Surface Texture Parameters
Professor : R. J. Chang
Student : R. Z. Huang
Date : 2004 / 04 / 14
Surface Texture Parameters
Amplitude Parameters Spacing Parameters Hybrid Parameters ADF and BRC Parameters
Roughness Amplitude Parameters
Ra Rq Rt 、 Rv 、 Rt Rtm 、 Rvm 、 Rtm Rymax Rz
Ra - Average Roughness
Continuous:
Discrete:
Ra is Not the End of the Story
These three surfaces all have the same Ra, even though the eye immediately distinguishes their different general shapes.
Rq - Root-Mean-Square Roughness
Continuous:
Discrete:
Rq is more sensitive to peaks and valleys
Rt, Rp, and Rv
Rtm, Rpm and Rvm
Rymax (or Rmax) and Rz
Rz(DIN), i.e. Rz according to the German DIN standard, is just another name for Rtm in the American nomenclature
Rymax (or Rmax) - Maximum Roughness Height Within a Sample Length
Roughness Spacing Parameters
Sm - Mean Spacing
Roughness Hybrid Parameters
Dq - RMS Average Slope
Continuous:
Da - Average Absolute Slope
Discrete:
Discrete:Continuous:
Statistical Analysis
The Amplitude Distribution Function
Rsk -Skewness
Continuous:
Discrete:
The Bearing Ratio Curve
tp as a parameter refers to the bearing ratio at a specified height
The bearing ratio curve is the integral (from the top down) of the ADF
Advanced Statistical and Bearing Ratio Analysis
Rk is the vertical height between the left and right intercepts of the - line through the ends of the minimum Htp 40% window.
This part of the surface is called the "core roughness"
Rk 、 Rpk 、 Rvk 、
MR1 、 MR2 、
A1 and A2 are determined by BRC
Rpk 、 Rvk 、 MR1 and MR2 Rpk Rpk is an estimate of the small peaks above the main plateau of
the surface. Rvk Rvk is an estimate of the depth of valleys which will retain lubri
cant in a functioning part. MR1 MR1 is the fraction of the surface which consists of small peaks
above the main plateau. MR2 MR2 is the fraction of the surface which will carry load during th
e practical lifetime of the part.
A1 and A2 A1 The "area" of the peak portion of the bearing ratio c
urve is denoted by A1. It is related to Rpk and MR1
A2 The "area" of the valleys in the Rk construction is de
noted by A2. It is related to Rvk and MR2:
Reference
http://www.predev.com/smg/parameters.htm#tp%20-%20Bearing%20Ratio
http://www.fujimfg.co.jp/benri/roughness.htm
http://www.htskorea.com/tech/spm/profile.pdf
Top Related