The hard metal tamer
BleSta GmbH, specializes in the production of industrial sieves and screens as tailor-made components of recycling plants. To cope with the input materials, some of which are highly abrasive, BleSta uses wear-resistant steels such as Hardox and CREUSABRO and bends them into shape using an EHT VarioPress with a press force of 1,000 tons.
Started by three founding partners, BleSta now employs 20 people. As well as performing job work for customers from the region around its headquarters in Eisenhüttenstadt, the company still focuses primarily on producing industrial sieves
and screens, both as an OEM for plant manufacturers and as a spare parts supplier.
Industrial screens essentially do the same job as a regular household sieve, holding back the chopped-up input material until the grains are the right size to fall through the screen mesh. The screen baskets are fitted inside drums which rotate at speeds between 80 and 300 revolutions per minute. Almost every plant operator has their own specific requirements when it comes to grain size and screen basket wear resistance — and much of this comes down to whether the plant processes metals or plastics. “That’s why every screen we produce is a tailor-made, one-off product,” says Dreger. Whatever their mesh size, and regardless of whether they are destined for a small plant or a large shredder, all the company’s screens are custom-made to each customer’s individual specifications. First, the metal is cut and rolled, and then it’s fine-tuned using the press brake.
You need an instinctive grasp of how to deal with stubborn hard metals.
Industrial screens typically weigh between two and 800 kilograms, though the current record-holder at BleSta is a screen head which weighed in at a healthy two tons. Up until 2014, BleSta limited itself to sheet thicknesses of up to 25 millimeters, but Dreger spotted a trend toward even thicker material: “We wanted to be able to process 40 millimeter-thick sheets ourselves anyhow, so we started looking for a suitable press brake.”Their criteria included plenty of power with enough pressure to exert 1,000 tons on the ram, as well as top-notch reliability — and the VarioPress from TRUMPF came out on top. “As well as the machine’s performance, we were also impressed by the professional advice and support we received from our contact at EHT. And it’s great that the company is now part of TRUMPF,” says Dreger.
The VarioPress has been up and running in an annex to BleSta’s main production hall since May 2015. Explaining why he is so pleased with the purchase, Dreger highlights features such as the perfect combination of a VarioV tool system and the point-based crowning system (load: 1,000 tons per meter) and the user-friendly touchscreen. Nevertheless, he argues, you still can’t do without highly qualified staff: “Every piece of sheet metal has its own unique character, even when you’re dealing with two pieces from the same batch — and that’s especially true when it comes to wear-resistant materials such as Hardox.” These hardy special steels have an enormous springback moment, which the machine operator should be able to anticipate based on their experience. Knowing how to handle each individual workpiece requires an instinctive grasp of the materials involved, says Dreger. “Our selling point is that we are specialists who work with screens on a daily basis. Competitors who only do it occasionally are constantly learning the hard way and failing to clear the quality hurdles.” At the end of the day, industrial screens and sieves require just as much precision as many other machine components.
Contact us: MastersofSheetMetal@trumpf.com
This article was first published in spring 2016.