Free-Form Fabrication Using Electrically Conductive Filaments

Free form fabrication of articles often requires the application of heat to melt the fabrication material feedstock, and controlled cooling to ensure that once the material is put into place, the fabricated structure does not suffer from distortion. Investigators at LaRC have developed a simple method to apply localized heat, by using an electrically conductive nozzle and a conductive plate as the electrodes for electrically conductive filaments. This method is intended to be used for laying down electrically conductive filaments in a fast, accurate and controlled manner with localized heat. The use of multifunctional composites such as mechanically reinforced, electrically and thermally conductive parts is of interest in a range of application areas. Especially interesting and important is where tailorability of function is achieved by strategic placement of materials with unique functionality in locations that may not be accessible by conventional manufacturing techniques. Examples include embedded conductive paths interspersed in components to act as sensing elements, or as heaters, or to carry current to power to permit other components to be plugged in. The processing of these materials requires adhesion of filaments to each other, as well as to a substrate.