A numerical and experimental approach to optimise sheet stamping technologies: Part I: mild steel press-forming

The development of press-formed sheetmetal components often implies long trial-and-error processes for die set-up. This leads to excessive costs in the case of low production rates (aerospace field) and protracted development phases when tight times-to-market are compulsory (automotive and appliances fields). This paper presents a numerical procedure, validated by experimental tests, devoted to optimising the stamping processes and aimed at avoiding/correcting the drawbacks due to spring-back and warpage. To this purpose, the press-forming of a mild steel microwave door frame is considered; the effects inducing residual stresses, spring-back and warpage are preliminarily analysed by means of a finite difference explicit dynamic code simulation. Then, producing the real component and comparing its features to the numerical predictions validates the procedure effectiveness. Finally, the proper corrective actions to overcome the drawbacks are pointed out.