Ilmenau Spring Day 2025 showcases innovative power of springs

We encounter springs in countless everyday products, usually rather inconspicuous and often even unnoticed, whether in a soap dispenser, hearing aid or insulin pump. They store energy, balance forces, buffer movements or enable precise control - for example as tension, compression and torsion springs, in micro and macro variants, curved, coiled or disk-shaped. They are also used in challenging environments and are therefore exposed to particular stresses: they are mechanically deformed, i.e. subjected to forces, torsional or bending moments, or work in corrosive, i.e. aggressive, environments that attack the material. In measuring devices, springs must be non-magnetic, in medical applications such as self-expanding stents they must have shape memory and in space, in industrial plants or cooling units they must be particularly heat-resistant or cold-resistant. "All of this must be taken into account when selecting suitable materials and developing springs," explains Prof. Ulf Kletzin, Head of the Machine Elements Group and the Steinbeis Transfer Center (STZ) Spring Technology at TU Ilmenau.

This is why most springs are still made from metallic materials today. "Spring steel is elastic, high-strength, low-wear and durable. Specifically required properties can be adjusted using alloy additives and production steps that need to be optimized," says Prof. Kletzin.

And the spring industry also needs to take a holistic approach to the new challenges of sustainability. With ecological sustainability, economic efficiency and social justice, sustainability encompasses several dimensions that need to be balanced.

In measuring instruments, springs must be non-magnetic; in medical applications such as self-expanding stents, they require shape-memory properties; and in space, industrial plants or cooling systems, they must be particularly heat- or cold-resistant. “All of this must be taken into account when selecting suitable materials and during spring development,” explains Prof. Ulf Kletzin, head of the Machine Elements Group and of the Steinbeis Transfer Center (STZ) Spring Technology at TU Ilmenau.

That is why most springs are still made of metallic materials. “Spring steel is elastic, high-strength, wear-resistant and durable. Specific properties can be tailored through alloying additions and optimized manufacturing processes,” says Prof. Kletzin.

The spring industry, too, faces new challenges in terms of sustainability, which must be addressed in a holistic way. Sustainability includes several dimensions – ecological responsibility, economic efficiency, and social equity – which must be carefully balanced.

New materials, new methods, new possibilities

Barbara Aichroth

For example, the transformation of the steel industry within the circular economy, driven by increasing use of recycled materials, brings new challenges. The conference therefore discussed how the proportion of recycled steel affects the lifespan of springs subjected to high dynamic loads, as well as the potential of new materials and manufacturing methods such as fiber-reinforced plastics or additively manufactured hollow metal structures. These can advance lightweight construction and thereby help reduce the CO₂ footprint – for instance in mobility applications.

Participants also explored how modern calculation and simulation methods, including AI, can accelerate the development process and replace time-consuming testing and verification steps. Finally, the presentations addressed how classical production steps such as end grinding and presetting of springs can be further optimized.

The conference was accompanied by a technical exhibition where companies showcased their latest innovations – from software for component dimensioning and new blasting media for surface treatment to measuring equipment for determining residual stresses. Laboratory tours at TU Ilmenau’s Machine Hall offered additional opportunities for exchange, networking, and new ideas.

Now in its eighth edition, the Ilmenau Spring Day – organized by the Steinbeis Transfer Center for Spring Technology under the direction of Prof. Ulf Kletzin, in close cooperation with the Wire and Spring Research Group at TU Ilmenau, the Association of the German Spring Industry (VDFI) and the Iron and Steel Wire Association (ESV) – once again demonstrated how much innovative potential lies hidden in seemingly simple components.