3D printing is just shapes on top of shapes. The simplest way I can imagine to make a 3D printer is to put circles on top of circles. Circles are the logical choice for this project because a circle can be made my squeezing molten material between two plates and it will naturally form a circle. So, circles on top of other circles will form something that looks like it was produced on a lathe.
The least expensive nozzle and heating element I could think of was a hot glue gun. The parts can be cheaply and readily obtained. A hot glue gun is a simple resistive heating element so it can even use a regular light dimmer to regulate the temperature. Hot glue is a very inexpensive medium to print in.
The mechanism for feeding the glue will have to be a little more precise since the amount of glue fed in at a given time will directly correlate with how large of a circle is made. Fortunately a continuous rotation hobby servo is less than $20 so it will be one of the more expensive parts of the build but hardly a bank buster.
The printing head, made from the hot glue gun, will be stationary while the platen where the printed material goes will be movable. This will probably be some ¼-20 threaded rods which act as support structures and the way to move the platen simultaneously. They will all rotate at the same time by having sprockets attached. The sprockets will be from bike derailleurs. This will be driven by a gear motor or another continuous rotation servo.
Cooling the glue after it forms a circle will most easily be done by water. Raising the water level will be easier than lowering the printing head and platen. The only dilemma is that it shouldn’t get the top of the new circle wet since the next circle will be printed there. After consideration the easiest way to raise the water will be to have an overturned container, like a drinking cup, and pump air into it with an aquarium pump. When the air fills the cup the water level will rise. The cup is held to the side of the water container by magnets and there are magnets on the other side of the container attached to a standard servo which only rotates 180°. This servo will tilt the cup when it is time to lower the water level and allow some air to escape. The amount of air released will correspond to how much the water is lowered.
The first project will be to print a simple cone to test the capability of the device. A more complex and interesting shape will be a chess piece like a pawn. These are not practical and still qualify as only baubles. The most inspired thing I can think to print with a printer like this is a bar code roller. A bar code roller would be similar to an ordinary paint roller but would instead lay down different line widths and gaps which would machine readable as a 1D bar code.
Another option would be to put crayons in the glue gun and print candles. Random numbers could be input to generate unique candles. Relevant data, such as a bank balance, could also generate abstract shapes. Naturally a wick would be inserted after the printing process.
- Takes too long to raise coolant
- Takes too long to lower coolant
- Platen doesn't change position
- Glue doesn't feed
- No more data
- Layer is drastically larger than previous later