A Roundness Control function for Marposs’ Fenar L in-process gauge system for crankshaft orbital grinding applications is now available. The added capability allows checking roundness of a crankshaft main or pin journal diameter immediately after grinding without removing the part from the machine for inspection using an off-line metrology gauge.
The Fenar L gauge was developed to complement the versatility of the modern CNC “orbital” crankpin grinder in which the grinder’s wheel head follows the non-concentric crankpin as it rotates about the crankshaft’s main bearing centerline. The gauge is capable of controlling size on mains and pins, in a range of up to 25 mm, without mechanical adjustment. Reductions in cycle time and a reduction of the size range in various production lots through the continuous value monitoring by the gauge system of part size and cutting speed to within microns/millisecond is possible, the company says.
Using the same gauge, a chordal measurement across three contact points can be performed with one to two rotations of the part to check roundness after the grinding cycle is complete. A data stream from the gauge is sent to a PC, either within the machine control or off line, where the roundness calculations are made. The measurement is performed to determine if the part roundness is within specified limits. According to the company’s engineers, on-machine roundness checking can save production time and avoid scrap.