ASTM D3419-00(2006)
(Practice)Standard Practice for In-Line Screw-Injection Molding Test Specimens From Thermosetting Compounds
Standard Practice for In-Line Screw-Injection Molding Test Specimens From Thermosetting Compounds
SCOPE
1.1 This practice covers the general principles to be followed when injection molding test specimens of thermosetting materials. It is to be used to obtain uniformity in methods of describing the various steps of the injection molding process and in the reporting of those conditions. The exact molding conditions will vary from material to material, and should become part of the material specification or be agreed upon between the purchaser and the supplier.Note 1The utility of this practice has been demonstrated for the molding of thermosetting molding compounds exhibiting lower-viscosity non-Newtonian flow.
1.2 The values stated in SI units are to be regarded as standard. The values given in brackets are for information only.
This standard does not purport to address all of the safety problems, 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.
1.3 This practice assumes the use of reciprocating screw injection molding machines.Note 2
This standard is similar in content (but not technically equivalent) to ISO 10724: 1994(E).
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D3419–00 (Reapproved 2006)
Standard Practice for
In-Line Screw-Injection Molding Test Specimens From
Thermosetting Compounds
This standard is issued under the fixed designation D3419; 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 2.2 ISO Standards:
ISO 10724: 1994(E)—Plastics—Thermosetting Moulding
1.1 This practice covers the general principles to be fol-
Materials—Injection Moulding of Multipurpose Test
lowed when injection molding test specimens of thermosetting
Specimens
materials. It is to be used to obtain uniformity in methods of
ISO 3167: 1993, Plastics—Multipurpose Test Specimens
describing the various steps of the injection molding process
and in the reporting of those conditions. The exact molding
3. Terminology
conditions will vary from material to material, and should
3.1 Definitions:
become part of the material specification or be agreed upon
3.1.1 General—Definitions of terms applying to this prac-
between the purchaser and the supplier.
tice appear in Terminology D883.
NOTE 1—The utility of this practice has been demonstrated for the
3.1.2 injection molding—the process of forming a material
molding of thermosetting molding compounds exhibiting lower-viscosity
by forcing it, in a fluid state and under pressure, through a
non-Newtonian flow.
runner system (sprue, runner, and gate(s)) into the cavity of a
1.2 The values stated in SI units are to be regarded as
closed mold.
standard. The values given in parentheses are for information
3.1.3 Discussion—Screw-injection molding and reaction-
only.
injection molding are types of injection molding.
1.3 This standard does not purport to address all of the
3.2 Definitions of Terms Specific to This Standard:
safety problems, if any, associated with its use. It is the
3.2.1 breathing, v—theoperationofopeningamoldorpress
responsibility of the user of this standard to establish appro-
for a very short period of time at an early stage in the process
priate safety and health practices and determine the applica-
of cure.
bility of regulatory limitations prior to use.
3.2.2 Discussion—Breathing allows the escape of gas or
1.4 This practice assumes the use of reciprocating screw
vapor from the molding material and reduces the tendency of
injection molding machines.
thick moldings to blister.
3.2.3 cavity (of a mold), n—the space within a mold to be
NOTE 2—This standard is similar in content (but not technically
filled to form the molded product.
equivalent) to ISO 10724: 1994(E).
3.2.4 landing (of a cavity), v—the practice of relieving the
2. Referenced Documents
mold around the cavity (cavities), thus reducing the surface
2.1 ASTM Standards: area of the flat mating surfaces of the mold halves. Typical
3 1
D883 Terminology Relating to Plastics lands are 4.5 mm ( ⁄16 in.) to 6 mm ( ⁄4 in.) in width. Landing
D958 Practice for Determining Temperatures of Standard pads should be incorporated to hold the mold open 0.0125 mm
ASTM Molds for Test Specimens of Plastics (0.0005 in.) to prevent damage to the lands.
4. Significance and Use
Thispracticeisunderthe jurisdiction ofASTM CommitteeD20onPlasticsand
4.1 This practice is subject to the definition of injection
is the direct responsibility of Subcommittee D20.09 on Specimen Preparation.
molding given in 3.1.2 with the further provision that with
Current edition approved March 15, 2006. Published March 2006. Originally
approved in 1975. Last previous edition approved in 2000 as D3419 - 00. DOI:
in-line screw injection the plastic compound, heated in a
10.1520/D3419-00R06.
chamber by conduction and friction, is fluxed by the action of
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
a reciprocating screw and then is forced into a hot mold where
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
the ASTM website.
3 4
Withdrawn. The last approved version of this historical standard is referenced Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
on www.astm.org. 4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3419–00 (2006)
it solidifies. Hereafter, in-line screw-injection molding will be 5. Apparatus
referred to simply as injection molding.
5.1 In-Line, Screw-Injection Machine— A device incorpo-
4.2 The mold referenced in this section (see Fig. 1)is
rating a hydraulically or electrically driven screw which,
generally useful, and describes what have been the most
working against a predetermined back pressure, draws material
common specimens required for the testing of thermosets. ISO from the feed hopper and by frictional and conducted heat
specimens and testing are gaining favor, however. ISO 10724
works a charge of material into a hot plastic state. Following
describes the layout and practice for injection molding the the plasticating step, the screw stops rotating, moves forward
multi-purpose specimens in accordance with ISO 3167.
and forces the hot material through the nozzle, sprue, runner,
and gate into the cavity. The machine should be capable of
4.3 Typically, injection-molded test specimens are made
accurately delivering and maintaining suitable injection and
with shorter cycles than those used for similar moldings made
clamp pressures within the range from 70 to 140 MPa (10,000
by compression, and the cycle is equal to or faster than that for
to 20,000 psi). Measurement of actual molding pressures can
transfer molding.
be made with pressure transducers placed strategically in the
4.4 Breathing of the mold is not usually required to release
cavities.
trapped volatile material as the gas is free to flow from the vent
5.1.1 The clamp force of the machine shall be sufficient to
end of the mold. This is particularly advantageous for heat-
prevent excessive flashing under all operating conditions (see
resistant compounds and reduces the tendency for molded
5.2.5).
specimens to blister at high exposure temperatures.
5.2 Mold—The mold cavities and layout will depend on the
4.5 Injection molding is intended for low-viscosity com-
specimens required by the tests in question. Fig. 1 has been
pounds. One set of processing parameters cannot be specified
found satisfactory, although molds with fewer cavities, or
for all types of thermosetting materials, nor for samples of the
different configurations, or both may be used. Molds with
same material having different plasticities.
multiple-identical-cavity layouts with symmetrical gates and
4.6 Materials containing fibrous fillers such as glass roving,
runners are normally recommended. Single cavity molds are
chopped cloth, or cellulosic fibers can be injection molded, but
not recommended. In either case, it is important to describe the
their properties will be affected depending upon how much
mold in the report on the specimen preparation.
fiber breakdown occurs as the compound is worked by the
5.2.1 Family molds like the one shown in Fig. 1 require
screw and as it passes through the system of runners and gates.
properprecautionstoensurethatconstantanduniformfillingis
The orientation of the fibers in the molded specimen will also
achieved in all cavities.
affect injection-molded properties.
5.2.2 Gate dimensions equal to two-thirds of the width and
4.7 Flow and knit lines in a molded piece are often sites of
heightofend-gatedspecimensarerecommendedforspecimens
mechanical or electrical weakness.The fluxed material passing
not greater than 4-mm (0.16-in.) thickness. For specimens over
throughthegatewrinklesandfoldsasitproceedsintothemold
4-mm (0.16-in.) thickness, or for other than end-gated speci-
cavity. Knit lines may be found to some degree throughout the
mens, gate dimensi
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