TPT September 2007

D esign, P roduction & M anagement S oftware

for rollforming) is a software module for this purpose, which has been continually developed for twelve years via extensive research and user feedback. industrial application and research at various institutes has shown that there is no formula or guideline that provides an ‘optimum roll tool layout’. The only way to optimize a roll tool set is to tailor it to a specific application (depending on parameters like material properties, tube mill restrictions and material quality). However, there is a way to get to an optimum in roll tool engineering: by means of verification of Experience gained from

Essential rollforming software for auto parts production

Given the variety of their applications, open or closed roll formed sections have taken on increasing importance in recent years, finding their ways into new sectors like the automobile industry. The reasons for this include the introduction of new materials and improved possibilities for designing roll tools. Advantages that go along with the overall process are the large choice of cross- sections and the work hardening of the material. This results from the forming operation, which can be utilised in many cases by applying the right design skills. For this reason, optimum tube and profile quality requires optimum roll tool engineering. The development of a new set of rollforming tools and the subsequent production of a proper metal tube might

seem without serious considerations. Nevertheless there can be problematic hurdles such as down times of the rollforming line during installation, startup and try-outs of tool sets. Internal strain and work hardening in the rollformed material might cause deformation of the end-product.

Due to these difficulties rollforming or manufacturing welded tubes used to be treated as a black art. A software program for

rollforming supports the steps in the development of open or closed profile cross-sections. These steps include the design of the final cross-section to be produced, through definition of the various shaping steps (passes or flower) to generation of technical

the production process by non-linear, elasto plastic finite element simulation.

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In the past, the only way to create a properly functioning roll set was through practical trials on

› Copra RF eases the design process and simulates the rollforming process using a non-linear elasto plastic solver

documentation (ie production drawings, parts lists, CNC programs).

In addition to verification of how a roll tool set will perform, this method also provides decisive information on what is actually happening with strip material during the forming process. It also shows how the properties of a tube or profile may change. Although this may sound sophisticated, the user is not required to closely manage the definition of the finite element computing model, selection of suitable element types or definition of boundary conditions. Fully integrated into the software process chain, these factors are considered automatically by the software. Both the finished tube or profile design and the individual shaping steps are presented in 3D, colour images. The user can utilize

the machine. Today there is an alternative...

In the past, the only way to create a properly functioning roll set was using practical trials on the machine. Today there is an alternative with simulation via finite element analysis (FEA), which

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fi Finite element simulation by Copra FEA RF. Strip edge waviness due to residual stress after first breakdown pass (below); strip edge buckling after fin passes in practice (below right)

speeds up this t ime - consumi ng and costly set- up process, and avoids any reworking of the tools altogether. Launched a few years ago, Copra ® FEA RF (finite element analysis

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S eptember /O ctober 2007