ASTM_D_647_-_88a_scan.pdf

ASTM Db47 REV*A 88 0759530 O039340 2(&Designation:D 647-88a AMERICAN SOCIETY FOR TESTINQ AND MATERIALS 1916 Race St.,Philadelphia.Pa.19103 Reprinted from the Annual Book o f ASTM Standards,Copyright ASTM If not listed in the current combined index,will appear in lhe next edition.Standard Practice for Design of Molds for Test Specimens of Plastic Molding Materials Tbis standard is issued under the fied designation D 647;the number immediately following the designation indicates the year of onghal adoption or,in the c a s e of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(6)indicates an editorial change since the last revision or reapproval.This standard has been approved fir use by agencies of the Deparimenr o f Definse.Consult the DoD Index of Speccations and aandards fir the specc year of issue which has been adopted by the Depariment o f Definse.1,Scope 1.1 This practice covers the design of molds for test specimens of plastic materials.Designs are shown for com-pression molds(Figs.1-4),a transfer mold(Fig.5)for use in producing bar,disk,and tensile test specimens in thermoset-ting plastic materiais primarily,and an injection mold(Fig.5)for use in producing bar,disk,and tensile test specimens in either thermoplastic or thermosetting materials.The plastic and mold temperatures,pressure and cycle timing used for the molding material should conform to the appropriate molding practice,if available,or to the material specification.If such information is not available,the recom-mendations of the material supplier should be followed,1.2 Designs shown have been found suitable for a broad range of plastics but may not be optimum for any given materiai.Only the specimen dimensions are actually standardized?1.3 The values stated in SI units are to be regarded as the standard.The values in parentheses are given for informa-tion only.1.4 This standard may involve hazardous materials,oper-ations,and eqirbment.This standard does not purport to address all ofthe safety probletns associated with its use.It is the responsibility o f the user o f this standard to establish appropriate safty and health practices and determine the applicability of regulatory limitations prior to use.2,Referenced Dacuments 2.1 ASTM Standards:D 256 Test Methods for Impact Resistance of Plastics and D 570 Test Method for Water Absorption of Plastics3 D 638 Test Method for Tensile Properties of Plastics3 D651 Test Method for Tensile Strength of Molded Elec-D 648 Test Method for Deflection Temperature of Plastics Elecfricai Insulating Materials3 trical Insulating Materials4 Under Flexural had3 I This prad is under the jurisdi.hion of ASTM Committee D-20 on Plastics and i s the direct rwponsibility of Subcommittee D20.09 on Specimen&para-tiom Cumnt edition approved Nov.25,1988.Published January 1989.Onginally published BS D 647-41.Last previous edition D 647-88.Blueprints of detailed drawings for the construction of the molds shown in Fw.1,3,4,and 6 n available at a nominal ost from ASTM Headquarters.Request i 12406470-10,30,60,and 7 0.Annual Book gfASThiStandards,Vol 08.01.Annual Book ofASThf slandards.Vol 10.01.D 790 Test Methods for Flexural Properties of Plastics and D955 Method for Measuring Shrinkage From Mold Electrical Insulating Materials3 Dimensions of Molded Plastics3 3.Significance and Use 3.1 A material is subjected during the molding process to a complex interaction of many variables.Standardization of the mold design can assist in the control of some of these variables by controlling the uniformity of the specimen geometries.A standardized mold design does not necessarily equate to uniform and equivalent test specimens because of processing variables and the effect of these variables on property results.4.Compression Molds for B a r Test Specimens 4.1 Compression molds for bar test specimens 12.7 mm(112 in.)in width by 127 mm(5 in.)or 64 mm(2112 in.)in length,and 12.7(112 in.),6.4 mm(114 in.),or 3.2 mm(18 in.)in thickness may be the single-bar,singleavity,positive mold shown in Fig.1.2 5.Compression Molds for Disk Test Specimens 5.1 Compression molds for the disk test specimens 51 mm(2 in.)or 102 mm(4 in.)in diameter may be of the design shown in Fig.2.6.Compression Molds for Tension Test Specimens 6.1 Compression molds for the test specimen for deter-mining the tensile strength of molded electrical insulating materiais(Note 1)shall be of the design shown in Fig.3.2 NOTE 1-See T e s t Method D 651 fer additional information.6.2 Compression molds for the test specimen for deter-mining the tensile properties of plastics(Note 2)shali be of the design shown in Fig.4.2 7.Mold for Injection Molding of Test Specimens 7.1 Layout-A four-cavity mold has been designed as a suitable means of preparing frequently used test specimens with most injection molding machines of 55-g or greater capacity.The arrangement shown in Fig.5 can be adapted to most mold bases 22.5 by 30.0 c