Spindle Error Analyzer 8 - Lion Precision - #6

Some Tests Performed by the Spindle Error Analyzer

Rotating Sensitive Radial acquires displacement data from two probes positioned 90° apart. The probes measure the X and Y displacement of the axis of rotation to generate a polar plot. Rotating Sensitive Radial tests are valid for processes such as milling, boring, and drilling, where the tool is rotating in the spindle.

Fixed Sensitive Radial acquires displacement in the X direction relative to spindle angular location and displays the data in a polar plot. Fixed Sensitive Radial tests are valid for processes such as turning and some grinding processes where the part is rotating in the spindle, or where the point of contact between the grinding wheel and part are at a fixed position such as surface grinding.

Using a probe pair in the X axis or Y axis, spindle tilt is measured and displayed at different angular locations. Display either standard polar plots or 3D plots. The test allows prediction of performance at any location along the spindle axis. Tilt measurements indicate the increase in error sources as the workpiece or tool are extended farther from the spindle face.

Axial Error Motion acquires displacement data from one probe in the Z axis. The probe measures the axial displacement of the spindle. Spindle angular location data is also required which is obtained from the eccentric­ity measured by another probe in the X or Y axis or an index or encoder signal. In addition to a polar plot, axial error motion can also be displayed in a linear, oscilloscope type display.

The FFT analysis test acquires data from a single probe and displays the relative amplitude of its frequency components. A graph of amplitude vs. frequency is produced. The graph is updated once per second, showing the FFT results on the most recent data set. FFT data is used in identify­ing bearing frequencies, resonant frequencies, harmonics, RPM, and structural vibration.

Stability tests measure the effects of heat produced by the spindle itself during operation. These short-duration tests are performed while the spindle is rotating. This measures changes in relative position between the tool and workpiece which affect machine tool performance, such as: loca­tion of features on a part at any distance from the spindle face, location of a hole, depth of a hole, location of a contour. The test also isolates simple X and Y motion from more complex tilt motions.

Generate a spreadsheet of consecutive test runs. Check performance over time or at different spindle speeds. Information can be linked to an Excel spreadsheet for later graphing, printing, sharing, and custom analysis, .

TVE tests for movement of the tool relative to the workpiece due to ambi­ent temperature changes. This test is performed without spindle rotation and with power to the machine turned off. Because of the slow changing nature of ambient temperature and the time required for the thermal mass of a machine tool to "soak out" to the ambient temperature, these tests are of long duration with twenty-four hours being typical. This mea­surement is performed with probes in the X, Y, and Z axes.

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