Compression molding of composite tailboom frames

Composite helicopter tailboom frames were manufactured by compression molding using a carbon fiber thermoset bulk molding compound. A mold was designed for compression molding and installed in a hydraulic press. The mold features two shear edges, guide pins and an integrated part ejection system. A material preforming method was developed to improve consistency in material distribution, which improved process robustness. A number of parts were produced and inspected for void content and dimensional stability. No significant porosity or voids were found in the samples examined. Part thickness uniformity was studied and improved, in order to meet the required tolerances. Dimensional inspection before and after a free standing post cure showed no significant part distortion. This work showed that compression molded tailboom frames are a viable alternative to current tailboom frames using continuous pre-impregnated fabric materials and cured by autoclave. This alternate processing method has the potential to reduce touch time and manufacturing costs.Peer reviewed: YesNRC publication: Ye