Abstract:
The present invention makes use of loose fibrous material (for instance, chopped fibers) as reinforcement matrix material in the manufacture of carbon-carbon composites. In accordance with this invention, a constraint fixture is provided which can be separated from the mold. The constraint fixture has an internal shape corresponding to the shape of a desired preform component, with the internal shape being defined by a bottom plate (2), an annular ejector plate (3, 3'), a inner wall (10), an outer wall (4), and an annular top plate (11, 11'). The constraint fixture is normally made of metal, porous ceramic, or carbon material. The constraint fixture of the mold holds the loose matrix materials (fibers, along with any fillers and/or additives). The mold assembly itself is segmented, so that the constraint- fixture and the loose fill materials in the fixture can be removed and subjected to further processing as a unit. Such further processing may include Chemical Vapor Deposition or resin or pitch infiltration or Resin Transfer Molding. The preform matrix may remain in the constraint fixture through such processing steps as densification and until it is removed therefrom for final machining.
Abstract:
Annular brake disc preform (15), wherein 40 to 80 layers of reinforcement fibers of at least two different lengths (11, 19) ranging from 10-60 mm are distributed in a planar gradient throughout the body of the preform, with the reinforcement fibers located near the exterior planes of the disc being predominately shorter fibers (11) and with the reinforcement fibers located in the central planes of the disc being predominately longer fibers (19). Also, process of making carbon-carbon composite preforms by: providing chopped pitch or PAN fibers (11, 19) of at least two different lengths; directing a robotic spraying apparatus to spray the chopped fibers into an annular mold (5) in 40 to 80 concentric iterations of chopped fiber deposition to provide a matrix of fibers in the mold; depositing a curable binder into the mold to intermix the binder with the fiber matrix; compressing the fiber matrix and curable binder within the mold; curing the binder to form a preform matrix; filling the preform matrix with pitch to form a pitch matrix; and subjecting the pitch matrix to chemical vapor deposition to form a carbon-carbon composite preform (15).
Abstract:
A preform for a carbon-carbon composite part (55) comprising multiple layers of fibrous mats (51, 52, 53) wherein each of the fibrous mats (51, 52, 53) comprises a random carbon-containing fibrous matrix (11) within which is distributed a polymeric binder and wherein adjacent mat layers (51, 52, 53) are bound together by additional polymer binder, stitching and interlocking tabs. The preform of the present invention may be an aircraft landing system brake disc. Also, a method of manufacturing a thick multi-layer composite preform. The method includes the steps of: providing an optionally reconfigurable tool including a perforated screen through which a vacuum can be drawn; delivering chopped fibers (b), such as pitch fibers, polyacrylonitrile fibers, or mixtures thereof, to said tool while drawing vacuum therethrough, to form a fibrous object; delivering binder (c), for instance in the form of a spray, to said fibrous object; melting or curing said binder (d), for instance by the application of heat or ultraviolet light, to make a fibrous mat (51, 52, 53); assembling, preferably in the substantial absence of cutting or other mechanical modification, a plurality of said fibrous mats (51, 52, 53) and additional binder into the shape of a preform (e); and heat-pressing the resulting mat assembly (f) into a finished thick preform (55).
Abstract:
Annular brake disc preform (15), wherein 40 to 80 layers of reinforcement fibers of at least two different lengths (11, 19) ranging from 10-60 mm are distributed in a planar gradient throughout the body of the preform, with the reinforcement fibers located near the exterior planes of the disc being predominately shorter fibers (11) and with the reinforcement fibers located in the central planes of the disc being predominately longer fibers (19). Also, process of making carbon-carbon composite preforms by: providing chopped pitch or PAN fibers (11, 19) of at least two different lengths; directing a robotic spraying apparatus to spray the chopped fibers into an annular mold (5) in 40 to 80 concentric iterations of chopped fiber deposition to provide a matrix of fibers in the mold; depositing a curable binder into the mold to intermix the binder with the fiber matrix; compressing the fiber matrix and curable binder within the mold; curing the binder to form a preform matrix; filling the preform matrix with pitch to form a pitch matrix; and subjecting the pitch matrix to chemical vapor deposition to form a carbon-carbon composite preform (15).
Abstract:
The present invention makes use of loose fibrous material (for instance, chopped fibers) as reinforcement matrix material in the manufacture of carbon-carbon composites. In accordance with this invention, a constraint fixture is provided which can be separated from the mold. The constraint fixture has an internal shape corresponding to the shape of a desired preform component, with the internal shape being defined by a bottom plate (2), an annular ejector plate (3, 3'), a inner wall (10), an outer wall (4), and an annular top plate (11, 11'). The constraint fixture is normally made of metal, porous ceramic, or carbon material. The constraint fixture of the mold holds the loose matrix materials (fibers, along with any fillers and/or additives). The mold assembly itself is segmented, so that the constraint- fixture and the loose fill materials in the fixture can be removed and subjected to further processing as a unit. Such further processing may include Chemical Vapor Deposition or resin or pitch infiltration or Resin Transfer Molding. The preform matrix may remain in the constraint fixture through such processing steps as densification and until it is removed therefrom for final machining.
Abstract:
The present invention makes use of loose fibrous material (for instance, chopped fibers) as reinforcement matrix material in the manufacture of carbon-carbon composites. In accordance with this invention, a constraint fixture is provided which can be separated from the mold. The constraint fixture has an internal shape corresponding to the shape of a desired preform component, with the internal shape being defined by a bottom plate (2), an annular ejector plate (3, 3'), a inner wall (10), an outer wall (4), and an annular top plate (11, 11'). The constraint fixture is normally made of metal, porous ceramic, or carbon material. The constraint fixture of the mold holds the loose matrix materials (fibers, along with any fillers and/or additives). The mold assembly itself is segmented, so that the constraint- fixture and the loose fill materials in the fixture can be removed and subjected to further processing as a unit. Such further processing may include Chemical Vapor Deposition or resin or pitch infiltration or Resin Transfer Molding. The preform matrix may remain in the constraint fixture through such processing steps as densification and until it is removed therefrom for final machining.