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The portfolio of the company EMK-Allstedt Email-, Metall- und Kunststoffverarbeitung GmbH features a high variety of variants. The fully automatic production cell Flexistar made by weil technology guarantees the required high flexibility for rollforming and welding of tubes made of thin metal sheets.  This property, its high performance, and the high quality of the welded parts resulted in an increased efficiency of production at EMK Allstedt. 

„At the first sight, I have seen: This is exactly the machine we need," says Steffen Lüttig.  At the end of 2008, the managing partner of the EMK Allstedt Email-, Metall- und Kunststoffverarbeitung GmbH visited the industrial trade fair Euroblech and for his company, he looked for a highly flexible solution for sheet metal working. He found what he wanted at the exhibition stand of the weil engineering GmbH.

weil engineering from Müllheim (Baden-Wuerttemberg), a provider of semi- and fully automatic system solutions for rollforming, welding and handling technologies, presented the flexible production cell Flexistar as innovation at the trade fair. Flexistar can be used for the fully automatic production of thin-walled tubes with diameters of 60 to 150 mm or 80 to 400 mm, with material thicknesses between 0.2 and 0.8 mm or 0.4 and 1.0 mm and tube lengths of 300 to 2,200 mm or 120 to 1,250 mm without loss of cycle time.  The special advantage of the machine is it that it is operated without any change-over parts.  That means, tool changes, changing over or mechanical adjustment are not required.

Prize-winning Technology

The core of the machine line is the automatic diameter adaptation unit for rounding and welding processes. Outside arranged movable clamping bars provide for the continuous passage of the tube to be formed below a welding source. This allows fully-automatic production reaching from the metal sheet to the welded tube.  The tubes can directly be further processed. For this development, weil engineering has been awarded the MM-Blechnet-Award 2008 in the category Joining and Mounting Technology.

weil engineering could not fulfil Steffen Lüttig's desire immediately and sell him the exhibited machine. Mid 2009, nearly half a year later, however, a Flexistar system was commissioned at EMK-Allstedt. Beside enamelling and powder coating, the processing of light gauge sheet metal is the core competency of the company located in Allstedt in Saxony-Anhalt. The processed materials include: black sheet, stainless steel, aluminium, copper, hot-dip galvanized steel sheet and FAL. These products are used in the field of air-conditioning, chimney construction, exhaust gas and fire protection as well as in drinking water and fire distinguishing systems.

Flexible production of 180 different parts

On the Flexistar type 400/1250, EMK-Allstedt welds short tubes of light-gauge sheet metal with thicknesses between 0.4 mm and 1.0 mm, diameters of 80 mm to 400 mm and lengths of 250 mm to 1,250 mm. Steel sheets, stainless steel, as well as galvanized and hot-dip aluminized metal sheets are used as materials. All in all, about 180 different parts are produced on this machine. 

weil engineering delivered a destacking unit, an automatic feed table, the fully automatic rollforming and welding cell Flexistar, a storage table as well as safety devices. A CO2-laser TruCoax made by Trumpf served as welding source. 

After welding tests using a laser of a higher power, finally, the company decided to buy a device with a power of 1,000 W. The tests had shown that it was also possible to weld and cut thicker materials without problems. Furthermore, the high quality of the welding seams spoke in the favour of the Trumpf laser, even though the cut edges of the plates were a bit rougher.  Lüttig: „The welded seams of the CO2-lasers are of better quality than the TIG- or plasma welded seams. Additionally, it can be better adjusted in case of material deviations“.

The pre-cut plates are placed on the destacking unit in pallets of 600 parts. Generally, Flexistar provides the possibility to destack different plate sizes.  Until now, EMK-Allstedt has not used this advantage. The sheet blanks are individually unloaded from the pallet stack, guided to the rollforming cell, are automatically rounded and finally, laser-welded in the welding cell.  Rollforming and welding can be carried out in parallel. 

As cycle time, weil engineering specifies 20 seconds for the Flexistar. Practice in Allstedt evidenced that the production cell was able to work faster. „We could several times beat the piece numbers, quoted by the manufacturer as possible, “emphasises Steffen Lüttig.

Up to six times faster than welding benches

He says that he appreciates the Flexistar because of its wide range of performances and its high flexibility for lengths and diameters. The last becomes especially important for customers with partially very short delivery times of 48 hours from receiving the order to delivery.  „We do not have to change tools, but only to call the belonging program. “

Compared to welding benches where the tubes were welded before, there is the additional advantage of quickness. Some parts are completed on the Flexistar six times faster than on a welding bench.  "In each case, the efficiency of the production has been increased. weil engineering has built something great," explains the managing director. 

He still mentions another advantage of the production cell, i.e. the gain in safety for the operator.  „A risk of bruising, as it exists for manual loading of sheet blanks into the rollforming machine, is completely excluded for the Flexistar. “

Fully automatic process chain as objective

From the beginning, the Flexistar met all demands and requirements specified by Steffen Lüttig. Since it has been commissioned, the machine works without failures and with the desired quality.

For Lüttig, however, the integration of the Flexistar is just the beginning. In June 2010, a laser tube cutting machine RSM 600/1250 made by weil engineering was put into operation in Allstedt which follows the Flexistar in the process.  Currently, individual products are further processed on the RSM 600/1250.

„We have acquired new products, especially in the field of fire protection and we want to see how their piece numbers develop.  In the way the two machines from weil engineering are designed, we will be able to connect them at any time and to fully automate the process," explains the general manager of EMK-Allstedt.

Company profile: EMK-Allstedt

As traditional enterprise founded in 1896, the company has been managed by Steffen Lüttig with the name EMK-Allstedt since 1995. The company has about 105 employees and 8 trainees and is specialized in metal processing, surface coating and chimney systems made of stainless steel. EMK-Allstedt works for leading boiler and fitting manufacturers and companies in the chemical, food, and automotive industry and as own brand, it delivers its products to about 1,000 building markets in Germany. From the sheet blank to the forming, the welding process and the completion and compiling of the packages, EMK-Allstedt provides everything from one source.