Summaries - Research
Back Additive Manufacturing of Gun Propellants using Vibration Assisted Direct Write Printing
|Division||Graduate School of Engineering & Applied Science|
|Department||Mechanical & Aerospace Engineering|
|Investigator(s)||Gunduz, Ibrahim E.|
|Sponsor||Strategic Environment Research & Development Program (DoD)|
Many of the existing fabrication technologies for propellants utilize solvents and generate a large amount of hazardous waste. In addition, solvent-less formulations that were designed to circumvent these issues have significant manufacturing hazards, as well as performance, aging and safety concerns. The proposed effort aims to help reduce the adverse environmental impact of propellant fabrication through the use of a novel direct-write additive manufacturing (AM) technology that enables the printing of extremely viscous (µ > 10000 Pa·s) mixtures, which requires less solvent for formulations, while benefiting from the ability to fabricate unique designs through AM. The vibration assisted direct write system enables the rapid deposition of extremely viscous materials through sub-mm sized nozzles and yields fully dense 3D printed structures. The high resolution (~0.1 mm) of the system can enable the in-situ deposition of low solvent mock formulations, or different components of existing double-base or triple-base formulation analogues with enough solvents and additives, while completely eliminating mixing cycles, which generate most of the solvent waste. Furthermore, thermoplastic elastomer (TPE)-particle composites are compatible with the system and can be printed at lower than typical temperatures, while using pellets instead of pre-formed filaments since flow is controlled at the nozzle. This can alleviate the brittleness issues for the associated with filaments which contain solids loadings in excess of more than 50 wt.%. The mild printing conditions can also enable the use of novel material formulations that cannot be processed using existing methods. The AM system enables the fabrication of graded compositions and the inclusion of designed porosity, which allow for significant improvements in propellant performance and tailorability. The work will also characterize the mechanical properties and performance of printed parts as a function of process and material parameters.
If successful, the proposed effort will enable the AM of propellants and other engineering materials with both lower environmental impact and cost, due to reduced solvent usage. These advancements will be realized through the development of a fundamental understanding of the effects of material-process-structure-function relationships.
|Keywords||Additive Manufacturing Propellants direct write heterogeneous materials|
|Publications||Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal|
|Data||Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal|