LOW TEMPERATURE CURE BISMALEIMIDE COMPOSITE TOOLS WITH EXCELLENT TOOL LIFE

Composite tools have been developed using a new and unique Bismaleimide (BMI) prepreg that allows for reduced cost and lead time without sacrificing performance. The BMI tools are capable of being cured initially at 121°C (250°F) followed by a 204 °C (400 °F) cure in a free-standing manner. The 121°C (250°F) initial cure allows use of a lower cost master mold. In this paper, performance of carbon fiber reinforced BMI tools as well as the unique characteristics of the BMI prepreg and the corresponding composite properties are presented. Accelerated life cycle testing was performed using carbon fiber and fiberglass prepreg molded in the autoclave. Life cycle testing demonstrates the hygrothermal stability of the machined BMI tools. The evaluations have shown that the tools fabricated using the new BMI prepregs meet the requirements for repeated cures at 177°C (350°F) while providing cost and schedule benefits.