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Anglicky v odborných předmětech "Support of teaching technical subjects in English “

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  1. Anglicky v odborných předmětech"Support ofteachingtechnicalsubjects in English“ Tutorial: Engineeringmetrology Topic:Measuringofsurfaceparameters Preparedby:Ing. Pavel Rožek Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

  2. Measuring of surface parameters

  3. Surface profile 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 uneveness • Surface waviness • Surface shape – Factor with largest pitch uneveness determined by basic profile

  4. Standard ČSN EN ISO 4287 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,

  5. Basic standard terms • Surface profile is line of intersection of the real surface of given plane. • Scanned profile is midpoint’s 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.

  6. Basic terms in mentioned standard • 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.

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

  8. Basic parameters of surface uneveness (inequality) • 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 length Evaluated length

  9. Basic division of measured surface parameters Grinding, sparking Turning, milling Periodical surface (turning, milling…) Surfaceroughness Irregular surface (grinding, sparking…) Measuringconditions up to Limit wavelength Basic length Measuredlength Totallength Point radius Digitalised distance Maximalheigthofprofilrroughness Grovesmiddle distance ofroughnesselements Arithmeticdividingvalue

  10. Texture surface designationin technical documents ground a – Upper data Uor lower Lof 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 (ČSN EN ISO 11562)

  11. Texture surface designation in technical documents 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.

  12. Rules for surface roughness evaluation 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 notreach maximal 16 % of all measured values of chosen parameters. Maximum rule It 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.

  13. Question 1: What kinds of geometrical parameters does ČSN EN ISO 4287 standard define? R – W - P - Question 2: Explain terms: • Basic roughness length (lr), • Evaluation length (ln).

  14. Literature • BUMBÁLEK, Leoš. Kontrola a měření. 1. Praha: Informatorium, 2009. 205 s. ISBN 978-80-7333-072-9 • Mahr, MINIKATALOG – VÝROBNÍ MĚŘICÍ TECHNIKA Translation: • • • JANATA, Petr. Handy slovník technický anglicko-český a česko-anglický. Plzeň: Nakladatelství Fraus, 2000. ISBN 80-7238-075-3 • Lingea LEXIKON 5, Technický slovník anglicko-český a česko-anglický. 2010.