| Steelmaker Corus has developed a computer aided engineering (CAE) technique to improve the production of complex stamped panels. In-Form is designed to significantly reduce press shop lead-times by reducing the iterative trial and error process used to refine tooling, while improving panel quality.
Still regarded as something of a black art, press shop techniques have been markedly improved by CAE forming simulation, which reduces the number of trial parts required in tooling prove-outs by introducing changes at the design stage rather than after the tools have been made. Some packages, such as Pam-stamp also model die compensation for springback.
However, software is not (at present) able to fully develop the exact tooling form required to produce complex automotive parts such as bodysides. The difficulty in accurately modelling the forming process has been exacerbated by increased use of dual phase and high strength steels, tailored blanks, deeper draws and more complex surface geometry.
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Laser scanner captures component geometry to compare with CAD data |
In-Form uses an advanced laser scanner to capture surface data of the tools and the stampings. This information, together with the original CAD data, is fed back into the forming software to establish where the problem areas are and quantify the changes required to produce the desired part.
In so doing, the number of tooling modifications and subsequent trials can be reduced because design is leading the process. There is also the benefit that the CAD model of the tooling can be updated each time a change.
Corus R&D customer support engineer Hans Brouwer said: “In our experience with press shop support, we see that the tool geometry needs final adjustments before production is OK. The CAD model will not be updated with these adjustments; reasons might be time pressure, or that different departments are involved. This results in a die surface that is different from the CAD drawings with respect to crucial radii or drawbeads for example.
“When Corus is called in, it usually is about complex parts like doors or bodysides. Since we are mostly called in after several trials of the press shops themselves, the tools are likely to be different from original CAD. In-Form helps us produce an up-to-date CAD model of the die set to make a simulation, such as for blank cutout optimisation.”
Brouwer said: “We also use In-Form to scan the part itself. When compared to a CAD file of the jig, we can accurately measure and visualise where the part shows geometry defects due to springback or twist. This helps OEM engineers to understand where changes need to be made so it speeds up the trial process.”
All the In-Form hardware and software is portable, so Corus engineers can work directly with OEMs in their press shops, reducing process times still further.
Brouwer said: “We are the first material supplier to offer this technology which combines accurate measurement of 3D geometry, the latest forming analysis techniques and materials expertise, to deliver significantly reduced lead times during the tool tryout stages.
“Additionally, In-Form allows us to assess the performance of new grades of steel during a current vehicle’s life-cycle, and confidently demonstrate the performance benefits of proposed material changes to our customers without the risk of costly downtime associated with physically proving out new changes to the tool or the material specification.”
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