R-TEST MEASURING SYSTEM
Rotary Axis analyzer (R-Test): Cost effective solution to determine 5 axis performance with a high level of accuracy.
In modern workshops, the application of five-axis machining becomes increasingly common. In order to be able to machine workpieces with sufficient accuracy, the real position of a rotary axis with respect to the other machine’s axes must be known accurately. This generally requires a considerable measurement effort. At IBS Precision Engineering an innovative 3D measurement system, the so called R-Test, has been developed which can be used for three measuring purposes:
- Machine acceptance
- Rotary table position and compensation
- Dynamic analysis
Unique strengths of our R-Test measuring system:
- Measurement of 5-axis machine operation in 3D
- Both static and dynamic measurements
- Calibration of the rotary table position
- Calibration of the rotary table squareness
- Easy compensation thanks to kinematic parameters
- Machine acceptance according to ISO 10791-6
- Easy to use
With the patented MT-Probe belonging to our R-Test system, the location of a master ball is determined accurately in the 3 dimensions X, Y and Z simultaneously. This probe measures the real position of the master ball centre point, which is mounted to the rotating part of the machine. The probe is fixed to the non-rotating part of the machine and its readings are displayed on a laptop near the machine. All of this happens according to ISO standards and can be performed both statically and dynamically.
1. Machine acceptance
The R-Test is a very efficient tool to perform a machine acceptance test verifying the kinematic accuracy of the machine. Different kinematic tests can be defined, but the most common are the tests according to ISO 10791-6, defining circular motion by simultaneous three and five-axis control. With three-axis control the accuracy of the circular trajectories is verified when the circular interpolation motion of two linear axes is synchronized with the rotation of a rotary axis at contact speed. With five-axis control (xK3 and xK4) the accuracy of the circular trajectories is verified when the circular interpolation motion with three linear axes and two rotary axes are controlled simultaneously at constant feed rate.
The ISO 10791-6 differs between three different machine types:
- swivel head machines
- rotating table or trunnion machines
- swivel head and rotary table combined
All these machine configurations can be measured with the R-Test measurement system.
2. Rotary table position and compensation
With a simple R-Test measurement the actual location of a rotary table can be determined with a high degree of accuracy (measuring uncertainty R-Test probe is 0,8 μm). The machine is programmed to incrementally step through the range of the rotary axis with the linear axes following the motion. After each step the machine is stopped and a measuring point is taken. The R-Test probe head measures the actual location in 3D simultaneously.
Based on this static measurement procedure the R-Test software determines:
- Location of the rotary table
- Squareness of the rotary table
The results are directly presented in the machine’s coordinate system and therefore can be applied to correct the machine’s kinematic model present in the controller. A repeat of the measurement will reveal the improvement of the machine’s positioning behaviour achieved. Please find a demonstration of the rotary table compensation here.
3. Dynamic analysis
Besides the static R-Test measurement procedure, dynamic measurements are performed to reveal the machine’s accuracy of the paths described by the simultaneous movement of two or more NC linear and rotary axes. In this case measuring points are taken on-the-fly.
The dynamic R-Test measurement is a very advanced measurement method showing the machine’s accuracy with all motion axes included in the measurement. The measurement is giving the machine’s accuracy as one can expect when making a work piece.
The software provides many advanced functions to analyse the measurement data and give a full insight in the dynamic behaviour of the machine. The software provides, next to the dynamic position and squareness error of the rotary axis, which can be different during a continuous movement, also FFT analysis in X-, Y- and Z-direction, period extraction, linear and polar plots showing radial, axial and tangential errors motions among others. Finally static and dynamic measurement results can be compared overlaying the results in a single graph.
For more details and specifications, please open / download our brochure below: