In this entry, we will be discussing our machining of the wooden roller coaster. We chose to machine our mini rides, and large ride supports, with the Taig CNC mill.
But let’s take a step back and discover where the numbers and code come from…
It all starts with our design phase. In the design phase we have a two dimensional (2D) plan look at where we want the ride to go. Once the layout is determined, we then move to the vertical layout.
This is where the calculations of kinetic and potential energy come into play. For this test track we have calculated one design hill. Based on theoretical friction values from our steel bearing wheels, we want the cars to apex the hill at one (1) foot per second. With these constraints in mind, we created a hi-order polynomial for the hill’s shape. Yes, remember back to Trig and Calculus.
Roller coaster hills are a combination of circular curves and varying parabolic curves.
If you use what’s called a “cross-product” you can cross the plan with the profile and make a three dimensional (3D) curve.
Now that we have our calculated support, or bent, heights, we can machine them with our CNC milling machine.
We begin by drilling the foundation holes and the holes to mount the track brackets. Our next procedure is to use an end mill and cut out the profile shape of the support to our design height.
Now the support is ready to be sanded to remove the holding tabs. Being that this was our first attempt at machining our supports, we kind of messed it up…
We accidentally broke the support while sanding with a router. Since we ruined the support, we decided to try using blind rivets that will hold the track brackets in place.
This design didn’t work since the rivet expanded and broke more of the support. Fortunately we have a few other tricks up our sleeves.
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