123D Printing Prototypes

This photo is a magazine loading coil gun firing section I designed in Autodesk 123D Beta, it has a place for a magnet to hold the ball bearings in place and a piston to push the ball bearing through the photo trigger and air vents I needed to add to my original design.  I spend more of my spare time building creations of my mind then I do any other thing, some of my creations are my toys others are my tools.

I spend hours thinking how I want to shape the parts sketching them and days making them, God forbid they don’t work well or they don’t work at all and I need to start all over. This coil winder or this coil gun are made from multiple metal and plastic parts that I cut and shape by hand, and they are a pain if I need to remake a part because it doesn’t work the way I want or if I screw one piece up while making it. The coil winder in the first photo took me a week to build and it worked perfectly, the magazine coil gun in the second photo took me two days to build and although it worked it needed something to hold the ball bearings in place and an air vent to let in air when fired.

I wanted a multi coil barrel for my coil gun that used a moving magnetic field like the rotating field in a three phase induction motor. In a ¼ horse motor the surface of the armature moves at 2300 feet per second or twice the speed of sound depending on the motor.  5 inches x 3.14159 x 1750 / 12 = 2290.74 feet per second. For the firing sequence of the coils I decided on a Fibonacci sequence for the fire time. (0, 1, 1, 2, 3, 5, 8, …)

To design this barrel assembly I started by first drawing it in 2D.

Then I did a 3D drawing in 2D

I like this program it is free with on line tutorials and it is easy to use. Once I made sketches I opened Autodesk 123D Beta on my computer and designed my 3D print in an hour this prints 4 sections of the barrel at a time. I can’t wait for my parts to come I NEED THE PRINTER.

Now I am working on a long projectile coil gun and a flyback coil holder for tailor made flybacks I collect flyback coil cores.