Grinding Stations Designed for Worm Gear Manufacture

Holroyd Precision’s WG grinding stations are designed to provide high levels of accuracy and finish in worm gear shaft production. Depending on the model, the machines are capable of grinding precision worm shafts to AGMA 14/DIN 2 in sizes ranging from 3 to 500 mm in diameter and thread lengths ranging to 1,600 mm, with a 130-mm diameter through-bore workhead to accommodate long shaft lengths.

The spindle provides speeds as fast as 3,000 rpm, and the machine’s feed rates are variable to 7.5 m/min. Digital drives to all CNC servo axes incorporate fiber-optic serial real-time communications system (SERCOS) and digital closed-loop feedback. Digital servo drives and high-torque density synchronous servomotors provide a reliable drive package, the company says. A fully automatic grinding wheel balancing system is built into the machine spindle with power monitoring for machine overload protection. Other features include a  two-axis CNC wheel dresser with diamond dressing disk, a programmable rough and finish grinding and automatic wheel profile calculation. 3D measurement and an integrated correction probe enable in-machine inspection of ground components.

The grinding machine also is equipped with the Holroyd HTG eight-axis CNC with a touchscreen and graphical, menu-driven user interface. The control is said to simplify the transfer of data from gear drawings to produce profile and grinding paths, generate standard tooth forms, or perform topological modifications. A gear manufacturing and design analysis program helps to reduce the margin for error, ensure consistency and extend gear life. Fully automatic programmable cycles include dressing with compensation for dressing disk wear, and gear tooth grinding with probing and form measurement.

Renishaw’s SP80 scanning probe with 1-micron resolution in the X, Y and Z axis can be added to the grinding stations as an option for measuring tooth position shaft run-out, tooth depth, helical lead and more.