How to test the accuracy of the spindle of a used Youjia FTC450 CNC lathe?

Author:           Date:2025-04-09

Detection of used Youjia FTC450 CNC lathe spindle accuracy, you need to use professional tools for radial runout, axial runout and other indicators to measure, but also through the machining of test pieces to carry out a comprehensive assessment. Specific methods are as follows:
1. Preparation
Before testing the machine tool spindle and related components need to be cleaned up to ensure that no debris, oil and other factors affecting the accuracy of the test. At the same time, prepare the tools required for testing, such as percent gauge, micrometer, magnetic table base, inspection rod, etc..
2. Radial runout detection
- **Installation of the percentile table**: Fix the magnetic table base on the machine bed or other stable parts, make the head of the percentile table perpendicular to the spindle's cylindrical surface, and the head and the spindle surface in good contact with the spindle, gently rotate the spindle, so that the pointer of the percentile table can rotate freely.
- **Measurement of radial runout**: manually rotate the spindle, so that the spindle slowly rotate a week, observe the swing range of the gauge pointer, the maximum reading of the gauge pointer and the minimum reading difference is the radial runout value of the spindle. In order to ensure the accuracy of the measurement, the spindle can be in different positions (such as near the end of the chuck, the middle part, near the end of the tailstock) for multiple measurements, and record the results of each measurement.
3. Axial runout detection
- **Installation of the meter**: Install the meter on the magnetic meter base so that the meter head is perpendicular to the end face of the spindle and the meter head is in good contact with the end face of the spindle.
- **Measurement of axial runout**: Apply a certain amount of force along the axial direction of the spindle by hand, so that the spindle produces axial displacement, and then observe the swing of the gauge pointer, the difference between the maximum and minimum readings of the gauge pointer that is, the axial runout value of the spindle. Similarly, can be measured several times and take the average value, in order to reduce the measurement error.
4. Spindle taper hole radial runout detection
- **Installation of inspection rod**: Insert the inspection rod with high precision into the spindle taper hole to ensure that the inspection rod and the spindle taper hole are closely matched.
- **Installation of the percentage table**: Fix the percentage table on the magnetic table base, so that the head of the percentage table is perpendicular to the surface of the outer circle of the test rod, and the head of the test rod and the surface of the test rod in good contact.
- ** Measurement of taper hole radial runout **: manually rotate the spindle, so that the test rod with the spindle with the rotation, observe the swing range of the meter pointer, the meter pointer of the largest reading and the smallest reading of the difference between the spindle taper hole that is the radial runout value. In order to fully understand the accuracy of the spindle taper hole, can be measured at different lengths of the inspection rod.
5. Comprehensive accuracy testing
- **Machining specimen**: Comprehensive assessment of spindle accuracy by machining some specific specimens. For example, machining an external surface, and then measure the roundness of the external circle, cylindricity and other indicators; or machining an end face, testing the flatness of the end face.
- **Testing the accuracy of the test piece**: Use measuring tools (such as calipers, micrometers, coordinate measuring machines, etc.) to measure the accuracy of the processed test piece, and compare the measurement results with the accuracy standards of the machine tool, so as to judge the accuracy performance of the spindle in actual processing. If the accuracy deviation of the test piece is large, it means that the accuracy of the spindle may have problems.

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