Telescoping ballbar systems
The telescoping ballbar is almost universally accepted as the most practical, convenient and comprehensive tool for assessing the contouring accuracy of CNC machine tools.
Renishaw ballbars have been dominant in this market for nearly 20 years and that leadership continues today with the QC20-W wireless ballbar system.
This telescoping ballbar provides a simple, rapid check of a CNC machine tool's positioning performance to recognised international standards (e.g. ISO, ASME etc) allowing users to benchmark and track the performance of their machines and to quickly diagnose problems that may require maintenance and the error sources that produce them.
Regular ballbar testing of machine tools helps to
What is a Renishaw ballbar?
The Renishaw QC20-W ballbar system consists of the ballbar itself (essentially a very high accuracy, telescoping linear sensor with precision balls at each end) and precision magnetic mounts, one (adjustable) attached to the machine table and the other to the machine spindle or spindle housing. In use the balls of the sensor are kinematically located in the magnetic cups. This arrangement enables the ballbar to measure minute variations in radius as the machine follows a programmed circular path around the mount on the machine table.
The data collected is sent to a PC, where Renishaw's software calculates overall measures of positioning accuracy (circularity, circular deviation) in accordance with international standards such as ISO 230-4 and ASME B5.54 or in Renishaw’s own analysis reports. This report uses a unique mathematical analysis to diagnose many additional individual machine errors from the set of linear readings. Data is displayed graphically as well as in numeric format to aid and support diagnosis.
The ballbar came to prominence following the work of James B. Bryan at Lawrence Livermore National Laboratory in the USA, who received a US patent for a 'Telescoping Magnetic Ball Bar Test Gage' in 1984. Renishaw plc launched their first ballbar, the QC10 Mk1 in 1991, to be followed the next year by the QC10 Mk2; using a serial interface rather than the internal PC board of the Mk1.
The QC10 continued in manufacture until October 2009 when it was superseded by the QC20-W system. The new QC20-W system is based around a completely new Renishaw designed sensor, Bluetooth® wireless technology and substantially updated testing and analysis capability. Renishaw ballbars have been adopted by many thousands of machine tool users worldwide and are considered vital equipment by most leading machine tool OEMs and their distributors as well as many independent calibration service providers and end users.