Clean connection in the premium dishwasher

The developers at V-ZUG AG know how to raise dishwashers, hobs and washing machines to the highest level of quality. The Swiss manufacturer's appliances are used in private households as well as in the catering sector and feature innovative technologies. The beginning was much simpler: Verzinkerei Zug AG was founded in 1913 as a manual galvanising company that also manufactured sheet metal products for households, agriculture and the construction industry. Initially, the company focussed on appliances for the laundry room and launched its first hand-operated drum washing machine seven years after it was founded. The first small washing machine followed in 1949. Over the years, the portfolio grew to include washing machines, tumble dryers and dishwashers. V-ZUG AG has been trading under its current name since 1981. In the meantime, the former contract manufacturer has developed into a premium supplier and Swiss market leader for household appliances.

A special feature of the latest development sets new standards in terms of ergonomics: at the beginning of 2020, V-ZUG presented the new Adora dishwasher line with the so-called OptiLift. This is an ergonomic function that raises the lower crockery basket. This allows plates and co. to be conveniently sorted and later removed again. To accommodate the guide rails and mechanism of this drawer and the ergoPlus cutlery drawer, stainless steel plates had to be fixed inside the dishwasher housing.

The clinching process from TOX^® PRESSOTECHNIK GmbH & Co. KG is ideal for this task: it joins the thin stainless steel sheets reliably and quickly. In contrast to riveting or welding, the surface and the material structure remain intact and therefore sealed. "It's the most efficient solution for us," emphasises Patrick Bon, Head of Dishwasher Design at V-ZUG. "Although we have been using TOX^® Clinch tools for several years, we have not yet had a complete system from TOX^® PRESSOTECHNIK," he adds.

The specific task was to fix three components to each of the two housing sides of the large-capacity vats. "Our customers expect top quality. It is therefore clear to us that the result must also be visually and technically flawless," emphasises Patrick Bon.

TOX^® PRESSOTECHNIK developed a system concept that allows two casing walls to be clinched in a single operation. The centrepiece is the TOX^® Single Point Clamp TE-CM with the electromechanical drive TOX^® ElectricDrive in compact design. The C-frame is designed for a maximum pressing force of 80 kilonewtons. The maximum tool opening is 73 millimetres and is therefore completely sufficient for the Swiss project. The EPMR press drive is installed on the die side and works with a nominal force of 80 kilonewtons. Sensors monitor the force and displacement. The accuracy of the high-precision force sensor is ± 1.0 per cent of the measuring range end value. The piston of the drive operates highly dynamically at a speed of up to 200 millimetres per second. The component surface is wetted before each clinching point is set. This reduces friction and thus protects the tools and sheet metal surfaces. TOX^® PRESSOTECHNIK has added a spraying device to the system for this purpose.

After placing the three sheets on the work table - mix-ups and incorrect assembly are ruled out thanks to the template-like component holders - the worker places the 60-litre large-capacity tubs on top. He releases the path-controlled process via the TOX^® STE single-hand control. The housings are fixed in place and the clinching process starts. The tongs move on an X-Y axis to process two side walls one after the other with 15 TOX^® Points each.

There are two programmes: One for clinching three trays and one for two trays per side. "This allows us to produce the housings for dishwashers with and without the comfort slide function for the cutlery drawer on one system," explains Christoph Fässler, Project Manager for System Planning. As soon as the process is complete, the control system automatically opens the component clamps. The operator then removes the housing, reloads the worktable and places the vat, which has been rotated 180 degrees, back down to repeat the process on the second side wall. The user can create movement sequences and operating modes via a touchscreen and view evaluation results. The screen is connected to the axis controller via an Ethernet connection.

To prevent errors or even injuries, TOX^® PRESSOTECHNIK has equipped the system with several safety features. For example, sensors check whether the required components have been inserted and the vat has been placed in position. The system is only accessible from the front, with light protection grids monitoring access during the process. The other sides are sealed off by Makrolon panes. This allows the workers to keep a safe eye on the joining process.

And V-ZUG thinks flexibly. The control system can be expanded at a later date to accommodate additional vat variants. All component fixtures are also designed as interchangeable parts and can be retrofitted at a later date.

The system arrived at V-ZUG in Zug ready to use and only needed to be connected to electricity and compressed air. "Everything went smoothly," recalls Christoph Fässler.