Surface Finish Hybrid Parameters

What are Surface Finish Hybrid parameters?

R∆q, W∆q, P∆q, Rλq, Wλq, Pλq

where θ (x) is the slope of the profile at any given point, x.

Rλq is the root-mean-square (rms) wavelength of the roughness profile and is a measure of the spacings between local peaks and valleys, considering their relative amplitudes and individual spatial frequencies.

W∆q, Wλq, P∆q, and Pλq are the corresponding parameters from the waviness and primary profiles, respectively.

Material Ratio Rmr(c), Rmr, RSc

Material Ratio Rmr(c) is the length of bearing surface at a level c. The level may be defined in different ways. The figure above shows the level defined as a depth below the highest peak.

Rmr is defined as the material ratio determined at an offset relative to a previously defined reference level. Rδc – the height difference between two section levels of given material ratio.

Material Ratio

The material ratio (or Abbott-Firestone) curve below, shows how the material ratio varies with level.

Rpk, Rk, Rvk, Mr1, Mr2

These parameters were specifically designed for the control of the potential wear in cylinder bores in the automotive manufacturing industry.

Rpk is the Reduced Peak Height – the top portion of the surface which will quickly be worn away when the engine begins to run. Rk is the Kernel Roughness Depth – the long term running surface which will influence the performance and life of the cylinder. (The depth of the Roughness Core Profile).

Rvk is the Trough Depth – the oil retaining capability of the deep troughs which have been machined into the surface. Mr1 is the material ratio corresponding to the upper limit of the roughness core. Mr2 is the materix ratio corresponding to the lower limit of the roughness core.