Computational Process Model Development for Direct Digital Manufacturing (DDM)

ABSTRACT: Powder-bed based additive manufacturing (AM) technologies typically involve rapid solidification after a laser or electron beam melts a region of powder. Although parameters can be optimized for lowest cost, highest precision, or optimum microstructure, these optimizations require trade-offs between scan rate, layer thickness, bed heating, and use of support materials. The University of Louisville"s (U of L) Dislocation Density based Crystal Plasticity Finite Element Method (DDCP-FEM) enhanced in Phase I for Ti64 materials to predict local and global strengths, grain morphologies, and other layer-by-layer interfacial characteristics will be enhanced for Co-Cr including a detailed Design of Experiments, and developed support structure optimization. By coupling this model with a selective laser melting (SLM) process development cell, constructed at Mound Laser & Photonics Center (MLPC), parameters determined by the software will be experimentally tested, validated, and used for input in the iterative model. Upon validation between model and development cell, an OEM selected component will be fabricated using a commercial SLM station at U of L. Scientific Simulation Systems (S^3) will port the Phase II model to a high performance computing system in addition to programming a usable interface to facilitate commercialization transition. BENEFIT: Due to the lengthy development time and cost found in current direct digital manufacturing (DDM) technologies, the proposed work would provide savings in cost and time for fabricating complex components from a digital design. Commercial propulsion and airframe applications stand to greatly benefit from improved DDM especially by the elimination of tooling, dies, and casting molds. The time savings for engineering development in the form of rapid prototyping of designs as well as complex geometries that do not lend themselves to conventional machining techniques would greatly benefit both commercial and military applications. With the addition of a high performance computing system, the modeling process will be real-time during fabrication of components.