You’ve all heard of chocolate bunnies, and you’ve probably all eaten peanut butter cups—but have you ever tried to make your own chocolates? If you are interested in concocting professional-looking bonbons, you will need a mold—and what better way to put your stamp on homemade chocolates than to design your own mold? In just a few steps, you can design and print a custom mold for your signature chocolates. (Note: Final product not intended for use by children)

If you’re a teacher, this project is a great vehicle for teaching students some of the principles of science and design thinking. Students gain a better understanding of concave and convex surfaces by designing a candy mold. For a video on the topic of concave and convex surfaces within design thinking, see the video below.  You can also find a complete lesson plan devoted to these topics, as well as instructional materials such as learning objectives, test materials, and evaluation rubrics here.

Before you start, download and install Autodesk 123D Design (it’s totally free). 123D Design makes it easy to manipulate all kinds of shapes and create viable designs using numerous materials.  For a general tour of the interface and commands, see these short tutorials:

## Step 2: Model Your Chocolate

Using the sketch>polyline tool, draw the profile of one side of your candy. Once you have closed off the profile, it should change color.

Select the profile, and select revolve from the menu. Select the axis, and type in 360 degrees for a full revolution. This should already look a lot like a pretty basic chocolate.

For a step-by-step video tutorial on this stage, see below.

## Step 3: Customize Your Chocolate

Now that you have the basic structure of your candy, it’s up to you to tweak it how you see fit.  Want your chocolate to have a design impressed on the top? Bring it to life using the Sketch>Polyline tool.

Make your design into a cutout by selecting Extrude from the menu, and dragging it down into the chocolate. Be sure to soften any sharp edges by selecting the edges and using either the Chamfer or Fillet tool.

If the design you created is symmetrical, you can save yourself a lot of work by just designing one piece of it and using the pattern tool. Select all the faces you would want to copy, the type of pattern (circle, square, etc.), the axis around which the pattern copies should revolve, and the number of copies that should be made.

Lastly, add the material by selecting all faces, choosing a material, and applying it. For a step-by-step video tutorial on this stage, see below.

## Step 4: Create the Mold

Now that you've created what your chocolate will look like, it's time to create the actual mold.

First, open a new document, and insert the chocolate that you have designed so far. Flip the chocolate so that the base is facing you, and draw a rectangle or square around the base of the chocolate using the Sketch tool.

Next, Extrude the rectangle or square such that your new shape engulfs the chocolate. (Note: Be sure to check that you're creating this second shape as a new solid).

Lastly, hide sketches. Using the Combine tool, select both shapes and subtract the candy from the new shape. Ta-da! You have officially designed a chocolate mold.

For a step-by-step video on this stage, see the tutorial below.

## Step 5: Print!

In order to print parts from 123D on your MakerBot you will need to install the Autodesk 3D Print Utility which will prepare your parts for printing. For more information on the Autodesk 3D Print Utility click here.

Once a part has been created and is ready for printing you can select 3D Print option from the 123D Menu. This will bring up the 3D printer dialog where you can select your printer and options for printing.

After setting up your printer options, you will be given the choice to save as a .stl file or send directly to the Makerware software for printing.

If your printer is not listed in the Autodesk 3D Print Utility, you can still export to a .stl file directly. This will allow you to use any software your printer requires. This can be done by selecting the Export STL option from the 123D Design menu.

Lastly, if you don’t have a 3D printer, places like TechShop have the tools to turn your design files into physical objects, and staff the people who can show you how. Places like Shapeways can even print them for you.
Have you been able to successfully make a chocolate using a mold made on a 3d printer that produced a quality chocolate? I have tried on a Dimension printer and found that the surface finish was too rough and small logos or text just look like a blob of melted plastic. I have a website about making custom chocolate molds www.thechocolatemoldfactory.com and have been researching different methods of how to make a chocolate molds for years. I have talked to most of the 3d printer manufacturers and all of them agree that to produce the quality necessary for a chocolate mold, you need to go to the FDM technology, which is cost prohibitive. So, milling machines still are the best option.
<p>Do you have a new website? I went to the link and this website no longer exists. I would love to see the info you ad posted. Thanks! If you have another one, please email me at shoge@umich.edu Thanks!</p>
<p>I saw an instructable a while back that used an acetone-soaked cloth or something like that to smooth out ABS prints. That might work here if you make sure to wash it off afterwards.</p>