Technology, processes, equipment, tools, process monitoring, services - with its modular range of products and services, the southern German technology company Tox Pressotechnik has once again won over Miele, the world's leading manufacturer of household appliances for dishwashing, laundry washing and drying. Namely Miele, the world's leading manufacturer of household and industrial appliances for dishwashing, laundry washing, drying and the like. In this case, it was a question of the reliable and process-safe connection of the two components, the drum base and drum shell made of stainless steel sheets, to the drum of industrial washing machines with a drum volume of 110 liters.

This end customer ordered a rotary transfer system from a manufacturer of special machines and production equipment. The sheet metal processing and joining technology specialists from Tox Pressotechnik were brought on board for the "joining stainless steel sheets" part. After analyzing the requirements and the general conditions, they proposed the use of the Tox round-point sheet metal joining process and designed a complete solution that could be integrated into the rotary transfer system as a ready-to-connect subsystem by the special machine manufacturer.

The subsystem consists of two CRH machine tongs with HZO hydraulic drive cylinder, the round-point tool set, an SP spraying device and the Tox CEP process monitoring system for quality assurance. (Image: Tox-Pressotechnik)

From the modular system to the ready-to-connect process station
The subsystem, in the form of a ready-to-use clinching unit, is based on the Tox modular system and consists of two CRH machine tongs with HZO hydraulic drive cylinder, the Tox round-point tool set (punch and die) for clinching, an SP spray unit for oiling the clinching tool and the Tox CEP process monitoring unit for quality assurance.

The machine tongs have a notch depth of 35 millimetres and an opening of 49 millimetres and are designed for pressing forces of up to 100 kilonewtons. The two components, drum base and drum shell, are joined by clocked placement of 97 Tox round points with a diameter of eight millimetres. Clamping is carried out with a pressing force (including hold-down force) of 75 kilonewtons. The die depth is 1.2 millimetres and the control dimension X (the residual base thickness in the clinching point after joining) is 0.85 millimetres. Each clinch point results in enormous head tensile/shear tensile strengths of 2,300 newtons and 2,700 newtons respectively, with process monitoring ensuring absolutely reproducible and documented joint quality.

The Tox-Clinch system as a ready-to-connect and ready-to-operate subsystem resulted in economic and time benefits for both Miele and the special machine manufacturer. The end customer benefited from the process know-how for sheet metal connections and received a complete solution that was tailored to their needs and worked reliably. And the special machine manufacturer was able to concentrate on the design and construction of the rotary transfer system and only had to integrate the subsystem. The consistent use of standardized mechanical engineering, drive, peripheral, control and process monitoring components from the modular system meant that special machine construction could also be carried out cost-effectively. as