What is the first step in the bumping operation when forming a streamline cover plate?

In the bumping operation for forming a streamline cover plate, the first step involves tapping the edges lightly. This technique is essential because it gradually shapes and stretches the metal, allowing for a more controlled and smooth transition into the desired form. Tapping the edges helps to avoid overstressing the material, which can cause unwanted warping or cracking.

This method also ensures that the metal is evenly worked and reduces the risk of creating localized stress points that could compromise the integrity of the plate. By starting at the edges, the operator can effectively manage how the metal flows and forms around the contours, leading to a better overall finish.

The process of bumping is delicate and requires a careful approach to ensure the aluminum retains its properties and structure throughout the forming process. Thus, beginning with light taps at the edges sets a foundation for successful shaping.