep stirring
3. When the chocolate is about 95F, rub the chocolate from the thermometer onto a tiny square of parchment paper, and stick it into the freezer. After about a minute, you can take it out and test if it snaps. If it does, then the chocolate is tempered. If it doesn't, and slowly bends, then you probably overcooked it.
4. The reserved chocolate is good for when you overcook the chocolate. You can solve the broken-down cocoa crystals problem by adding new chocolate, with crystals intact. The overcooked chocolate can heat the new chocolate.
5. After you've tempered, use a mini spatula to put a small amount of chocolate into the silicon molds. You want to make sure that chocolate is in all the crevices. Just pouring a lot could trap air in the mold, which would result in holes in the surface. (You can spot some holes in the cookies here if you look closely)
6. After you detailed the mold, you can fill the rest of the mold up.
7. Tap the mold repeatedly to get air bubbles to float to the top
8. Place Parchment paper into the freezer below where you are putting the molds, and then place the molds. Wait 5ish minutes before taking them out.

Step 11: French Biscuits

I got the instructions for these cookies from this website, but here are my rephrased instructions. Feel free to use whichever you like.

Ingredients:

• 1 Egg
• 1 Cup of Sifted All-Purpose Flour
• 1/2 Cup of Sifted Powdered Sugar
• 1/4 Teaspoon Pure Vanilla Extract
• 1/4 Teaspoon Salt
• 1/2 CUP Cold Unsalted Butter, (Chopped up into super small bits)

Needed: 2 Sheets of Wax Paper, Silicon Baking Mat, Baking Sheet

Steps:

1. Mix egg, flour, sugar, vanilla, and salt in a Large Bowl. It'll kinda look like sand
2. Add the Butter in Knead the dough with your hands. If dough/butter becomes too melted, put into the freezer until firm, and finish kneading. Cold Butter/Dough at all times is important!
3. Sandwich dough between two sheets of Wax Paper and flatten out the dough to 0.5 cm thickness
4. Place into Freezer for 1 hour
5. After 1 hour, use a cookie cutter to cut out biscuits. I CADed my own because I didn't have the size I wanted, and the files are linked below.
6. Put the biscuits BACK into the freezer for 10-15 mins + Preheat Over 350F/175C
7. Place biscuits onto a Silicon Baking mat, (no wax paper) and bake for 10-15 mins. The edges should be slightly brown. Turn off the heat and let sit for another 5 minutes, then take them out to cool.

Step 12: Viola!

And here we are! The Left image is the cookies I was able to make in my better-equipped home environment, I didn't have enough biscuits to show off all the designs unfortunately, but hey! I think they turned out pretty well!

The Right image is the cookies my club and I were able to make during our baking day. They also turned out well.

Step 13: Hot Chocolate Fish

Image 1: Filling sides with chocolate, including marshmallows. I made the fish too small so there is not any room for powder.... but isn't hot chocolate just chocolate in water?? 😅

Image 2: Because the fish is small, all the limbs are fragile. I was too scared to shave the back down to be flush. Supposedly in a different design, you would use a hot knife to weld/seal the two sides together

Image 3: Hold your breath.

Image 4: So..... it looks better than it tastes, which means it tasted pretty bad. Although not horrible, just very very watery chocolate. I've had this idea for a while so I want it to work eventually. When I have more time ill probably revisit this, pour a new mold, and update here, or somewhere else.

Step 14: Other Creations

Here are some experimental utilities with these chocolate molds. I tried to double-boil Jolly Ranchers to pour into the molds, but it turns out that the molds are microwave-safe. You can literally just plop 2-3 ranchers onto the mold, run it for 30 seconds, and let gravity ooze the candy into its crevasses. Unfortunately, because the molds were made for chocolate having a shallow detail, the rancher result was less visible. These hard candies can handle deeper detailed molds.

I also went for a more Petit Ecolier size/look approach with square cookies

Lastly, there is a Chocolate Plane that one of my members wanted to create, they CADed up a plane, and here was my best attempt at getting it out. 😅

Step 15: Notes on Teaching This Project

Thanks if you made it to the end!

I ran this project with my club over the course of about 6 weeks. We only meet once a week for an hour so different steps were broken up into different meetings. As you can see there were a lot of steps I did myself, and that was mostly because it was more practical to do large batches at the same time. As the teacher, doing this project does mean a lot of commitment because you'll probably have to do a lot of baking, and preferably practice tempering chocolate. (Now that I think about it this wouldn't be a bad project for a high school culinary class). It's worth it however to see the look on people's faces when they see their finished chocolate and know that they chose the design, created the mold, and went through all of the motions to arrive at the finished project. My club members were able to take home their custom mold and who knows what they'll do with them.

For a class/club environment, the key learning you get from this is how to use elementary Fusion 360 in addition to getting your hands dirty casting silicon and putting in chocolate. Needing to deal with real dimensions to churn out a physical product is noticeably different from some other Fusion 360 basics tutorials where you make some arbitrary object that may or may not have real-world utility. Granted, if you just wanted to learn Fusion 360 this might not be the most expedient way... but nevertheless, this project teaches much more!

Thank You Again for Reading! Please Consider Leaving a comment or like :P and have a great new year!