2009 SIMULIA Customer Conference 1 Aluminum Bottle Forming Simulation with Abaqus Kunming Mao DASSAULT SYSTEMES SIMULIA CORP., Central Region, West Lafayette, IN, 47906, USA Alejandro Santamaria The CocaCola Company, One CocaCola Plaza, Atlanta, GA, 30313, USA Abstract: This paper presents several modeling techniques for simulating and optimizing aluminum bottle forming using Abaqus/Explicit. Designing and tuning sheetmetal forming tools for aluminum bottles are quite complicated and time consuming tasks. These tasks must take into consideration a number of potential issues, such as the success rate of forming, bottle shape smoothness, bottle load capacity, sheetmetal overthinning, and metal wrinkl ing. To shorten the design cycle and reduce the number of forming tool prototypes for the Coke Contour aluminum bottle, simulations wi th Abaqus served as virtual test grounds to provide valuable insight into the bottle’s complex forming processes. Because of large deformation and contact interactions, Abaqus nonlinear capabilities were well suited for these tasks. This paper demonstrates Abaqus forming applications that helped resolve issues arising from realistic industrial forming design and production processes. Three bottleforming simulations used to predict sheetmetal forming instability, metal overthinning, and metal wrinkling are used to illustrate the effectiveness of numerical simulations. Keywords: Coke bottle, sheet metal forming, forming instability, FLSD, FLD, MSFLD, surface smoothness, load capacity, die, closure system, thread forming, reverse draw f orming 1. Introduction A few years ago, The CocaCola Company (Coke) decided to revolutionize the beverage industry by developing a lightweight resealable aluminum bott le that would use the current aluminum can making process as its base platform. The making of this bottle involved a number of forming stages, including cupping, cylinder drawing and ironing, die forming, and topfinish forming (threading and curling). Developing the related tools was complicated and time consuming, due to the extensive list of package performan ce requirements, the manufacturing process robustness, cost optimization, and other factor s. Numerical simulations using Abaqus provided strong virtual test grounds for investigating these issues, validating design ideas, and seeking new optimized solutions. This paper presents several simulation techniques using Abaqus to model three aluminumbottle forming processes: · The cupping forming process that turns a flat sheet of aluminum blank in to a cup shape2 2009 SIMULIA Customer Conference · The die necking and expansion pr ocesses that transforms a cylinder into th e iconic Coke Contour shape · The topfinish forming process Although not presented here in detail, numerical simulations have also been used to investigate a number of other design and optimization issues, such as sheetmetal selection, bottlefor ming visual sur face discontinuities, formed bottle toploading capacity, sheetmetal thickness optimization, and topfinish formation speed optimization. These simulations have pr ovided information that is not easily or economically achieved in a physical test lab. They ha ve also proven to be powerful complements to the physical lab tests. The first step of the bottlemaking process is cupping, where a blank cut from a rolledflat aluminum sheet is drawn into a cup. The cup for aluminum bottles is dimensionally uni que and requires an additional forming step not typically used when making cups for regular cans. Metal wrinkling and overthinning were two undesirable phenomena experienced dur ing the initial prototyping of the Contour bottle. Abaqus/Explicit simulation was able to mimic the wrinkling observed in the real world, allowing the design team to identify key setup parameters and tooling design changes to prevent wrinkling and overthinning. Die necking is a wellknown technique used to reduce the dia meter of aluminum cylinders at high speeds, but its application has been limited to the top 10 centimeters of the metal cylinder being shaped due to physical limitations of commercially available machines. Coke, in partnership with its suppliers, worked to bring longer stroke dieneckin g machines from other industries to the beverage landscape and br oke the 10 centimeter threshold, creating the opportunity to produce previously una ttainable metal packaging shapes. The resulting forming process all owed Coke to produce the iconic Contour shape with one of the most vastly used packaging materials: aluminum. Abaqus sheetmetal form ing instability prediction capability (SIMULIA, June 2008) provided extremely valuable insights after an unacceptable rate of sheetmetal fractures was observed during the bottle’s initial prototyping process. Simulations were used to optimize tooling geom etries and forming steps as well as to compare material selections in order to improve forming success rates. Because of the relatively large amount of metal displacement required to achieve the shape of the bottle’s upper portion, the top dienecking process can cause some small visible surface discontinuities, referred to as witness rings, which were categorized as unaccept able by Coke’s marketing team. The simulations were effective for optimizin g the dienecking tool profiles to alleviate the witness rings. The bottle’s column load resistance, or toploading capacity, was another concern during the bottleshape design. Simulations were also used to predict the toploading capacity of the formed bottle, which led to selection of the initial sheetmetal thickness during the design stage. This ensured that the final bottle had enough strength to withstand the required capping axial loads without overusing material.2009 SIMULIA Customer Conference 3 During the bottle’s topfinish formin g process, metal overthinning was observed in physical tests. Simulations of the topfinish forming pr ocess reproduced the overthinning phenomenon and provided a means to evaluate and optimize th e tooling parameters required to prevent this defect. The following sections describe how Abaqus/Explicit simulations were applied to aluminum bottleform ing processes. These simulations focus on sheetm eta l forming in stability prediction during the bottle necking and expansion, sheetmetal