1、Designation: D6478 10 (Reapproved 2014)Standard Test Method forDetermining Specific Packability of Fabrics Used inInflatable Restraints1This standard is issued under the fixed designation D6478; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers procedures for determining theability to fold and pack fabrics used fo
3、r inflatable restraintsusing an index of specific packability.1.2 Procedures in this test method describe operator tech-niques that must be followed closely to obtain repeatable andaccurate results. Since these techniques are difficult to conveyin writing, supplemental training for operators is requ
4、ired. Atraining video is available from ASTM (see AdjunctsADJD6478 and ADJD6478A).1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 Procedures and apparatus other than those stated in thispractice may be used as agreed upo
5、n between the purchaserand the supplier with specific deviations from this practiceacknowledged in the report.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safet
6、y and health practices, and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD1776 Practice for Conditioning and Testing TextilesD2904 Practice for Interlaboratory Testing of a Textile TestMethod that
7、Produces Normally Distributed Data (With-drawn 2008)3D6799 Terminology Relating to Inflatable RestraintsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ASTM Adjuncts:ADJD6478 17 Detailed Drawings4ADJD6478A Videotape-Supplemental Training43. Termino
8、logy3.1 For all terminology relating to D13.20, Inflatablerestraints, refer to Terminology D6799.3.1.1 The following terms are relevant to this standard:inflatable restraint, packability, specific packability.3.2 For all other terms related to textiles, see TerminologyD123.4. Summary of Test Method4
9、.1 Afabric specimen is folded uniformly in a “Z” pattern inthe warp and fill directions.4.2 The folded specimen is placed into a transparent boxthat confines the specimen securely during compression.4.3 The folded specimen is compressed using a tensile testeroutfitted with special hardware, and the
10、resulting volume isrecorded at specified loads. The total of all the individualvolumes recorded at each specified cell is the specific pack-ability of the fabric.5. Significance and Use5.1 This test method is useful for determining the specificpackability of uncoated and coated airbag fabrics. Fabri
11、cpackability is an important factor in the design of airbagmodules due to their inherent spacial constraints.5.2 A folded specimen exhibits better specific packability ifit occupies a lower total volume at the specified loads com-pared to another specimen.5.3 The time required to test one sample (fo
12、ur specimensfrom the same lot of fabric) is approximately 1.5 h using thistest method. Due to the length of time required by this testmethod to perform a single test, this test method is most1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility
13、of Subcommittee D13.20 on Inflatable Restraints.Current edition approved July 1, 2014. Published August 2014. Originallyapproved in 1999. Last previous edition approved in 2010 as D647810. DOI:10.1520/D6478-10R14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cu
14、stomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from ASTM International Headquarters. For 17 Detailed
15、 CADDrawings, Order Adjunct No. ADJD6478. For Videotape-Supplemental Training,Order ADJD6478A.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1suitable for use in design and development analysis or forinclusion in a list of required te
16、sts conducted for annualcertification of an airbag fabric.6. Apparatus6.1 Tensile Tester, outfitted with a rigid base to support thespecimen box, and a compression foot attached to the load cellwith a coupling having adjustment and locking capability tomaintain fixed parallel alignment to the base.
17、Tensile testershould be calibrated annually by an independent agency whoseresults are traceable to the National Institute of Science andTechnology (NIST) or other national standards laboratory.NOTE 1The frame of the tensile tester can be used as the rigid base ifit is a solid metal surface which can
18、 support compression loading of 200Nwithout deforming, is perfectly flat, and supports the entire footprint of thespecimen box.6.2 Apparatus Manufactured in Accordance With Drawings5(See Fig. 1):6.2.1 Rectangular Box, 100 by 1506 0.1mmwith 99 by 1496 0.1 mm cover plate constructed of transparent pol
19、ycarbonatematerial.6.2.2 Rectangular Template and Rotary Cutting Pad, 750 by800 mm 6 0.5 mm , for cutting specimens from fabric samples(optional).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 positionduring folding.6.2.4 Compress
20、ion Gage Blocks, with thickness of 10, 20,and 30 6 0.1 mm.6.2.5 All dimensions shall be verified at time of manufac-ture using measuring devices traceable to the National Instituteof Science and Technology (NIST) or other national standardslaboratory.6.3 Rotary Razor Cutter.6.4 Large Paperclips (Thr
21、ee), preferably with a serratedsurface to improve gripping capability.6.5 Permanent Marking Pen, pen with fine tip.7. Specimen Preparation7.1 Condition fabric samples for a minimum of3hinthestandard atmosphere for testing textiles in accordance withPractice D1776.7.2 Without fraying or fusing the ed
22、ges, cut four 750 by 8006 5-mm specimens from each sample, with the 800-mmdimension aligned in the warp direction and the cuts alignedwith the warp and weft yarns in the fabric.7.3 Write the fabric sample identification and the specimennumber on the lower right corner of the specimen (warp yarnsrunn
23、ing up/down and weft yarns running right/left relative tothe operator) at a location about 50 mm from the bottom edgeand 50 mm from the right edge.8. Procedure8.1 Tensile Tester Set-Up and Calibration Check:(See X1.1.)8.1.1 Set tensile tester for compression mode, install loadcell with maximum force
24、 rating of 200 to 1000N, set crossheadspeed to 25.0 6 1.0 mm/min, set data acquisition equipment torecord thickness with an accuracy of 0.1 mm at loads of 20 to180N in 20N increments (nine total points), set samplingfrequency at 25 Hz and set test endpoint at 200N8.1.2 Mount the rigid base to the te
25、nsile tester frame, mountthe coupling to the load cell, and attach the compression foot tothe coupling, leaving the adjustment locking mechanism loose.(See Note 1)8.1.3 Lower the crosshead slowly until 200 6 50N force isachieved and lock the compression foot into position. (SeeX1.1.1.)8.1.4 Raise th
26、e crosshead until there is a gap of approxi-mately 1 mm between the compression foot and the base andvisually check for parallel alignment in both directions. (SeeX1.1.2.)8.1.5 Raise the crosshead, place the specimen box on thetensile tester base, and insert the top cover plate into the box.8.1.6 Ra
27、ise the specimen box by hand until the compressionfoot is inside the box, then lower the crosshead and boxtogether until the box rests on the support base and thecompression foot is not touching the cover plate. Position thebox so that the compression foot is in the approximate centerof the box.NOTE
28、 2Exercise caution to avoid possible operator injury from thepinch-point between the compression foot and the specimen box.8.1.7 Lower the crosshead until a force of 100 6 30N isachieved and set zero.NOTE 3An alternate zero can be used to simplify the test. To use thealternate zero, set the true zer
29、o as specified, raise the crosshead to thedesired point, and zero the crosshead position again. The position of thealternate zero should be selected such that the compression foot does nottouch the cover plate when the fabric specimen is in the box. A positionof +35 mm is suitable for most airbag fa
30、brics.8.1.8 Raise the crosshead, place the specimen box on thetensile tester base, insert the 10-mm gage block and then thecover plate into the box.8.1.9 Raise the specimen box by hand until the compressionfoot is inside the box, then lower the crosshead and boxtogether until the box rests on the su
31、pport base and thecompression foot is not touching the cover plate. Position thebox so that the compression foot is in the approximate centerof the box. (See X1.1.3.)8.1.10 Initiate the compression test and record thickness atall specified loads.8.1.11 Repeat 8.1.8 8.1.10 using the 20 and 30-mm gage
32、blocks.8.1.12 Ensure that the thickness measured for each gageblock at 100N force is within 65.0 % of the actual thickness.Excessive variation indicates the need for equipment servicing.8.2 Specimen Folding:(See X1.2.)5Equipment designed by AlliedSignal Performance Fibers, is manufacturedaccording t
33、o drawing #61-27A-7906-2 and is available from Precision MachineCompany, Inc., 2915 West Lehigh Street, Richmond, VA23230. Copyright for CADdrawings held by AlliedSignal and provided to ASTM with full unlimited authori-zation to distribute copies and/or to designate other parties to distribute copie
34、s.D6478 10 (2014)28.2.1 Place the folding jig on a table approximately 0.8 m inheight with the “A” side of the jig to the left of the operator andplace all slats on the table in ascending numerical order fromtop to bottom. The “A” and “B” identification marks on the jigbase and all slats indicate co
35、rrect orientation for installationand numbers on the slats indicate the correct sequence forinstallation. (See X1.2.1.)8.2.2 Place the base slat in the jig.8.2.3 Place the fabric specimen in the jig with the identifi-cation mark up and at the bottom right corner, nearest theoperator, and align the e
36、dges of the specimen with the outerguide lines on the jig base.8.2.4 Fold the specimen using the wide slats, #1 to #5,visually inspecting and adjusting at each step to ensure that allfolds are straight, are aligned to within 61 mm and that thefabric is tight around the slats.FIG. 1 ApparatusD6478 10
37、 (2014)3NOTE 4If slippage or misalignment occurs, the following procedurecan be repeated using the same specimen if there is sufficient fabricremaining for the trimming step at the beginning and end of the foldingprocess.8.2.4.1 Install slat #1 on top of the fabric specimen. Slidethe specimen into p
38、osition so that the fabric protrudes approxi-mately 5 mm under the back edge of the slat.8.2.4.2 Run the rotary razor cutter along the back edge ofslat #1 and remove the trimmed excess fabric. (See X1.2.2.)8.2.4.3 Pull the fabric front to back across the top of slat #1,and install slat #2.8.2.4.4 Pu
39、ll the fabric from back to front across the top ofslat #2, and install slat #3. (See X1.2.3.)8.2.4.5 Pull the fabric from front to back across the top ofslat #3, and install slat #4.8.2.4.6 Pull the fabric from back to front across the top ofslat #4, and install slat #5.8.2.4.7 Run the rotary razor
40、cutter along the front edge ofslat #5 and remove the trimmed excess fabric. (See X1.2.4.)8.2.5 Position the jig so that the “B” side faces toward theoperator.8.2.6 Using a fine-tip permanent marker, make thin horizon-tal marks on the fabric at three locations along the right side ofslots #2 and #4 a
41、s indicated by guide lines on the jig base.Make thin vertical marks on the fabric specimen adjacent to thehorizontal marks using a vertical edge of the 30 mm gage blockas a guide. When making the vertical marks, insert the pen tipslightly under slat #1 so that the bottom single layer of fabricalso w
42、ill be marked. (See X1.2.5.)8.2.7 Remove the slat bracket on the “B” side.8.2.8 Remove the wide slats one at a time from top tobottom.8.2.8.1 Slide slat #5 out and slightly left.8.2.8.2 Slide slat #4 out and slightly left.8.2.8.3 Slide slat #3 out and slightly right. (See X1.2.6.)8.2.8.4 Slide slat
43、#2 out and slightly left.8.2.8.5 Slide slat #1 out and slightly right.8.2.9 Pinch the fabric folds and the single layer of fabrictogether using the horizontal and vertical marks to align theedges directly on top of each other. Insert a large papercliphalfway over the tow folds and the edge of the si
44、ngle layer offabric at each of the three locations marked.8.2.10 Invert the folded stack and adjust the individual foldsand the edge of the single fabric layer so that the alignment isexact at each of the three locations clipped. Carefully revert thefolded stack so that the specimen identification m
45、ark is on thetop.8.2.11 Reinstall the slat bracket on the “B” side.8.2.12 Position the jig with the “A” side left of the operator,position the folded stack so the specimen identification mark isat the front edge of the jig facing the operator, and align theedges of the folded stack with the inner gu
46、idelines on the jigbase. (See X1.2.7.)8.2.13 Fold the specimen using the narrow slats #1 to #7,visually inspecting and adjusting at each step to insure that allfolds are straight, are aligned to within 61 mm and that thefabric is tight around the slats. (See X1.2.8.)NOTE 5If slippage or misalignment
47、 occurs, the procedure below canbe repeated using the same specimen if there is sufficient fabric remainingfor the trimming step at the beginning and end of the folding process.8.2.13.1 Install slat #1 on top of the fabric specimen. Slidethe specimen into position so that the fabric protrudes approx
48、i-mately 5 mm under the back edge of the slat.8.2.13.2 Check and adjust the relative alignment of thefolded edges under slat #1 so that they are directly on top ofeach other.8.2.13.3 Use the back edge of slat #1 to hold the foldedspecimen in position and remove the paperclip under the slat.8.2.13.4
49、Run the rotary razor cutter along the back edge ofslat #1 and remove the trimmed excess fabric. (See X1.2.9.)8.2.13.5 Pull the fabric from front to back across the top ofslat #1, and install slat #2.8.2.13.6 Pull the fabric from back to front across the top ofslat #2, and install slat #3.8.2.13.7 Pull the fabric from front to back across the top ofslat #3, and install slat #4.8.2.13.8 Remove the second paperclip from under slat #4.8.2.13.9 Pull the fabric from back to front across the top ofslat #4, and install slat #5.8.2.13.10 Pull the fabric from front to back acros
