ASTM D6478-02(2007)
(Test Method)Standard Test Method for Determining Specific Packability of Fabrics Used in Inflatable Restraints
Standard Test Method for Determining Specific Packability of Fabrics Used in Inflatable Restraints
SIGNIFICANCE AND USE
This test method is useful for determining the specific packability of uncoated and coated airbag fabrics. Fabric packability is an important factor in the design of airbag modules due to their inherent spacial contraints.
A folded specimen exhibits better specific packability if it occupies a lower total volume at the specified loads compared to another specimen.
The time required to test one sample (four specimens from the same lot of fabric) is approximately 1.5 h using this test method. Due to the length of time required by this test method to perform a single test, this test method is most suitable for use in design and development analysis or for inclusion in a list of required tests conducted for annual certification of an airbag fabric.
SCOPE
1.1 This test method covers procedures for determining the ability to fold and pack fabrics used for inflatable restraints using an index of specific packability.
1.2 Procedures in this test method describe operator techniques that must be followed closely to obtain repeatable and accurate results. Since these techniques are difficult to convey in writing, supplemental training for operators is required. A training video is available from ASTM (see Adjuncts ADJD6478 and ADJD6478A and ).
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not exact equivalents; therefore, each system must be used independent of the other.
1.4 Procedures and apparatus other than those stated in this practice may be used as agreed upon between the purchaser and the supplier with specific deviations from this practice acknowledged in the report.
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.
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D 6478 – 02 (Reapproved 2007)
Standard Test Method for
Determining Specific Packability of Fabrics Used in
Inflatable Restraints
This standard is issued under the fixed designation D 6478; 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.
1. Scope D 6799 Terminology Relating to Inflatable Restraints
E 691 Practice for Conducting an Interlaboratory Study to
1.1 This test method covers procedures for determining the
Determine the Precision of a Test Method
ability to fold and pack fabrics used for inflatable restraints
2.2 ASTM Adjuncts:
using an index of specific packability.
ADJD6478 — 17 Detailed Drawings
1.2 Procedures in this test method describe operator tech-
ADJD6478A- Videotape-Supplemental Training
niques that must be followed closely to obtain repeatable and
accurate results. Since these techniques are difficult to convey
3. Terminology
in writing, supplemental training for operators is required. A
3.1 Definitions:
training video is available from ASTM (see Adjuncts
3.1.1 For definitions of other textile and statistical terms
ADJD6478 and ADJD6478A and ).
used in this standard, refer to Terminology D 123, Practice
1.3 The values stated in either SI units or inch-pound units
D 2906 and Terminology D 6799.
are to be regarded separately as standard. The values stated in
each system are not exact equivalents; therefore, each system
4. Summary of Practice
must be used independent of the other.
4.1 Afabricspecimenisfoldeduniformlyina“Z”patternin
1.4 Procedures and apparatus other than those stated in this
the warp and fill directions.
practice may be used as agreed upon between the purchaser
4.2 The folded specimen is placed into a transparent box
and the supplier with specific deviations from this practice
that confines the specimen securely during compression.
acknowledged in the report.
4.3 Thefoldedspecimeniscompressedusingatensiletester
1.5 This standard does not purport to address all of the
outfitted with special hardware, and the resulting volume is
safety concerns, if any, associated with its use. It is the
recorded at specified loads. The total of all the individual
responsibility of the user of this standard to establish appro-
volumes recorded at each specified cell is the specific pack-
priate safety and health practices, and determine the applica-
ability of the fabric.
bility of regulatory limitations prior to use.
5. Significance and Use
2. Referenced Documents
5.1 This test method is useful for determining the specific
2.1 ASTM Standards:
packability of uncoated and coated airbag fabrics. Fabric
D 123 Terminology Relating to Textiles
packability is an important factor in the design of airbag
D 1776 Practice for Conditioning and Testing Textiles
modules due to their inherent spacial contraints.
D 2904 Practice for InterlaboratoryTesting of aTextileTest
5.2 Afolded specimen exhibits better specific packability if
Method that Produces Normally Distributed Data
it occupies a lower total volume at the specified loads com-
D 2906 Practice for Statements on Precision and Bias for
pared to another specimen.
Textiles
5.3 The time required to test one sample (four specimens
from the same lot of fabric) is approximately 1.5 h using this
This test method is under the jurisdiction ofASTM Committee D13 onTextiles
test method. Due to the length of time required by this test
and is the direct responsibility of Subcommittee D13.20 on Inflatable Restraints.
method to perform a single test, this test method is most
Current edition approved July 1, 2007. Published August 2007. Originally
approved in 1999. Last previous edition in 2002 as D 6478–02
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Available from ASTM International Headquarters. For 17 Detailed CAD
Standards volume information, refer to the standard’s Document Summary page on Drawings, Order Adjunct No. ADJD6478. For Videotape-Supplemental Training,
Order ADJD6478A.
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 6478 – 02 (2007)
suitable for use in design and development analysis or for 8. Procedure
inclusion in a list of required tests conducted for annual
8.1 Tensile Tester Set-Up and Calibration Check:
certification of an airbag fabric.
8.1.1 Set tensile tester for compression mode, install load
cell with maximum force rating of 200 to 1000N, set crosshead
6. Apparatus
speed to 25.0 6 1.0 mm/min, set data acquisition equipment to
6.1 Tensile Tester, outfitted with a rigid base to support the record thickness with an accuracy of 0.1 mm at loads of 20 to
specimen box, and a compression foot attached to the load cell 180N in 20N increments (nine total points), set sampling
with a coupling having adjustment and locking capability to frequency at$ 25 Hz and set test endpoint at 200N
maintain fixed parallel alignment to the base. Tensile tester 8.1.2 Mount the rigid base to the tensile tester frame, mount
should be calibrated annually by an independent agency whose
thecouplingtotheloadcell,andattachthecompressionfootto
results are traceable to the National Institute of Science and the coupling, leaving the adjustment locking mechanism loose.
Technology (NIST) or other national standards laboratory.
(See Note 1)
8.1.3 Lower the crosshead slowly until 200 6 50N force is
NOTE 1—The frame of the tensile tester can be used as the rigid base if
achieved and lock the compression foot into position.
it is a solid metal surface which can support compression loading of 200N
withoutdeforming,isperfectlyflat,andsupportstheentirefootprintofthe 8.1.4 Raise the crosshead until there is a gap of approxi-
specimen box.
mately 1mm between the compression foot and the base and
visually check for parallel alignment in both directions.
6.2 Apparatus Manufactured in Accordance With Drawings
8.1.5 Raise the crosshead, place the specimen box on the
(See Fig. 1):
tensile tester base, and insert the top cover plate into the box.
6.2.1 Rectangular Box , 100 by 1506 0.1mm with 99 by
8.1.6 Raise the specimen box by hand until the compression
149 6 0.1 mm cover plate constructed of transparent polycar-
foot is inside the box, then lower the crosshead and box
bonate material.
together until the box rests on the support base and the
6.2.2 Rectangular Template and Rotary Cutting Pad, 750 by
compression foot is not touching the cover plate. Position the
800 mm 6 0.5 mm , for cutting specimens from fabric samples
box so that the compression foot is in the approximate center
(optional).
of the box.
6.2.3 Jig, consisting of two sets of slats (wide and narrow)
for making the folds and a frame that holds the slats in position
NOTE 2—Exercise caution to avoid possible operator injuy from the
during folding.
pinch-point between the compression foot and the specimen box.
6.2.4 Compression Gage Blocks, with thickness of 10, 20
8.1.7 Lower the crosshead until a force of 100 6 30N is
and 30 6 0.1 mm.
achieved and set zero.
6.2.5 All dimensions shall be verified at time of manufac-
ture using measuring devices traceable to the National Institute
NOTE 3—An alternate zero can be used to simplify the test. To use the
of Science and Technology (NIST) or other national standards alternate zero, set the true zero as specified, raise the crosshead to the
desired point, and zero the crosshead position again. The position of the
laboratory.
alternate zero should be selected such that the compression foot does not
6.3 Rotary Razor Cutter.
touch the cover plate when the fabric specimen is in the box. A position
6.4 Large Paperclips (Three), preferably with a serrated
of +35 mm is suitable for most airbag fabrics
surface to improve gripping capability.
8.1.8 Raise the crosshead, place the specimen box on the
6.5 Permanent Marking Pen, pen with fine tip.
tensile tester base, insert the 10- mm gage block and then the
cover plate into the box.
7. Specimen Preparation
8.1.9 Raise the specimen box by hand until the compression
7.1 Condition fabric samples for a minimum of3hinthe
foot is inside the box, then lower the crosshead and box
standard atmosphere for testing textiles in accordance with
together until the box rests on the support base and the
Practice D 1776.
compression foot is not touching the cover plate. Position the
7.2 Without fraying or fusing the edges, cut four 750 by 800
box so that the compression foot is in the approximate center
6 5 - mm specimens from each sample, with the 800 mm
of the box.
dimension aligned in the warp direction and the cuts aligned
8.1.10 Initiate the compression test and record thickness at
with the warp and weft yarns in the fabric.
all specified loads.
7.3 Write the fabric sample identification and the specimen
8.1.11 Repeat 8.1.8-8.1.10 using the 20 and 30- mm gage
number on the lower right corner of the specimen (warp yarns
blocks.
running up/down and weft yarns running right/left relative to
8.1.12 Ensure that the thickness measured for each gage
the operator) at a location about 50 mm from the bottom edge
block at 100N force is within 6 5.0 % of the actual thickness.
and 50 mm from the right edge.
Excessive variation indicates the need for equipment servicing.
8.2 Specimen Folding:
8.2.1 Place the folding jig on a table approximately 0.8 m in
Equipment designed by AlliedSignal Performance Fibers, is manufactured
height with the “A” side of the jig to the left of the operator,
according to drawing #61-27A-7906-2 and is available from Precision Machine
and place all slats on the table in ascending numerical order
Company, Inc., 2915West Lehigh Street, Richmond,VA23230. Copyright for CAD
from top to bottom. The “A” and “B” identification marks on
drawings held by AlliedSignal and provided to ASTM with full unlimited authori-
zation to distribute copies and/or to designate other parties to distribute copies. the jig base and all slats indicate correct orientation for
D 6478 – 02 (2007)
FIG. 1 Apparatus
installation, and numbers on the slats indicate the correct 8.2.4 Fold the specimen using the wide slats, #1 to #5,
sequence for installation.
visually inspecting and adjusting at each step to ensure that all
8.2.2 Place the base slat in the jig.
folds are straight, are aligned to within 6 1 mm and that the
8.2.3 Place the fabric specimen in the jig with the identifi-
fabric is tight around the slats.
cation mark up and at the bottom right corner, nearest the
operator, and align the edges of the specimen with the outer
guide lines on the jig base.
D 6478 – 02 (2007)
NOTE 4—I
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