Ultra-precision air spindle rotation accuracy
I developed by the ultra-precision spindle spindle) (hereinafter referred to as the air can be used for ultra-precision machine tools or high precision measuring instrument of the spindle system. Spindle to adopt advanced technology of gas static pressure, radial SUNTHAI bearing and two-way thrust SUNTHAI bearing of the working face of surface static pressure gas, and through strict dynamic equilibrium, thus realized the non-contact and high precision rotary, has the characteristics of no vibration, low noise.
Because of the gas film on the average error of shaft parts processing, and the rotating precision of shafting assembly after can be higher than the precision of parts. For spindle main technical indexes of spindle rotation accuracy requirements to less than 0.1 microns. Such precision index, although processing out, also difficult to measure its accuracy, and thus brings to the measurement of the great difficulties. Through several years of exploration, research, and finally by the two-way transfer method to measure the spindle rotation accuracy (0.07 microns). Now the measurement method is introduced to the reader.
1 detection
1.1 test conditions
Ambient temperature: 20 + / - 1 ℃ per hour change: < 0.1 ℃
Relative humidity: 30% ~ 60%
Main shaft being measured at room temperature constant temperature time not less than 24 h.
Spindle and standard instruments being measured temperature is not more than 0.2 ℃;
Based on measured spindle should be placed in isolation, no violent vibration and impact around; At 0.4 + / - 0.02 MPaq gas pressure stability
1.2 inspection instruments and apparatus
1) TESA palisade inductive micrometer (Switzerland) 0.01 microns (resolution),
(2) the standard ball roundness not 0.05 microns or less British roundness instrument accessories)
1.3 test methods
The bidirectional measurement method is adopted, the measuring device as shown in figure 1.
Measuring device
The standard glass ball as a measurement tool, through the adjustable eccentric and can transfer tooling, installed on the spindle. Inductive micrometer probe from the axis of spindle vertical alignment, and perpendicular to the sphere, adjust the ball and basic concentric axis rotation axis. Its eccentricity as small as possible, generally at about 0.5 microns. As a first step, measuring head start from zero direction measurement, uniform rotation axis, from scratch every 10 ° of interval theta I = 0 °, 10 °, 20 ° ~ 350 °. Read the inductive micrometer reading, measuring 3 ~ 5 laps, average X1 (theta I) for the forward reading, then fixed axis, the ball with the measuring head relative to the shaft rotate 180 °, namely the backward, the eccentricity of the reverse ball after will have change, readjust the eccentric measurement after 3 ~ 5 laps, averaged for reverse after reading X2 (theta I). The second step, starting with 90 ° direction measurement, repeat the above steps measurement, measurement process is shown in figure 2. Yi (theta) I to forward against reading, and then fixed axis, the ball with the measuring head relative to the shaft rotate 180 °, namely from 90 ° to 90 °. Y2 (theta) I to reverse after reading.
