Two highly accurate methods for pitch calibration

The ultra-precision master gear with high pitch accuracy has important applications in the calibration of high-precision gear measuring instruments or coordinate measuring machines and in military industries. In order to improve pitch deviations of ultra-precision gear, two gear-grinding techniques to improve pitch deviations of ultra-precision gear were proposed. First, based on the indexing plate system, the working principle of indexing plate and error transferring rules were discussed, and the technical approaches of decreasing the geometric eccentricity were proposed. Then according to the error interference principle, the offset-compensated technique and the neighbour-tooth translocation technique were proposed to improve the pitch machining accuracy of ultra-precision master gear. Finally, precision gear-grinding experiments were conducted by adopting the neighbour-tooth translocation technique based on offset-compensated technique. And the single pitch deviation fp of the test specimen is reduced from 1.06 to 0.63μm and the total cumulative pitch deviation Fp is reduced from 3.11 to 1.98μm with measurement uncertainty U95 = 0.33μm, which both reach the highest class (class 1 defining in ISO 1328-1:2013). The results show the efficiency and practicability of the two gear-grinding techniques to machine ultra-precision master gear.

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“…According to the closure measuring technique, 6–8 the algebraic sum of the individual SPD f pi should be 0, that is…”

Section: Gear-grinding Techniquesmentioning

confidence: 99%

Two gear-grinding techniques to improve pitch deviations of ultra-precision gears

Ling

Zhang²,

Zhang³

et al. 2014

Proceedings of the Institution of Mechanical Engineers, Part B:

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“…This makes it possible to perform a pitch calibration without using an additional reference standard by measuring the workpiece at different relative angular positions with respect to the measuring instrument. A method that makes use of this principle is the so-called three-rosette method [2,3]. Due to the high Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Validation and uncertainty analysis of a reduced self-calibrating method for pitch measurements of cylindrical gears

Keller¹,

Stein²,

Kniel³

2021

Meas. Sci. Technol.

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The three-rosette method is a well-established self-calibrating error-separation method used for highly accurate pitch calibrations of cylindrical gears on coordinate measuring machines or gear measuring machines. It is based on the principle of circle closure and uses multiple measurements in different relative positions of the gear with respect to the measuring device. However, since its measurement effort is proportional to the square of the number of teeth, the method is of limited usability for gears with a large number of teeth. In this paper, a reduced method which requires much fewer measurements is described. This method is based on the same error model and is still self-calibrating. The measurement uncertainties for this method are only slightly higher than for the complete method. After an introduction to the three-rosette method, this paper describes the impact of the number and choice of the measured relative positions on the measurement uncertainty. Moreover, the problem of an erroneously determined gear axis is addressed. Finally, the effectiveness of the reduced three-rosette method is shown in intercomparison measurements with four participants. The obtained E n scores show that the reduced three-rosette method allows pitch calibrations with nearly the same accuracy as can be achieved with the complete method. The reduced three-rosette method is part of the TraCIM online service (https://tracim.ptb.de) of the Physikalisch-Technische Bundesanstalt (PTB) allowing software manufacturers or calibration laboratories to obtain a certificate for their algorithms of the reduced three-rosette method after a successfully performed software test. Moreover, calibration laboratories can receive accreditation by the German national accreditation body (DAkkS) for pitch calibrations performed by using the reduced three-rosette method.

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“…High precision measurement methodologies, including coordinate measurement machines (CMM) [22,21,24], spindle [17,18], roundness [7] and gear measurement procedures [9,15], often use error separation and self-calibration techniques to separate the errors of the artefact and the measurement device. Self-calibration procedures provide an accurate measurement result with-out using externally calibrated artefacts.…”

Section: Introductionmentioning

confidence: 99%

“…In the field of gear measurement, Guenther et al [9] developed a method for the self-calibration of a ball plate artefact on a coordinate measuring machine (CMM). This method relies on the Rosette method, which is presented in [15] and is able to separate the errors of the artefact and the used CMM. The approach can separate the error contributions of the artefact, the linear axes and the rotary axes in radial direction.…”

Section: Introductionmentioning

confidence: 99%

Self-calibration of rotary axis and linear axes error motions by an automated on-machine probing test cycle

Zimmermann

Ibaraki

2020

Int J Adv Manuf Technol

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Efficient, precise and automated in-process calibration schemes are essential to improve the accuracy and productivity of five-axis machine tools. This paper presents a new calibration approach, which combines an on-machine measurement cycle and self-calibration techniques, to evaluate the position errors and the error motions of a rotary axis using a touch trigger probe and an uncalibrated cylindrical artefact. This significantly reduces the downtime of machine tools required for the calibration process. In contrast to many common calibration strategies for rotary axes of fiveaxis machine tools, the presented self-calibration concept does not neglect the positioning errors of the linear axes when identifying the position errors and the error motions of the rotary axis. The self-calibration procedure is able to separate the positioning errors of the linear axes in radial direction, the radial error motions and the position errors of a rotary axis, as well as the errors related to the uncalibrated artefact. This error separation is realized by a test cycle consisting of four tests in which the measurements are conducted by particular axis movements. Furthermore, the uncertainty analysis of the self-calibration concept is conducted to visualize

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Two highly accurate methods for pitch calibration

Cited by 21 publications

References 2 publications

Two gear-grinding techniques to improve pitch deviations of ultra-precision gears

Two gear-grinding techniques to improve pitch deviations of ultra-precision gears

Validation and uncertainty analysis of a reduced self-calibrating method for pitch measurements of cylindrical gears

Self-calibration of rotary axis and linear axes error motions by an automated on-machine probing test cycle

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