ASTM D2562-1994(2015) Standard Practice for Classifying Visual Defects in Parts Molded from Reinforced Thermosetting Plastics《增强热固塑料模制零件中可见缺陷分类的标准实施规程》.pdf
《ASTM D2562-1994(2015) Standard Practice for Classifying Visual Defects in Parts Molded from Reinforced Thermosetting Plastics《增强热固塑料模制零件中可见缺陷分类的标准实施规程》.pdf》由会员分享,可在线阅读,更多相关《ASTM D2562-1994(2015) Standard Practice for Classifying Visual Defects in Parts Molded from Reinforced Thermosetting Plastics《增强热固塑料模制零件中可见缺陷分类的标准实施规程》.pdf(6页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: D2562 94 (Reapproved 2015)Standard Practice forClassifying Visual Defects in Parts Molded from ReinforcedThermosetting Plastics1This standard is issued under the fixed designation D2562; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers acceptance criteria for visual in-spection of parts molded from rein
3、forced thermosetting plasticsby compression and transfer molding.1.2 This practice presents word descriptions of possibledefects to serve as a guide for contracts, drawings, productspecifications, and final inspection.1.3 This practice also categorizes different inspection re-quirements for grades o
4、f product quality.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 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 standar
5、d to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 1There is no known ISO equivalent to this standard.2. Acceptance Criteria2.1 The method and frequency of sampling and the allow-able defects may be previously agreed t
6、o by the purchaser andthe seller.2.2 Dimensions and TolerancesMolded parts shall beinspected for conformance with the dimensions and tolerancesspecified on the product drawing. Parts with any dimensionsfalling outside the specified limits shall be rejected.2.3 InsertsAll inserts, nuts, studs, and lu
7、gs shall not bedamaged in any way, nor coated with molding materials insuch a way as to impair function or mechanical fit. Threads inmolded-in inserts shall be clean, smooth, and free of nicks,tears, or other damage. There shall be no molding material orflash on the threads. If necessary, threaded i
8、nserts may beretapped to clean them or remove flash. Threads containinglocking features may not be retapped.2.4 Molded-In Threads or Cored HolesMolded-in threadsor cored holes shall be free of visible defects, such as nicks,cracks, shorts, etc. Molded-in threads may be retapped orrepaired unless oth
9、erwise specifically noted on the productdrawing.2.5 WorkmanshipWorkmanship shall be in accordancewith good commercial practices.2.6 Critical AreasAreas in which the presence of imper-fections is considered to be detrimental to the proper functionof the part shall be designated as critical areas. The
10、 areas of apart that are critical structurally, aerodynamically, or electri-cally shall be uniform and free of defects as listed in Table 1,if so stated on the product drawing. Critical areas may bedesignated on the product drawing by one of the followingmeans,2.6.1 Encircle critical areas, or2.6.2
11、Cross-hatch areas to designate areas of various levels,or2.6.3 Word description.2.7 Acceptable DefectsUnless otherwise specified, thefollowing defects shall be acceptable in all instances:2.7.1 Ripple SurfaceGenerally occurs in parts moldedfrom long, glass-fiber-filled, high-impact-type plastics. Su
12、ch asurface is a phenomenon resulting from the difference inshrinkage between the resin binder and reinforcement.2.7.2 Shrink-MarkA dimple-like depression in the surfaceof a molding where it has retracted from the mold, and whichhas well-rounded edges. A shrink-mark generally occurs onone surface of
13、 a part where there is a boss, flange, rib, or otherheavy section on the opposite surface. The shrink-mark may becaused by the difference in total shrinkage when there is asudden change in section along the surface of the part.2.7.3 Resin VoidsApplicable to chopped fabric-reinforcedmolding compounds
14、 only, appearing as multiple surface inter-ruptions which conform to the pattern of the cloth weave. Thisis usually due to an insufficient flow or shrinkage of the resin,which fails to fill all of the interstices of the fabric reinforce-ment. These defects occur only at the surface layer of resin in
15、contact with the mold.1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.18 on Reinforced ThermosettingPlastics.Current edition approved . Published September 2015. Originally approved in1966. Last previous edition approved i
16、n 2008 as D2562 94 (2008). DOI:10.1520/D2562-94R15.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.7.4 Surface DiscolorationAn apparent nonuniformity ofa material, evidenced by the appearance of dark streaks.Surface streaks are freq
17、uently caused by incorporation into theplastic of ejector pin lubricant, mold release, or metallic matterabraded from ejector pins.2.7.5 Weld- or Knit-LinesMarks on, or weaknesses in, amolded plastic, formed by the union of two or more streams ofplastic flowing together, that do not result in a brea
18、k orinterruption of the molded surface.2.8 Allowable DefectsDefects which, by nature, content,or frequency, do not affect serviceability of the part. Theseallowable defects shall be fully described as to type, size,number, extent allowed, and spacing. The appropriate accep-tance level (Table 1) for
19、defects in these areas must bespecified. Defects in excess of those listed as allowable in theproduct specifications, drawings, or contracts for the part shallbe cause for rejection.2.9 Repairable DefectsRepairable defects, if any, shallconsist of those which can be repaired without affecting theser
20、viceability of the part, unless otherwise specifically prohib-ited on the product drawing.Acceptable methods of repair shallhave been agreed to previously by the purchaser and the seller,and shall be fully described on the product specifications,drawings, or contracts for parts.TABLE 1 Allowable Def
21、ectsName DefinitionVisual Acceptance LevelsLevel I Level II Level IIIChip a small piece broken off an edge or surface none maximum dimension of break, 3.0mm (18 in.)maximum dimension ofbreak, 6.5 mm (14 in.)Crack an actual separation of the part, visible onopposite surfaces, and extending through th
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