It has been unexpected found that the sound dampening characteristics of powder metal parts can be dramatically improved by incorporating coarse graphite into the part. This is beneficial in applications where parts to generate noise during operation, such as in gears, rotors and sprockets. Surprisingly, the incorporation of the coarse graphite into such parts does not significantly compromise the strength, durability, wear characteristics, or service life of the part. Such parts can also be manufactured to a high level of tolerance and with good uniformity. Such parts are comprised of a sintered powder metal composition which includes 0.1 weight percent to 5 weight percent of a coarse graphite having a particle size wherein at least at least 30 percent of the coarse graphite will not pass through a 325 mesh screen.

Provided is an insert adapter for direct ink writing printers (DIW) and methods of fiber alignment in direct ink writing. The insert adapter is sized to fit snugly inside a print barrel DIW 3D printer. The adapter includes channels. The DIW printer with insert adapter, can be used in a passive method for microfiber alignment in DIW printing. The method includes feeding a non-Newtonian ink including microfibers through the print barrel such that the ink flows into the channels of the insert adapter before exiting through a print nozzle, causing the microfibers to align along the direction of ink flow.

Provided is an insert adapter for direct ink writing printers (DIW) and methods of fiber alignment in direct ink writing. The insert adapter is sized to fit snugly inside a print barrel DIW 3D printer. The adapter includes channels. The DIW printer with insert adapter, can be used in a passive method for microfiber alignment in DIW printing. The method includes feeding a non-Newtonian ink including microfibers through the print barrel such that the ink flows into the channels of the insert adapter before exiting through a print nozzle, causing the microfibers to align along the direction of ink flow.