| 摘要 |
PURPOSE:To improve flatness remarkably by forming projections partially projecting from surrounding blank surface and adjusting the height of projections by reducing the thickness of plate thickness of projections by compression, and thereby limiting the area of flatness correction to a narrow part. CONSTITUTION:A part of thin blank 2 is half blanked and >=2 projections 5 are formed. The thickness of projections 5 is adjusted using two punches 6, 7, and the height of projections 5 is made uniform to obtain flatness. Flatness is improved by this method as adjustment of the height of local projections 5 can be made according to the amount of warping by compression without restraining the wraping of the thin blank 2. The flatness is improved remarkably from 0.1mm. which is the limit of flatness of conventional press formed product to 0.02mm.. |
