Inline process monitoring and failure management concept for ATL
Topic(s) : Manufacturing
Co-authors :
Neha YADAV (AUSTRIA), Ralf SCHLEDJEWSKI , Ewald FAUSTER (AUSTRIA)Abstract :
Automated tape laying (ATL) is an advanced composite manufacturing process which is used extensively for high performance industries such as aerospace and automotive. The aerospace industry, with its growing use of both composites and ATL, demands greater part complexity, reduced waste and stricter control over product quality and geometric tolerances. The process is predisposed to manufacturing defects which are not only detrimental to the structural performance, but also, due to a lack of robust monitoring and control system, lead to productivity loss. Defect detection and rectification as a part of failure management are the main process bottlenecks.
This research work provides an industry ready, engineering solution-based, holistic defect monitoring and control concept for thermoplastic in-situ consolidated ATL. The frequency of incidence as well as the effect of defects concerning severity of structural damage, serve as defect selection criteria. A complete monitoring cycle consisting of defect identification, inline detection, treatment and control based on analysis of the process behavior is established. Going beyond remedial rectification (removal, rework and repair), preemptive strategies are discussed and selectively implemented. For robust failure management, crucial defects are identified, detected and managed in a cyclic manner.
In particular, the following sensor technologies were involved as schematically shown in Figure 1:
•FBG sensors are used for residual strain detection at both lamina and laminate level.
•Infrared thermography is used for detecting foreign objects and debris (FOD) as small as 2.5 mm. Local bonding defects and thermal anomaly can be detected as well.
•Positioning defects such as gaps and overlaps having a size of 0.2 mm and above can be well detected using light section sensors.
Sensor specific best practices are highlighted and utilized. For the given set-up, residual strain, substrate temperature and compaction force can be controlled to alleviate shape distortion, bond inhomogeneity as well as gaps and overlaps, respectively. Furthermore, a limited parametric study has been performed for compaction force control with regards to tape width. For effective overlap and gap management, correlation models consisting of width spread values for different parametric sets are acquired. Based on the size of the gap, width spread and corresponding process parameters are selected for the process run. Process parameter control ultimately leads to process optimization and time, cost and weight savings. All the scientific findings have been benchmarked against existing industrial standards, making the concept completely ready for direct industrial implementation.
This research work provides an industry ready, engineering solution-based, holistic defect monitoring and control concept for thermoplastic in-situ consolidated ATL. The frequency of incidence as well as the effect of defects concerning severity of structural damage, serve as defect selection criteria. A complete monitoring cycle consisting of defect identification, inline detection, treatment and control based on analysis of the process behavior is established. Going beyond remedial rectification (removal, rework and repair), preemptive strategies are discussed and selectively implemented. For robust failure management, crucial defects are identified, detected and managed in a cyclic manner.
In particular, the following sensor technologies were involved as schematically shown in Figure 1:
•FBG sensors are used for residual strain detection at both lamina and laminate level.
•Infrared thermography is used for detecting foreign objects and debris (FOD) as small as 2.5 mm. Local bonding defects and thermal anomaly can be detected as well.
•Positioning defects such as gaps and overlaps having a size of 0.2 mm and above can be well detected using light section sensors.
Sensor specific best practices are highlighted and utilized. For the given set-up, residual strain, substrate temperature and compaction force can be controlled to alleviate shape distortion, bond inhomogeneity as well as gaps and overlaps, respectively. Furthermore, a limited parametric study has been performed for compaction force control with regards to tape width. For effective overlap and gap management, correlation models consisting of width spread values for different parametric sets are acquired. Based on the size of the gap, width spread and corresponding process parameters are selected for the process run. Process parameter control ultimately leads to process optimization and time, cost and weight savings. All the scientific findings have been benchmarked against existing industrial standards, making the concept completely ready for direct industrial implementation.