Investigation on the effect of process parameters in atmospheric pressure plasma treatment on carbon fiber reinforced polymer surfaces for bonding

ABSTRACT

Carbon Fiber Reinforced Polymer (CFRP) is used extensively in aerospace applications. Acceptance of bonded CFRP structures, mainly for aerospace applications, requires a robust surface preparation method with improved process controls to ensure high bond quality. Consistent repeatability is a factor lacking from many surface preparation processes. Atmospheric pressure plasma surface treatment is one of the robust surface preparation processes that have drawn wide attention in recent years. This process is capable of being applied in a production clean room environment that would minimize the risk of contamination and reduce cost. In plasma surface treatment the process parameters are easily controlled, documented providing a repeatable process with a high level of consistency. In this paper, the process parameters for atmospheric pressure plasma surface treatment and their effect on bonding for Out-Of-Autoclave (OOA) CFRP composite panels were fully investigated. A mechanized machine with sensory feedback to plasma treat surfaces was developed to change the process parameters for application on larger panels. By the aid of Design of Experiment (DOE) methodology critical process parameters were identified and a mathematical regression model was developed. The mathematical regression model was used to quantify the effect of process parameters on the bonding strength and the model was optimized to find the optimum settings.

KEYWORDS:

• Plasma
• surface
• bonding
• polymer
• process
• manufacturing
• effects
• parameters
• polymer
• composite
• design
• experiments

Acknowledgments

This work was sponsored by Northrop Grumman Aerospace Corporation from 2014 to 2016. The authors wish to recognize the technical assistance of Northrop Grumman experts. The authors wish to acknowledge the SurfX Technologies Company in providing feedback on their commercialized plasma head and their facility to run experiments. The authors would also like to thank Dr. Bob Minaie and Dr Ehsan Barjasteh for their support and feedbacks.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by the Northrop Grumman [Plasma Treatment of Composite Structures].