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Design requires maximum flexibility

Increasing demands placed on the design, functionality and quality of kitchen and bath fittings require special, efficient solutions during manufacturing. For this reason, robotic rinding and polishing systems are increasingly replacing conventional rotary table systems.

The venerable Hansa company believes “experiencing water” requires designing not only the required fixtures but also the medium of water itself. The Stuttgart-based manufacturer of fixtures, Hansa Metallwerke AG, produces a wide range of bath and kitchen fixtures such as shower heads and systems as well as electronic fixtures for private and public facilities. Whether designer-oriented or classic, Hansa has the right brand-name product for every taste. The company has developed over the years from a brand targeting German craftsmen to an international leader in quality fixtures. The design inspiration develops from the most abundant source in the world: water – and numerous design prizes attest to the fact that Hansa understands precisely how to unite design with functionality. The honors bestowed on the company include the DesignPlus, reddot design, iF design, Design Center Stuttgart, Designpreis Deutschland and Good Design awards. Still, designer style does come at a cost – and that doesn’t merely refer to the sales price. This is because designer fixtures, which need to be produced in mall to moderate or even large batches, present production lines with new and serious challenges, since they require elaborate and therefore expensive manufacturing processes. “We have widely varying product and design models, so we divide the grinding and polishing requirements for high-quality realization of the designs into A, B and C areas,” said Hans-Peter Wittmann, Head of Manufacturing at the Hansa Metallwerke AG production plant in Burglengenfeld, Germany.

Highly automated manufacturing s a central component of quality

The modern production plant in Burglengenfeld plays a leading role within the Hansa Group, which currently employs roughly 1,200 people. The company has three sites in Stuttgart (head office, research and development) and production facilities in Burglengenfeld, in Unterkulm, Switzerland, and in Kralovice, Czech Republic. To allow efficient optimization of current and future production tasks, successive investments have been made here in new and even more capable production equipment, with greater reliance than ever on flexible robot solutions. With these solutions, the people at the Burglengenfeld plant are capable of producing the precise, highly demanding shapes used in the designer pieces. The required precision grinding and polishing tasks are carried out entirely and automatically by robots in order to maintain competitiveness in terms of production efficiency and quality. “We have a lot of experience in the area of robotic grinding,” Wittmann said. “We performed the first grinding and polishing trials in 1990 and the first robotic grinding and polishing lines were acquired in 1992. Some of these continuously updated robots are still being fully deployed. We’ve been working since then with the specialists in robotic grinding and polishing at SHL, in order to effectively optimize the most expensive manufacturing processes – namely, grinding and polishing the castings, which can weigh up to 6.5 kg (14.3 lb). This process takes between 100 and 300 seconds.” The latest project was the complete retrofitting of an existing robotic grinding and polishing line. In the process, both the grinding and polishing work was being taken back from external service providers in order to increase internal creation of value, and that new designer products had to be processed on the system. Wilhelm Tillinger of the Sales Department at SHL Automatisierungstechnik AG in Böttingen is responsible for the account of Hansa, a long-time customer. “We worked together to analyze the capacity needs and the required application flexibility as well as the producibility,” Tillinger said of the new project. “In doing so we came to the conclusion that we should essentially rebuild an existing line and equip it with additional robot booths for grinding and polishing the fixtures, which are more challenging in terms of their design. Meanwhile, the big challenge was to maintain control of the clamping, handling, grinding and polishing of what are basically eight different types, of which two – each having two different designs – were to be simultaneously processed during mixed operation on the line, in order to produce them reliably in multiple-shift operation.”

Robotic grinding and polishing booths make production “flexible in terms of variation, design and volume”

After the intensive retrofitting job, the “new” robotic grinding and polishing line essentially consists of two robotic grinding booths and two robotic polishing booths, the continuous material flow system that transports pallets holding work pieces, and one manual workstation each. The robotic grinding booths, in turn, consist of two 6-axle KUKA KR 60/3 industrial robots with 60 kg load capacity and KR C2 controls, basic adaptors for pneumatic and vacuum clamping devices, two x two = four SHL FKS 250/450 free-belt and contact-roll grinding machines, and lifting and swiveling units for the FKS that allow the FKS to position each work piece in order to machine difficult design areas. The robotic polishing booths for this are similarly equipped and constructed, but feature two swiveling SHL DP1000 ROBDPE- G double polishing machines each, and two SHL P550 ROB polishing machines, as well as six high-pressure polish guns for applying polishing compound. The scope of supply and services also included the modification and enlargement of the pallet conveying system and the replacement and integration of existing and still serviceable robots. For redundancy and capacity reasons, there are always twoidentical robotic grinding and polishing lines available, both retrofitted successively. Both robotic grinding and polishing lines are divided into three sectors: rough grinding, finish grinding and polishing. The manual workstation, where the pallet is furnished with unmachined parts or where the finished fittings are removed after completing the cycle, is located at the head of the line. The new grinding and polishing strategy, based on four new robots and the integration of two existing robots, allowed the old indexing tables to be completely eliminated, and the new systems are now capable of meeting any conceivable design challenge.


The grinding and polishing of fittings made at Hansa from corrosion- resistant brass (MS 63) involves difficult and demanding mechanical processing. One indicator of the difficulty is the fact that up to 0.6 mm of material must be removed from certain points of the work pieces during grinding in the robotic booths, using the grinding belts and contact disks with grain sizes of 80 or 280. During polishing, a smooth and flawless surface is the ultimate goal, so that a perfect surface finish can be obtained during the subsequent galvanic coating process. To handle the daily order volumes, robots are being used today at Hansa in Burglengenfeld for single-hole sink fittings and bidet fittings, for bath and showerhead fittings and for small batches and special parts, with two different parts always running through or being processed on each line at the same time. Wittmann expressed his full satisfaction with the collaboration with SHL and said robotic solutions from Germany will also be deployed in the future. “Today we have a total of 42 SHL-modified industrial robots in highly productive operation within 30 robotic grinding and polishing systems,” Wittmann said. “There are 35 employees performing the support, operation and charging tasks in the grinding and polishing shops, which include quality management and subsequent 100 percent visual inspection. With these employees and the robotic equipment, we send about 4,500 fittings through the grinding and polishing shops each day. If you add in the roughly 1,500 pieces in the form of in-wall components, then we process over 180 tons of cast parts made from MS 63 per month, which results in a large number of work pieces produced. This would not be possible without the consistent use of robots, meaning fully automated grinding and polishing equipment, particularly since we and our output are also heavily dependent on maximum availability of technical systems. With SHL, we have a partner who supports us fully in every area of concern, and who also ensures the design quality and overall product quality through the use of robot technology.”