ASTM_D_6289_-_13.pdf

Designation:D628913Standard Test Method forMeasuring Shrinkage from Mold Dimensions of MoldedThermosetting Plastics1This standard is issued under the fixed designation D6289;the number immediately following the designation indicates the year oforiginal adoption or,in the case 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.Scope*1.1 This test method is intended to measure shrinkage frommold cavity to molded dimensions of thermosetting plasticswhen 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 after aging(postshrinkage at elevated temperatures).1.3 This method 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 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 The values stated in SI units are to be regarded asstandard.The values given in parentheses are for informationonly.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-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE1This test method and ISO 2577-1984 are equivalent when barsof 120 mm length,15 mm width,and 10 mm thickness are used forcompression molding;or flat,square plaques approximately 120 by 120by 4 mm are used for injection molding.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD796 Practice for Compression Molding Test Specimens ofPhenolic Molding Compounds(Withdrawn 1992)3D883 Terminology Relating to PlasticsD1896 Practice for Transfer Molding Test Specimens ofThermosetting CompoundsD3419 Practice for In-Line Screw-Injection Molding TestSpecimens From Thermosetting CompoundsD5224 Practice for Compression Molding Test Specimens ofThermosetting Molding CompoundsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standards:4ISO 291 PlasticsStandard Atmospheres for Conditioningand TestingISO 295 PlasticsCompression Molding Test Specimens ofThermosetting MaterialsISO 10724 PlasticsThermosetting Molding MaterialsInjection Molding of Multipurpose Test SpecimensISO2577-1984 PlasticsThermosettingMouldingMaterialsDetermination of Shrinkage3.Terminology3.1 GeneralDefinitions of terms applying to this testmethod appear in Terminology D883.3.2 Definitions:3.2.1 For the purpose of this test method,the followingdefinitions apply:3.2.2 molding shrinkagethe difference 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.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.09 on Specimen Preparation.Current edition approved April 1,2013.Published April 2013.Originallyapproved in 1998.Last previous edition approved in 2008 as D6289-08.DOI:10.1520/D6289-13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.3 post-shrinkageshrinkage of a plastic product aftermolding,during post-treatment,storage or use.4.Significance and Use4.1 Compression MoldingIn compression molding,thedifference between the dimensions of a mold and of the moldedarticle produced therein from a given material vary accordingto 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 the 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 ca