Modern Machine Shop
Hardinge’s DD100 direct-drive super-precision rotary table is a high-speed parts positioner with ±3 arcsecond accuracy and 4 arcsecond repeatability. It is designed for the aerospace and medical industries and also works well for drill and tap, and laser processing, the company says.
The rotary table is capable of spindle speeds ranging to 4,200 degrees per second and as much as 600 rpm continuous rotation. The A2-4 spindle nose accepts standard 5C tooling when used with a collet closer to provide high-precision gripping of various part shapes, sizes and materials. 5C gripping options include collets, expanding collets, step chucks for larger part diameters, jaw chucks and fixture plates.
The table design consists of a housing, bearings, an encoder and a spindle. A rare earth, permanent-magnet DC torque motor is wrapped around the spindle and operates with a programmed gear ratio of 1:1. The encoder is mounted directly to the spindle to provide precision position feedback, the company says. The cross-roller spindle bearing is permanently lubricated, and because the direct-drive torque motor has no mechanical gearing, there is no backlash, the company says. It guarantees a maximum runout of 0.0002 TIR.
The standard rotary package uses the company’s direct-drive all-digital servo control and can be used with most machines, but the company says the unit is most productive as a true fourth axis. The direct-drive technology complements machines that have faster axis travel and is compatible with “look-ahead” programming when integrated as a fourth axis to the machine. The units are designed for large part runs on a dedicated machine producing a family of similar parts.