Hydroforming as a workshop-compatible method

To form undercuts in a deep-drawn part is the internal high-pressure forming suitable. In this paper we show how this method, often associated with high levels of investment, can also be performed on a single-action press.

This method was developed by us.

Innenhochdruckumformen von Ziehteilen mit Ausbauchen.
Illustration 1  Drawn parts manufactured with hydroforming: Teapot, coffee pot and deformation element

For generating a pressure inside the drawn material it has to be filled with fluid. Therefore, this method is performed in the flat position.

The hydroforming mold must be divided into two, to ensure demoulding of the undercut. If the drawn material has a flange the sealing of the pressure chamber can take place there. Illustration 2 shows the loading situation at the left and the hydroforming situation at the right. During the forming process, the hydroforming punch penetrates into the cavity and by the internal pressure, the sheet is embossed to the internal shape.

In order to carry this out on a single-action press, a die cushion must be placed between hydroforming die and press.

IHU von Kleinserien
Illustration 2  Method representation, left insertion situation, right forming situation
Illustration 3  Seal variants, left surround bead, right O-ring
Ausbauchen von Ziehteilen
Illustration 4  Insertion situation
Ausbauchen von Ziehteilen
Illustration 5  Drawing part undercut and demolded

This embodiment of the hydroforming is suitable especially for small to medium quantities.