Browsing by Subject "nylon parts"

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A Comparative Evaluation of Energy Consumption of Selective Laser Sintering and Injection Molding of Nylon Parts
(University of Texas at Austin, 2011) Telenko, Cassandra; Seepersad, Carolyn Conner
Additive manufacturing is often advocated as a sustainable alternative to competing manufacturing technologies. This research study focuses on estimating and comparing the energy consumption required for different production volumes of nylon parts using either selective laser sintering (SLS) or injection molding (IM). For IM & SLS, energy consumption is estimated for nylon material refinement and part fabrication. For IM, energy consumption is also estimated for manufacturing the injection molds and refining their metal feedstock. A paintball gun handle serves as a representative part for calculating and normalizing material flows and processing times. For different sets of assumptions, cross-over production volumes are calculated, at which the per-part energy consumption of the two processes is equivalent. These energy-based cross-over production volumes are compared to similar economic cross-over production volumes available in the literature.
The Effects of Dry Heat Sterilization on Parts Using Selective Laser Sintering
(University of Texas at Austin, 2010) George, Mitchell J.; Crawford, Richard H.
Selective Laser Sintering (SLS) is a manufacturing process that can build arbitrarily shaped parts without part specific tooling. Its advantages have been employed in many different fields, one of these being medical surgery. Currently, SLS is limited in medical applications as a pre-operative modeling tool. For SLS manufacturing to progress in areas like compliant surgical tooling and patient specific bone matrices, concurrent work is needed to investigate the effects of medical sterilization on SLS materials. This paper presents the results of sterilization experiments on SLS parts built from nylon 11. To simulate the process of introducing tools into a sterile environment, these specimens were subjected to multiple rounds of dry heat sterilization. Changes to the dimensions, tensile strength and flexibility were recorded and analyzed. It was found that the specimens’ dimensions remained relatively constant. Both the tensile modulus and the flexural modulus decreased as the sterilization cycles progressed. The tensile modulus decreased by 25% and the flexure modulus decreased by 19% after ten rounds of sterilization.
Thermal Model of the Build Environment for Polyamide Powder Selective Laser Sintering
(University of Texas at Austin, 2010) Diller, Timothy T.; Sreenivasan, Rameshwar; Beaman, Joseph; Bourell, David; LaRocco, Janna
Precise thermal control of selective laser sintering (SLS) is desirable for improving geometric accuracy, mechanical properties, and surface finish of nylon, or polyamide (PA) parts. A modeling and measurement system was set up to facilitate development of thermal control strategies to improve these characteristics. A SinterStation 2500 SLS machine was used as a test machine for studying builds of parts made of DuraformTM PM nylon powder. Internal temperature measurements of the process were made using resistance temperature detectors (RTDs) embedded in the part bed powder. Surface temperature was measured with an infra-red camera aimed through the front window. A macro-scale time-dependent thermal numerical model of the build chamber and powder bins was developed as a means of evaluating temperature control of the build process. By comparing the measured and predicted temperature profiles, various estimates of the thermal diffusivity of the nylon powder were evaluated.