Optimized surfaces for highly stressed and durable components

Choosing the right machining process has a significant impact on the quality and service life of technical components. In many industrial applications, from the automotive and aerospace industries to power generation, precisely machined components are required to minimize friction and thus wear. An optimized surface finish can make the components more compact, efficient and durable.

The influence of machining on friction and wear
A comparison of the machining processes turning, grinding and superfinishing shows clear differences in frictional properties, wear behavior and surface topography.

Turning is a classic machining process with a defined cutting edge that enables efficient material removal, but leaves a comparatively coarsely structured surface. This can be problematic, particularly in the case of sliding and rolling contact, as the contact ratio of the machined surfaces is often only around 40 percent.

Grinding significantly improves the surface structure and increases the contact ratio to around 70 percent. However, the high temperatures in the grinding gap, where a cooling lubricant cannot act, often result in residual tensile stresses in the surface. In combination with a so-called “soft skin” (temperature-related change in material properties), this can reduce the advantage of the improved load-bearing surface again, causing components to wear prematurely.

This is where superfinishing comes in, combining high surface quality with minimal thermal stress. This process, which works at very low cutting speeds, only heats the workpiece by a few degrees. The tools are always in surface contact with the workpiece surface and create an exact topography with a high contact ratio through superimposed movements. Surfaces with a plateau structure offer particular advantages: They form oil retention chambers, which have a positive effect on sliding and rolling friction.

Superfinish: precision meets economy

The superfinishing process offers numerous advantages, but does not achieve the high removal rates that are possible with hard turning or grinding, for example. It is therefore preferably used as a downstream process. In order to achieve outstanding component quality economically, feed rates, dressing cycles and tool change intervals can be optimized and surface roughness can be increased in a targeted manner. At the same time, the geometry requirements for pre-machining can be significantly reduced – a decisive advantage in the production chain. The insensitivity of the superfinishing process to fluctuating input tolerances is particularly noteworthy. This ensures constant process reliability and the highest surface quality. The results speak for themselves: friction losses are minimized, heat generation during operation is reduced and the service life of the components is extended. This not only means less maintenance and reduced operating costs, but also increased reliability – a decisive factor for industries in which downtimes are associated with high costs.

Practical examples: Energy generation and medical technology

The added value of superfinishing is particularly evident in applications that

place the highest demands on efficiency and durability. In energy generation, such as offshore wind turbines, components have to work reliably for decades under extreme conditions. One example is large roller bearing components, where superfinishing achieves roundness values of 1 µm and a surface roughness of Ra < 0.2 µm. Such precision reduces maintenance costs and avoids expensive downtimes.

In medical technology, implants such as artificial hip joints benefit from highly polished, finely machined surfaces. These minimize deposits, facilitate cleaning and reduce the risk of infection. Roundness values of 0.5 µm are achieved here, for example, while the surface structure can only be checked using reflection measurement systems.

The right balance between technology and economy

“The choice of the optimum superfinishing parameters, the type of tool and the suitable machining solution depends on the pre-machining and the specific requirements. Our aim is to work with the customer to find the ideal balance between technical feasibility and economic efficiency,” explains Christian Feuchter, Project Manager & Technical Sales. Modern machines, precise measuring equipment and experienced specialists are available for this purpose.

Thanks to superfinishing technology, friction losses can be reduced, heat generation minimized and the service life of components significantly extended. In industries where maximum precision is required, this process represents a decisive competitive advantage.