Blanking Press for EV Motor Laminations Launched

In order to increase the efficiency of electric vehicle (EV) motors, the geometries of motor laminations have become more and more complex, and consequently the dies needed to stamp them are getting longer and longer, says Schuler Group (schulergroup.com) E-Mobility product manager Simon Schmidt. So to address this, the company has developed the Smartline EV 3.8 blanking press.

The EV 3.8 has a slide length of 12.1 feet, up from the 8.8-foot slide on earlier presses in the series; it can process material widths up to two feet (630 mm).

Another change in lamination design is that the materials are becoming thinner. While current customers of Schuler equipment are producing laminations in a range from 0.0098 up to 0.0108 inches (0.25 – 0.275 mm), the EV 3.8 accurately handles material as thin as 0.007 inches (0.2 mm). The penetration depth control can be adjusted in increments of 0.00039 inches (0.01 mm) through the entire stroke range.

Given the considerable length of the slide, “there is deflection we have to consider,” Schmidt says. To compensate, Schuler put a strain gauge into the kiss blocks of the die which enables the press force to be kept constant and the deflection of the slide controlled.

“We can run the full speed of 250 strokes per minute with the full press force of 316.1 ton-force [3,150 kN] and the maximum upper die weight of up to 6.6 tons [6 metric tons],” Schmidt says.

The first Smartline EV 3.8 is slated for delivery to Gebr. Waasner Electrotechnical Fabrik GmbH in Forchheim, Germany.