Third Attempt: Finally making progress on the HBLB foam model!

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To get a smoother finish, I borrowed technology from the remote controlled plane modelers. They are using hot-wire cnc to cut air foils for their wings. I figured if it could cut an aif foil accurately enough, why not a HBLB?? So, I built a conversion kit for my cnc router. Now with just a couple of bolts, I can switch between cnc router and cnc hot-wire foam cutter! Here is what I learned.

It is just so amazing how many attempts that have failed before I got to this point. I have cut at least 100 of these foam shapes trying to get the right dimensions while compensating for the loss from the hot wire and other variables. Wow, what a lot of work!

 

Finally, yes finally, I have found a process that will work to make the foam patterns for the HBLB! I am so excited to start pouring these parts to see how they turn out. This pattern is 8" deep, with excellent resolution and squareness throughout the cut.

 

On this pattern, the wire was a bit too hot and the cut distorted a bit. You can see this by noting the thickness of the right leg of the center core. It is so critical to get the temperature of the wire just right. The trick with hot-wire cnc foam cutting is: SLOW and COOL!

 

Here is a 4" deep pattern that is nearly perfect!

 

A shot of the machine that makes the magic happen.

 

Cutting a HBLB from the glued foam billet

 

See what I mean? I see this shape wherever I look; I can't get away from it. HELP...