Heated composite tool and method for building and use

A heated composite tool, useful for forming, debulking, and/or curing prepreg materials, comprising:

• a composite build structure having a shape of a composite part that is to be produced, configured to receive and support the prepreg materials during lay-up, and comprising:
• a base structure having holes;
• a heating structure physically coupled to the base structure, and including:
• at least one heating element, comprising:
• a carbon nanotube structured layer defining a current path having a first end and a second end, and having holes that correspond with the holes of the base structure;
• and
• a first electrical terminal electrically coupled to the first end and a second electrical terminal electrically coupled to the second end, wherein at least one of the first and the second electrical terminals comprises:
• at least one electrode having a corresponding hole to the corresponding holes in the carbon nanotube structured layer and the base structure, and in electrical contact with and placed against the carbon nanotube structured layer;
• a threaded fastener having a head and a threaded shaft, the threaded shaft inserted and passing through the corresponding holes in the at least one electrode, the carbon nanotube structured layer, and the base structure;
• an insulating washer sized to the threaded fastener and placed over the threaded shaft of the threaded fastener and against the base structure, the insulating washer preventing the threaded fastener from making electrical contact with the base structure;
• and
• a nut sized to the threaded fastener and placed on the threaded shaft of the threaded fastener, and tightened against the insulating washer, the threaded fastener and the nut sandwiching the at least one electrode and the carbon nanotube structured layer together,
• wherein the threaded fastener extends the current path, and
• wherein the at least one electrode, the threaded fastener, and the nut comprise at least one of FeNi36 and titanium, having a coefficient of thermal expansion matched to that of carbon fiber;
• and
• a first isolation ply disposed between the base structure and the at least one heating element, the first isolation ply forming an electrical insulating gap between the base structure and the at least one heating element,
• wherein the carbon nanotube structured layer is responsive to an electromotive force applied across the first and the second electrical terminals to heat the tool.