ISMR June 2022 - Page 36

FOCUS ON WELDING

A FRESH APPROACH

A KUKA robotic cell takes on the welding of large components , such as fan blades , at drying technology specialist , STELA Laxhuber , in Germany .

“ The German SME outlines the path it has taken to automated welding for its production .”
The KUKA cell4 _ arc robot cell welds fan components at STELA .

Now managed by its third family generation representative , Thomas Laxhuber , the Bavarian family business STELA Laxhuber GmbH in Massing , Germany , is a “ hidden champion ” among system builders . STELA , named after its founder , Stefan Laxhuber , and its 235 employees design , weld and manufacture sophisticated drying systems in different sizes and applications for customers worldwide . International customers of these products include end-users in the agricultural ; food ; fodder ; cellulose material and paper industries as well as the water management sector .

At the heart of these drying systems are massive fans that activate a stream of warm air to extract moisture from products such as grain , corn , wood or recycled plastic . The fan rotors in the dryers can have a diameter of 1.60m and weigh half a tonne . When such a colossus is accelerated up to 1500rpm , highly robust components are essential . One of its latest dryers is the new Stela BTU RecuDry ® low-temperature belt dryer with heat recovery , which dries sawmill residues at the HS Timber Group site in Kodersdorf . It draws the initial moisture content of around 50 % down to a residual moisture content of 10 %, saving a reported one third of heating power .
A feed-and-turn dryer produced by STELA .
The company moved into new administration and production buildings in 2016 and was also , it told ISMR , a ‘ Bavarian SME 2021 / 2022 ’ award-winner . This year , STELA celebrates its 100th anniversary as well as an innovative KUKA robotic cell , which is now welding large components such as fan blades , for the manufacturer .
The KUKA robot welds the fan drum at STELA .
Taking control
“ There is a high level of vertical integration at STELA Laxhuber ,” stressed Thomas Laxhuber , who stepped into the management role in 2001 . “ To continue producing worldleading drying systems , we want
to manufacture the key components of our machines by ourselves to the greatest extent possible . We see this as a prerequisite for the long service life of the systems .”
This is particularly true for highly robust components , such as the fan rotors . The blades of these radial fans suck air in via the motor axis and blow it out again at an angle of 90 °.
Andreas Utz stands in the middle of the production hall in front of a welding cell of approximately 40 square meters . The production manager for fan construction at STELA is controlling its new cell4 _ arc robot cell . Inside the cell , the six-axis KUKA KR CYBERTECH robot welds rhythmically , using its orange arm to guide the sensor-controlled torch to the fan drum .
“ Previously , Andreas Utz had screwed the steel construction unit in place on the positioner . Once the positioning unit was swivelled into the interior of the cell , an intelligent line laser initially scanned the component using KUKA . SeamTech Finding and determined the optimal starting point for the torch . Critical precision welding could then begin . The robot welds seam after seam with the same accuracy choreographed by the KUKA . ArcSense software . In the welding shop , time is money . Robotic welding cells increase productivity ,” KUKA explains .
After 50 minutes , the radial fan has been welded . As the finished workpiece leaves the
36 | sheetmetalplus . com | ISMR June 2022