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-Nov-2002
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ASTM D4703-02 - Standard Practice for Compression Molding Thermoplastic Materials into Test Specimens, Plaques, or Sheets
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 4703 – 02
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.
6
1. Scope * Specimens of Thermoplastic Materials
1.1 This practice covers the compression molding of ther-
3. Terminology
moplastic granules and milled stock for the preparation of test
2
3.1 Definitions of Terms Specific to This Standard:
specimens.
3.1.1 average cooling rate (°C/min), n—the cooling rate
1.2 While conditions for certain materials are given, the
calculated by dividing the difference between the molding and
primary source of specific conditions shall be the material
demolding temperatures by the time required to cool the mold
specification standards for each type of material.
to the demolding temperature.
1.3 The values stated in SI units are to be regarded as the
3.1.2 cooling rate (°C/h), n—the rate of cooling obtained by
standard. The values given in parentheses are for information
controlling the flow of the cooling fluid in such a way that
only.
during each 10-min interval, the deviation from this specified
1.4 This standard does not purport to address all of the
cooling rate shall not exceed the specified tolerance.
safety concerns, if any, associated with its use. It is the
3.1.3 demolding temperature, n—the temperature of the
responsibility of the user of this standard to establish appro-
mold or the press platens at the end of the cooling time,
priate safety and health practices and determine the applica-
measured in the nearest vicinity to the molded material.
bility of regulatory limitations prior to use.
3.1.3.1 Discussion—For positive molds, holes are normally
NOTE 1—The main body of this practice is equivalent to ISO 293-1986.
drilled in the mold for measuring the temperatures defined in
Annex A1 and ISO 293-1986 differ in some details; however, specimens
3.1.3 and 3.1.4.
prepared using Annex A1, Procedure A should be equivalent to those
3.1.4 molding temperature, n—the temperature of the mold
prepared using ISO 293-1986, Cooling Method D. Specimens prepared
or the press platens during the preheating and molding 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 according 3.1.5 molding time, n—the time during which full pressure
to ISO Cooling Method B may not be equivalent to Annex A1, Procedure
is applied while maintaining the molding temperature.
C.
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
2. Referenced Documents
specified shape and dimensions of the final molding. The
2.1 ASTM Standards:
thickness of the metal is dependent on the desired thickness of
3
D 618 Practice for Conditioning Plastics for Testing
the finished molding, taking into consideration the shrinkage of
D 1248 Specification for Polyethylene Plastics Extrusion
the material to be molded. The picture frame mold is some-
3
Materials for Wire and Cable
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.
5
Extrusion Materials
ISO 293-1986 Plastics—Compression Moulding Test
4. Significance and Use
4.1 The methods by which sample materials are prepared
and molded influence the mechanical properties of the speci-
1
This practice is under the jurisdiction of ASTM Committee D20 on Plastics and
men. Unlike injection molding, the objective of compression
is the direct responsibility of Subcommittee D20.09 on Specimen Preparation.
Current edition approved November 10, 2002. Published January 2003. Origi- molding is to produce test specimens or sheets that are both
nally approved in 1991. Last previous edition approved in 2000 as D 4703 – 00.
2
This practice was created as a coalescence of and replacement for Practices
D 1928, D 2292, D 3010, and D 3463.
3 6
Annual Book of ASTM Standards, Vol 08.01. ISO/IEC Selected Standards for Testing Plastics, available from ASTM. Also
4
Annual Book of ASTM Standards, Vol 08.02. available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th
5
Annual Book of ASTM Standards, Vol 08.03. Floor,
...

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