LOW COST TOOLING MATERIAL & PROCESS FOR GRAPHITE & KEVLAR

A NEW TOOLING CONCEPT, SUITED TO THE MANUFACTURE OF COMPONENTS FABRICATED FROM MODERN POLYMERS AND COMPOSITES, IS INVESTIGATED. NEW POLYMER & COMPOSITE TECHNOLOGIES HAVE OUTSTRIPPED THE TOOLING TECHNILOGY REQUIRED TO PRODUCE PARTS. AEROSPACE TOOL BUILDING PRACTICES AND MATERIALS THAT WERE ADEQAUTE FOR METAL FROMING AND FIBERGLASS COMPOSITE MANUFACTURE WILL NOT SUFFICE FOR THE NEW SPACE-AGE COMPOSITES. NEW MATERIALS HAVING LOW THERMAL EXPANSION COEFFICEINTS AND REQUIRING HIGH TEMPERATURE PROCESSING DEMAND NEW APPROACHES IN MOLD BUILDING. PRODUCTIVITY OF COMPOSITE PARTS HAS BEEN HAMPERED DUE TO HIGH COST OF MACHINED METAL MOLDS OR HIGH MATERIAL COST OF GRAPHITE COMPOSITE TOOLS. THE NEW TOOLING MATERIAL CONCEPT, A REPLACEMENT FOR LAMINATED FIBERGLASS TOOLING UTILIZES CERAMIC FILLERS THAT HAVE A HIGH NEGATIVE THERMAL COEEFICIENT OF EXPANSION TO COUNTER THE HIGH THERMAL COEFFICIENT OF EXPANSION OF THE POLYMER MATRIX. THE NEGATIVE THERMAL COEFFICIENT OF EXPANSION FILLER ALONG WITH PRE-CATALYZED RESIN IS EXTRUDED INTO A VOID FREE SHEET THAT IS VISCOELASTIC IN ITS UNCURED STATE. BEFORE THIS MATERIAL CAN CURE OR POLYMERIZE, IT IS FROZEN TO PREVENT CURE DURING SHIPPING AND STORAGE. THE VISCOELASTIC SHEET WILL HAVE A HIGH TEMPERATURE POLYMER MATRIX WITH VERY LOW THERMAL COEEFICIENT OF EXPANSION AND WILL CURE INTO A MONOLITHIC NON-LAMINATED MOLD.