Motion Control

A project log for Microwave Aluminium Printing

Metal parts for people other than blacksmiths. A system to perform aluminium "lost PLA" casting with no propane, and no danger to humans.

julia-longtinJulia Longtin 08/18/2014 at 05:300 Comments

The hard work is done - we have successfully got the Aluminum to melt in our microwave kiln, and we have been able to cast objects from the molds that we designed. The system works - huzzah! 

Now, we must build a simple remote-controlled automation system to remove the kiln from the microwave and pour the material into our mold. Design for this system is complete and the construction is underway.

The three main stages of design are:
I. Remove the kiln from the microwave.
II. Remove the top of the kiln.
III. Remove the crucible holding the aluminum, pour it into a heated steel funnel.

And then replace everything exactly as it was.

The proposition (Part I):

The base of the assembly consists of a plate mounted atop two long threaded rods. On the end of each rod is a 5/8" nut that is connected to a motor. The motor turns the stationary nut, and thus the rods move forwards and backwards. Both motors will be controlled by the same Pololu motor controller. On this plate will be 2" of firebrick to place the kiln on.

Two more long threaded rods are mounted perpendicular to the base, about 6" apart. The microwave will be resting roughly 18" from the ground - attached perpendicularly to these rods (oriented towards the front of the assembly), roughly 20" && 28" from the ground, will be two sets of 5/8" x 15" steel rebars. The bottom set will be equipped to move vertically through the same nut-motor system as the base.

How it works:

The threaded rods that the base of the assembly rests on will extend under an open table on which the microwave is seated. The kiln will have two sets of holes drilled through it - one set on the base, and one set on the top. The whole assembly will slide forward towards the microwave, in such a way that the steel rebars slide into the aforementioned holes. The bottom set of rebar will move upwards slightly (to obtain some traction), and the assembly will slide backwards, removing the kiln from the microwave. The bottom set of rebar will move the kiln down and set it on the firebrick atop the base; the top set will remain stationary and suspend the top of the kiln.

The first two stages are thus complete. Next time: Stage III!