Abstract
Creep-age forming (CAF) is a proven forming technique in the aerospace industry for the production of large integrally stiffened panels. One of the most urgent issues to be addressed in CAF is the development of flexible tooling. Flexible tools already have a long-standing reputation for the economic impact they have brought to the aircraft industry. However, with the rising need to establish comprehensive springback prediction models for CAF, the need for flexible CAF tools is now stronger than ever. In this article, an existing state-of-the-art CAF tool is described followed by the introduction of a novel design concept for flexible tooling. Based on the proposed design method, which utilises mechanical splines and sparsely spaced controlling points, a proof-of-concept prototype is built and characterised using corresponding analytical and finite element models that have been developed. Three parameters that can influence forming surface error: (i) the number of control points, (ii) spaces between control points and (iii) spline thickness are identified and optimised. Finally, an integrated optimisation process for tool offsetting is introduced, and its use is demonstrated. It is confirmed that this design method can be used to make flexible CAF tools with less than ± 1 mm error (defined as vertical difference from prediction) in the forming surface. In addition, this error can eventually be compensated and thus eliminated from CA-formed parts by using the developed optimisation technique. This article provides CAF tool designers confirmed advices for making new flexible CAF tools. Lightweight and flexible CAF tools can now be constructed through the use of mechanical splines and sparse controlling points.
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References
Holman MC (1989) Autoclave age forming large aluminum aircraft panels. J Mech Work Technol 20:477–488
Zhan L, Lin J, Dean TA (2011) A review of the development of creep age forming: experimentation, modelling and applications. Int J Mach Tools Manuf 51(1):1–17
Airbus Press Office (2013) Airbus Aircraft 2013 Average List Prices (mio USD). http://www.airbus.com/presscentre/corporate-information/key-documents/?docID=14849&eID=dam_frontend_push. Accessed 24 March 2014
Levers A (2003) Jumbo processes. IEE Manuf Eng 82(3):42–45
Jeunechamps P-P, Ho KC, Lin J, Ponthot J-P, Dean TA (2006) A closed form technique to predict springback in creep age-forming. Int J Mech Sci 48(6):621–629
Eberl F, Gardiner S, Campanile G, Surdon G, Venmans M, Prangnell P (2008) Ageformable panels for commercial aircraft. Proc Inst Mech Eng Part G J Aerosp Eng 222(6):873–886
Woods QT (1990) Assembly jig and method for making wing panels. PAT US 4,894,903. 23 Jan 1990
Gan W, Wagoner RH (2004) Die design method for sheet springback. Int J Mech Sci 46(7):1097–1113
Pitcher PD, Styles CM (2000) Creep age forming of 2024A, 8090 and 7449 alloys. Mater Sci Forum 331–337:455–460
Ho KC, Lin J, Dean TA (2004) Modelling of springback in creep forming thick aluminum sheets. Int J Plast 20(4–5):733–751
Yang H, Davies CM, Lin J, Dear JP (2013) Prediction and assessment of springback in typical creep age forming tools. Proc Inst Mech Eng Part B J Eng Manuf 227(9):1340–1348
Walczyk DF, Lakshmikanthan J, Kirk DR (1998) Development of a reconfigurable tool for forming aircraft body panels. J Manuf Syst 17(4):287–296
Walczyk DF, Hardt DE (1998) Design and analysis of reconfigurable discrete dies for sheet metal forming. J Manuf Syst 17(6):436–454
Li M, Liu Y, Su S, Li G (1999) Multi-point forming: a flexible manufacturing method for a 3-D surface sheet. J Mater Process Technol 87(1–3):277–280
Liu C, Li M, Fu W (2006) Principles and apparatus of multi-point forming for sheet metal. Int J Adv Manuf Technol 35(11–12):1227–1233
Tan FX, Li MZ, Cai ZY (2007) Research on the process of multi-point forming for the customized titanium alloy cranial prosthesis. J Mater Process Technol 187–188:453–457
Chen J-J, Li M-Z, Liu W, Wang C-T (2004) Sectional multipoint forming technology for large-size sheet metal. Int J Adv Manuf Technol 25(9–10):935–939
Chen J-J, Liu W, Li M-Z, Wang C-T (2005) Digital manufacture of titanium prosthesis for cranioplasty. Int J Adv Manuf Technol 27(11–12):1148–1152
Levers A (2008) Aircraft component manufacturing tool and method. PAT EP 1581357 B1. 26 Mar 2008
Levers A, Wiles G (2011) Assembling and shaping laminate panel. PAT US 2011/0143100 A1. 16 Jun 2011
Inforzato DJ, Costa PR Jr, Fernandez FF (2012) Creep-age forming of AA7475 aluminum panels for aircraft lower wing skin application. Mater Res 15(4):596–602
Lin J, Ho KC, Dean TA (2006) An integrated process for modelling of precipitation hardening and springback in creep age-forming. Int J Mach Tools Manuf 46(11):1266–1270
Zhu A, Starke EA Jr (2001) Materials aspects of age-forming of Al-xCu alloys. J Mater Process Technol 117:354–358
Newkirk TL, Holman MC (1998) Method and apparatus for constructing a complex tool surface for use in an age forming process. PAT US 5,729,462. 17 Mar 1998
Brewer HM Jr, Holman MC (1992) Method of tool development. PAT US 5,168,169. 1 Dec 1992
Bornschlegl H, Kohler W (2001) Process for forming a plate-like component. PAT US 6,264,771. 24 Jul 2001
Airbus Group (2014) Creep forming. Airbus Technology Licensing. http://www.technology-licensing.com/etl/int/en/What-we-offer/Technology-videos.html. Accessed 21 March 2014
Timoshenko SP (1953) History of strength of materials. McGraw-Hill Book Company, Inc., New York
Benham PP, Crawford RJ, Armstrong CG (1996) Mechanics of engineering materials, 2nd edn. Education, Pearson
Macaulay WH (1919) Note on the deflection of beams. Messenger Math 48:129–130
Phillips AL, Johnson WT, Crawford GL, Barnett TD, Scriber LJ, Breidenbach DI (2006) Stringer check fixture and method. PAT US 7103985 B1. 12 Sep 2006
Moler CB (2004) Numerical computing with MATLAB. Society for Industrial and Applied Mathematics
Stephen NG (2007) Macaulay’s method for a Timoshenko beam. Int J Mech Eng Educ 35(4):285–292
Swift KG, Booker JD (2003) Process selection from design to manufacture. 2nd Ed. Butterworth-Heinemann
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Lam, A.C.L., Shi, Z., Lin, J. et al. A method for designing lightweight and flexible creep-age forming tools using mechanical splines and sparse controlling points. Int J Adv Manuf Technol 80, 361–372 (2015). https://doi.org/10.1007/s00170-015-6982-9
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DOI: https://doi.org/10.1007/s00170-015-6982-9