What is surface roughness of seals
Sep 14, 2021
The surface roughness of the seals refers to the small spacing and the unevenness of the small peaks and valleys of the processed surface. DSH seals believes that the distance (wave distance) between its two wave crests or two wave troughs is very small (below 1mm), which is a microscopic geometric shape error. The smaller the surface roughness, the smoother the surface.
The purpose of all surface finish sealing processing is to provide a surface that causes minimal wear for the seals.
Sealing on the moving surface and the piston rod seals may be damaged by fine abrasives adhering to the rough surface. Therefore, the surface roughness value of the piston rod seals should be small, while having a surface and corrosion resistance similar to the best hard chromium. The ideal surface roughness value is between 0.16 to 0.40 μm (Ra) or 1.0 to 2.5 μm (Ra).
The piston seal that seals on the inner surface of the cylinder is not greatly affected by abrasive dirt particles entering from the atmosphere, so it can allow rougher surfaces. The ideal surface roughness value is between 0.25 to 0.63 μm (Ra) or 1.6 to 4.0 μm (Ra). When assessing surface properties, work pressure must also be considered. Under higher working pressure, the oil film between the seal and the sealing surface is thinner and the friction is larger. Under such working conditions, the level of surface roughness should be selected at a lower value within the range of data given above.
The surface grade of the static sealing groove surface should be about 1.6μm (Ra) or 10μm (Ra).
