The solution for mass production of small precision parts


Basic Data

The KRONOS S 250 centreless grinding machine is designed for plunge and throughfeed grinding of small precision workpieces with a diameter range of 1.5 to 35 mm and with a maximum infeed width of up to 245 mm.

    Machine description

    • Working range 1.5...35 mm, plunge length up to 245 mm
    • Highest values in cycle time and cost effectiveness
    • Short set-up and changeover times
    • Thermally stable, vibration-damping GRANITAN® machine bed
    • Cross-slide systems for grinding and regulating wheels
    • Grinding spindles mounted on hybrid bearings for max. 150 m/s
    • Exact reproducibility of grinding results, even in tolerance ranges of ±0.5 µm
    • Designed for mass production
    • Highest safety standard thanks to full enclosure

    Possible technologies

    • Plunge grinding
    • Throughfeed grinding
    • 6° angular plunge-cut
    • Plunge grinding in mass production
    • Oscillation grinding
    • Grinding of multiple operations in one cycle by offsetting the workpiece or the grinding wheel


    Granitan® machine bed

    The basis of the KRONOS S is the proven Granitan® machine base with excellent damping characteristics. High thermal stability ensures temporary temperature fluctuations are extensively compensated and a high capacity to hold the tolerance can be guaranteed throughout the day.

    Cross slide system

    The KRONOS S 250 has a fixed grinding zone. All infeed and compensation movements are conducted by the cross slide system on the grinding wheel side (X1-axis / Z2-axis) and the cross slide system on the regulating wheel side (X4-axis / Z3-axis).

    Modular dressing system

    Depending on the grinding task, stationary dressing tools such as diamond blades and single-point diamonds or rotating dressing tools such as diamond dressing discs or diamond profile rolls are available. Dressing of the regulating and grinding wheel occurs in the center of the machine on the workpiece plane. This way highest accuracies are achieved.

    Grinding spindle

    The grinding wheel width is a maximum of 250 mm with a bore diameter of 203.2 mm. The grinding spindle mounted on hybrid bearings is suitable for use with conventional grinding wheels as well as superabrasive cutting materials such as CBN or diamond.

    Regulating spindle

    The regulating spindle is portal-mounted with high precision pre-tensioned spindle bearings. The regulating spindle allows for the use of 250 mm wide regulating wheels. The drive is a digital servo motor and V-ribbed belt driven by a clutch, free of lateral forces.

    Control system

    The KRONOS S comes with a SIEMENS SINUMERIK 840D sl control system as standard. MIKROSA has integrated a special operator interface for centerless grinding into the SIEMENS interface. The added symbols and icons are easy to understand and make programming even easier.

    Hardware / Software
    • Maintenance and service friendly SIEMENS Sinumeric 840D sl control system
    • Heureeka - special MIKROSA softwarefor optimizing the grinding zone geometry
    Technical Data
    kg / cm
    lb / inches

    Linear Axes

    Max. Travel X 205 mm
    Max. Travel Speed X 5.000 mm/min
    Max. Travel Z 415 mm
    Max. Travel Speed Z 5.000 mm/min

    Spindle drive

    Max. Spindle Power 15 kW
    Max. Number Of Revolutions 6.685 /min
    Max. Grinding Wheel Diameter 450 mm
    Max. Grinding Wheel Width 250 mm

    Swiveling Axes

    Swiveling Range A 10 °
    Swiveling Range C ∞ °

    Workpiece Data

    Workpiece Length 0 - 245 mm
    Workpiece Diameter 1,5 - 35 mm
    Max. Workpiece Weight 2 kg
    Center Height 1.125 mm

    Linear Axes

    Max. Travel X 8,071 inch
    Max. Travel Speed X 196,850 inch/min
    Max. Travel Z 16,339 inch
    Max. Travel Speed Z 196,850 inch/min

    Spindle drive

    Max. Spindle Power 20,115 hp
    Max. Number Of Revolutions 6.685 rpm
    Max. Grinding Wheel Diameter 17,717 inch
    Max. Grinding Wheel Width 9,843 inch

    Swiveling Axes

    Swiveling Range A 10 deg
    Swiveling Range C ∞ deg

    Workpiece Data

    Workpiece Length 0 - 9,646 inch
    Workpiece Diameter 0,059 - 1,378 inch
    Max. Workpiece Weight 4,189 lbs
    Center Height 44,291 inch
    pdf, 2 MB
    Product brochure KRONOS S
    pdf, 1 MB
    Overview of the KRONOS series
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