How to Make a Wood Mooncake Mold

A mooncake is a type of Chinese baked good commonly associated with the Mid-Autumn Festival, when the moon is (according to traditional belief) at its brightest and fullest.

Ingredients, fillings, and flavor profiles vary dramatically, but mooncakes almost always have intricate designs created by special molds. Those molds usually produce mooncakes around 4" in diameter and about 1.5" thick.

This mooncake mold was a farewell gift for an employee leaving Hackster and I'm going to show you how I made it, so you can create your own!

What You'll Need:

• A block of hardwood
• Sandpaper and/or Dremel
• Howard Cutting Board Oil
• CNC mill or router
• 1/8" ball nose end mill

When selecting wood for this project, you might want to check the scrap/cutoff bin at your local wood supplier. You don't need much wood (it just needs to be a little bigger than the mold), so you can find really nice wood at a low price.

You should choose a hardwood and do a quick Google search to make sure it is safe for food—most are, but some varieties can cause irritation.

Other than selecting a safe hardwood, just pick whatever looks the prettiest! Some hardwoods mill better than others, so it is also worth considering that.

Design the Mold in CAD

I used Autodesk Fusion 360 to model my mold. I suggest you do the same, so you can take advantage of Fusion's fantastic CAM (Computer-Aided Manufacturing) features.

There are a few important factors to consider when modeling:

• The maximum working area of your CNC machine (including what you can reach with your end mill).
• The size of design elements. Too small, and you won't be able to get the end mill in there.
• Moon cake size. They're usually around 4x1.5", but you might need to adjust that based on the other factors.
• Draft angle and "overhangs."

That last point is particularly important. To ensure easy removal of the cake from the mold, you should put a significant draft angle on the walls. I recommend at least 10 degrees.

You also want to avoid any "overhangs." You wouldn't be able to cut those on a three-axis machine anyway.

With those rules in mind, have fun and get creative! I took advantage of the circular pattern tool to create the outer profile on my mold. Combined with the draft angle, it resulted in a neat effect.

I added the Hackster logo for obvious reasons, but you can creative whatever design you like. But once again, make sure you'll be able to cut that design with your end mill.

Important: if your design has something like text, which needs to be read in a specific direction, be sure to mirror it! The mold is a reverse of the final product.

I've attached the Fusion 360 file for my design if you'd like to make it.

3D-Print a Test Mold

Before chewing into your nice wood, I recommend doing a quick 3D-print of your mooncake mold for testing.

The 3D-printed mold won't be food safe (if you use it more than once), so this is just to make sure it looks good and works properly!

I printed mine in PLA with normal settings. You don't need anything fancy.

I then tested mine using chocolate chip cookie dough, because that is what I had on hand. That was much firmer than actual mooncake dough, but it was helpful test. In my case, it made me realize I needed more of a draft angle on the outer walls.

Create CAM Toolpaths

Once you're happy with your mold design, you can head to the "Manufacture" workspace in Autodesk Fusion 360 to create your CAM toolpaths for milling.

This will vary dramatically based on your CNC mill/router, so I can't give you specifics. But the general workflow is pretty straightforward.

Start by setting up the job with your "stock." That is your block of hardwood and its dimensions should match your actual piece of wood.

Then begin adding toolpaths. I suggest starting with a 3D Adaptive Clearing operation to hog out the bulk of the material. Then you'll want to refine the shape with additional operations.

I used a 2D Pocket operation to clean up the Hackster logo. Then I used a 3D Radial operation to finish the interior cavity of the mold.

When carving 3D geometry like this with a ball nose end mill, you're always going to need to balance time and refinement.

Finally, a simple 2D Contour operation (with several stepdowns) will let you quickly cut out the exterior of the mold from the wood block. Be sure to leave some tabs! You don't want the mold coming free while the endmill is still in contact!

Before post-processing and exporting the g-code file (which is dependent on your machine), be sure to use Fusion 360's simulation features to run through the whole program and check to see that it works as intended.

Prepare the Workpiece

This step will also be highly dependent on your CNC mill/router.

You need to fix the wood block to your machine, while still allowing for access through the entire program and avoiding collisions.

I did this by drilling a hole in two corners of the wood block, with counterbores for bolts. I then bolted the wood block to my mill's table t-slots, with a thin piece of plywood between the block and the table acting as a spoil board.

Because the mooncake mold is round, squareness and alignment isn't critical. But you should have it good enough that you can properly set your origin.

Run the CNC Program

Now you get to watch the magic happen!

I suggest watching closely (at least in the beginning) to make sure your feeds and speeds are appropriate. You'll also want to vacuum up the sawdust and chips regularly, if your machine isn't equipped with a vacuum dust collection system.

Milling will take a long time—it always does with 3D carving.

Mine took about 8 hours to complete. But, if I were to run it again, I could make it much more efficient and likely cut that time in half.

Free the Mold

Once the milling finishes, you'll need to cut those tabs holding the mold in the wood block.

I did that...poorly. I used a bandsaw meant for cutting metal, because it is what I had on hand. But that was a mistake, because I ended up actually getting some saw marks on the mold itself.

However, I was able to lean into that and give the mold a more rustic/handmade vibe that actually looked really nice, as you can see in the final photos.

Sanding

You'll probably need to do some sanding to give the mold nice, smooth finishes.

If you have one, a belt sander will speed up the job, letting you quickly smooth out the exterior. I used that as an opportunity to give the exterior a more uneven finish to enhance the aforementioned saw marks.

Sanding the interior is more difficult. You'll need to use a sheet of sandpaper by hand to get into all the nooks and crannies. A Dremel can speed that up, but be careful, as it can take off material really quickly.

As always with sanding, start rough and then work your way up to the finer grit levels. Take as much time as you need to get a finish you're happy with.

(Optional) Laser Engraving

If you'd like to add a message to the bottom of the mold, as I did, now is the time to do it!

I used a Creality Falcon2 Pro 60W laser cutter/engraver for this job.

You don't want to ruin your mold after all this work, so I recommend testing the engraving on some scrap first. Make sure the power, speed, and size all work well.

When you perform the actual engraving on your mold, take special care when setting your origin and positioning the cuts.

Finishing

At this point, your mold should be nice and smooth. But the wood probably looks dull. That's what finishing is for!

For a mooncake mold like this (or anything wood coming into contact with food), the finish needs to do three things:

• Look nice
• Protect the wood
• Maintain food safety

Wood is porous, which gives moisture and bacteria a place to hide. Finishing products fill the pores in the woods and/or seal the exterior to prevent that. They also protect the wood, enhance the grain for aesthetics, and create a nice, shiny surface.

There are many, many finishing products to choose from and people debate endlessly about which are best. No matter what you choose, make sure it is food safe!

I chose to use Howard Cutting Board Oil. It is available at most home improvement stores and is a food-grade mineral oil that is easy to work with.

To apply it, first make sure that your mold is nice, clean, and free of any dust from sanding.

Then apply a generous amount of oil to the wood, using a lint-free cloth to rub it in. You really can't have too much oil at this stage.

The goal is to let the wood soak up that oil until it is saturated, then wipe away any excess. Repeat that at least two more times, with 12+ hours between coats.

Let the final coat settle for a full day, then use a clean lint-free cloth to wipe away any oil still on the surface.

Enjoy!

Your mooncake mold is now ready to use!

There are lots of great mooncake recipes available out there on the internet, with all kinds of regional variations ranging from sweet to savory.

As this mooncake mold was a gift, I didn't get to try making a mooncake myself. So post photos of the ones you make, so I can live vicariously through you!