Width deformation of thermoplastic prepreg tapes during Automated Fiber Placement
Topic(s) : Manufacturing
Co-authors :
Sovit AGARWAL (GERMANY), Daniël PEETERS (NETHERLANDS), Dominik DELISLE , Daniel STEFANIAKAbstract :
Automated Fiber Placement (AFP) with in-situ consolidation of thermoplastic prepreg tapes has the potential to provide a fast and cost-effective manufacturing solution for large composite structures. However, the robustness of the process and the laminate quality is still lacking for widespread industrial use because of the complex mechanisms associated with short processing times involved and the occurrence of several defects, especially gaps and overlaps. One of the reasons for the formation of these gaps and overlaps is the tape width deformation during placement.
Current literature on tape width deformation shows that the resulting tape width is influenced by processing parameters such as temperature, pressure and placement speed. However, results from different studies do not agree with each other, indicating that the tape temperature distribution might be at play [1]. Additionally, the conventionally considered tape width deformation mechanism, namely transverse squeeze flow has been suggested to be incorrect for the AFP process as the experimental deformations do not agree with the results of the transverse squeeze flow model [1]. Therefore, this study experimentally investigates the width deformation mechanism and the influence of processing parameters for thermoplastic prepreg tapes using in-situ AFP manufacturing with a xenon flashlamp as the heating device.
The specimens were manufactured according to a full-factorial Design of Experiments with heated length, nip-point temperature and compaction force as the variables and two settings for each. The tape width was measured for all the specimens to investigate the influence of these processing parameters and some post-processing analyses i.e., width measurement in the heating phase of the process, surface roughness analysis, tape cross-section profile inspection and fiber-resin content analysis were conducted to understand the tape width deformation mechanism.
From the post-processing analyses and investigations, it was found that the tape does not only widen in the consolidation phase of the process, but also in the heating phase. Additionally, the cross-section images show that the conformable roller led to the tape edge profile to have a gradual decrease in thickness with a clear slope and the tape edges show a clear indication of spreading of the fiber-resin mixture due to the presence of both fibers and resin. Moreover, the surface roughness data show an indication of the role of temperature distribution. A detailed discussion on the influence of the investigated parameters will be presented in the full paper.
Current literature on tape width deformation shows that the resulting tape width is influenced by processing parameters such as temperature, pressure and placement speed. However, results from different studies do not agree with each other, indicating that the tape temperature distribution might be at play [1]. Additionally, the conventionally considered tape width deformation mechanism, namely transverse squeeze flow has been suggested to be incorrect for the AFP process as the experimental deformations do not agree with the results of the transverse squeeze flow model [1]. Therefore, this study experimentally investigates the width deformation mechanism and the influence of processing parameters for thermoplastic prepreg tapes using in-situ AFP manufacturing with a xenon flashlamp as the heating device.
The specimens were manufactured according to a full-factorial Design of Experiments with heated length, nip-point temperature and compaction force as the variables and two settings for each. The tape width was measured for all the specimens to investigate the influence of these processing parameters and some post-processing analyses i.e., width measurement in the heating phase of the process, surface roughness analysis, tape cross-section profile inspection and fiber-resin content analysis were conducted to understand the tape width deformation mechanism.
From the post-processing analyses and investigations, it was found that the tape does not only widen in the consolidation phase of the process, but also in the heating phase. Additionally, the cross-section images show that the conformable roller led to the tape edge profile to have a gradual decrease in thickness with a clear slope and the tape edges show a clear indication of spreading of the fiber-resin mixture due to the presence of both fibers and resin. Moreover, the surface roughness data show an indication of the role of temperature distribution. A detailed discussion on the influence of the investigated parameters will be presented in the full paper.