Calibrating the Rotary Axis
Renishaw's wireless XR20-W and new off-axis rotary software work with laser interferometers to test the accuracy of lathes, multi-axis machine tools, mill-turn machines, trunnion tables and spindles.
Renishaw's wireless XR20-W and new off-axis rotary software work with laser interferometers to test the accuracy of lathes, multi-axis machine tools, mill-turn machines, trunnion tables and spindles. The calibration system wirelessly measures the angular position of rotary axes to within ±1 arc second. It works in conjunction with XL-80 or ML10 laser interferometers, as the system combines the readings of the rotary calibrator and laser to determine positioning errors in axes.
Off-axis rotary software extends application flexibility by allowing the XR20-W to be used even when it cannot be positioned directly on the rotary axis being tested. The software calculates true position and records axis performance and errors when compared with the intended target. The test takes about 10 minutes, and results are sent to a PC via a Bluetooth connection.
“The rotary axis calibrator has transformed the way we calibrate rotary axes on machine tools,” says Tony Morley, president of Morley Machine Tool Alignment, a service and maintenance provider in Milton, Wash. “Before, our technicians relied on the old Renishaw RX10 and our in-house designed 'Morleyometer' for applications where the calibrator could not be mounted on the center of rotation. While these devices got the job done, they were heavy, cumbersome and slow. Setup could be challenging, and the associated cables and fixturing meant that great care had to be taken to ensure the test proceeded smoothly. Setup is now quick and easy.
“The XR20-W can even be used in ‘off center’ applications such as trunnions and head type five-axis machines,” Mr. Morley adds. “The new methodology allows mechanical setups to be done quickly with only a simple generic mounting fixture, allowing a fully automatic test routine to proceed without delay. This tool has enabled us to offer our customers (typically high-end aerospace component manufacturers) an exceptionally high standard of service and has helped our company grow from only four employees a few years ago to the 20-strong team we have today.”
The XR20-W’s lightweight (just more than 2 pounds) and wireless operation allow fast setup and eliminate safety hazards created by cables. It attaches to a rotary axis via a flexible mounting ring assembly and is centered within ±1 mm (0.04 inch) using a visual aid. Flexible mounting options include an adapter plate for rotary tables with unsuitable center recesses and a chuck adapter for lathes. Various mounting options are included for faster setup and to minimize alignment errors that can lead to measurement errors.
“We have reduced our test setup time by 40 percent and test run time by 20 percent,” says Luke Wang, assistant general manager of the Quality Control Department at Hurco, Taiwan. “And, the Bluetooth wireless technology allows safer testing, making supervision a non issue. As a result, we do not disrupt shop floor activity.”
More information about the calibration system, including a video detailing its features, can be found on Renishaw’s website.
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