“Hot Forming” Process vs Cycle Parametrization: Ancillary Materials, Risks by Contamination and Prepreg Aging

Abstract

Aeronautical process globalization and the growth in number of composite materials suppliers have allowed the development of creativity since processes parametrization point of view as well as the use of ancillary materials that guarantee the product quality in the currently available resin systems in the composites world. Hot-forming process optimization in order to provide the development of high thickness parts and complex shape must meet a minimum parameters (temperature, time and vacuum) which are determinated by experimental methods and are in relation with: 1) Prepreg Material (tape / resin system); 2) Ancillary Materials, particulary the release film due to contamination risk of un-cured prepreg during hot-forming process; 3) Indication and control systems of temperature. Nowadays, the new thermoset resin systems are more complex due to an increase of the requirements from OEMs to manufacturers of composites in order to obtain a products optimization (functional and structural) in a more effective way.This aspect, joined to the study and the industrial capability analysis of a determinated equipment, allowed us the development of a tests campaign on structural parts of unidirectional prepreg (UD) to define the maximum and minimum temperature, time and ancillary materials to be used in a “hot-forming” process. Non contamination of the part and no material aging are guaranteed, as well as the internal quality after a process of consolidation by co-curing process in autoclave for any thermoset resin system available in the composite world.

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