Charged with new possibilities
Bechtold relies on Schröder-Fasti slip bending roll
Customer
If an enquiry is interesting enough, it may be worth purchasing a machine specifically for that order. This is what happened at Günter Bechtold GmbH in Weilheim i. Ob. With the 134 slip bending machine from Schröder-Fasti, the company is now a supplier for a charging station manufacturer.
There is a difference between being able to manufacture something in principle and being able to produce it in series. But before this can be decided, there must first be interest from a potential customer—and this arose in connection with the topic of charging stations via a customer of Günter Bechtold GmbH, who in turn supplies the electronic components for a southern German manufacturer of e-mobility charging stations. Thanks to this referral, Bechtold received an enquiry asking whether the company was able to supply curved stations with eight different, varying radii.
Günter Bechtold GmbH specializes in sheet metal processing and carries out tasks ranging from simple laser cutting to highly complex sheet metal parts for partners in industry and trade. With its “hot table,” the company also offers its own innovative product range: tables with integrated cooking and grilling facilities. When folding steel, stainless steel, and aluminum, the Bechtold team works with bending presses with up to 230 tons of pressing force. Masterful control of these machines also includes polygon folding: curves can be created through many small folding steps, and a pattern for the charging station was produced using this process.
“Step-by-step slip bending is obviously too slow for series production, but I knew who to turn to: the Schröder Group,” reports Florian Krichenbauer, operations manager at Günter Bechtold GmbH, who is personally acquainted with Thomas Ostermair, sales manager at Hans Schröder Maschinenbau GmbH in Wessobrunn-Forst, 16 kilometers away. While the main focus there is on manufacturing folding machines and sheet metal shears, the subsidiary Schröder-Fasti is known for its high-precision slip bending rollls, among other things. Contact was quickly established and Bechtold sent sample sheets and the requirements to Schröder-Fasti in Wermelskirchen, North Rhine-Westphalia. The folding results were impressive, and Bechtold decided on the spot to purchase the exhibition machine on which the charging station samples had been bent.
Asymmetrical slip bending roll
The Schröder-Fasti 134 is an asymmetrical slip bending roll. Thanks to its design, which differs from most standard machines on the market, it can be used to bend from the rear and finish from the front. Unlike symmetrical slip bending rolls, this leaves no straight section behind. The machine has a change gear for different rolls, which are characterized by their unique roundness. This parabolic geometry, which corresponds to the cambering on a folding machine, is a unique feature of Fasti machines. It ensures precisely fitting ends so that tubes can be welded perfectly. The positioning accuracy of the machine is one tenth of a millimeter. Its extremely stable construction with cast iron side plates and high-quality drives gives the machine the power reserves that allow continuous operation at the limits of the specifications – something that also benefits Bechtold.
Framework agreement for 2,000 charging stations
Bechtold impressed the client and was awarded a framework contract for 1,000 charging stations. This was followed by a second order for another larger model, also for 1,000 units, which will be delivered gradually. Since summer 2024, around 400 of the complex folding jobs have already been completed. Bechtold is also responsible for powder coating, cutouts, doors, and sealing the housings.
“It’s fascinating to see how precisely the Schröder-Fasti slip bending roll works and how the radii merge perfectly into one another,” says Krichenbauer. “I can only praise Schröder employee Ralf Oberberg. He perfected the control system for folding the charging stations and also trained us at the same time.” The settings for the folding program are determined empirically, and the program then behaves like a curve control system.
For both types of charging stations, 1.25 mm thick V2A steel sheets (1.4301) measuring 1400 x 400 mm and 1700 x 450 mm are used. “We are pushing our parameters to the limits of what is possible,” admits Krichenbauer. This requires a step that would not otherwise be necessary: the sheet metal is passed through the machine twice. The reason for this is that the springback properties of the stainless steel sheet and the very tight minimum radius of the workpiece (73 mm) mean that repeating the folding program improves dimensional accuracy.
“The Schröder-Fasti 134 slip bending roll has enabled us to get involved in two major charging station projects. The precision with which we can now bend is impressive, and I am excited to see what other orders we can win with this new production capacity,” says Florian Krichenbauer.
Machine in operation
Slip bending roll type 134
- Size 15/2
- 1540 mm working length
- Sheet thickness at 400 N/mm²: 2.0 mm
- Roll diameter: 100 mm
- Motor power: 1,1 kW
- Colour: RAL 7035 light grey/RAL 5003 sapphire blue
