What is CNC milling? - Fusion 360 Tutorial

- [Narrator] If you're watching this course, you may have some basic idea of what CNC routing is and its many applications. Here, we're going to hyper-focus on its many uses creating high quality, cost-effective, topographic site models. So, what is CNC milling, also known as CNC routing? CNC milling combines the precision of a computer with the power of a handheld router. CNC stands for computer numeric code, and it's the directions that we create to tell the computer how to move a router to strategically cut away material to create an object. There are a few general steps we follow to transform our digital model into a physical scale model. You need to start with a digital model of your site. For this course, we're going to use Fusion 360 to create this digital model from a civil site map import. After we have the site model, we have to consider what are the best end mills to use to cut away our material, to reveal our model. With these cutting tools in mind, we can determine a cutting tool path for them to follow, to get the best detail possible. Usually, we're going to start with a larger diameter tool in a roughing path to remove a majority of our material, then we'd move down to a smaller diameter end mill for a finishing path to reveal a finer detail. With our tool paths created, we can convert these directions into CNC. And finally, we can send those directions to our CNC router to follow. Now, keep in mind, this is a very condensed description of the CNC process with a few details left out to simplify those concepts. End mills, as I mentioned earlier, are the various cutting tools inserted into our router to cut out the different shapes of our model. Most of these tools look a lot like a common drill bit, but they can do a lot more than just cut out holes. End mills remove material by following a computer controlled cutting path while spinning. So there are many cutting strategies you could use to remove material effectively. In this diagram, we can see in red how just one tool, using different paths can remove material to revealed wildly different shapes. In this example, we can see a preview of a parallel cutting path I'm using to cut out a smooth slope of topography with an indented surface to fit in my building walls. That preview translates into a real life cutting path. I'm using laminated basswood as my Spock material to cut out my shape. To cut a smooth surface, I use a half an inch diameter ball nose end mill to run along the contours of my model. The finished product reveals a subtly smooth site model that represents the real life topography. Here is the final product with all the detailed building components. Using the CNC router to construct the base allowed me to use the exact same material as the building pieces to create a monotone classic look. Another common tool we use with a CNC router is high density foam or HDF for short. In this course, we're going to focus on tool paths and cutting strategies for 20 pound HDF because it's easy to mill and creates a really great final product. In this example, we can see a roughed out city with building massings and roads, and here's the final product painted with a wooden frame. All of the complex details of the site were modeled digitally, so we had to do very little post finishing to the site model once we pulled it off of our machine. Without a CNC router, the process of creating each building with either hand cut or 3D printed massings would have been much more time consuming. This process also lets us do small scale production of the same site over and over again, because most of the hard work was done digitally, and the CNC fabrication process is fairly automated. In this particular project, our client wanted two site models, one in-house and one for their client. A CNC router can even create a high level of detail for topography contours and other site information at a very small scale. In this finished one to 1000 scales site model, we can see small pathways and water feature details represented accurately. In most professional cases, I use CNC milling as just the first step out of many to create a complete site model. I'd for instance, first create a site model with topographic information to add on other elements like context buildings and the design intervention. In this example, the site is CNC routed out of high density foam with hand-cut wood building massings added to the site afterwards. The model building process usually uses a variety of different tools other than just CNC milling to achieve the best finish. If you're interested in learning more about other common tools available to a model builder other than CNC routing, check out my course on architectural scale models, digital file prep.