Flexible and sustainable production of high performance rolling bearings (Turn2Flex)

The Turn2Flex project aims to increase the production flexibility for the manufacture of large sized bearings.

Such components are today manufactured through forming, soft machining, heat treatment, grinding, hard turning (HaT), polishing, honing etc., which together helps to shape the bearings into the required dimensions and tolerances. However, each single process step has their limitation and boundaries, which together limits mass customization as well as it increases the manufacturing lead time and the production cost. Therefore, Turn2Flex aims to increase the production flexibility by reducing the number of process steps and improving the properties of the components using a novel hard turning strategy.

This strategy will generate a unique high-strength metallic surface, called Mechanical White Layers (M-WLs), which will improve the surface mechanical properties hence the life of the bearings at service. Turn2Flex qualifies the HaT process so it could potentially be used as a finishing process significantly increasing the production flexibility, thus enables rough and finish machining in one clamping setup. This allows for reducing the manufacturing lead- time, the energy consumption and enable mass customization. However, today the main limitation for the HaT is that the process is only used as a semi-finishing operation [11], which limits the expected production flexibility.

The challenges to secure the process as a rough-to-finish machining operation can be summarized accordingly

• Microstructure alteration: the near surface microstructure transforms from martensite to a nano-crystalline microstructure, usually called white layer (WL).
• Residual stresses: the excessive heat induces high surface tensile residual stresses.
• Dimensional accuracy: the tool wear results in an inferior surface topography.

The Turn2Flex project will address the identified challenges to demonstrate the significant benefits in increased production flexibility by utilizing the HaT process as a finishing process and simultaneously increase the performance of the produced bearing elements as used for example in wind turbines. The project is expected to contribute to the utilization of innovative HaT strategies as a key enabler for high value-added products and materials at the forefront of Swedish industrial development. The project therefore directly supports the goal of strengthening Swedish manufacturing industry.

The Turn2Flex project contributes to the 7th, 8th, 9th and the 12th sustainability development goals (SDG) in Agenda2030 securing a sustainable industry with innovation capacity by providing a solution to advanced Flexible Production through innovative and resource efficient technology like HaT. The project addresses Produktion2030 area of strength Flexible Production, where the combination of increased flexibility with improved product quality and shortened lead time will provide new competitive solutions. The project also contributes to the Produktion2030 area of strength Resource effective production, focusing on reduced scrap rate and less energy consumption.

This will be demonstrated through the selected target application, which if proven successful, could constitute a significant breakthrough for future product realization, becoming a game changer within the manufacturing industry.

The project covers the whole production chain from material manufacturer (Ovako), cutting tool manufacturer (Sumitomo), product design (SKF), HaT process expertise (RISE, Sumitomo, SKF), product and materials assessment and evaluation (SKF, Chalmers and RISE), to dissemination to SME (SKTC). Also, partners like SST will enable a transformation of the knowledge into other applications, which broadens the industrial impact by introducing the Turn2Flex strategy for other products.

Turn2Flex is based on the pre-study projects HybridSurf-I/II in which several of the project members from Turn2Flex were active. The aim of the pre-study project was to i) create an industrial consortium and ii) answer some scientific questions to secure the level of TRL before applying for a full-scale project. The outcome was highly positive, and the pre-study projects secured the TRL 5 level, hence the industrial partners jointly decided to actively seek for full-scale project to take the next step and push towards adoption and industrialization. Therefore, there is a strong commitment from all partners with strong anchoring within their respective organizations.

Project leader
Seyed Hosseini, RISE IVF AB
[email protected]
+46 707806169

Participating organisations
→ RISE IVF AB
→ Chalmers Tekniska Högskola
→ AB SKF
→ Ovako AB
→ SUMITOMO ELECTRIC Hartmetall GmbH
→ Slitskyddsteknik AB
→ Skärteknikcentrum Sverige AB