ASTM D4703-10

Standard Practice for Compression Molding Thermoplastic Materials into Test Specimens, Plaques, or Sheets

SIGNIFICANCE AND USE
The methods by which sample materials are prepared and molded influence the mechanical properties of the specimen. Unlike injection molding, the objective of compression molding is to produce test specimens or sheets that are both homogeneous and isotropic. Molded specimens may be made from powder or pellets such as are received directly from a material manufacturer, particles produced in a recycle recovery operation, or from a milled preform or sheet prepared on a two-roll mill. The powder, pellets, particles, preform, or sheet are melted and molded in a mold designed to produce a finished specimen of a given geometry, size, and thickness, or melted and molded in the form of a smooth plaque or sheet of uniform thickness from which desired specimens are cut, punched, or machined. Working a compound on a two-roll mill prior to molding will disperse and distribute the compound additives in a manner that will affect the physical properties of the compound. The need for milling a sample prior to compression molding may be determined by reference to the relevant material specification or the material manufacturer. It is important to treat different samples of the same type of material in the same way: if milling was done prior to molding on a material which is to be used as a standard for comparison, all new materials to be tested against this practice should be prepared and molded in a similar manner.
The apparatus and exact conditions required to prepare adequate specimens may vary for each plastic material. Apparatus and procedures which should be satisfactory for molding many different plastic materials are given in this practice in Sections 5 and 6. The apparatus and procedures which have been found satisfactory for molding certain specific materials are given in the Appendix. In any case, the apparatus and procedures to be used in producing compression-molded specimens of a given material may be obtained by reference to the relevant material specification and sho...
SCOPE
1.1 This practice covers the compression molding of thermoplastic granules and milled stock for the preparation of test specimens.  
1.2 While conditions for certain materials are given, the primary source of specific conditions shall be the material specification standards for each type of material.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.4 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—The main body of this practice is equivalent to ISO 293-1986. Annex A1 and ISO 293-1986 differ in some details; however, specimens prepared using Annex A1, Procedure A should be equivalent to those prepared using ISO 293-1986, Cooling Method D. Specimens prepared using Annex A1, Procedure C should be equivalent to those prepared using ISO 293-1986, Cooling Method B. However, due to the greater cooling rate tolerances of the ISO standard, specimens prepared in accordance with ISO Cooling Method B may not be equivalent to Annex A1, Procedure C.

General Information

• Status: Historical
• Publication Date: 31-May-2010
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.09 - Specimen Preparation

Relations

• Replaces: ASTM D4703-07 - Standard Practice for Compression Molding Thermoplastic Materials into Test Specimens, Plaques, or Sheets
• Effective Date: 01-Jun-2010
• Referred By: ASTM F2947/F2947M-21a - Standard Specification for 150 to 1500 mm [6 to 60 in.] Annular Corrugated Profile-Wall Polyethylene (PE) Pipe and Fittings for Sanitary Sewer Applications
• Effective Date: 01-Jun-2010
• Referred By: ASTM F2136-18 - Standard Test Method for Notched, Constant Ligament-Stress (NCLS) Test to Determine Slow-Crack-Growth Resistance of HDPE Resins or HDPE Corrugated Pipe
• Effective Date: 01-Jun-2010
• Referred By: ASTM D5885/D5885M-20 - Standard Test Method for Oxidative Induction Time of Polyolefin Geosynthetics by High-Pressure Differential Scanning Calorimetry
• Effective Date: 01-Jun-2010
• Referred By: ASTM D955-21 - Standard Test Method of Measuring Shrinkage from Mold Dimensions of Thermoplastics
• Effective Date: 01-Jun-2010
• Referred By: ASTM D1505-18 - Standard Test Method for Density of Plastics by the Density-Gradient Technique
• Effective Date: 01-Jun-2010
• Referred By: ASTM D2103-15 - Standard Specification for Polyethylene Film and Sheeting
• Effective Date: 01-Jun-2010
• Referred By: ASTM D2839-16(2023) - Standard Practice for Use of a Melt Index Strand for Determining Density of Polyethylene
• Effective Date: 01-Jun-2010
• Referred By: ASTM D4976-12a(2020) - Standard Specification for Polyethylene Plastics Molding and Extrusion Materials
• Effective Date: 01-Jun-2010
• Referred By: ASTM D3004-08(2020) - Standard Specification for Crosslinked and Thermoplastic Extruded Semi-Conducting, Conductor, and Insulation Shielding Materials
• Effective Date: 01-Jun-2010
• Referred By: ASTM D5397-20 - Standard Test Method for Evaluation of Stress Crack Resistance of Polyolefin Geomembranes Using Notched Constant Tensile Load Test
• Effective Date: 01-Jun-2010
• Referred By: ASTM D7436-17 - Standard Classification System for Unfilled Polyethylene Plastics Molding and Extrusion Materials with a Fractional Melt Index Using ISO Protocol and Methodology
• Effective Date: 01-Jun-2010
• Referred By: ASTM D3981-09a(2016) - Standard Specification for Polyethylene Films Made from Medium-Density Polyethylene for General Use and Packaging Applications
• Effective Date: 01-Jun-2010
• Referred By: ASTM D1998-21 - Standard Specification for Polyethylene Upright Storage Tanks
• Effective Date: 01-Jun-2010
• Referred By: ASTM D1248-16 - Standard Specification for Polyethylene Plastics Extrusion Materials for Wire and Cable
• Effective Date: 01-Jun-2010

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D4703–10
Standard Practice for
Compression Molding Thermoplastic Materials into Test
1
Specimens, Plaques, or Sheets
This standard is issued under the fixed designation D4703; 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* D3350 Specification for Polyethylene Plastics Pipe and
Fittings Materials
1.1 This practice covers the compression molding of ther-
D4976 Specification for Polyethylene Plastics Molding and
moplastic granules and milled stock for the preparation of test
2 Extrusion Materials
specimens.
2.2 ISO Standard:
1.2 While conditions for certain materials are given, the
ISO 293-1986 Plastics—Compression Moulding Test
primary source of specific conditions shall be the material
4
Specimens of Thermoplastic Materials
specification standards for each type of material.
1.3 The values stated in SI units are to be regarded as the
3. Terminology
standard. The values given in parentheses are for information
3.1 Definitions of Terms Specific to This Standard:
only.
3.1.1 average cooling rate (°C/min), n—the cooling rate
1.4 This standard does not purport to address all of the
calculated by dividing the difference between the molding and
safety concerns, if any, associated with its use. It is the
demolding temperatures by the time required to cool the mold
responsibility of the user of this standard to establish appro-
to the demolding temperature.
priate safety and health practices and determine the applica-
3.1.2 cooling rate (°C/h), n—therateofcoolingobtainedby
bility of regulatory limitations prior to use.
controlling the flow of the cooling fluid in such a way that
NOTE 1—ThemainbodyofthispracticeisequivalenttoISO 293-1986.
during each 10-min interval, the deviation from this specified
Annex A1 and ISO 293-1986 differ in some details; however, specimens
cooling rate shall not exceed the specified tolerance.
prepared using Annex A1, Procedure A should be equivalent to those
3.1.3 demolding temperature, n—the temperature of the
prepared using ISO 293-1986, Cooling Method D. Specimens prepared
mold or the press platens at the end of the cooling time,
using Annex A1, Procedure C should be equivalent to those prepared
measured in the nearest vicinity to the molded material.
using ISO 293-1986, Cooling Method B. However, due to the greater
cooling rate tolerances of the ISO standard, specimens prepared in 3.1.3.1 Discussion—For positive molds, holes are normally
accordance with ISO Cooling Method B may not be equivalent to Annex
drilled in the mold for measuring the temperatures defined in
A1, Procedure C.
3.1.3 and 3.1.4.
3.1.4 molding temperature, n—the temperature of the mold
2. Referenced Documents
or the press platens during the preheating and molding time,
3
2.1 ASTM Standards:
measured in the nearest vicinity to the molded material.
D618 Practice for Conditioning Plastics for Testing
3.1.5 molding time, n—the time during which full pressure
D1248 Specification for Polyethylene Plastics Extrusion
is applied while maintaining the molding temperature.
Materials for Wire and Cable
3.1.6 picture frame mold, n—aflatpieceofmetal,usuallyof
brass or steel, that has a center portion removed to provide the
1
specified shape and dimensions of the final molding. The
ThispracticeisunderthejurisdictionofASTMCommitteeD20onPlasticsand
is the direct responsibility of Subcommittee D20.09 on Specimen Preparation.
thickness of the metal is dependent on the desired thickness of
CurrenteditionapprovedJune1,2010.PublishedJuly2010.Originallyapproved
thefinishedmolding,takingintoconsiderationtheshrinkageof
in 1991. Last previous edition approved in 2007 as D4703 – 07. DOI: 10.1520/
the material to be molded. The picture frame mold is some-
D4703-10.
2
times referred to as a chase.
This practice was created as a coalescence of and replacement for Practices
D1928, D2292, D3010, and D3463.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM ISO/IEC Selected Standards for Testing Plastics, available from ASTM. Also
Standards volume information, refer to the standard’s Document Summary page on available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th
the ASTM website. Floor, New York, NY 10036.
*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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D4703–10
3.1.7 preheating time, n—the time required to heat the
m
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This document is not anASTM standard and is intended only to provide the user of anASTM 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:D4703–07 Designation:D4703–10
Standard Practice for
Compression Molding Thermoplastic Materials into Test
1
Specimens, Plaques, or Sheets
This standard is issued under the fixed designation D4703; 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*
1.1 This practice covers the compression molding of thermoplastic granules and milled stock for the preparation of test
2
specimens.
1.2 While conditions for certain materials are given, the primary source of specific conditions shall be the material specification
standards for each type of material.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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—The main body of this practice is equivalent to ISO 293-1986. Annex A1 and ISO 293-1986 differ in some details; however, specimens
prepared usingAnnexA1, ProcedureAshould be equivalent to those prepared using ISO 293-1986, Cooling Method D. Specimens prepared usingAnnex
A1, Procedure C should be equivalent to those prepared using ISO 293-1986, Cooling Method B. However, due to the greater cooling rate tolerances of
the ISO standard, specimens prepared in accordance with ISO Cooling Method B may not be equivalent to Annex A1, Procedure C.
2. Referenced Documents
3
2.1 ASTM Standards:
D618 Practice for Conditioning Plastics for Testing
D1248 Specification for Polyethylene Plastics Extrusion Materials for Wire and Cable
D3350 Specification for Polyethylene Plastics Pipe and Fittings Materials
D4976 Specification for Polyethylene Plastics Molding and Extrusion Materials
2.2 ISO Standard:
4
ISO 293-1986 Plastics—Compression Moulding Test Specimens of Thermoplastic Materials
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 average cooling rate (°C/min), n—the cooling rate calculated by dividing the difference between the molding and
demolding temperatures by the time required to cool the mold to the demolding temperature.
3.1.2 cooling rate (°C/h), n—the rate of cooling obtained by controlling the flow of the cooling fluid in such a way that during
each 10-min interval, the deviation from this specified cooling rate shall not exceed the specified tolerance.
3.1.3 demolding temperature, n—the temperature of the mold or the press platens at the end of the cooling time, measured in
the nearest vicinity to the molded material.
3.1.3.1 Discussion—For positive molds, holes are normally drilled in the mold for measuring the temperatures defined in 3.1.3
and 3.1.4.
3.1.4 molding temperature, n—the temperature of the mold or the press platens during the preheating and molding time,
measured in the nearest vicinity to the molded material.
3.1.5 molding time, n—the time during which full pressure is applied while maintaining the molding temperature.
3.1.6 picture frame mold, n—a flat piece of metal, usually of brass or steel, that has a center portion removed to provide the
1
This practice 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 AprilJune 1, 2007.2010. Published April 2007.July 2010. Originally approved in 1991. Last previous edition approved in 20032007 as
D4703 – 037. DOI: 10.1520/D4703-107.
2
This practice was created as a coalescence of and replacement for Practices D1928, D2292, D3010, and D3463.
3
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
4
ISO/IEC Selected Standards for Testing Plastics, available from ASTM. Also available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor,
New York, NY 10036.
*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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