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

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 according to ISO Cooling Method B may not be equivalent to Annex A1, Procedure C.

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Publication Date
09-Dec-2000
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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 4703 – 00
Standard Practice for
Compression Molding Thermoplastic Materials into Test
1
Specimens, Plaques, or Sheets
This standard is issued under the fixed designation D 4703; 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 (e) indicates an editorial change since the last revision or reapproval.
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1. Scope * Extrusion Materials
ISO 293-1986 Plastics—Compression Moulding Test
1.1 This practice covers the compression molding of ther-
6
Specimens of Thermoplastic Materials
moplastic granules and milled stock for the preparation of test
2
specimens.
3. Terminology
1.2 While conditions for certain materials are given, the
3.1 Definitions of Terms Specific to This Standard:
primary source of specific conditions shall be the material
3.1.1 average cooling rate (°C/min), n—the cooling rate
specification standards for each type of material.
calculated by dividing the difference between the molding and
1.3 The values stated in SI units are to be regarded as the
demolding temperatures by the time required to cool the mold
standard. The values given in parentheses are for information
to the demolding temperature.
only.
3.1.2 cooling rate (°C/h), n—the rate of cooling obtained by
1.4 This standard does not purport to address all of the
controlling the flow of the cooling fluid in such a way that
safety concerns, if any, associated with its use. It is the
during each 10-min interval, the deviation from this specified
responsibility of the user of this standard to establish appro-
cooling rate shall not exceed the specified tolerance.
priate safety and health practices and determine the applica-
3.1.3 demolding temperature, n—the temperature of the
bility of regulatory limitations prior to use.
mold or the press platens at the end of the cooling time,
NOTE 1—The main body of this practice is equivalent to ISO 293-1986.
measured in the nearest vicinity to the molded material.
Annex A1 and ISO 293-1986 differ in some details; however, specimens
3.1.3.1 Discussion—For positive molds, holes are normally
prepared using Annex A1, Procedure A should be equivalent to those
drilled in the mold for measuring the temperatures defined in
prepared using ISO 293-1986, Cooling Method D. Specimens prepared
3.1.3 and 3.1.4.
using Annex A1, Procedure C should be equivalent to those prepared
3.1.4 molding temperature, n—the temperature of the mold
using ISO 293-1986, Cooling Method B. However, due to the greater
cooling rate tolerances of the ISO standard, specimens prepared according or the press platens during the preheating and molding time,
to ISO Cooling Method B may not be equivalent to Annex A1, Procedure
measured in the nearest vicinity to the molded material.
C.
3.1.5 molding time, n—the time during which full pressure
is applied while maintaining the molding temperature.
2. Referenced Documents
3.1.6 picture frame mold, n—a flat piece of metal, usually of
2.1 ASTM Standards:
brass or steel, that has a center portion removed to provide the
3
D 618 Practice for Conditioning Plastics for Testing
specified shape and dimensions of the final molding. The
D 1248 Specification for Polyethylene Plastics Extrusion
thickness of the metal is dependent on the desired thickness of
3
Materials for Wire and Cable
the finished molding, taking into consideration the shrinkage of
D 1928 Test Method for Preparation of Compression-
the material to be molded. The picture frame mold is some-
3
Molded Polyethylene Test Sheets and Test Specimens
times referred to as a chase.
D 3350 Specification for Polyethylene Plastics Pipe and
3.1.7 preheating time, n—the time required to heat the
4
Fittings Materials
material in the mold up to the molding temperature while
D 4976 Specification for Polyethylene Plastics Molding and
maintaining the contact pressure.
4. Significance and Use
1 4.1 The methods by which sample materials are prepared
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 Dec. 10, 2000. Published March 2001. Originally
published as D 4703 – 91. Last previous edition D 4703 – 93.
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This practice was created as a coalescence of and replacement for Practices Annual Book of ASTM Standards, Vol 08.03.
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D 1928, D 2292, D 3010, and D 3463. ISO/IEC Selected Standards for Testing Plastics, available from ASTM. Also
3
Annual Book of ASTM Standards, Vol 08.01. available from American National Standards Institute, 11 W. 42nd St., 13th Floor,
4
Annual Book of ASTM Standards, Vol 08.02. New York, NY 10036.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM
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