Mikrosa KRONOS S

The key differentiators are the Granitan mineral casting bed (vs. cast iron in lower-cost machines), the Siemens 840D sl control platform (providing process recipe storage and advanced dressing control), and United Grinding Group application engineering and service support. These features translate to better roundness, lower chatter, faster process setup, more consistent part-to-part results, and better long-term machine accuracy. Lower-cost centerless grinders may achieve similar outputs on straightforward applications but struggle to maintain consistency in demanding production environments.

Achieving sub-micron roundness in centerless grinding requires precise control of all process variables: blade height (critical — even 0.01 mm deviation affects roundness), regulating wheel speed (controls workpiece rotation rate and stability), grinding wheel peripheral speed, wheel dressing geometry, and coolant temperature stability. The Granitan base attenuates vibrations that generate lobing. The Siemens 840D sl control maintains precise axis positions and dressing accuracy. Together, these factors allow the KRONOS S to consistently achieve 0.5–1 µm roundness in production on hardened steel components.

The KRONOS S handles hardened steel (60–65 HRc for bearing components), case-hardened steel, stainless steel, titanium, and cemented carbide (with diamond wheels). Aluminum and brass can be ground with appropriate wheel selection and coolant, but non-ferrous grinding is less common in production centerless grinding. The machine's 60 m/s maximum grinding wheel speed supports both conventional abrasive wheels (aluminum oxide, silicon carbide) and superabrasive CBN and diamond wheels.

Yes. The KRONOS S is frequently configured for lights-out or minimally-attended production. With a vibratory bowl feeder or hopper for part loading, a parts chute or robot arm for unloading, and in-process or post-process gauging for size monitoring, the machine can run complete grinding cycles and sort finished parts without operator intervention. The Siemens 840D sl provides integration interfaces for all of these peripheral systems. Cycle monitoring and alarm-based notification can alert operators remotely if the machine stops or a size drift is detected.

Both are German production centerless grinders. The KRONOS S has a larger 400 mm grinding wheel (vs. 250 mm on the SZ 250), a Granitan casting base (vs. cast iron on the SZ 250), and is positioned as a higher-volume, higher-precision platform — particularly suited to bearing and automotive production. The SZ 250 is a capable machine for job shops and medium-volume production at a lower price point. For bearing-quality OD grinding (roundness under 1 µm) at high production rates, the KRONOS S is the more appropriate choice.