CNC topographical wooden state

Avatar Evan | September 29, 2017 289 Views 0 Likes 0 Ratings

If y’all have seen our stuff before, you might know that we sell 3D printed topographic Texas wall hangings. We wanted to try making one out of solid wood too. Check out the video below to see how we did it (and scroll to the bottom if you want links to the tools and materials we used).

Things like this are great if you want to start selling stuff you make, because they’re easy to batch, and whether you’re using a 3D printer, a CNC, or any sort of automated making machine, it will pay for itself over time. Check out our video on selling handmade goods for more tips on that here:

In the above video we’ll zoom through the steps, but we’ll focus mainly on how to turn a 3D model of your state into something your can cut on a CNC. We’ll go into more detail on this and touch briefly on how to make a 3D model of your state below:

Making the 3D model

Our model data came from Texas Natural Resources Information System and was translated into a high resolution STL file. For this project, instead of using the super high resolution topographical data, I wanted to reduce the polygon count in Autodesk Meshmixer.

There are files like this available for every state here.

I used the reduce command to bring the polygon count down and make it easier to handle:

Which ended up making this:

This was accurate but not dramatic enough. So I reduced the polygons again (using the same tool) and used the brush and scale tools to emphasize the topography:

 

CAD to CAM

Once you have your model you can import it into Autodesk Fusion 360. We’re using Fusion 360 because it’s one of the most powerful free programs that can take 3D data and produce code that a CNC machine can execute (aka CAD to CAM conversion), which is super cool. It makes using these machines way more accessible to the average person.

Translating from CAD to CAM involves these 3 steps:

  1. Defining your stock (aka material that you’re cutting into)
  2. Setting up the tool you’re gonna use to cut the stock
  3. Telling the CNC where to cut

We’re going to use a square piece of 1×12 pine for our stock. Defining this, and where our model is within this stock, tells the CNC what material it’s going to remove to create the final model. Here are the settings you’ll need for your Fusion 360 setup:

Next use the tool library to build a tool for your machine. This defines the specifics of the tool doing the cutting. The wizard walks you through it, and we used digital calipers to get the dimensions of the tool diameter, length, etc. We used a flat end mill with a large step-down so that our final product had visible layers, which gave it a topographic look. We’ve highlighted the important areas where you’ll need to enter the dimensions you measured:

Now the setup is complete and we can tell the CNC where to move and cut our model. There are lots of settings that define this, and they all depend on the material you’re cutting into, how you want the cuts to look, etc. The Shapeoko wiki is really helpful when doing this step

These are the settings we used for pine:

  • Toolpath type
    • Adaptive
  • Tool
    • 4 flute square end mill, 1/4″ diameter
  • Speed and Feed
    • Speed = 3 on our dewalt router
    • Surface speed = 100 m/min
    • Cutting feedrate = 2000 mm/min
  • Geometry
    • Machine boundary = sihlouette
    • Additional offset = 6.35 mm
  • Passes
    • Direction = climb
    • Maximum roughing stepdown = 5 mm
    • Fine stepdown = 1 mm

There are a lot of settings here that really depend on your machine, so it would be hard to write a tutorial that is relevant for everyone out there. We hope that if you don’t have a CNC, this inspires you to look into the cool stuff it can do, and if you do have access to a CNC, this offers some useful information. If you have any questions or need any additional information on setup, etc. let us know in the comments below and we’ll update the tutorial with that info!

One cool thing is you can preview the toolpaths, how long things will take, and how the final product will look before you actually cut anything. Once you’re happy with the preview, you export the code using one of the post-processors in Fusion 360. There are sooo many machines built in so just select the one you’re using. Then you open the code you generated in Fusion 360 with your machine control software, and we were soooo excited when we first did this step, it was magic to see the machine move around!

Tools & materials

NOTE: we really recommend a dust collection system. We plan to install the Suckit dust boot

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Comments

This post currently has 2 responses.

    • Evan Sheline

      September 29, 2017 at 11:10 pm

      Steve, thanks SO much, that is super helpful! We’ll try to make a tutorial just focused on manipulating models one day… once we figure out how to make software tutorials entertaining. They just don’t seem to do as well for us.

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