This is an attempt at a printable/castable electromagnet. The coil is made from plastic castings and low-melt alloy. There is one base-disk and four coil-disks in the assembly. Each coil-disk has 1.5 turns, so there is a total of 6 turns in the coil. The magnetic core is made from iron powder mixed with epoxy.

This electromagnet did not work very well. With a current of tens of amps it can barely move a paperclip. Poor performance is probably mostly due to the low permeability of the magnetic core. It is possible that the same device with a solid iron/steel core would work much better.

Maybe you can improve on the design, or at least avoid making the same mistakes that we did. The construction techniques may also be of some interest. We used plastic castings, but the disks can probably be printed or laser-cut. The use of multiple disks avoids the overhang problem common in 3D printers, but it does not capitalize on the printer's strengths, such as the ability to print a single part with complex internal geometry.

An experimental solid is also uploaded with coils formed from internal cavities. The coil block is about 3cm tall and contains 11.5 turns. The internals were designed to minimize overhangs. I have no idea if this object will print well or not. As a visual aid, an inverse of the coil block is also provided (coilChannel) so you can see what is going on inside the block.

If anyone makes a working electromagnet you could put it on this thing thingiverse.com/thing:329 to make a motor!