Surface characteristics of covered rollers

Roughness · ISO 6123/2-1982

CARACTÉRISTIQUES DE SURFACE DES ROULEAUX GARNIS

The information in this sheet refers to standard ISO 6123/2-1982, which defines the roughness specifications of rubber-covered rollers.

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Roughness measurement

The finish of rubber-covered rollers is expressed in micrometers (µm) — or in microinches (µin) in North America. 1 µm ≈ 39.37 µin.

Two standardized parameters:

Ra
— arithmetic mean deviation of the profile from the mean line.
Rz
— average height of irregularities over 5 points (peak-to-valley amplitude).

Roughness profile — Ra: deviation from the mean line · Rz: peak-to-valley amplitude.

Portable roughness tester

direct reading of Ra / Rz (µm or µin)

Possible finishes

Polishing

On soft elastomers the surface is velvety; on harder elastomers it is smooth. Grinding marks and scratches must not be visible to the naked eye; isolated grinding defects are allowed. Note: not all elastomer grades can be polished.

Fine grinding

Light grinding and feed marks are visible to the naked eye but are not perceptible when touching the roller.

Standard grinding

Very light grinding and progression traces are visible but barely perceptible when the roller is touched.

Turning

The surface is turned only, with the smallest possible lathe feed. Turning scratches are visible and perceptible to the touch.

As-is (raw)

The roller surface has no surface treatment or dressing: a canvas imprint as it comes from vulcanization, or polyurethane casting marks.

Special finish

This finish applies to any surface finish other than those described above, or outside the standards.

Hardness vs roughness

The same treatment gives different roughness values depending on the cover hardness — and, to some extent, the compound. In each cell: µm (top) and µin (bottom).

Finish type	Cover hardness
	Shore A < 50		50 to 70		71 to 99		≈ 100
	P&J > 120		P&J 120 to 70		P&J 69 to 10		P&J 9 to 10
	Ra	Rz	Ra	Rz	Ra	Rz	Ra	Rz
Polishing	5 197	31.5 1240	3.15 124	20 787	1.6 63	10 394	1 39	6.3 248
Fine grinding	6.3 248	40 1575	4 157	25 984	2.5 98	16 630	1.6 63	10 394
Standard grinding	10 394	63 2480	6.3 248	40 1575	4 157	25 984	2.5 98	16 630
Turned	∗ Not available ∗
As-is	∗ Not available ∗

Standardized roughness values — µm (top) / µin (bottom, microinches). "Turned" and "As-is": values not available (depending on compound and treatment).

Soremag expertise

As specialists in roller grinding and polishing, with our equipment and know-how we routinely achieve surface finishes significantly finer than the standardized values in this table. Tell us about your specifications.

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