# US 2022/0080680 A1 · Tool and Method for Forming Contoured Composite Stringers Having Reduced Wrinkling > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0080680 A1 - Document ID: US20220080680A1 - Status: Published application - Kind: A1 - Application number: 17/447,591 - Filed: 2021-09-14 - Published: 2022-03-17 - Earliest claimed: 2020-09-17 - Assignees: The Boeing Company - Applicants: The Boeing Company - Inventors: Steven Joseph Plummer; Kurtis Shuldberg Willden; Andrew Elmer Modin; Paul Chace Wilcoxson - Web page: https://patentgrep.com/patent/US20220080680A1 ## CPC - B29C 70/342: {using isostatic pressure} - B29C 70/462: {Moulding structures having an axis of symmetry or at least one channel, e.g. tubular structures, frames} - B29C 33/202: {Clamping means operating on closed or nearly closed mould parts, the clamping means being independently movable of the opening or closing means (clamping devices for injection moulding machines B29C45/64)} - B29C 33/505: {cores or mandrels, e.g. inflatable (B29C33/0016 takes precedence; for winding and joining B29C53/824; for supporting articles during joining B29C66/634; flexible cores for vulcanizing tyres B29D30/0654)} - B29C 70/446: {Moulding structures having an axis of symmetry or at least one channel, e.g. tubular structures, frames} - B29C 70/549: {Details of caul plates, e.g. materials or shape} - B29D 99/0003: {Producing profiled members, e.g. beams} - B64C 1/064: {Stringers; Longerons} - B29C 2033/205: {mould clamping by membranes, e.g. inflatable membranes or cushions} - B64C 2001/0072: {from composite materials} - Y02T 50/40: Weight reduction - 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) - B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00) - B64C: AEROPLANES; HELICOPTERS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A tool for making contoured composite hat stringers allows control of stringer wrinkling. The tool includes a set of first openings that allow the tool to flex during contouring of the stringer, and a set of second openings into which portions of the composite charge may strain during the contouring. ## Claims ### Claim 1 A tool for forming a composite charge into contoured composite stringer, comprising: a tool body, the tool body being flexible and having a length, the tool body having a set of transversely extending first openings therein configured to allow the tool body to flex during forming of the composite charge, the tool body having a set of transversely extending second openings therein into which portions of the composite charge may strain during the forming. ### Claim 2 (depends on 1) The tool of claim 1, wherein: the first openings are configured to at least partially close during forming of the composite charge, and the second openings are configured to remain substantially open during forming of the composite charge. ### Claim 3 (depends on 1) The tool of claim 1, wherein the tool body has a cross-sectional shape substantially matching a cross-sectional shape of the composite stringer. ### Claim 4 (depends on 3) The tool of claim 3, wherein: the first openings each extend entirely across the cross-sectional shape of the tool body, and the second openings extend only partially across the cross-sectional shape of the tool body. ### Claim 5 (depends on 1) The tool of claim 1, wherein the first openings and second openings are alternately arranged along the length of the tool body. ### Claim 6 (depends on 1) The tool of claim 1, wherein the tool body is a compactor configured to compact the composite charge against a contoured die surface. ### Claim 7 (depends on 1) The tool of claim 1, wherein: the tool body is a punch configured to form the composite charge into a die cavity, and each of the first and second openings is a slot in the punch. ### Claim 8 (depends on 1) The tool of claim 1 wherein each of the second openings is a groove in a surface of the tool body. ### Claim 9 (depends on 1) The tool of claim 1, wherein each of the second openings has a width configured to allow formation therein of a wrinkle in the composite charge during the forming. ### Claim 10 A tool for forming a composite charge into a contoured stringer having a desired cross sectional shape, comprising: a punch configured to form the composite charge into a formed stringer having the desired cross sectional shape, and to contour the formed stringer along a length of the formed stringer, the punch having openings therein into which the composite charge may strain as the formed stringer is being contoured along its length. ### Claim 11 (depends on 10) The tool of claim 10, wherein the punch is formed of a flexible material. ### Claim 12 (depends on 10) The tool of claim 10, wherein: the punch is flexible along a length of the punch and is configured to flex as the formed stringer is being contoured, and the openings include slots in the punch extending transversely through the punch, each of the slots being configured to remain open as the formed stringer is being contoured. ### Claim 13 (depends on 12) The tool of claim 12, wherein the punch includes openings therein that are configured to provide the punch with flexibility and at least partially close when the formed stringer is being contoured. ### Claim 14 (depends on 10) The tool of claim 10, wherein the openings into which the composite charge may strain and the openings providing the punch with flexibility are arranged in alternating relationship to each other along the length of the punch. ### Claim 15 (depends on 10) The tool of claim 10, wherein the openings into which the composite charge may strain are grooves extending partially into a surface of the punch. ### Claim 16 A method of making a contoured composite stringer with reduced wrinkling, comprising: forming a flat composite charge into a stringer having a desired cross sectional shape using a tool; contouring the stringer, including flexing the tool; using a first set of openings in the tool to allow the tool to flex; and using a second set of openings in the tool to relieve stress in the composite charge during the contouring by allowing portions of the composite charge to strain into the second set of openings. ### Claim 17 (depends on 16) The method of claim 16, wherein: forming the flat composite charge is performed using a punch, and using the first set of openings includes allowing the first set of openings to at least partially close during the contouring. ### Claim 18 (depends on 16) The method of claim 16, wherein using the second set of openings in the tool includes holding each of the openings in the second set of openings open during the contouring. ### Claim 19 (depends on 16) The method of claim 16, wherein the contouring is performed using a compactor. ### Claim 20 (depends on 16) The method of claim 16, further comprising: producing a vacuum by drawing air in through at least some of the openings; and drawing the stringer against the tool using the vacuum.