THERMOFORMING OF ADVANCED THERMOPLASTIC COMPOSITES .1. SINGLE CURVATURE PARTS

Thermoforming has been studied for a single curvature part made from various advanced thermoplastic matrix composite prepregs. For parts with acceptable shape conformity, preheating of the composite laminates to a processing temperature of 350 to 400-degrees-C is necessary prior to forming with molds maintained at 200-degrees-C. However, only PEEK/carbon fiber prepreg tapes yielded parts with acceptable microstructural integrity and a matrix crystallinity level of about 30 percent. Amorphous matrix based PXM 8505/T500 fabric prepregs also result in lamination and void free parts, but fiber matrix distribution in this case was rather poor. Parts thermoformed from other prepreg laminates contained voids and/or were delaminated, thereby indicating the need for higher mold temperature and forming pressure than that afforded by the present study, in which a standard lab-scale thermoforming machine was used.