Advanced Process Control for Laser Sintered Thermoplastics

ABSTRACT: Paramount has previously developed thermal controls for the SLS process and documented some of the required in-situ sensing capabilities to achieve full process stability. Paramount"s partners have previously modeled the laser energy density for the process and other composite manufacturing processes. SLS as an out-of-the-box technology does not have the required manufacturing controls to reduce the cost of process quality control and guaranteed the quality of parts. Therefore, a business opportunity exists to fully derive, validate and implement the required physics-based process-structure-property models that can direct the design and development of sensing capabilities and adaptive controls for the existing SLS technology. The findings and recommendations from Phase I alone will significantly increase the understanding of SLS within the defense community. These results will also provide the basis for an appropriate technology insertion roadmap for SLS within the defense aerospace manufacturing industry. Paramount"s approach increases the probabilities of implementing several of the proposed technology improvements for existing SLS systems that are already making parts for other DDM commercial applications. BENEFIT: Paramount"s Phase I objectives are to demonstrate the feasibility of collecting process data and developing accurate physics based model that can be used to improve the quality control of the entire process and optimize the results in mechanical properties. Paramount Industries is confident that those objectives will be successfully achieved and anticipates the following results: 1. A set of individual process models that capture the important process phenomena such as laser energy density, thermal distribution, heat transfer, polymer consolidation, layer bonding, polymer degradation, and residual stresses. 2. An overall generic and flexible model, requiring only the basic material properties and details related to heat sources and laser energy inputs. 3. Demonstration of uniform heat distribution through adaptive thermal controls and sensing capabilities for the heat at the surface of the fabrication area and through the volume of the build envelop. 4. Preliminary Engineering designs and solutions for visual inspection of powder deposition and in-situ monitoring of true laser power.