Comparison between New and Old Standards of Surface Roughness

The main difference between the old and new standards is Rz, and the original Rz is the average height of ten points. Expressed by the average width Rsm of the contour unit. Within the sampling length, the average value of the micro-roughness spacing of the profile. Microroughness spacing refers to the length of contour peak and adjacent contour valley on the midline. ?

It is expressed by the contour support length ratio Rmr(c), which is the ratio of contour support length to sampling length. The length supported by contour lines is the sum of the lengths of line segments parallel to the center line and at a distance c from contour lines and their peak lines.

Extended data:

The surface roughness code requires marking roughness parameter value, sampling length value during measurement, processing texture, processing method, etc. The annotation direction of code and parameters is shown in the figure. When most parts have the same surface roughness, the most commonly used symbols and codes can be uniformly marked on the upper right corner of the drawing, and the word "other" should be added.

The height of uniformly marked codes and characters should be 1.4 times the height of codes and characters marked on other surfaces on the graph. In the face code injection method at different positions, the tip of the symbol must point to the surface from the outside of the material, and the direction of the number in the code is the same as that of the size number.

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