Comment by TacticalCoder
4 hours ago
Amazing: I'm watching lots of homemade builds atm.
I've got a question: why CNC milling and not just FDM 3D printed parts? TFA doesn't talk much about it except saying she went to a machine shop.
> 2. CNC milling forms out of G-10 fiberglass (arms) and 5mm carbon fiber (body)
TFA also says this:
> The solution for this is to 3D print a 0-tolerance assembly jig to hold the arms in perfect position while the center of the drone is superglued together.
Why not 3D print it all?
There's this guy who built a drone that can fly for 3 hours and cover hundreds of miles, 3D printed at home on a $250 printer:
Then there was the $200 K quote for the body for a car that just did Pike's Peak with a four times Pike's Peak champion and instead the team... 3D-printed the car's body at home (something like 40 parts, assembled together), which cost them less than $2 K to make (1/100th of the quoted price for the car's body). Here's the vid where they print all the parts (on a $1500 consumer printer):
Basically: why CNC milling and not 3D printing at home when many drones enthusiasts (and now too people building race cars) simply print parts at home on a consumer-grade 3D printer?
For "copter" style drones, 3D printing is basically a "noob" meme at this point; everyone thinks it's a good idea, tries it, and realizes that it's actually really hard and doesn't work.
Copter-style drones are exposed to vibration across a huge frequency range in every axis, and it's almost impossible to avoid really nasty resonance issues using generally-printable FDM filaments and "standard" design techniques; it's a lot easier to just use super-stiff carbon fiber and CNC it.
For planes, like what you linked, 3D printing is more "plausible" than for copters but also not really practical; you can 3D print a good plane, but plastic lacks the durability and favorable weight characteristics of foam - plastic planes tend to be "one time crashed" while foam is easy to repair, restore, and rebuild.
Stiffness. Important for how the frame behaves under load and buffetting etc.