VDA 2007-2007 Geometrical product specification - Surface texture - Definitions and characteristic values of the dominant waviness《产品几何技术规范 表面结构 主导波纹的定义和特征值》.pdf

1、VDA Recommendation February 2007 Geometrical Product Specifications Surface Texture Definitions and Parameters of the Dominant Waviness VDA 2007 Descriptors: surface texture, waviness, evaluation, rules, methods Page 1 of 7 GERMAN ASSOCIATION OF THE AUTOMOTIVE INDUSTRY (VDA) Westendstrae 61, 60325 F

2、rankfurt Distribution: DOKUMENTATION KRAFFAHRTWESEN E.V. (DKF) Ulrichstrae 14, D-74321 Bietigheim-Bissingen Preface This VDA Recommendation deals with periodically occurring waviness in surfaces. It describes an evaluation method that identifies the periodic dominant surface characteristics and eval

3、uates them using a WD waviness profile, from which parameters are subsequently derived. In particular, the division of wavelength ranges into a grid with graduated wavelength limit as suggested in DIN EN ISO 4288 is omitted in the determination of the waviness profile WD. The dominant wavi-ness meth

4、od thus ensures that periodic waviness is always correctly identified and evaluated. Ex-periences have been primarily made in the field of static and dynamic mating surfaces. Changes The following changes have been made as compared to the 2003-07 issue: The validity range was defined in Section 3.10

5、. Only one dominant form of waviness is defined. Sections 3 to 8 are changed accordingly. The validity range represents an additional item to be indicated where vertical parame-ters are specified (Section 8). The examples in Appendix A were revised and reduced in number. 1 Scope This Recommendation

6、applies to surfaces whose function can be influenced by waviness. Periodic waviness is detected and evaluated within a wide range of period lengths varying from 0,02 mm to several mm. 2 Normative references The following normative documents contain specifications that, through reference in this text

7、, con-stitute provisions of this VDA Recommendation. For dated references, subsequent amendments or revisions to this publication do not apply. Users of this VDA Recommendation are nevertheless requested to check whether it is possible to use the latest versions of the following normative documents.

8、 For undated references, the latest edition of the normative document referred to ap-plies. Members of ISO and IEC maintain directories of the valid international standards. VDA 2005: 2006, Geometrical Product Specifications (GPS), Engineering Drawings, Specification of Surface Texture VDA 2006: 200

9、3, Geometrische Produktspezifikation (GPS), Oberflchenbeschaffenheit, Regeln und Verfahren zur Beurteilung der Oberflchenbeschaffenheit (Geometric Product Specification (GPS), Surface Texture, Rules and Methods for Evaluating Surface Texture - only available in German) DIN EN ISO 3274: 1998, Geometr

10、ical Product Specifications (GPS), Surface Texture: Profile Me-thod, Nominal Characteristics of Contact Stylus Instruments DIN EN ISO 4287: 1998, Geometrical Product Specifications (GPS), Surface Texture: Profile Me-thod, Terms, Definitions and Surface Texture Parameters DIN EN ISO 4288: 1998, Geome

11、trical Product Specifications (GPS), Surface Texture: Profile Me-thod Rules and Procedures for the Assessment of Surface Texture The English translation is believed to be accurate.In case of discrepancies the German version shall govern. Numerical notation according to ISO practice (seeVW 01000). Pa

12、ge 2 VDA 2007: 2007-02 3 Definitions 3.1 Surface profile The surface profile is defined in DIN EN ISO 4287. The measurement direction can be specified in the drawing. Otherwise, the measurement direction shall be selected such that measurement is conducted in areas where waviness is most pronounced

13、and where it has the shortest period. 3.2 Primary profile The primary profile is generated from the surface profile, as described in DIN EN ISO 3274. How-ever, the application of the s filter for short wavelengths is not permitted on principle. For excepti-ons see VDA 2006. 3.3 Periodic waviness Per

14、iodic waviness in a surface includes irregularities arising due to oscillations caused by produc-tion or machining as well as due to oscillation-like relative movements. 3.4 Frequency analysis A surface profile is understood to be the sum of sine waves with different wave lengths. The fre-quency ana

15、lysis transforms the surface profile into the frequency range and determines the ampli-tude and phase position of the sine wave for each frequency. 3.5 Amplitude spectrum The amplitude spectrum shows the characteristics of the surface depending on the ordinal number, which indicates how often a wave

16、 length is contained in the evaluation length. The period lengths with dominant characteristic are identified in the amplitude spectrum. The ordinal numbers 1 to 5 are not taken into consideration, since a wavelength must be contained at least 5 times in an evaluation length in order to ensure a rel

17、iable evaluation (Section 5). 3.6 Zero bandpass filter The zero bandpass filter is a bandpass filter with a nominal bandwidth of zero. In this particular case, the wavelength limit of the low-pass filter is equal to the wavelength limit of the high-pass filter. The signal transmission at the point o

18、f the wavelength limit is reduced by double-filtering and is again compensated to 100% by an appropriate multiplication, for example by a factor of 4 in the case of the Gaussian filter. Thus, other wavelengths in the surface are not transmitted or are only transmitted in a highly damped manner. 3.7

19、Dominant wave length The dominant wavelength is a period length in the horizontal direction, for which the wavelength characteristics in the vertical direction are dominant. Such dominant characteristics are detected when limit criteria are met. The analysis defines 0 or 1 dominant wavelength. 3.8 D

20、ominant waviness profile WD The dominant waviness profile WD is derived from the primary profile. Influences of the roughness and shape are eliminated using the zero bandpass method. Page 3 VDA 2007: 2007-02 3.9 Profile elements Profile elements refer to the WD profile and are defined as in DIN EN I

21、SO 4287. 3.10 Validity range The validity range is the range of period lengths specified in the drawing note or by the choice of measuring conditions, in which the vertical parameters WDc and/or WDt are evaluated or in which those parameters must not exceed their respective limit value. If the measu

22、red WDSm value lies outside the validity range, the vertical parameters are not subjected to any limitations. 4 Definitions of the dominant waviness parameters 4.1 Vertical waviness parameters 4.1.1 Mean height of profile elements WDc The mean height of profile elements WDc of the dominant waviness

23、profile WD is the mean value of the vertical differences of the highest and lowest points of the profile elements within the evalua-tion length based on DIN EN ISO 4287 section 4.1.4. 4.1.2 Total profile height WDt The total height WDt of the waviness profile WD is the vertical difference between th

24、e highest and lowest point within the evaluation length according to DIN EN ISO 4287 section 4.1.5. 4.2 Horizontal waviness parameter WDSm In the amplitude spectrum, the dominant wavelength as described in Section 3.7 meets the limit conditions for the property dominant waviness. It characterizes th

25、e horizontal dimension of the pro-file elements and determines the horizontal waviness parameter WDSm. The parameter WDSm, which is derived from the amplitude spectrum, generally corresponds to the mean width of the pro-file elements of the WD profile. 5 Identifying dominant waviness Manufactured su

26、rfaces are tested for dominant waviness characteristics. In the amplitude spec-trum, each order is assigned a corresponding amplitude. The period length WDSm with dominant amplitude is identified by comparing the amplitudes with one another, provided that horizontal and vertical limit criteria are f

27、ulfilled. The evaluation length is chosen either as in a roughness measurement according to DIN EN ISO 4288 Table 2 or based on the drawing note. Period lengths are examined for domi-nance within the range 0,02 mm WDSm ln/5. In order to identify dominant characteristics for WDSm ln/5, the evaluation

28、 length must be increased. Page 4 VDA 2007: 2007-02 6 Determining the dominant waviness tolerance There are 2 different approaches for the design engineer to determine the dominant waviness tol-erance: dominant characteristics are permissible up to an upper limit value dominant characteristics are p

29、ermissible to a limited extent in range of period lengths having either an upper limit or both an upper and lower limit 7 Drawing notes Drawing notes are based upon the different tolerances described in section 6 and upon the way in which the evaluation length was determined. Further examples can be

30、 found in VDA 2005. The validity range shall preferably be specified in the drawing note. 7.1 Drawing notes without specification of validity range The evaluation length ln is chosen according to DIN EN ISO 4288. The validity range of the exam-ined period lengths WDSm is 0,02 mm WDSm ln/5. No period

31、ic characteristics have yet been observed below 0,02 mm. 7.1.1 Surface with a limit to dominant waviness Drawing notes permitting dominant waviness to a limited extent are: WDc 1,6 and/or WDt 2,5 This means that the upper limit value for the mean height of profile elements is 1,6 m and 2,5 m for the

32、 total height of the WD profile. The validity range extends from 0,02 mm to ln/5 mm. 7.2 Drawing notes with upper limit to validity range The design engineer selects the upper limit of the period length WDSm for the drawing note ac-cording to the function of the surface. The lower limit is 0,02 mm.

33、The evaluation length is greater than or equal to 5 times the upper limit. Page 5 VDA 2007: 2007-02 7.2.1 Surface with a limit to dominant waviness Drawing notes permitting dominant waviness to a limited extent include, for example: upper limit value of period length number of period lengths paramet

34、er upper limit value of parameter 1,2 x 5 / WDc 1,6 The validity range extends from 0,02 mm to 1,2 mm. 7.3 Drawing notes with upper and lower limit to validity range The design engineer selects the lower/upper limit of the period length WDSm for the drawing note according to the function of the surf

35、ace. The evaluation length is greater than or equal to 5 times the upper WDSm limit. 7.3.1 Surfaces with a limit to dominant waviness Drawing notes permitting dominant waviness to a limited extent include, for example: lower limit valueof period length upper limit valueof period length number ofperi

36、od lengths parameter upper limit value of parameter 0,3 - 1,2 x 5 / WDc 1,6 The validity range extends from 0,3 mm to 1,2 mm. 8 Representation of measurement results The vertical parameters are represented in measurement reports such that the validity range of the individual parameters is specified.

37、 If a lower limit to the validity range is not specified in the drawing note, testing for dominant characteristics shall begin at a period length of 0,02 mm. The standard lower limit to the validity range of 0,02 mm is not specified in representations of the measurement results. If dominant characte

38、ristisc are located outside the validity range, they will not be included in the tolerance considerations. In this case, the parameter value is “0D“. Listed below are examples for results indicated in the measurement report (specifications in squared brackets = validity range): WDc2,5 WDt2,5 WDSm 0

39、m 0 m 0 mm surface does not exhibit dominant characteristics WDc1,5 WDt1,5 WDSm 0D m 0D m 2,5 mm surface exhibits dominant characteristics outside the validity range, which remain unevaluated WDc0,8 WDt0,8 WDSm 1,8 m 2,3 m 0,6 mm surface exhibits dominant characteristics WDc0,3 2,5 1,1 m surface exh

40、ibits dominant characteristics WDt0,3 2,5 1,9 m WDSm 0,4 mm WDSm = 0 means that the evaluated range of period lengths does not exhibit any dominant char-acteristics. If tolerance limits are specified for WDSm, these requirements are fulfilled for WDSm = 0. Page 6 VDA 2007: 2007-02 Appendix A (inform

41、ative) Graphical representation of a dominant waviness profile WD Example 1: Surface characteristic with one dominant waviness profile WD Figures 1 to 3 show the unfiltered P profile in comparison to the W and WD profiles derived from it. The unusual aspect of the WD profile is that it is separate f

42、rom all roughness influences, non-periodic waviness and shape influences and represents only the periodic dominant waviness. Figure 1: P profile Figure 2: W profile, c=2,5 mm Figure 3: WD profile with WDc2,5 = 2,42 m WDt2,5 = 3,94 m WDSm = 1,15 mm Page 7 VDA 2007: 2007-02 Example 2: Surface characteristics without dominant waviness profile WD This ground surface is free of periodic waviness and accordingly has no WD profile. Figure 4: P profile Characteristic values: WDc2,5 = 0 m WDt2,5 = 0 m WDSm = 0 mm Profile height in m evaluation length in mm