Ready for patent No more bottom cracks in sheet metal parts with ultrasonic deep drawing

Vibrodraw has been developed at Fraunhofer-IWU. This process reduces scrap in deep drawing of sheet metal components.

In many household appliances, in building technology, and in countless pipe and hydraulic lines, there are small, cylindrical sheet metal parts manufactured through deep drawing, according to researchers from the Fraunhofer Institute for Machine Tools and Forming Technology (IWU).

Deep drawing of sheet metal is a long-established forming process, but it puts a significant strain on the material. The consequences are excessive thinning of the material thickness and surface damage. In the worst-case scenario, the sheet metal surface tears at the most stressed area. However, supportive ultrasonic vibrations can combat the problem, say the IWU experts.

Deep draw sheet metal with significantly less friction

That ultrasound can reduce friction when deep drawing and thus protect both tools and material has been known for some time. Manufacturers of pipes and fittings (connecting material) would also like to take advantage of the energy-saving potential resulting from the lower forces. However, in the Vibrodraw process, Fraunhofer-IWU, together with Mark Metallwarenfabrik GmbH and Devad GmbH, has now succeeded in effectively coupling ultrasonic vibrations into industrially relevant deep-drawing processes with cycle rates of up to 500 strokes per minute, as the participants emphasize. For vibration excitation, the active tool parts such as punch and die as well as the blank holder, which holds the sheet metal in the desired position during forming, are possible options, as it is further stated. The researchers have explicitly chosen the die for this. Because it bears the largest share of the relative movement during forming. About 20 percent friction reduction has already been achieved. However, there is still room for improvement. The forming usually occurs in a sequence of several stages, regulated by the process force transferable from the workpiece, explain the researchers from Dresden.

Two forming stages saved in deep drawing

With reduced friction, significantly deeper drawing can be achieved in a single stage without damaging the material. For example, two conventional forming steps were sufficient instead of three. Less friction also means less heat input into the sheet metal part, allowing for higher stroke rates. Additionally, the service life of the tools is extended, and the so-called coking of the lubricants used due to too much heat during forming is a thing of the past. (In the image, you can see the production of a cup-shaped part about five centimeters high once with Vibrodraw (right) and once without).

Now they want to deep draw cell housings for batteries in this way

For a rapid transfer into business practice, the IWU is now further advancing its activities regarding ultrasound plus deep drawing. The current focus is on the ultrasonic deep drawing of cell housings needed in high-voltage storage units of battery-electric vehicles, as reported. Larger cell formats are targeted, which make better use of space and, due to increased energy density, ensure higher ranges for e-mobiles. The patent application for Vibrodraw (EPA WO2025/012830 A1) has already been filed.

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