99--TECHNOLOGY TRANSFER OPPORTUNITY - COMPOSITE MANUFACTURING USINGDOUBLE-VACUUM BAGS

NASA Langley Research Center in Hampton, VA solicits interest from companiesinterested in obtaining license rights to commercialize, manufacture and market thefollowing technology. License rights may be issued on an exclusive or nonexclusive basisand may include specific fields of use. THE TECHNOLOGY: NASA Langley Research Center has developed composite manufacturing techniques to improvetraditional single vacuum-bag (SVB) processes. Although using an SVB technique in an ovenis a cost-effective non-autoclave method for producing high-performance composites, it isoften ineffective when a reactive resin matrix, or solvent containing matrix or prepregis used. NASA Langley has developed a double-vacuum-bag (DVB) process to overcome SVBdeficiencies by improving volatile managementand eliminating excessive resin bleed situations.To produce a void-free quality laminate from resin-impregnated prepregs, it is imperativeto deplete volatiles and solvents before commencing forced consolidation. The traditionalSVB assembly inherently hinders and/or retards the volatiles depletion mechanisms duringcomposite fabrication because a vacuum-generated compaction force is applied to thelaminate during volatile depletion period (i.e., B-stage). NASA designed their DVBtechnique to overcome such a deficiency. Specifically, NASAs DVB process eliminates thecompaction force generated by vacuum suction while in the meantime maintaining the vacuumeffectiveness for the volatile depletion. The technique has been proven and validated tobe effective for volatile management and resin content control in composites withreactive resin matrices such as solvent-containing phenolic and polyimide resin matrixprepregs.The NASA DVB process can also combine the infusion of resin and consolidation ofcomposite in one processing step. The molding assemblys double-vacuum environmentenables the improved void management and laminate net shape control. By using two vacuumenvironments during the curing process, a vacuum can be drawn during a B-stage of atwo-step cycle without placing the composite under significant compressive pressure.During the final cure stage, a significant pressure can be applied by releasing thevacuum in one of the two environments. Inner and outer bags are useful for creating thetwo vacuum environments, with a perforated tool between the two. The composite is placedon a tool, with the inner bag and tool plate defining the first environment. The secondenvironment is characterized by the outer bag, which is placed over the inner bag and thetool platesee graphic on left.To express interest in this opportunity, please respond to Sean Sullivan at: NASA LangleyResearch Center, 17 West Taylor St., Mail Stop 218, Building 1212, Room 110 Hampton,Virginia, E-mail: [email protected], or phone: 757-864-5055. Please indicate thedate and title of the FBO notice and include your company and contact information.Contracting Office Address: NASA Langley Research Center17 West Taylor Street, Mail Stop 218Building 1212, Room 110Hampton, VA 23689-2199Primary Point of Contact: Sean SullivanNASA Langley Research [email protected]: 757-864-5055