ASTM D6289-08
(Test Method)Standard Test Method for Measuring Shrinkage from Mold Dimensions of Molded Thermosetting Plastics
Standard Test Method for Measuring Shrinkage from Mold Dimensions of Molded Thermosetting Plastics
SIGNIFICANCE AND USE
Compression Molding—In compression molding, the difference between the dimensions of a mold and of the molded article produced therein from a given material vary according to the design and operation of the mold. It is probable that shrinkage will approach a minimum where design and operation are such that a maximum of material is forced solidly into the mold cavity or some part of it, or where the molded article is hardened to a maximum while still under pressure, particularly by cooling. In contrast, shrinkages are higher where the charge must flow in the mold cavity but does not receive and transmit enough pressure to be forced firmly into all its recesses, or where the molded article is not fully hardened when discharged. The plasticity of the material used affects shrinkage insofar as it affects the retention and compression of the charge.
Injection Molding—In injection molding, as in compression molding, the differences between the dimensions of the mold and of the molded article produced therein from a given material vary according to the design and operation of the mold. The differences vary with the type and size of molding machine, the thickness of molded sections, the degree and direction of flow or movement of material in the mold, the size of the nozzle, sprue, runner, and gate, the cycle on which the machine is operated, the temperature of the mold, and the length of time that follow-up pressure is maintained. As in the case of compression molding, shrinkages will approach a minimum where design and operation are such that a maximum of material is forced solidly into the mold cavity and where the molded article is hardened to a maximum while still under pressure as a result of the use of a runner, sprue, and nozzle of proper size, along with proper dwell. As in compression molding, shrinkages are higher where the charge must flow in the mold cavity but does not receive and transmit enough pressure to be forced firmly into all of the recesses of the m...
SCOPE
1.1 This test method is intended to measure shrinkage from mold cavity to molded dimensions of thermosetting plastics when molded by compression, injection, or transfer under specified conditions.
1.2 This test method provides for the measurement of shrinkage of thermosetting plastics from their molds both initially (within 16 to 72 h of molding) and as they age (post–shrinkage at elevated temperatures).
1.3 This method will give comparable data based on standard specimens and can not predict absolute values in actual molded parts with varying flow paths, wall thicknesses, pressure gradiants and process conditions. Differences in mold shrinkage generally is observed between the specimen geometries described in this test method.
1.4 Knowledge of the initial shrinkage of plastics is important for the construction of molds and knowledge of post molding shrinkage is important for determining the suitability of the molding material for manufacturing thermosetting plastic components with accurate dimensions.
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Note 1—This test method and ISO 2577-1984 are equivalent when bars of 120 mm length, 15 mm width, and 10 mm thickness are used for compression molding; or flat, square plaques approximately 120 by 120 by 4 mm are used for injection molding.
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Designation: D6289 − 08
StandardTest Method for
Measuring Shrinkage from Mold Dimensions of Molded
1
Thermosetting Plastics
This standard is issued under the fixed designation D6289; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This test method is intended to measure shrinkage from
D618 Practice for Conditioning Plastics for Testing
mold cavity to molded dimensions of thermosetting plastics
D796 Practice for Compression Molding Test Specimens of
when molded by compression, injection, or transfer under
3
Phenolic Molding Compounds (Withdrawn 1992)
specified conditions.
D883 Terminology Relating to Plastics
1.2 This test method provides for the measurement of
D1896 Practice for Transfer Molding Test Specimens of
shrinkage of thermosetting plastics from their molds both Thermosetting Compounds
initially (within 16 to 72 h of molding) and as they age D3419 Practice for In-Line Screw-Injection Molding Test
Specimens From Thermosetting Compounds
(post–shrinkage at elevated temperatures).
D5224 PracticeforCompressionMoldingTestSpecimensof
1.3 This method will give comparable data based on stan-
Thermosetting Molding Compounds
dard specimens and can not predict absolute values in actual
E691 Practice for Conducting an Interlaboratory Study to
molded parts with varying flow paths, wall thicknesses, pres-
Determine the Precision of a Test Method
4
sure gradiants and process conditions. Differences in mold
2.2 ISO Standards:
shrinkage generally is observed between the specimen geom-
ISO 291 Plastics—Standard Atmospheres for Conditioning
etries described in this test method.
and Testing
ISO 295 Plastics—Compression Molding Test Specimens of
1.4 Knowledge of the initial shrinkage of plastics is impor-
Thermosetting Materials
tant for the construction of molds and knowledge of post
ISO 10724 Plastics—Thermosetting Molding Materials—
molding shrinkage is important for determining the suitability
Injection Molding of Multipurpose Test Specimens
of the molding material for manufacturing thermosetting plas-
ISO 2577-1984 Plastics—Thermosetting Moulding
tic components with accurate dimensions.
Materials—Determination of Shrinkage
1.5 The values stated in SI units are to be regarded as
3. Terminology
standard. The values given in parentheses are for information
3.1 General—Definitions of terms applying to this test
only.
method appear in Terminology D883.
1.6 This standard does not purport to address all of the
3.2 Definitions:
safety concerns, if any, associated with its use. It is the
3.2.1 For the purpose of this test method, the following
responsibility of the user of this standard to establish appro-
definitions apply:
priate safety and health practices and determine the applica-
3.2.2 molding shrinkage—the difference in dimensions be-
bility of regulatory limitations prior to use.
tween a molding and the mold cavity in which it was molded,
NOTE1—ThistestmethodandISO2577-1984areequivalentwhenbars
both the mold and the molding being at 23 6 2°C when
of 120 mm length, 15 mm width, and 10 mm thickness are used for
measured.
compression molding; or flat, square plaques approximately 120 by 120
by 4 mm are used for injection molding.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
1
This test method is under the jurisdiction ofASTM Committee D20 on Plastics the ASTM website.
3
and is the direct responsibility of Subcommittee D20.09 on Specimen Preparation. The last approved version of this historical standard is referenced on
Current edition approved April 15, 2008. Published May 2008. Originally www.astm.org.
4
approved in 1998. Last previous edition approved in 2003 as D6289 - 03. DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/D6289-08. 4th Floor, New York, NY 10036, http://www.ansi.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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D6289 − 08
3.2.3 post-shrinkage—shrinkage of a plastic product after 5. Sample Preparation
molding, during post-treatment, storage or use.
5.1 Some materials require special treatment before they are
molded. Materials to be tested shall be prepared for molding in
4. Significance and Use
accordance with the relevant materi
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:D6289–03 Designation: D 6289 – 08
Standard Test Method for
Measuring Shrinkage from Mold Dimensions of Molded
1
Thermosetting Plastics
This standard is issued under the fixed designation D 6289; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1This1.1 This test method is intended to measure shrinkage from mold cavity to molded dimensions of thermosetting plastics
when molded by compression, injection, or transfer under specified conditions.
1.2 This test method provides for the measurement of shrinkage of thermosetting plastics from their molds both initially (within
16 to 72 h of molding) and as they age (post–shrinkage at elevated temperatures).
1.3This1.3 This method will give comparable data based on standard specimens and can not predict absolute values in actual
molded parts with varying flow paths, wall thicknesses, pressure gradiants and process conditions. Differences in mold shrinkage
generally is observed between the specimen geometries described in this test method.
1.4 Knowledge of the initial shrinkage of plastics is important for the construction of molds and knowledge of post molding
shrinkage is important for determining the suitability of the molding material for manufacturing thermosetting plastic components
with accurate dimensions.
1.5 The values stated in SI units are to be regarded as the standard. The values given in bracketsparentheses are for information
only.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
NOTE 1—This test method and ISO 2577-1984 are equivalent when bars of 120 mm length, 15 mm width, and 10 mm thickness are used for
compression molding; or flat, square plaques approximately 120 by 120 by 4 mm are used for injection molding.
2. Referenced Documents
2
2.1 ASTM Standards:
D 618Practice for Conditioning Plastics and Electrical Insulating Materials for Testing Practice for Conditioning Plastics for
Testing
3
D 796 Practice for Compression Molding Test Specimens of Phenolic Molding Compounds
D 883 Terminology Relating to Plastics
D 1896 Practice for Transfer Molding Test Specimens of Thermosetting Compounds
D 3419 Practice for In-lineIn-Line Screw-Injection Molding of Test Specimens fromFrom Thermosetting Compounds
D 5224 Practice for Compression Molding Test Specimens of Thermosetting Molding Compounds
E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
4
2.2 ISO Standards:
ISO 291 Plastics—Standard Atmospheres for Conditioning and Testing
ISO 295 Plastics—Compression Molding Test Specimens of Thermosetting Materials
ISO 10724 Plastics—Thermosetting Molding Materials—Injection Molding of Multipurpose Test Specimens
ISO 2577-1984 Plastics—Thermosetting Moulding Materials—Determination of Shrinkage
3. Terminology
3.1 General—Definitions of terms applying to this test method appear in Terminology D 883.
1
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.09 on Specimen Preparation .
Current edition approved November 1, 2003. Published January 2004. Originally approved in 1998. Last previous edition approved in 1998 as D6289-98.
Current edition approved April 15, 2008. Published May 2008. Originally approved in 1998. Last previous edition approved in 2003 as D 6289 - 03.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Withdrawn
4
Available 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 standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
D6289–08
3.2 Definitions— For the purpose of this test method, the following definitions apply:
3.2.1 molding shrinkage—the di
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