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Anglicky v odbornch pedmtech"Support of teaching technical subjects in EnglishTutorial:Engineering metrology

Topic: Measuring of surface parameters

Prepared by: Ing. Pavel Roek

Projekt Anglicky v odbornch pedmtech, CZ.1.07/1.3.09/04.0002je spolufinancovn Evropskm socilnm fondem a sttnm rozpotem esk republiky.

Measuring of surface parameters

In accordance with new conception of geometrical product specification, presently surface inequality devide and separate the unevenes as follows: Surface roughness factor with smallest pitch unevenessSurface wavinessSurface shape Factor with largest pitch uneveness determined by basic profileSurface profile

Defines following geometrical parameters:

R (Roughness) parameter calculated of roughness profile,

W (Waviness) parameter calculated of waviness profile,

P (Profile) parameter calculated of basic profile,Standard SN EN ISO 4287

Surface profile is line of intersection of the real surface of given plane.

Scanned profile is midpoints geometrical place of scanned point of given parameters.

Roughness profile is obtained from basic profile by suppression of long-wave components, it is the base for roughness parameters evaluation.

Filter profile is filter dividing profile components to long-wave and short-wave.

Basic standard terms

Basic roughness length (lr) is length in axis direction x used for uneveness identification characterising evaluated roughness profile. It numerically equals to wavelength of profile filter roughness.

Evaluation length (ln) is length in axis direction x used for evaluation of considered profile. Evaluated length can contain one or more basic lengths.Basic terms in mentioned standard

Average arithmetical tolerance of considered profile roughness (Ra) is arithmetic diameter of absolute ordinate values Z(x) in basic length range.Basic parameters of surface texture

Dividing line

Total height of roughness profile (Rt) is sum of height (Zp) of the highest profile lug and depth (Zv) of the lowest profile roughness depression in the evaluated range.Basic parameters of surface uneveness (inequality)

Basic lengthEvaluated length

Basic division of measured surface parameters

Turning, millingGrinding, sparkingSurface roughnessPeriodical surface (turning, milling)Irregular surface (grinding, sparking)Groves middle distance of roughness elementsArithmetic dividing valueMaximal heigth of profilr roughnessLimit wavelengthBasic lengthMeasured lengthTotal lengthPoint radiusDigitalised distance

Measuring conditions up to

abcdefgUX0,08-0,8Rz5Max.1,6Texture surface designation in technical documentsa Upper data U or lower L of determined limit requirements for surface quality can be given with one sided or 2 sided tolerance.

b - Filter type X normalized filter is Gauss filter (SN EN ISO 11562)

ground

c Filtration window limits wavelength range which are included into evaluation. Filters are characterised by limit wavelength value - cut-off.

d Profile and parameter complete graphic sign enables usage of 3 normalised groups of texture surface parameters.

e Evaluated length determined by basic length numbers.

f Interpretation of determined limit rule 16 % or max

g Limit value in micrometers.Texture surface designation in technical documents

Rule 16 %For parameters specified by upper parameter limit (U ) surfaces are acceptable if value mentioned in production documents exceeds maximal 16 % of all measured values of chosen parameters .For parameters specified by lower parameter limit (L ), surfaces are acceptable if values mentioned in production documents do not reach maximal 16 % of all measured values of chosen parameters.

Maximum ruleIt provides that at requirements specifying the highest parameter values during control, any of measured parameters values on whole controlled surface can not exceed value mentioned in production documents.Rules for surface roughness evaluation

Question 1:

What kinds of geometrical parameters does SN EN ISO 4287 standard define?

RW-P-Question 2:Explain terms:

Basic roughness length (lr),

Evaluation length (ln).

BUMBLEK, Leo. Kontrola a men. 1. Praha: Informatorium, 2009. 205 s. ISBN 978-80-7333-072-9

Mahr, MINIKATALOG VROBN MIC TECHNIKATranslation:www.seznam.czwww.slovnik.czJANATA, Petr. Handy slovnk technick anglicko-esk a esko-anglick. Plze: Nakladatelstv Fraus, 2000. ISBN 80-7238-075-3Lingea LEXIKON 5, Technick slovnk anglicko-esk a esko-anglick. 2010.

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