3-D printing machine to facilitate observation of printing phenomena

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1998.Includes bibliographical references (leaf 156).The understanding of binder-powder interaction during the Three Dimensional Printing process is critical to improving the characteristics of parts produced by this process. The ability to observe the binder-powder interaction taking place could aid its investigation greatly. In the case of Three Dimensional Printing of fine ceramics, in which powderbeds are deposited as a liquid slurry before printing with a binder is done, the deposition of the powderbed itself is a part of the process the investigation of which could benefit from convenient automated image acquisition. Such observation requires flexible imaging capabilities of a nature that cannot easily be realized by using attachments to existing Three Dimensional Printing machines. This motivated the design and construction of a specialized imaging-oriented Three Dimensional Printing machine, the droplet impact observation station, which this thesis documents. The requirements of the machine are presented, the realized design and operation of the machined described, the results of initial tests of operation presented and areas for further work and improvement outlined. The droplet impact observation station constructed moves a carriage back and forth over a travel of up to 46.5 inches, at speeds of up to 2 mis with a total velocity ripple of approximately 0.007 mis. In the station's primary mode of operation, the moving carriage transports a powderbed, while the printhead remains stationary. Tests in which strobe illuminated images of crosshairs mounted on the moving carriage were obtained have demonstrated the ability to time a strobe flash to within +/- 1-2 microns. Strobe illuminated images of continuous-jetted droplets produced by the observation station have been obtained.by Akobuije Chijioke.S.M

Direct measurement of radiation pressure and circulating power inside a passive optical cavity

A mechanical force sensor coupled to two optical cavities is developed as a metrological tool. This system is used to generate a calibrated circulating optical power and to create a transfer standard for externally coupled optical power. The variability of the sensor as a transfer standard for optical power is less than 2%. The uncertainty in using the sensor to measure the circulating power inside the cavity is less than 3%. The force measured from the mechanical response of the sensor is compared to the force predicted from characterizing the optical spectrum of the cavity. These two forces are approximately 20% different. Potential sources for this disagreement are analyzed and discussed. The sensor is compact, portable, and can operate in ambient and vacuum environments. This device provides a pathway to novel nanonewton scale force and milliwatt scale laser power calibrations, enables direct measurement of the circulating power inside an optical cavity, and enhances the sensitivity of radiation pressure-based optical power transfer standards.Open access journal.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

The ruby pressure standard to 150 GPa

A determination of the ruby high-pressure scale is presented using all available appropriate measurements including our own. Calibration data extend to 150 GPa. A careful consideration of shock-wave-reduced isotherms is given, including corrections for material strength. The data are fitted to the calibration equation P=(A/B)[(/0)B–1] (GPa), with A=1876±6.7, B=10.71±0.14, and is the peak wavelength of the ruby R1 line.Validerad; 2005; 20061110 (ysko