Snoopy Earbuds Engraved Case - Engrave Curved Surfaces

In this tutorial you will learn how to engrave your earbuds case with a Snoopy Draw. Who does not love Snoopy? And it is just perfect for all the white earbuds cases like there are many models and brands that produce their earbuds in white. And why engrave it? It gives the case just a great feeling and finish. You can use rubber cases or stickers, but nothing like a engraved un removable finish.

For this tutorial you will need a CNC engraving machine or a modified 3D printer with a engraving motor instead the heater unit. If you have a friend with a 3d printer probably it will have the engraving mod as there are 3d printers everywhere. The CNC machine also will need a z max sensor or tool contact sensor, most of the CNC machines have this tool included. This tool is necessary to engrave curved faces.

A V shape milling bit.

Aluminum Foil.

Glue stick.

Contact Z limit Tool clips.

First we will need to select the image we want to engrave. I will select this image of Snoopy because I like how his face looks, you can select another one like Joe Cool or a relaxed Snoopy. Try to find an image with a good quality or high pixel count.

To convert and edit the image we selected we will Use Inkscape a free software you can use to edit SVG files.

Import your image into Inkscape.

Then go to Path - Trace Bitmap.

In this tool select multiple scans and Colors.

And Apply.

Your new SVG image will be over the original jpeg image

Select the new SVG pattern and right click over it and select Ungroup to separate the color.

Then erase the color that you won't use and the original image.

Save the SVG pattern as Plain SVG and it is ready to use in Fusion 360.

Now we go to Fusion 360. Here we create a new Sketch.

Then create a rectangle, the size of the rectangle must be the size of the area you have to engrave the snoopy draw. In my case is 40x20mm so I enter 40 press tab and enter 20 and press enter to create the rectangle.

Now we iimport our SVG file we created with Inkscape.

Go to Insert - import SVG, and Import from my Computer

And search the SVG file you created.

Once the SVG is imported it will appear in the Sketch, move the pattern using the arrows and scale it down or up according to your rectangle.

Once is the size you want click on OK. And Finish the Sketch

Now we have to create the model extruding the sketch.

Select all the sketch and press E or click on Extrude, enter 1 and press Enter. this will create a rectangle of 1mm thickness. But your sketch will disappear, don't worry, just find your sketch on the left menu and click on the eye icon to display your sketch again.

Select the pattern of the Snoopy draw and press E to Extrude. Now enter Offset of 1mm and extrusion distance of -0.5mm to create the engrave.

And you finish your model.

To create the pattern of the engraving process you have to go to the Manufacture section of Fusion 360.

Once there create a new setup, this setup represents the block that the machine will engrave.

Click on setup and select the model of the Snoopy engraving.

Then go to the 3rd tab and change the values to 0, to ensure your block is the same as the model.

Go back to the first tab and select the origin of the setup, this step is really important so you can place the engraving bit over the point of start. I selected the middle top point, because is easy to me to find the top middle part in my earbuds case. You can other point if it is easier to find that point in your CNC machine

Click on OK and now we will create the engrave pattern.

Click on 2D engrave.

Here you have to select the tool bit. I selected the v shaped engraving tool. Fusion 360 have many example tools in its library, but if you cannot find you same tool bit, you can right click over a similar tool and change its parameters.

After selecting your tool, change its speed like the image I used 100mm/min to engrave using a slow speed. This is because the bit is really thin and it can break in the middle of the engraving using a high speed.

The go to the next tab and select the pattern you want to engrave. Be sure to select the top model patterns and not the inside ones.

In the next tab select the maximum depth the tool will engrave. Select the top stock, and enter -0.5mm thats the maximum depth.

In the last tab select multiple depths and enter 0.2mm, this will let the tool create the engraving one step at a time. To avoid breaking the bit.

Click on OK and Fusion 360 will create the pattern

Now you can simulate your pattern and review if every path of the Snoopy draw is ok.

Finally right click on the engrave pattern and select process.

Enter the type of CNC machine you have. Mine works using Mach3 controller.

And save the file. This will create a .tap file

To engrave a curved surface like many of the earbuds cases, you will need to autolevel the pattern you created. For this you can download the program Autoleveller in the link: https://www.autoleveller.co.uk/downloads/

This program doesn't need installation, just double click and open it.

Inside click on open OGC and search your .tap file.

Then select the machine you have and enter the parameters

Click on Autolevel and save the .nc file.

This file will take points to modify the original pattern into a curved pattern. And that's why you need a z limit tool in your CNC machine. The new pattern takes the instruction to test if the tools touches the surface and replace this data to your new pattern.

Now we can open the .nc file in our CNC machine.

First find the home position, this is where your tool will move once the engraving is finished.

Then find the origin position. This is where I select the origin in the setup step. So I use the control of my machine to move the tool just over the middle top part of my engraving area.

Once the tool is placed in the origin point, press the zero button for each axis.

Once you placed your tool in the origin move the tool out to avoid hit it.

Use the glue stick on the case and glue a aluminum paper over.

Use the top of your nails to press the aluminum foil over the earbuds case, this will create a contact point for the z limit tool.

And your can press play or start in your CNC machine.

The code will show a message to put the z limit connectors in your tool and the aluminum foil. Place them and press play or continue.

Then the machine will start to test the points of the pattern to measure the curved surface. This process will take a while.

Once all the point are tested. The machine will show a message to remove the connector of the z limit tool. Remove them, and remove the aluminum foil and press continue.

The CNC machine will start to engrave the case. Just wait for the magic.

Once done remove the plastic dust generated by the tool and remove imperfections with and exakto knife.

To show the engraving use some nail polish.

Apply the nail polish without any concerns. It looks awful but you can use nail polish remover with a tissue and the engraving will remain with the nail polish showing your great engraving Snoopy that will not go anywhere because of the engraving. And it's done!!!

To ensure a great curved engraving you can reduce the distance of the test points, but 3mm is just enough.

Some aluminum papers or foils have a non conductive face, test which face is the conductive one. You need this because the z limit tool of the CNC machine need contact between the connectors.