SBIR-STTR Award

In this Small Business Innovation Research Phase I project, Precision Machining of Composite Structures, Third Wave Systems (TWS) will develop and demonstrate an innovative precision machining technique enabled by physics-based modeling, adaptive control machining and the generation of a machining digital twin the Navy requires to dramatically reduce machining-induced damage, improve manufacturing efficiency, and reduce consumable tooling cost by 50% during creation of finished precision fastener holes in aerospace composite structures. TWS approach will lead to the development of a cyber-physical system which integrates its physics-based modeling, NC toolpath optimization and data collection capabilities into a closed-loop adaptive control machining system. The system will monitor real-time force and temperature data, compare with an optimized digital baseline, and adjust the machining parameters to control machining-induced damage, optimize material removal rate and improve tool life. The resulting manufacturing data including temperature, forces, hole quality and dimensional accuracy will be retained and integrated into a part digital twin providing needed traceability of the part manufacturing process. The interoperability among machines, tools, sensors and people, a core design principle of Industry 4.0, will drastically improve quality control, increase manufacturing efficiency and reduce operational cost.

Benefit:
Special characteristics of fiber reinforced polymer (FRP) composites present problems during the drilling process of fastener holes, including rapid tool wear, thermal damage, and other machining-induced damages such as delamination and splintering, resulting in poor hole quality and high consumable tooling cost. Due to the lack of validated analysis tools to understand the impact of different machining strategies on these issues, trial-and-error approaches are currently being used to develop and improve drilling process for FRP composites. These approaches are expensive, time consuming and typically lead to sub-optimal solutions. Third Wave Systems (TWS) will develop and demonstrate an innovative precision machining technique enabled by physics-based modeling, adaptive control machining and the generation of a machining digital twin to provide a robust machining solution for composite drilling. TWS will build upon its current FRP composite machining models, improve data collection methods and enhance process optimization strategies. With these models it will be possible to predict forces, tool stresses, temperature and damage within the workpiece, heat generation and flow for cutting tool performance analysis and toolpath optimization. With the proposed data collection methods, in-process tool temperature measurement will be added to current force, chip and hole quality inspection capabilities. Combining this information with enhanced process optimization strategies will enable in-process adjustments of process parameters for maintaining part quality and reducing consumable tooling cost while taking into account the rapid tool wear. As a result, more effective tooling that lasts longer and cuts better will be designed and produced via force, stress, and temperature analyses. Moreover, machining-induced damage and dimensional accuracy of the hole will be predicted, managed, and improved. This innovative machining technique will allow composite drilling to be placed on a more scientific foundation, eliminating trial-and-error methods and ultimately producing higher quality fastener holes in a faster and more cost-effective manner. The validated analysis tool developed in the Phase I project would have immediate application in a number of commercial and DoD aerospace programs, including on the CH53-K, F-35 and Boeing 787. Furthermore, the technology developed in Phase I will be incorporated into TWS commercially available software, Production Module and AdvantEdge. This will ensure wide dissemination within TWSs current customer base of DoD and commercial aerospace structure manufacturers, as well as to potential new customers within military and commercial sectors such as aerospace, automobile, and marine. Anticipated benefits of the Phase I program are: Elimination of trial-and-error testing through the use of validated physics-based modeling capability Controlled hole quality and dimensional accuracy resulting from in-process data monitoring, physics-based damage and temperature prediction, and adaptive control machining Increased machining efficiency through optimized baseline setup and in-process optimization of machining parameters A 50 percent reduction in consumable tooling cost due to increased machining efficiency and more reasonable tool replacement strategy Maximized capabilities of existing capital equipment through tooling, process improvements and cost-effective sensor technology Improved quality control through traceability of manufacturing data enabled by part digital twin Broad applicability of developed technology to a wide variety of composite materials, machine tools and components in both the military and commercial sectors In addition to direct commercial benefits, this project will further increase the science and engineering knowledge base in both industry and academia regarding the fundamental relationships between materials, processes, and product quality of composite drilling.

Keywords:
Finite Element, Finite Element, Process Optimization, quality, Composites, machining, FRP, drilling, Modeling

In this Phase II project, Third Wave System will further advance the innovative technologies and methodologies to develop a fully functional prototype of physics-based simulation and optimization solution for countersunk fastener hole drilling in composite structures. TWS will develop and validate physics-based countersunk fastener hole drilling simulation capability predicting cutting force, temperature, heat energy, and damage during the drilling process. Innovative damage and temperature optimization technology will be developed to minimize damage while maximizing hole making rate. TWS will also develop a closed-loop adaptive modeling technology incorporating real-time machining feedback to ensure high and consistent hole quality throughout drilling processes and improve tool life. Throughout the project, TWS will demonstrate the developed technology with verified industry baseline materials and cutting conditions. A Non-destructive Inspection technology will be used to measure the hole quality and compare it with the quality of hole machined by a conventional process. The anticipated benefits of this project include a 50 percent reduction in countersunk hole machining cost; minimized damage, high placement accuracy, reduced consumable tooling cost, and optimal hole making; and consistent part quality and high productivity. TWS will also work an industry group to collect feedback, identify gaps, and develop commercialization plans.