Wooden Wireless Charger Using a CNC Machine

I am a high school student at Peoria Christian School, and I had a spare wireless charging coil left over from a different project. I also have a CNC machine, but have never used it before. I am used to working with 3d printers and I figured they would be pretty similar. Learning how to use a CNC machine will allow me to incorporate wood into my projects, and it will help me understand how this and similar machines work. Once I had decided on what I was making and how I was going to do it I decided it would be a gift for someone.

Supplies

CNC machine
a 1/2 x 4 x 4 piece of your favorite wood
a wireless charging coil
a penny or any other coin
a piece of white paper
a camera (the camera on your phone will work)
3d printer (optional)
wood stain (optional)

Software

Fusion360
Easel CNC Software - Easel – Inventables, Inc.

Step 1: Getting Refrence Images

In order to create a 3d model in fusion 360 we first need to get some pictures of the charger itself so that we can design the part around it. For me the best way to do this is to place the object on a sheet of white paper and place it on it. Put a penny on the piece of paper next to the charger. this will be used to help size your image in fusion 360. Next hold your phone about 2 feet high and put your phone camera in 0.5 mode. This will allow the photo to have a more 2D look that makes it easier to create a design from. You will also want an image of the design you will be putting on top. Simply go online and find one you like. I prefer to use black and white because it makes it easier to see the lines. After doing all of that simply export the picture to your computer and then you can get to work modeling.

Step 2: Sizing the Image

Once you have the images onto your computer you need to get them onto fusion 360. First start a new project, then click on the canvas button. Then click Insert from my computer. Next click on the picture you want to import. It will then show 3 planes on which you can put the picture. Choose the bottom one and hit enter.

Next you will want to click the arrow next to the canvas button on the left side of the screen. this will show all the images that you have imported into fusion 360. right click on the name of the image and click calibrate. Use the penny to calibrate. The diameter of a penny is 19.05 mm.

Wooden Wireless Charger Using a CNC Machine - Step #2
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Step 3: Making the Wireless Charger Model

The simplest way to make something in fusion 360 is to use the sketch feature. simply click on the sketch button and use the options under create to make your objects basic shape.

The first thing I did was find the center point of the wireless charger. To do that I used the 3-point circle feature under the circle category. All you have to do is draw 3 inner points on the middle circle and it will make a circle from those points. Then I used the midpoint from that circle to draw a 90mm circle that will make up the body of the wireless charger. After that I clicked finish sketch to exit sketch mode.

The next step was to turn my 2d sketch into a 3d model. all you have to do is click on the extrude feature and select the circle you made. then type 10 mm into the box next to the arrow to make the sketch into a 10 mm tall cylinder. this will be the base of the charger and everything you do after this will be based on this shape.

Now we need to carve out a shape for the charging coil to fit inside. Click on the bottom side of the model and use the sketch feature to draw a space on the circle so that the charger can fit inside. I used various different draw features like the line and 3-point circle to create the space. once you are happy with your sketch exit out of sketch mode and use the extrude feature to select the shape you created and type a negative value to carve out the space. I used -7.5mm so that the thickness of the top would be within 2-3mm.

Step 4: Adding Detail

Now that you have the outline for your charger you can now start to add detail to it. Using sketch and extrude you can put just about anything you want on the top of the charger. I choose to go with a Greek circle design because it has a nice pattern on it that is easy to replicate.

I first found a simple black and white image online that I could use as a reference and brought it into fusion 360, but instead of picking a plane I clicked on top of the circle. This did most of the work for calibrating and centering the image for me. Then I went to work sketching out the design. I first created the inner and outer ring because those were the easiest part. All you have to do is use the center point to create the top and bottom part of the ring. Next I continued to use the circle feature to add each layer of the middle section. I then went through the painful process of drawing each line. I found it easier to make large circles for the curves and then connect with the straight lines and use the trim feature to get rid of all the unnecessary lines. Once you are finished exit out of sketch mode and simply use the extrude feature to cut into the model .5 mm.

If you want to add a base so that the charger doesn't fall out all you need to do is click on the inside bottom face and extrude it about 4mm. Make sure you select new body so that it is its own part and not connected to the rest.

Congratulations you have completed the design!

Step 5: Testing Your Design Using a 3d Printer

This step is completely optional. It helps you find any problems in your design before you work on the final product.

I exported the model to Cura and set up the model to use minimal supports and then sent it to the printer. The settings you use don't really matter it's When I print things I tend to use a skirt instead of a raft to save filament but it is up to you.

Once it was finished, I put the charger inside and realized i need to design a bottom piece to hold the charging coil inside. So, I went back into fusion 360 and made a simple piece that could fill the gap on the bottom.

Step 6: Setting Up CNC Code

Now you can use fusion 360 to write the code for the CNC machine, but it was much easier for me to use Easel which lets you use a free 1-week trial. I took a picture of the bottom where the charger would go and turned it into a black and white picture that Easel could understand. The most important thing you can do when setting up the part it to make sure the top and bottom parts line up. The easiest way to do that is to cut a hole in the center of the piece of wood and have everything line up with that. Once you have that figured out you just have to adjust the size and set the depth to the level you want it to go and send it over to your CNC machine and you're all good to go.

Step 7: Using the CNC Machine

I am no expert on using a CNC machine I suggest watching a couple of videos for your specific machine, and running a couple of test pieces before making the real one. So, after spending a couple of minutes lining everything up using a hole I drilled into the center of my piece. Then I let it do its thing. the first attempt the piece of wood wasn't clamped down well enough, so I had to try a second time. The second time it worked perfectly. then I flipped it over for the other side.

Thanks to the hole I was able to line it up without struggling to find exactly where the piece was. This made cutting out the top much easier. On the first couple of tries I tried using a new bit, but it only ended up messing up the piece. But on the third attempt it worked perfectly.

Step 8: Post Processing

I needed to clean up the part because I did not have it cut all the way through. I took a Dremel and separated the part and used it to clean up the edges. Then I simply gave it a light sanding and coated it in a light stain it bring out the wood texture. After that I added the charger inside and used a 3d printed over for the base to hold it all together.

Step 9: Adding a Stain

This step is completely optional, but it gives it a much nicer finish. First, I tested the stain on one of the failed pieces to make sure it would give me the color I was looking for. Then I simply got a rag and rubbed the stain on and let it dry. After 24 hours the stain had fully set, and it was ready for me to put it together.