Double Inclined Angle Punch for Trimming of JSC590YN Ultra-High Strength Steel Sheet

One of the post-processing operations in the stamping of car body parts is trimming, where the scrap is removed from the main part. For car body parts made of the ultra-high strength steel (UHSS) sheet, the strength of the sheet is high, thus making the trimming process relatively challenging. When trimming UHSS car parts, the conventional flat-shaped punch simultaneously pushed and indented the steel sheet, resulting in a high trimming load and consequently resulting in a low quality sheared-edge surface. In this study, the trimming punch was designed to have an inclined angle with respect to the trimming direction and lateral surface of the punch. The results for trimming the parts made of JSC590YN grade UHSS having a tensile strength of about 630 MPa show that, by using the double inclined angle trimming punch, the trimming load was reduced up to 60% of that when using the flat trimming punch. Moreover, the quality of the sheared-edge was found to be better with a larger burnished surface, smaller fracture, and lower height of burr.