08: CNC Milling

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Lesson

In today's lesson, we learned about CNC Milling aka Computer Numerical Controlled Milling. The way these machines work are by making a path with thousands of little points/commands that the machine has to go through. There are three types of CNC Milling machines: 2d, 3d, and other orientation CNCs. These other orientation machines are very rare because they can spin the material it's cutting in different angles and the drill can also be orientated in different angles so that you can mill anything you want (except something that is hollow of course).

Demo

Below is a time-lapse of the whole CNC milling process of a bowl that was designed by one of the assistance teachers:

Here is a picture of the finished epoxy process of draping a cloth over the mold and using a vacumm seal to keep the glued cloth on the foam cut-out to make a solid bowl:

Lab

In today's lab time, we are going to CNC mill the stl designs that we were assigned to make at home. I decided to design an stl that could–like the bowl–be finished with a cloth cover and epoxy glue. Below is the design that I made using faces that were extruded using the loft tool in Fusion 360:

Click me to download this model (.stl file)

CNC Milling

After bringing in the stl file, I uploaded it to the CNC mill computer. From the computer hooked up to the CNC Mill, I can make the paths for the drill to cut the car out of. The first path was a rough cut to get rid of the bulk material. Here is a video of the rough cut:

After the rough cut, the finish cut began. This was a path for the drill that was much more precise and detailed which took more time to cut. Here is the time-lapse of this cut and pictures of the final outcome:

Epoxy -> Layering -> Vacuum

When the mold was finished up, we went through the process of layering canvas onto the mold while adding epoxy glue so we can make a shell-mold out of the cnc milled foam. After layering the canvas with epoxy glue, we put it into a vacuum-sealed bag so we could compress the canvas onto the 3d design to conserve the details of the mold. Here is a picture of the finished process of the whole vacuum, epoxy, and canvas stuff: