Abstract: Various implementations include systems and methods for simultaneously applying an electric field and localized energy from an energy source to ceramic particles on a layer by layer basis to form a ceramic workpiece using additive manufacturing. The workpiece may be freely removed from the unsintered ceramic particles. In some implementations, the workpiece is partially densified when removed from the unsintered ceramic particles, but it may be heated until fully densified. According to some implementations, these systems and methods remove or reduce the need for binders and reduce manufacturing time.

Abstract: An apparatus and method for detecting defects in an additive manufacturing process is provided. An example method may include depositing a first layer of material, depositing a second layer of material in at least partial contact with the first layer of material, and inducing a phase change between the first and second layers of material via an energy beam. Further, the method may include directing an electromagnetic radiation beam to at least a portion of a subsurface interface between the first and second layers, measuring radiation returned from the material, and based on the measured radiation, determining a location of a refractive index gradient within the material.

Abstract: Various implementations include systems and methods for simultaneously applying an electric field and localized energy from an energy source to ceramic particles on a layer by layer basis to form a ceramic workpiece using additive manufacturing. The workpiece may be freely removed from the unsintered ceramic particles. In some implementations, the workpiece is partially densified when removed from the unsintered ceramic particles, but it may be heated until fully densified. According to some implementations, these systems and methods remove or reduce the need for binders and reduce manufacturing time.

Abstract: Various implementations utilize electromagnetic energy in the microwave and/or radio frequency (RF) spectrum to volumetrically solidify selective regions of a base material powder bed (e.g., polymer or ceramic). When they are dry, base materials utilized in powder bed fusion and other additive manufacturing processes are relatively transparent to microwave and RF energy, making it very difficult to heat them with those energy sources. However, mixing or doping the base material powders with conducting particles, such as graphite or carbon black, enhances energy absorption at microwave and radio frequencies, enabling heating and melting. Thus, volumetric additive manufacturing may be achieved by selectively doping a 3D powder bed with energy-absorbing particles in the shape of the desired object and exposing the powder bed to microwave and/or RF energy fields, such that the doped regions are volumetrically sintered into desired objects, leaving the surrounding powder unaffected.

Abstract: An example apparatus for producing a part from a powder using a powder sintering process can include a build chamber including one or more walls and a build piston configured to support the powder and the part. Additionally, the build chamber can enclose a build cylinder and a build surface, and the build piston can be arranged at least partially within the build cylinder. The apparatus can also include a plurality of heat sources distributed in the walls of the build chamber, the build cylinder and/or the build piston, an energy source arranged outside of the build chamber and configured to produce and direct an energy beam to the build surface, and a controller configured to control the heat sources.