QC20-W ballbar system
The industry standard for quick, simple and effective machine tool performance verification.
What is a QC20-W ballbar test?
The QC20-W ballbar system consists of:
- the QC20-W ballbar (a very high accuracy, telescoping linear sensor with precision balls at each end)
- two precision magnetic mounts, one 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 Ballbar 20 software calculates overall measurements of positioning accuracy (circularity, circular deviation) in accordance with international standards 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.
Benefits of ballbar testing
Ballbar testing provides a simple, rapid check of a CNC machine tool's positioning performance to recognised international standards (e.g. ISO, ANSI/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:
- ensure accurate parts, first time, from CNC machines
- reduce machine down-time, scrap and inspection costs
- demonstrate compliance with machine performance and quality management standards
- implement fact based predictive maintenance
QC20-W ballbar overview
The QC20-W ballbar system draws on Renishaw's many years of experience with ballbar testing and offers significant performance and operational benefits:
- Bluetooth wireless technology ensures no wire handling issues, closed door operation and reduced possibility for system damage.
- Hardware and software which allows a 'partial arc' (220°) test. This gives you greater test flexibility including:
- Improved Z axis testing (no custom fixturing required).
- Tests where axis travel is limited (typically Z axis on machining centres and X axis on lathes).
- Ability to test 3 planes from a single set up, using 'partial arc' tests for 2 of the tests and present a 'volumetric analysis'.
- Faster data reading for enhanced analysis on small test circle and high feed rates.
- Enhanced Ballbar 20 software includes features for extended testing and greater ease of use.
The standard QC20-W ballbar kit includes a 100 mm long ballbar assembly and 50, 150 and 300 mm long extension bars. By assembling the ballbar with different combinations of extension bars it is possible to carry out ballbar tests with 100, 150, 250, 300, 400, 450, 550 or 600 mm radii.
The ball mounts have been designed to allow the QC20-W ballbar to carry out additional 220° 'partial arc' tests in planes through the centre pivot axis. This means that you can perform ballbar tests in three orthogonal planes without the need to reposition the centre pivot, so speeding up testing. If carrying out 'partial arc' tests with a radius greater than 150 mm custom fixturing is required.
The results can also be used in the 'volumetric analysis' report function within Ballbar 20 software with the assurance that all data has been gathered around the same point.
QC20-W ballbar can be used in conjunction with Ballbar Trace a time-based software package. Ballbar Trace's flexible use opens up QC20-W to many new applications, including 5-axis ballbar verification (to ISO 10791-6) and static monitoring. This software is free of charge to existing QC20-W users.
The standard QC20-W kit comes in its own robust carry case which includes the QC20-W wireless ballbar, battery, spindle and table mounts (pivots), 50 mm, 150 mm and 300 mm ballbar extensions (to allow various test diameters) and tools.
Ballbar 20 software and manual are supplied on a single CD with a 'Getting started' video guide provided on a separate DVD.
Also included is the ballbar calibrator for enhanced test analysis. (It enables absolute readings for scale errors and a handy means of checking that the ballbar is reading nominally correctly).
Fully traceable calibration certificates for the ballbar and calibrator, and validation labels to display test results on machines are also included in the kit.
Every QC20-W ballbar kit includes the 'Getting started with QC20-W ballbar' DVD which introduces the system, then takes you step-by-step through the set-up, installation and use of the system, showing you how to carry out a test and review the results.
A range of optional QC20-W ballbar accessories are available to extend ballbar functionality to test lathes, including vertical turning lathes and carry out 50 mm radius tests.
- With additional extensions it is possible to perform tests up to 1350 mm radius.
- The small circle accessory kit allows 50 mm radius tests to be carried out.
- Testing can also be carried out on two axis machines using the VTL adaptor and on many lathes using the 360° lathe accessory kit.
With all these options, plus the flexibility to use various feedrates, the QC20-W ballbar allows very flexible testing.