求助：表面粗糙度的關系。RA=1.06um, RMS=1.2um, 150 grit

李夏天

求助各位大俠：

請問這個幾個粗糙度的表達方式是什么關系？

8 e) C% B* q+ E, Q+ W% W6 vRA=1.06UM, RMS=1.2 UM, 150 grit
2 K; B7 J( f: X
印象當中粗糙度的等級里面沒有1.06的，還有RMS和RA有什么關系和區別？150 grit是指什么？
1 S: u+ q8 P! R, v3 J
! n. A; g2 [& x) B謝謝！

李夏天

頂起來。請大家幫忙啊。。。

伊凡

Surface roughness can be measured by a profilometer, a stylus device used to trace across the surface profile. The results are expressed either as RA, which is the arithmetic average deviation from the center line of the surface, or as RMS, which is the root mean square of the deviations from the center line. RA or RMS  values are given in either microns (same as micrometers or µm) or micro-inches (µ"). On drawings, surface roughness is specified as RA in micro-inches. RMS will be approximately 11 percent higher than the RA number for a given surface. [RA x 1.11 = RMS]
) W' `  f9 @' ^" M7 d
2 Z& ~4 F; P; \7 n3 QSurface Measurement Comparisons (Meltzer 1993)

RMS (microinch)	RMS(µm)	RA (microinch)	RA (µm)	Grit Size
80 58 " k- u/ i% o" x4 a  S47 34 ( q  }! v0 z! `6 I17 " R, Y2 `% }( S/ t+ k. q. B14 8 P' U# l: D: Y6 Q0 A	2.03 1.47 1.2 ; p2 Z& p3 F# ]! J0.6 0.43 0.36	71 52 42 30 15 ( f. `2 b  Z7 z- C12	1.90 1.32 1.06 1 H+ Y% O: d; b0.76 0.38 1 m$ B* \7 [" w" Z0.30 4 l( R4 a% h; `2 m6 P6 p4 ?	80 120 ; ^% \( Y2 e: y# w& l8 h150 + d' W: D* f. T5 U180 . z  K( I; I6 h240 8 s- o8 b4 A8 F7 `320 0 [$ k9 u# u+ a% L7 V! |
These values are the average data of many tests. Because of the many variables that create this data, deviations of ±5% would be considered well within good measurement parameters. From Bulletin on Material Welds and Finishers by DCI, Inc. (Meltzer 1993)

+ ]* \: [, O" B* w: i8 {; KRoot-Mean-Square【數】均方根(值)

9 M; {8 }4 I' W- ^5 z1 ^" C9 _[ 本帖最后由 ivantse 于 2008-1-14 10:51 編輯 ]

伊凡

Grit size refers to the size of the particles of abrading materials embedded in the sandpaper. A number of different standards have been established for grit size. These standards establish not only the average grit size, but also the allowable variation from the average. The two most common are the United States CAMI (Coated Abrasive Manufacturers Institute, now part of the Unified Abrasives Manufacturers' Association) and the European FEPA (Federation of European Producers of Abrasives) "P" grade. The FEPA system is the same as the ISO 6344 standard. Other systems used in sandpaper include the Japan Industrial Standards Committee (JIS), the micron grade (generally used for very fine grits). The "ought" system was used in the past in the United States. Also, cheaper sandpapers sometimes are sold with nomenclature such as "Coarse", "Medium" and "Fine", but it is not clear to what standards these names refer.

關于磨輪的grit size(From Answers.com)
* t& j% I  L1 Y
2 Q; y2 c: q9 q9 A& QSize of the abrasive particles on a grinding wheel.
4 b% ]+ T7 T1 K+ J* y, l1 X
" ^! L2 N+ w7 W6 I8 \- g% h% V4 I3 o[ 本帖最后由 ivantse 于 2008-1-14 10:59 編輯 ]

datafield

以前我一直認為RMS就是微英寸，原來是RA x 1.11 = RMS。伊凡給的資料很好！謝謝！