| 摘要 |
A method for sharp, crisp hemming inner and outer aluminum sheet metal panels in which a flange is formed along an outer edge so that the flange extends from a bend line and lies in a plane generally perpendicular to the plane of the outer panel. This bend line, furthermore, has an outer radius in the range of (1.0 mm+t)>R>(0.2 mm+t) where t=the thickness of the outer panel. The inner panel is then positioned on the outer panel so that an outer edge of the inner panel is adjacent the bend line. The flange is then bent so that the flange overlies the outer edge of the inner panel while simultaneously compressing the flange in the direction towards the bend line. Thereafter, the flange is compressed against the outer peripheral portion of the inner panel thus completing the hem. The present invention thus achieves a sharp radius bend on the outer edge of the panel with a layer radius bend on the inner panel as well as a class "A" surface on the outer panel adjacent the hem which is free of recoil or other distortion. |
