ASTM D621-64(1988)e1

Test Methods for Deformation of Plastics Under Load

General Information

• Status: Withdrawn
• Publication Date: 31-Dec-1987
• ICS: 83.080.01 - Plastics in general
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.30 - Thermal Properties

Standards Content (Sample)

An American National Standard
~~ Designation: D 621- 64 (Reapproved 1988)E1
AMERICAN SOCIETY FOR TESTING AND MATERIALS
19t6 Aace St., Philadelphia. Pa. t9103
Standard Test Methods for
Reprlnled from the Annual Book at ASTM Standards, Copyright ASTM
If not listed In the current combined Index, will eppear In the next edlllon.
Deformation of Plastics Under Load
This standard is issued under the fixed designation D 621; tbe number immediately following the designation indicates tbe year of
original adoption or, in the case of revision, the year oflast revision. A number in parentheses indicates the year oflast reapproval. A
superscript epsilon (ol indicates an editorial change since the last revision or reapproval.
These test methods Irave been approved for rISe by agencies ofthe Departmem ofDefense to replace Method 1101 of Federal Test
Method Standard 406. andfor Listing in the DoD Index ofSpecifications and Standards.
o. NOTE-The safety hazards caveat and the Precision and Bias section were added editorially in March 1988. The Referenced
Documents section was also added, causing the renumbering of subsequent sections.
D-618 Methods of Conditioning Plastics and Electrical
1. Scope
Insulating Materials for Testing
1.1 These test methods cover the determination of the
deformation under compression of nonmetallic sheet and
3. Significance and Use
molded plastic materials, of all classes and all commercial
3.1 Data obtained by Test Method A give a measure of
thicknesses, intended for structural and insulating purposes.
the ability of a rigid plastic in assemblies of conductors and
Two test methods are included, as follows:
insulators that are held together by bolts, rivets, or similar
Test Method A-For rigid plastics.
fastening devices, to withstand compression without yielding
Test Method B-For nonrigid plastics.
and loosening the assembly with time. Test Method A also
1.2 The word deformation is used herein in the broad
gives a measure of the rigidity of plastics at service tempera­
sense to cover(1) dimensional change due almost entirely to
tures and consequently can be used as an identification test
flow, and (2) dimensional change due to a combination of
for procurement purposes.
flow and shrihkage caused by loss of water or other volatile
3.2 Data obtained by Test Method B give a measure ofthe
matter. The word flow as used in these test methods may
ability of a nonrigid plastic to return to its original dimen­
describe either plastic or elastic defonnation or combinations
sions with time after having been deformed. Test Method B
thereof.
determines the extent to which the plastic will follow
associated parts in applications requiring elastic properties.
NOTIl I-The values slated in Sl units are to be regarded as the
standard.
TEST METHOD A-RIGID PLASTICS
NOTIl 2-Methyl methacrylate and polystyrene are examples of
materials that deform almost entirely by flow. Cellulose acetate,
cellulose acetate butyrate, phenolic laminated fiber, and vulcanized fiber
4. Nature of Test
are examples of materials that deform by a combination of flow and
4.1 The principle of Test Method A is essentially that of
shrinkage.
the parallel plate plastometer, namely, a constant-force
system whereby a test specimen is conditioned, if necessary,
1.3 This standard may involve hazardous materials, oper­
of a constant­
and is then placed between the parallel plates
alions, and eqllipmellt. Thi-s standard does not purport to
force device and the thickness observed over a required
address all ofthe safety problems associated with its use. It is
period at the stipulated temperature or temperatures.
the responsibility of the IIser of this standard to establish
appropriate sqfety and health practices and determine the
5. Apparatus
applicability ofreglilatory limitations prior to use.
5.1 Testing Machine-A machine capable of exerting a
constant force of 113 kg (250 Ib), 227 kg (500 Ib), and 454 kg
2. Referenced Documents
(1000 Ib) ±l % between the parallel anvils of the machine,
which shall be arranged so that they can be brought into
2.1 ASTM Standards:
contact with the test specimen before the load is applied. A
D 374 Test Methods for Thickness of Solid Electrical
machine suitable for this test is shown in Fig. 1. A recom­
Insulation
mended method for calibrating such a device is given in the
D 575 Tc:st Methods for Rubber Properties in Com­
Appendix. One of the anvils of the machine shall preferably
pression
be self-aligning and shall, in order that the load may be
applied evenly over the face of the specimen, be arranged so
that the specimen is accurately centered and the resultant of
I These lest methods are under the jurisdiction of ASTM Committee D·20 on
the load is through its center. The machine shall also be
Plastics and are tbe direct responsibility of Subcommittee D20.30 on Thermal
Properties (Section D20.30.07).
equipped with a dial gage or the equivalent capable of
Current edition approved Aug. 31, 1964. Published October 1964. OriginallY
measuring the relative movement of the faces to 0.025 mm
published as D 621 - 41. Last previous edition D 621 - 59.
(0.001 in.) or less. A thermometer of the total immersion
2 Anllual Book ofASTM Standards. Vol 08.01.
3 Annual Book ofASTM Stolldards. Vol 09.01. type shall be suspended in such a manner that the bulb is

4B1b 0621
HYf/rDlllic JacJc for
Raising Wtighl
El
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Metric Equivalents
In. 5 20 25
mm 127 508 635
FIG. 1 Deformation Testing Machine
approximately level with the specimen and not more than 76 bearing that number, a second strip shall be cut adjacent to
the first one, cut into pieces, and the required number of
mm (3 in.) therefrom.
5.2 Test Chamber-A test chamber of suitable size and squares taken from the appropriate pieces. The number of
construction to enclose the testing machine and maintain it squares to be cut from each piece is prescribed in Table 1.
during the test within ± 1°C (2°F) of the specified test
NOTE 3-Substantial variations in test values may occur, particularly
temperature, except for the short period at the beginning
with composite specimens, if tlie opposite faces of the specimens are not
when opening the door may cause a drop in temperature.
plane and parallel or if sink marks or other similar imperfections are
present. To minimize such variations, the squares used to form the
composite specimens, if necessary, shall be rendered plane and parallel
6. Test Specimens
and their adjoining surfaces shall be freed of sink marks and other
imperfections by milling, grinding, or other appropriate means. If solid
6.1 The test specimen shall be a 12.7-mm (1/2-in.) cube,
cubes are used, their opposite faces in contact with the anvils of the
either solid or composite. Materials over 12.7 mm (1f2 in.) in
testing machine, if necessary, shall be milled plane and parallel and shall
thickness shall be reduced to 12.7 mm (1f2 in.), and thinner
be smooth and free of imperfections.
materials shall be piled up with the total height as near to
12.7 mm (1/2 in.) as possible. The squares of the composite
7. Conditioning
specimen shall be accurately aligned in all cases. Surfaces of
7.1 Where deformation under average room conditions is
the test specimens shall be plane and parallel.
required, condition and test specimens in accordance with
6.2 The specimens for materials made in large sheets,
7.1.1 and 7.1.2.
such as phenolic laminated fiber, where moisture absorption
7.1.1 Conditioning-Condition the test specimens at 23 ±
characteristics may vary over the entire surface, shall be
2°C (73.4 ± 3.6°F) and 50 ± 5 % relative humidity for not
prepared, unless otherwise specified, in accordance with the
less than 40 h prior to test in accordance with Procedure A of
sampling method described in 6.3, which averages the effect
Methods D 618 for those tests where conditioning is re-
over the sheet by selecting squares comprising the specimen
in such a manner that each square represents the same
TABLE 1 Number of Squares to be Cut from Each Piece
proportional part of the entire area of the sheet.
NOTE-In case of material of thicknesses not inclUded in the table, the squares
6.3 Specimen /rom Sheet Materials-The specimen shall
used In the composite test specimen shall be selected In accordance with the
be selected from the whole sheet by cutting a strip 12.7 mm
method for nearest thickness given In the tabla. In case the thickness Is midway
(1/2 in.) in width from the sheet, parallel to the two long edges between two adjacent values In the table, the squares used in the composite test
specimen shall be selected In accordance with the Instructions for the thinner
if the sheet is not square or parallel to any two ifit is square,
material.
midway between them, and extending from the edge to the
Thickness of Total Number
Number of Piece
center of the sheet. If quarter sheets are used, the strip shall
Material, of Squares ------------­
be taken from the edge corresponding to the center-to-edge
mm(ln.) Required 2 3 4 6 6 7 8
section of the original whole sheet. The strip shall be divided
0.40 (11••) 32 B 6 6 4 3 3 2
into eight equal parts numbered from 1 to 8, beginning with
0.79 (1io2) 16 4 3 3 2 2 1 1
1.19(%.) 11 2
the piece corresponding to the edge of the sheet. The squares 2 2 2 1 1 1
1.59 (11,.) 8 2 1 1 1 1 1
used to form the composite test specimen shall be taken from
2.38 (0/32) 5 1 1 1 1 1
these pieces. If the whole piece is not used, the squares cut
3.2 (Yo) 4 1 1 1
from it shall be taken from the end which was originally 4.8 (3;;.) 3 1
9.5(%) 1 1
nearest the edge of the sheet. If any piece is insufficient for
12.7 (V2) 1 1
the number of squares required to be cut from a piece
~t 0621
c
FIG. 2 Jig for Composite SpecImen
quired. In caseS ofdisagreement, the tolerances shall be ± I·C
(±1.8·F) and ±2 % relative humidity.
7.1.2 Test Conditions-Conduct tests in the Standard
Laboratory Atmosphere of23 ± 2·C (73.4 ± 3.6·F) and 50 ±
I--t--£
S % relative humidity, unless othenvise specified in the test
F
methods or in these test methods. In cases of disagreement,
the tolerances shall be ±1°C (±l.S·F) and ±2 % relative
humidity.
7.2 In those materials where shrinkage is a large part of
A-Movabla anvil.
total deformation, the specimens shall be preconditioned for
B-Statlonary plate.
4 h at 65 ± 3°e (150 ± SOF) and then conditioned for 68 hat
C-Thickness Indicator.
D-Welght platform.
a temperature of 35 ± 1°C (95 ± 1.8°F) and a relative
E-Test specimen.
humidity of 90 ± 2 %, unless otherwise specified. The
F-Lower anvil mounted on ball support (F,) and loose plate (F,v.
specimens shall be supported during conditioning upon a
'Is-in. mesh wire screen or the equivalent in order to permit
FIG. 3 Low-Pressure Deformation Tester
free access of the atmosphere to all surfaces.
7.3 Where a quick measurement of total deformation is
are used, take care to ensure that the squares are well aligned.
desired, such as for procurement of materials wherein the
10.2 Apply the load to
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