Companies building CNC machines incorporating rotary axes would normally need to source and assemble a torque motor, a precision bearing and a high-resolution angle encoder. All three items can now be purchased from Heidenhain (GB) Ltd (www.heidenhaingb.com) as a single, compact unit following the company’s introduction of two new modules.

Designated SRP 5080 and SRP 5010, these are fitted with an incremental and an absolute encoder respectively.
Both can provide an all-in-one system for controlling rotary and tilting motions to within 2.5sec of arc and feeding the position back to a CNC system. Typical applications are on four-axis and five-axis machine tools, metrology
stations, articulated joints and other equipment where smooth and precise rotary positioning is essential.

The modules are a realistic alternative to air-bearing axes, especially as the motor has a very low detent torque and no discernible cogging; and because Heidenhain manufactures both the roller bearing and the encoder, they are highly compatible and require fewer components than conventional solutions.

The modules are available with a 35 or 100mm-diameter hollow shaft and an axial load capacity of 200N; they also feature a low and consistent frictional torque of less than 0.2Nm, promoting smooth motion at up to 3,000rev/min.

Axial guideway accuracy of the bearing is better than ±0.02µm; accuracy in the radial direction is better than 0.02µm — even under changing loads and varying operating temperatures (from 0 to 50°C). Customer-specific modifications are also possible.