FVA Involute Waviness Artifacts Tactile/Optical Comparison

<p style="text-align: center;"><img src="/ueditor/php/upload/image/20260911/1789138317269335.png" title="1789138317269335.png" alt="1.png"/></p><p><span style="font-size: 14px; font-family: arial, helvetica, sans-serif;">Since there were no conspicuous waviness on the Bosch-Shaft, but the question of reliable detection of waviness characteristics, with fringe projection systems for Bosch was in the foreground, two waviness artifacts from the Forschungsvereinigung Antriebstechnik e.V. (FVA) from the project FVA involute waviness artifacts (Ref. 6) could be used for the comparison. The two waviness artifacts are grinded artifacts with specifically applied waviness of different orders (Figure 12). Both waviness artifacts are helical external gears with: number of teeth (z) 37, normal module (mn) 1.75 mm, and facewidth (b) 40 mm. For the tactile/optical comparison, the waviness artifact B1 (order 37, 1. Tooth Mesh Order [TMO]) and D1 (order 45, 1. TMO ± 8) were available. In the FVA research project no. 733 I, twelve tactile Klingelnberg GMI were used to determine the waviness applied by production technology in a ring comparison in 2018. The amplitudes of the waviness were in a range &lt; 0.5 μm.</span></p><p><span style="font-size: 14px; font-family: arial, helvetica, sans-serif;">For the results presented below on the two FVA involute waviness artifacts, the same methods, repeatability measurements, and results presentations were used as described in the sections “Bosch-Shaft Tactile System Validation” and “Bosch-Shaft Tactile/Optical Comparison” for the Bosch-Shaft Table 4 shows the measurement scope and the measurement times.</span></p><p><span style="font-size: 14px; font-family: arial, helvetica, sans-serif;">As an example, Figure 13 shows the waviness characteristic order spectrum profile of the FVA involute waviness artifact B1 for the measurement data of Klingelnberg P40 (green), Zeiss Prismo verity (blue), and Zeiss Atos Q (yellow).</span></p><p><span style="font-size: 14px; font-family: arial, helvetica, sans-serif;">The color-coded topography plots for the visualization of the waviness characteristic helix angle of waviness (βw) of the FVA involute waviness artifact B1 are shown, in Figure 15, correspondingly, for the FVA involute waviness artifact D1.</span></p><p><span style="font-size: 14px; font-family: arial, helvetica, sans-serif;">The results obtained on the FVA involute waviness artifacts tend to be comparable to those on the Bosch-Shaft, and even significantly better for some characteristics, since the surface quality of the artifacts is of higher quality than that of the Bosch-Shaft. Note: The aim of this investigation with regard to the FVA involute waviness artifacts was primarily to analyze a suitable measurement object with specifically applied waviness with different measuring systems and not to achieve comparability with the FVA research project no. 733 I, since the detection of the helix angle of waviness (βw) was not part of the investigation in the FVA project at that time.</span></p><p><span style="font-size: 14px; font-family: arial, helvetica, sans-serif;">The use of fringe projection measuring systems for gear metrology is generally suitable. However, the suitability depends heavily on the measuring object. Classic characteristics are comparable to tactile measuring systems in the range of Δ &lt; 5 μm, and in some cases, much more accurate in the range of Δ &lt; 3 μm. Regarding waviness characteristics, suitability can be assessed as conditional. If orders are found, they are quite comparable in the range of 50 &lt; Δ &lt; 200 nm to the amplitudes found by tactile systems. However, noise in the low-frequency range of the order spectrum and the partial lack of detection of orders in the high-frequency range can lead to misinterpretations regarding the noise analysis. On the other hand, the very good comparability of the helix angle of waviness (βw) is remarkable. Both the Bosch-Shaft and the FVA involute waviness artifacts were comparable to tactile measurement results in the range of Δ &lt; 1° to 1.5°. Basically, the causes of differences between optical and tactile measurement results can be found in the physical measurement principle itself. The issue of orthogonal accessibility in tooth spaces and generally accessibility in internal gears limits suitability. In addition, the working distance and the measuring field used influence the measurement point density. The subsequent polygonization of the individual scans of fringe projection measurement systems negatively impacts the measurement result, especially in edge areas, as it results in rounding effects. Regarding gears, these are primarily the transition areas from the root or protuberance area to the main involute area, as well as the transition from this to the tip relief or tip chamfer area. The effect is a potentially strong influence on the regression elements in the sub-areas, which primarily affects the calculation of profile and helix slope deviations (and thus also on the profile and helix total deviations). Likewise, of course, on the calculation of the regression elements in the relief areas, if existing. Additional efforts, such as spraying-in and cleaning the measurement objects as well as the attachment and removal of reference marks, have a primary effect on the total measurement time and only in a subordinate way on the measurement results. This can certainly be optimized for series measurements by means of fixtures and spraying devices. In contrast to the above-mentioned points, one of the strengths of fringe projection is definitely the possibility of additional visualization options such as a holistic color-coded nominal/actual comparison, if a CAD model of the gearing is available. Since a complete STL data model of the gear is always available for the determination of gear characteristics, the measurement scope can be adjusted at any time, also after the measurement process itself. For example, in the event of a gearbox failure, the data of individual gears could be re-evaluated for additional analyses and also with additional detailed topographical evaluations. Fringe projection thus primarily offers added value as a supplementary tool for development and analysis. Special features of the measurement software from Zeiss are, on the one hand, the possibility that the same measurement programs from&nbsp;Calypso&nbsp;and&nbsp;Gear Pro&nbsp;can be used for tactile and optical measurements with an identical measurement and evaluation strategy, and on the other hand, the advantage that an all-tooth measurement is not necessarily required to determine the helix angle of waviness (βw) (Ref. 4).</span></p>