Mikrosa Kronos L 550 centreless external cylindrical grinding fits the bill for medium length shafts
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Leipzig-based grinding specialist Schaudt Mikrosa has designed Kronos L 550, a centreless external cylindrical grinding machine that slots in between the Kronos L 660 and the Kronos M 400. Tailored to the production of the very large number of mid-size shafts the automotive sector consumes, the 40 kW drive power and grinding wheel of the L 550 are aimed at reliably mass producing 400 to 545 mm long shafts with precise dimensional stability and surface quality.
The design of Mikrosa's Kronos L 550 is based on the technical quality of its larger stablemate and starts with the exceptionally stable and vibration-damped Granitan machine bed. The infeed of both slides is realised by servo drive via a pre-tensioned and backlash-free recirculating ballscrew. Linear measuring systems ensure exact positioning of the infeed axes with respect to the grinding wheel and regulating wheel.
In the interests of cost effectiveness, system tools have been precisely configured to the medium size workpiece. The maximum grinding wheel diameter is 660 mm. In comparison to the (smaller) grinding wheel of the Kronos M 400, it therefore remains in use for considerably longer. The useable area on the tool is 25% larger, and its service life is comparably longer. The regulating wheel has a maximum diameter of 400 mm. The service life is thus 25% higher than with the smaller machine model.
Carsten Otto, Schaudt Mikrosa technical director, explains: "The larger diameters of the grinding and regulating wheel directly reduce auxiliary times in comparison with smaller systems, because far fewer tool changes are required. And, of course, the tool costs are also reduced."
He underlines: "We adapt the system very specifically for each customer. The required workpiece determines the design of the machine."
Mikrosa therefore offers both infeed and throughfeed grinding configuration production solutions to suit a variety of components. In addition to throughfeed components such as shock absorber piston rods, brake pistons, roller bearing rings or rolling elements, infeed components such as camshafts, gear shafts and selector shafts can be ground on the system. For example, a gear shaft with spline toothing can be machined in two cycles using the infeed grinding method, due to the influence on roundness. After rough grinding, synchronisation to the finish-grinding position occurs in the machine. Both operations run simultaneously. Multiple production is also possible, depending on the length of the parts.
