ASTM D6289-2003 Standard Test Method for Measuring Shrinkage from Mold Dimensions of Molded Thermosetting Plastics《模制热固性塑料模型尺寸收缩率测量的标准试验方法》.pdf
《ASTM D6289-2003 Standard Test Method for Measuring Shrinkage from Mold Dimensions of Molded Thermosetting Plastics《模制热固性塑料模型尺寸收缩率测量的标准试验方法》.pdf》由会员分享,可在线阅读,更多相关《ASTM D6289-2003 Standard Test Method for Measuring Shrinkage from Mold Dimensions of Molded Thermosetting Plastics《模制热固性塑料模型尺寸收缩率测量的标准试验方法》.pdf(4页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: D 6289 03Standard Test Method forMeasuring Shrinkage from Mold Dimensions of MoldedThermosetting Plastics1This standard is issued under the fixed designation D 6289; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method is intended to measure shrinkage frommold cavity to molded dimensions of thermosetting plas
3、ticswhen molded by compression, injection, or transfer underspecified conditions.1.2 This test method provides for the measurement ofshrinkage of thermosetting plastics from their molds bothinitially (within 16 to 72 h of molding) and as they age(postshrinkage at elevated temperatures).1.3 This meth
4、od will give comparable data based on stan-dard specimens and can not predict absolute values in actualmolded parts with varying flow paths, wall thicknesses, pres-sure gradiants and process conditions. Differences in moldshrinkage generally is observed between the specimen geom-etries described in
5、this test method.1.4 Knowledge of the initial shrinkage of plastics is impor-tant for the construction of molds and knowledge of postmolding shrinkage is important for determining the suitabilityof the molding material for manufacturing thermosetting plas-tic components with accurate dimensions.1.5
6、The values stated in SI units are to be regarded as thestandard. The values given in brackets are for information only.1.6 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-pri
7、ate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 1This test method and ISO 2577-1984 are equivalent whenbars of 120 mm length, 15 mm width, and 10 mm thickness are used forcompression molding; or flat, square plaques approximately 120 by 12
8、0by 4 mm are used for injection molding.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics and ElectricalInsulating Materials for TestingD 796 Practice for Compression Molding Test Specimens ofPhenolic Molding CompoundsD 883 Terminology Relating to PlasticsD 1896 Pra
9、ctice for Transfer Molding Test Specimens ofThermosetting CompoundsD 3419 Practice for In-line Screw-Injection Molding of TestSpecimens from Thermosetting CompoundsD 5224 Practice for Compression Molding Test Specimensof Thermosetting Molding CompoundsE 691 Practice for Conducting an Interlaboratory
10、 Study toDetermine the Precision of a Test Method2.2 ISO Standards:3ISO 291 PlasticsStandard Atmospheres for Conditioningand TestingISO 295 PlasticsCompression Molding Test Specimensof Thermosetting MaterialsISO 10724 PlasticsThermosetting Molding MaterialsInjection Molding of Multipurpose Test Spec
11、imensISO 2577-1984 PlasticsThermosetting MouldingMaterialsDetermination of Shrinkage3. Terminology3.1 GeneralDefinitions of terms applying to this testmethod appear in Terminology D 883.3.2 DefinitionsFor the purpose of this test method, thefollowing definitions apply:3.2.1 molding shrinkagethe diff
12、erence in dimensions be-tween a molding and the mold cavity in which it was molded,both the mold and the molding being at 23 6 2C whenmeasured.3.2.2 post-shrinkageshrinkage of a plastic product aftermolding, during post-treatment, storage or use.4. Significance and Use4.1 Compression MoldingIn compr
13、ession molding, thedifference between the dimensions of a mold and of the moldedarticle produced therein from a given material vary according1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.09 on Specimen Preparation.Cu
14、rrent edition approved November 1, 2003. Published January 2004. Originallyapproved in 1998. Last previous edition approved in 1998 as D 6289 - 98.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandard
15、s volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr H
16、arbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.to the design and operation of the mold. It is probable thatshrinkage will approach a minimum where design and opera-tion are such that a maximum of material is forced solidly intothe mold cavity or some part of it, or where t
17、he molded articleis hardened to a maximum while still under pressure, particu-larly by cooling. In contrast, shrinkages are higher where thecharge must flow in the mold cavity but does not receive andtransmit enough pressure to be forced firmly into all itsrecesses, or where the molded article is no
18、t fully hardenedwhen discharged. The plasticity of the material used affectsshrinkage insofar as it affects the retention and compression ofthe charge.4.2 Injection MoldingIn injection molding, as in com-pression molding, the differences between the dimensions ofthe mold and of the molded article pr
19、oduced therein from agiven material vary according to the design and operation ofthe mold. The differences vary with the type and size ofmolding machine, the thickness of molded sections, the degreeand direction of flow or movement of material in the mold, thesize of the nozzle, sprue, runner, and g
20、ate, the cycle on whichthe machine is operated, the temperature of the mold, and thelength of time that follow-up pressure is maintained. As in thecase of compression molding, shrinkages will approach aminimum where design and operation are such that a maximumof material is forced solidly into the m
21、old cavity and where themolded article is hardened to a maximum while still underpressure as a result of the use of a runner, sprue, and nozzle ofproper size, along with proper dwell. As in compressionmolding, shrinkages are higher where the charge must flow inthe mold cavity but does not receive an
22、d transmit enoughpressure to be forced firmly into all of the recesses of the mold.The plasticity of the material used affects shrinkage indirectly,in that the more readily plasticized material will require a lowermolding temperature.4.3 Transfer MoldingIn transfer molding, as in compres-sion or inj
23、ection molding, the difference between the dimen-sions of the mold and of the molded article produced thereinfrom a given material vary according to the design andoperation of the mold. It is affected by the size and temperatureof the pot or cylinder and the pressure on it, as well as on moldtempera
24、ture and molding cycle. Direction of flow is not asimportant a factor.4.4 Materials StandardsAlways refer to material stan-dards for special treatment prior to molding, molding condi-tions and special handling of the test specimens after molding.In the event the material standard is unavailable, con
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