Multisurface Grinder For Complex Precision Components

Bryant Grinder, a division of Vermont Machine Tool Corporation, introduces a new modular multi-surface grinding machine with extended flexibility to grind complex workpieces. The LL2U-MS can be configured as a chucker, shoe-type centerless, roll-type centerless and center-type work (between centers). The machine features 10" (255 mm) of Z-axis travel, 10" (255 mm) of X-axis travel and an optional U axis, also with 10" (255 mm) of travel. All linear axes use the company’s round hydrostatic way system with 300 degrees of bearing wrap which is said to ensure accurate tracking in all degrees of freedom. This machine tool also features a small machine footprint.

Configured as a chucker, the machine can swing up to 14" (355 mm) diameter over the table, as a center type, 4.0" (100 mm) diameter × 10" (255 mm) long with a hydraulic tailstock and live centers. The center-type configuration may also be outfitted with a chuck and a C axis to grind OD non-round workpieces. Workpieces ranging to 6" (1250 mm) in diameter can be ground in shoes (hydrostatic shoes are available for special applications). The machine allows ±5 degrees of taper adjustment, configured with the optional B axis.

Linear glass scales provide position feedback with resolution of 0.000004" (0.0001 mm) on all linear axes. Linear prime movers are Fanuc linear motors with 6,000-N thrust positioned in the same plane as the linear way system. The motors are liquid cooled to optimize motor performance and minimize the heat transfer to other machine components.

The workhead rotary axis is powered by either a Fanuc servomotor or a Fanuc synchronous, built-in Dis servo torque motor with a high-accuracy, rotary encoder. Both applications use direct drive to maximize the relationship with other CNC axes and ensure geometric accuracy on non-round grinding applications.

The base is cast in granite epoxy and includes a thermal stability system with thermocouples strategically placed within the base to monitor temperature. With the optional thermal control system, the sensors provide feedback to the Fanuc 30 series control and the company’s Revelations software to control the base temperature by heating or cooling as required.