The work-pieces are bearing races, and the MVL’s main workload is hard-turning the outside diameter of the inner race components. Work-piece diameters range from roughly 20 to 45 inches, and heights are generally about 6 to 12 inches. Materials are hardened steel, with hardness ranging from 58 to 62 Rc.
The work utilizes an MVL-12 equipped for high precision with a WENtechnology magnetic chuck and Heidenhain linear scales. The MVL-12’s standard specs include a 1,250mm (49″) table diameter and 1,600mm (63″) swing. However, for this application a 1,600mm (63″) diameter magnetic chuck was used, in order to accommodate the customer’s largest diameter work-pieces.
The customer routinely turns bearing race surfaces on single-piece lot sizes, so no setup piece or multiples are available to dial in a process. And the MVL is holding surface profile tolerances of fewer than 20 microns. In fact, it is holding tolerances which in the customers’ other production facilities require either finished grinding after hard turning or highly-specialized and very expensive dedicated hard turning lathes.
‘We regularly hold sub-20 micron surface profiles when we hard-turn our bearing races. At our sister companies, this requires grinding or other specialized equipment. The Momentum has made us so efficient that we now do work for some of those facilities, too. There have been zero production quality or reliability issues with the machine.’
Customer: A leading OEM for bearings and seals for worldwide commercial and industrial applications. The plant which is subject of this case study primarily re-manufactures customers’ bearings.