表面粗糙度计量剖析剖析.ppt

表面粗糙度 计量 目录 1. 为什么要测量表面粗糙度? 表面的特性 表面的特性 表面的特性 表面的特性 表面的特性 表面的特性 在表面上有害的缺陷 在表面上需要的特性 为什么需要测量表面粗糙度? 为什么需要测量表面粗糙度? 为什么需要测量表面粗糙度? 为什么需要测量表面粗糙度? 为什么需要测量表面粗糙度? 2. 测量方法 测量方法 如何测量表面粗糙度? 测量方法 测量方法 压电式传感器 激光式传感器 3. 测量基准 测量基准 测量基准 测量基准 测量基准 测量基准 测量基准 4. 表面再现 表面再现 表面再现 表面再现 表面再现 5. 术语 6. 滤波 7. 参数 基底表面的峰将导致橙色油漆脱落 Effects of Surface Slopes on vibration noise 8. 承载区域 (材料比) 9. Rk 参数 10. 形状测量 11. 标定方法 Conics Aspherics 3D (Areal) Measurement Drawing Indication End Reproducing the Surface How Do We Measure Surface Finish? How Do We Measure Surface Finish? How Do We Measure Surface Finish? Surface finish instruments use three types of conventional filter as show above, these consist of analogue filters or digital filters which simulate analogue filters. Ideally the characteristics of the filter type should change abruptly at the selected cut-off length. Any wavelengths shorter than the cut-off length should pass through the filter unaffected, while those wavelengths greater than the cut-off length should be suppressed, hence the term “cut-off”. The ISO 2CR (2 capacitor 2 resistor) filter which was the first type of electronic filter to be used, has the ability to transmit 75% of the wavelengths at the cut-off value selected. Which means that the amplitudes of wavelengths equal to the cut-off length will be reduced by 75% of there value. The ISO 2CR filter exhibits a certain characteristic, which is shown on the following slide. If we compare the unfiltered profile and the same profile analysed using an ISO 2CR filter we can see that a shift in the phase of the profile has been introduced, causing some distortion. This effect is greatest at wavelengths which are close to the cut-off length. This phase shift is caused by a time delay in the filtering of the profile which is caused by the charge up time or rise time of the capacitor in the 2CR circuit. This time delay can have a significant effect on height parameters. To overcom