Motto "Sustainable!"

The fundamental difficulty with products in the field of machine safety is that new, environmentally friendly approaches to product design or the use of materials must not impair the quality and, in particular, the safety functions of the safety switching devices in any way. This means that the optimized devices must also comply with the standards, their suitability must be checked and confirmed by certification.

Cooperation with research institutions

However, Schmersal is working with universities and research institutes, such as the Lüdenscheid Plastics Institute, to achieve progress in this area. One current project involves the use of recycled material in the production of safety switches with plastic housings. "Our aim is to use 20 % recycled material in the switches manufactured using the injection molding process," says Matthias Banaszek, Head of Value Management / Innovation Manager at Schmersal. "Over the past two years, we have therefore collected around 30 tons of sorted material from production waste, such as sprues or start-up residues, i.e. unsuitable first components that accumulate when a new production batch is started."

According to the UL organization, which awards globally recognized safety test marks, a regranulate content of 25% is possible in safety switches. "This is approved for in-house processing. However, as this involves a great deal of effort, we have this carried out by an external, certified processor. Unfortunately, the UL regulations state that an admixture is only permitted with increased testing effort. However, we are in close contact with UL to work out a joint solution," explains Matthias Banaszek.

The TÜV would also certify safety switches with recycled content - provided that it can be proven that the recycled material used has no influence on the quality of the safety functions. To this end, the Plastics Institute is carrying out a comparative test with Schmersal's switches: Switches made purely from virgin material are tested in comparison with switches consisting of 80 % virgin material and 20 % recycled pellets. If the results of the comparative test from the Plastics Institute are available and meet expectations - i.e. there are no quality impairments due to the use of mixed material - the switches must be certified by TÜV in the next step. After that, the way would be clear for series production of the switches with regranulate content. This would make Schmersal the first manufacturer to use recycled material in the production of safety switches.

Project with innovation network

Schmersal has also joined the German innovation network Poly4Nature as an active partner. The aim of Poly4Nature is to produce plastics from alternative raw materials and with alternative processes, for example by using natural fibers or preliminary products from natural recyclable or waste streams, in order to replace fossil materials that have been used up to now. As a network partner, Schmersal has agreed a specific project with Poly4Nature: the development of biodegradable protective plugs based on alternative raw materials. These protective plugs are used to cover screws and screw-in holes and are used by Schmersal in their hundreds of thousands - exclusively for the transportation of switches. As soon as the user removes the switches from the transport packaging, the protective plugs are disposed of.

"The protective plugs are not safety-relevant components. It is therefore much easier to use alternative materials here," explains Matthias Banaszek. The alternative plastics for these packaging materials could, for example, be of marine origin, such as algae. The project will run until the beginning of 2026.