Thielenhaus Microfinish ZE 500

The Thielenhaus ZE 500's multi-stone head system mounts individual superfinishing stone assemblies at each main or rod journal position along the crankshaft. Each stone head has its own hydraulic pressure circuit and is individually controlled by the CNC — so stone pressure, oscillation frequency, and amplitude can be independently programmed for each journal. The crankshaft rotates in centers at a controlled speed while all stone heads oscillate simultaneously. Cycle time drops from sequential processing (e.g., 30 seconds per journal × 8 journals = 4 minutes) to parallel processing (30 seconds total for all 8 journals simultaneously). This is standard practice for high-volume automotive and diesel crankshaft superfinishing lines.

Large bearing ring superfinishing (raceways on bearings > 200 mm bore diameter) is required for wind turbine main shaft bearings, mining equipment slewing rings, rolling mill work roll bearings, and large gearbox shaft bearings. These applications combine extremely high loads with the requirement for hydrodynamic oil film separation — making Ra < 0.05 µm mandatory. A 500 mm bearing ring raceway that runs at Ra 0.10 µm will generate significantly more friction heat and wear than the same ring superfinished to Ra 0.03 µm, directly impacting gearbox efficiency and bearing service life.

Yes. Bearing ring superfinishing on the ZE 500 uses a powered workpiece spindle to rotate the bearing ring while the superfinishing stone engages the raceway surface. For inner rings, the stone contacts the inner raceway bore surface; for outer rings, the stone contacts the outer raceway OD surface. The CNC oscillation produces the characteristic cross-hatch superfinishing texture on the raceway. This is a standard Thielenhaus application — bearing ring superfinishing fixtures are available for common ring geometries and can be custom-designed for non-standard ring profiles.

Large industrial bearing raceways are specified to Ra, Rz, and bearing ratio (Abbott-Firestone) curve parameters. Typical bearing manufacturer specifications for large cylindrical roller and spherical roller bearings call for Ra 0.025–0.063 µm, Rz < 0.4 µm, and a bearing ratio Rmr (at 40% depth) of > 70%. The Rsk (skewness) is specified negative — meaning the surface has more bearing area plateaus than peaks — which is the defining characteristic of a properly superfinished (vs. ground-only) surface. Thielenhaus can certify process capability against bearing manufacturer surface texture specifications.

Thielenhaus Technologies has a North American subsidiary (Thielenhaus Technologies Inc.) based in Michigan, serving the automotive and industrial machine tool market. For large ZE 500 installations, Thielenhaus provides factory acceptance testing at the Wuppertal plant, rigging and installation support, and application commissioning at the customer site. Ongoing support is provided through Thielenhaus North America service technicians supplemented by factory specialists for complex process development issues. Spare parts and tooling (stones, stone holders, film systems) are stocked at the US location.