1、Designation: F 548 03ae1Standard Test Method forIntensity of Scratches on Aerospace Transparent Plastics1This standard is issued under the fixed designation F 548; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTESection 4 was editorially corrected in August 2005.1. Scope1.1 This test method covers the visual inspection of shallowor superfic
3、ial scratches on the surface of aerospace transparentplastic materials.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine th
4、e applica-bility of regulatory limitations prior to use.2. Summary of Test Method2.1 A visual comparison is made between a set of gradedscratch standards and the scratch on the plastic material todetermine the relative intensity of the scratch.3. Significance and Use3.1 Scratches exist on all transp
5、arent plastic surfaces. Usu-ally they are very fine scratches from cleaning operations thatare not visible when looking through the plastic. Deeperscratches may result from careless cleaning or handling. Whilethese may not be deep enough to affect the structural integrityof the part, their appearanc
6、e in certain locations may bedistracting to the observer looking through the plastic. There-fore, a procedure to define these scratches is useful.4. Reference MaterialsNOTE 1Adjuncts are not currently available.5. Procedure5.1 Place the part in a suitable inspection position. This maybe horizontal o
7、n a padded table, vertical against a neutralbackground, or at an angle. The scratched surface shall betoward the observer. The light level shall be a minimum of 80lux. Either natural or artificial light may be used. Place thescratch in the visual comparison standard beside and parallel tothe scratch
8、 on the plastic material. Rotate the part or viewingangle to get the best definition of the scratch. Disregarding thelength of the scratch on the plastic material and on thestandard, select and record the highest standard scratch thatmost clearly matches the appearance of the scratch on theplastic m
9、aterial. Measure and record the length of the scratch tothe nearest 1 mm (0.04 in.).6. Interpretation6.1 Customer specifications for transparent plastic materialsand parts may detail allowable frequency, location, length, andstandard number for scratches and they may assign maximumscratch limits for
10、 critical and noncritical optical viewing areas.7. Report7.1 For each scratch within the scope of the plastic scratchstandard, report its standard number, length, frequency, andlocation.8. Precision and Bias28.1 Precision:8.1.1 The repeatability of judging the intensity of a scratchwithin one scratc
11、h value, for the same observer, is 92 % orbetter.8.1.2 The reproducibility (between observers) of judgingthe intensity of a scratch within one scratch value is 90 % orbetter for scratch values 14 and above. The reproducibility ofjudging the intensity of a scratch within two scratch values is92 % or
12、better for scratch values below 14. The data reflect thatit is more difficult to judge finer scratches.8.2 BiasThe procedure in this test method has no biasbecause the scratch intensity is defined only in terms of the testmethod.9. Keywords9.1 comparison standard; scratches; transparent plastic1This
13、 test method is under the jurisdiction of ASTM Committee F07 onAerospace and Aircraft and is the direct responsibility of Subcommittee F07.08 onTransparent Enclosures and Materials.Current edition approved July 12, 2005. Published November 2003. Originallypublished in 1981. Last previous edition app
14、roved in 2003 as F 548 03.2A research report is available from ASTM International Headquarters. RequestRR:F07-1007.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.APPENDIX(Nonmandatory Information)X1. COMPARISON OF GLASS AND PLASTIC
15、SCRATCH RATINGSX1.1 A study was performed to determine equivalentrelationships between glass and plastic scratch adjuncts. Thisempirically defined relationship can be used if needed when:(1) only glass adjuncts are available to judge the intensity ofscratches in plastic, (2) only plastic adjuncts ar
16、e available tojudge the intensity of the scratches in glass, or (3) it is desirableto convert between the glass and plastic scales.X1.2 Five trained observers rated eight glass and eightplastic scratches. Each scratch was rated using both glass andplastic adjuncts three times. The 96 trials for each
17、 observerwere randomized with the constraint that there be at least fivetrials between replications of the same scratch and either glassor plastic adjunct.X1.3 Fig. X1.1 contains the estimated relationship betweenthe glass (G) and plastic (P) scratch ratings and between theplastic and glass ratings.
18、 Fig. X1.2 shows the number of trialsfor each observer and scratch having a particular scratch ratingwhen compared with either glass or plastic adjunct.NOTE 1The 3 means near (P = 11,G=3)andthe2means near (P = 15,G=8)were not used since they contained multiple trials where the glassrating was either
19、 3 or 8+.FIG. X1.1 Non-Linear Regression Fit of Mean Scratch Ratings (N = 15)F 548 03ae12FIG. X1.2 Number of Trials for Each Observer and Scratch (N = 3) Having a Particular Scratch Ratingwhen Compared with Either Glass or Plastic AdjunctF 548 03ae13ASTM International takes no position respecting th
20、e validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard i
21、s subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International He
22、adquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This s
23、tandard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F 548 03ae14
