# US 10,307,974 B2 · Method and apparatus for reducing ply wrinkling of composite laminates during forming > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,307,974 B2 - Document ID: US10307974B2 - Status: Granted - Kind: B2 - Application number: 15/373,347 - Filed: 2016-12-08 - Published: 2017-03-30 - Granted: 2019-06-04 - Earliest claimed: 2013-03-19 - Assignees: The Boeing Company - Applicants: The Boeing Company - Inventors: William Thomas Kline; Christopher Gary Harris - Web page: https://patentgrep.com/patent/US10307974B2 ## CPC - B29C 70/56: Tensioning reinforcements before or during shaping - B29C 43/32: Component parts, details or accessories; Auxiliary operations - B29C 70/342: {using isostatic pressure} - B29C 70/44: using isostatic pressure, e.g. pressure difference-moulding, vacuum bag-moulding, autoclave-moulding or expanding rubber-moulding - B29C 70/541: {Positioning reinforcements in a mould, e.g. using clamping means for the reinforcement (positioning inserts in moulds B29C33/12; lay-up on a mould B29C70/30)} - B29K 2307/04: Carbon - B29K 2309/08: Glass - B29L 2009/00: Layered products - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES ## Abstract Ply wrinkling during hot drape forming of a composite laminate is reduced at corner radii. A tensioning material placed over an uncured composite laminate charge maintains a compressive force on the laminate charge as the charge is formed over a tool. ## Claims ### Claim 1 Apparatus for hot drape forming a composite laminate part, comprising: a tool over which a composite laminate charge may be formed, the tool including at least one corner feature for forming a radius on the part; a forming membrane adapted to form the laminate charge over the tool; and tensioning material between the tool and the laminate charge for applying a compressive force on the laminate charge at the corner feature to reduce wrinkling of the laminate charge at the radius during the forming; wherein the tensioning material has a tensile strength allowing the tensioning material to tear as the laminate charge is being formed over the tool, wherein the tensioning material includes a sheet having surface tack adherence to the laminate charge. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein: the tensioning material includes at least one sheet disposed in face-to-face contact with the laminate charge and having an outer periphery extending beyond outer edges of the laminate charge. ### Claim 3 (depends on 2) The apparatus of claim 2, further comprising: weights distributed around and loaded onto the outer periphery of the sheet for retaining the sheet around the outer periphery thereof. ### Claim 4 (depends on 2) The apparatus of claim 2, wherein at least the one sheet is disposed in face-to-face contact with an entire area of the laminate charge. ### Claim 5 (depends on 3) The apparatus of claim 3, wherein the weights are distributed about an entire periphery of the composite laminate charge. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the tensioning material comprises a stretchable material. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the tensioning material is removable from the laminate charge before and after the laminate charge is formed into the composite laminate part. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the tensioning material comprises a resin impregnated cloth. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the at least one corner feature of the tool comprises a 90-degree corner. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein: the tensioning material is a first material; the composite laminate charge is made of a second material; and the first material is different than the second material. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein: the forming membrane is made of a third material; and the third material is different than the first material and the second material. ### Claim 12 Apparatus for hot drape forming a composite laminate part, comprising: a tool over which a composite laminate charge may be formed, the tool including at least one corner feature for forming a radius on the part; a forming membrane adapted to form the laminate charge over the tool; tensioning material between the tool and the laminate charge for applying a compressive force on the laminate charge at the corner feature to reduce wrinkling of the laminate charge at the radius during the forming; a forming table for supporting the forming membrane, the composite laminate charge, and the tensioning material between the forming table and the tool; and a heating element integrated into the forming table and operable to heat the laminate charge. ### Claim 13 (depends on 12) The apparatus of claim 12, further comprising a first membrane sealed to the forming table to form a vacuum tight cavity between the first membrane and the forming membrane. ### Claim 14 (depends on 13) The apparatus of claim 13, further comprising a vacuum within the vacuum tight cavity, wherein the vacuum is configured to draw the first membrane down against the tool and to draw the tensioning material up against the tool. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein the vacuum is configured to place the tensioning material in tension and cause the tensioning material to compress the composite laminate charge against the forming membrane. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein: a portion of the composite laminate charge forms a flange of the composite laminate part; and the tensioning material compresses the portion of the composite laminate charge that forms the flange of the composite laminate part against the forming membrane. ### Claim 17 Apparatus for hot drape forming a composite laminate part, comprising: a tool over which a composite laminate charge may be formed, the tool including at least one corner feature for forming a radius on the part; a forming membrane adapted to form the laminate charge over the tool; and tensioning material between the tool and the laminate charge for applying a compressive force on the laminate charge at the corner feature to reduce wrinkling of the laminate charge at the radius during the forming, wherein: the tensioning material comprises a plurality of sheets positioned adjacent each other along the composite laminate charge; each sheet of the plurality of sheets has a tensile strength allowing the sheet to tear as the laminate charge is being formed over the tool; and each sheet of the plurality of sheets has surface tack adherence to the laminate charge; and weights distributed around and loaded onto an outer periphery of the plurality of sheets for retaining the plurality of sheets around the outer periphery. ### Claim 18 (depends on 17) The apparatus of claim 17, wherein the plurality of sheets abut each other in an end-to-end manner. ### Claim 19 (depends on 17) The apparatus of claim 17, wherein the plurality of sheets overlap each other.