1、Designation: D 4168 95 (Reapproved 2008)e1Standard Test Methods forTransmitted Shock Characteristics of Foam-in-PlaceCushioning Materials1This standard is issued under the fixed designation D 4168; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTESections 2 and 3.1 were updated editorially in April 2008.1. Scope1.1 These test methods determi
3、ne the shock-absorbing char-acteristics of foam-in-place packaging materials.1.2 Test Method A uses a free-fall package drop test appa-ratus.1.3 Test Method B uses a shock-test apparatus.1.4 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are math
4、ematicalconversions to SI units that are provided for information onlyand are not considered standard.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 safety and he
5、alth practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 996 Terminology of Packaging and Distribution Environ-mentsD 3332 Test Methods for Mechanical-Shock Fragility ofProducts, Using Shock MachinesD 5276 Test Method for Dro
6、p Test of Loaded Containers byFree FallD 5487 Test Method for Simulated Drop of Loaded Con-tainers by Shock Machines3. Terminology3.1 General definitions for packaging and distribution envi-ronments are found in Terminology D 996.3.2 Definitions:3.2.1 accelerationthe rate of change of velocity of a
7、bodywith respect to time, measured in inches per second per second(metres per second per second).3.2.2 velocitythe rate of change of position of a body in aspecified direction with respect to time, measured in inches persecond (metres per second).3.3 Definitions of Terms Specific to This Standard:3.
8、3.1 equivalent free-fall heightthe calculated height offree fall in a vacuum required for a falling body to attain ameasured or given impact velocity.3.3.2 foam-in-place cushioning materiala material that isformed by dispensing chemical components which react andexpand to produce a foam cushioning m
9、aterial in a container ormold.3.3.3 free rise core densitythe density of a foam sampletaken from the interior of a bun of foam (without skin) that wasproduced under unrestricted (free-rise) conditions in poundsper cubic foot (kilograms per cubic metre).3.3.4 static loadingthe applied mass in pounds
10、(kilo-grams) divided by the area, measured in square inches (squaremetres) to which the mass is applied in pounds per squaresinches (kilograms per square metre).1These test methods are under the jurisdiction of ASTM Committee D10 onPackaging and are the direct responsibility of Subcommittee D10.13 o
11、n InteriorPackaging.Current edition approved April 1, 2008. Published April 2008. Originallyapproved in 1982. Last previous edition approved in 2002 as D 4168 95(2002).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual
12、 Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.3.5 velocity changethe sum of the impact velocity andany rebound velocity.3.
13、4 Symbols:Symbols:3.4.1 gsymbol for the acceleration due to the effects of theearths gravitational pull. While somewhat variable, it isusually considered a constant of value 386 in./s/s (9.8 m/s/s).4. Summary of Test Methods4.1 The test methods consist of using the cushioning mate-rial to be tested
14、to support a weighted test block inside apackage. The complete package is subjected to drops orcontrolled shocks and the accelerations transmitted to the testblock are measured.4.2 Either Test Method A or B may be used. However, thetwo methods will not necessarily give the same result.5. Significanc
15、e and Use5.1 Data obtained by these methods may be used to deter-mine the transmitted shock cushioning characteristics of foam-in-place packaging materials. These data allow design ofcushioning systems that can provide adequate and efficient useof foam for protection of goods during a distribution l
16、ife-cycle.5.2 These methods, in contrast to other methods that usuallytest only the cushioning foam, are designed to evaluatefoam-in-place cushioning materials in a manner in which thefoam-in-place packaging material is used. In particular, themethod includes simultaneous use of a plastic film, the
17、foam,and the box usually used in this method of packaging. See Fig.1.6. Apparatus6.1 Test Method A:6.1.1 The free-fall drop test apparatus shall conform to therequirements as described in Test Method D 5276.6.2 Test Method B:6.2.1 The shock test apparatus shall conform to the require-ments as descri
18、bed in Test Method D 5487.6.3 Instrumention and Shock SensorsAccelerometers,signal conditioners, and data storage apparatus are required tomonitor acceleration versus time histories at various points onthe test apparatus and test specimen. The instrumentationsystems shall have the following minimum
19、properties:6.3.1 Frequency response range from 2 Hz or less to at least1000 Hz.6.3.2 Accuracy of reading to be within 65 % of the actualvalue.6.3.3 Cross-axis sensitivity less than 5 % of full scale.6.4 Test Block:6.4.1 The test block shall have a rigid square bottom face ofnot less than 8 in. (203
20、mm) on a side. Its height shall be aminimum of half the bottom square dimension and a maximumof the full bottom square dimension.6.4.2 The test block shall include provisions for firmlymounting ballast weight to adjust its total weight to a desiredvalue.6.4.3 An accelerometer mounting attachment sha
21、ll be pro-vided near the center of gravity of the block. The block shall bedesigned and constructed to be as rigid as possible and tominimize motion of the various components.6.4.4 A recommended configuration is shown in Fig. 2.Also, it is suggested that the box weight be evenly distributedabout the
22、 center of the bottom face of the test block.6.4.5 Ballast weights are added or removed to achieve thedesired static loading on the cushioning material. The acceler-ometer shall be considered as a portion of the ballast weight.FIG. 1 Specimen Ready For Test FIG. 2 Test BlockD 4168 95 (2008)e126.5 Ou
23、ter Container, shall be a regular, slotted container(RSC) corrugated box fabricated with 200 psi (1380 kPa) test“C” flute fiberboard.7. Sampling7.1 Because users form their own cushioning materials, it isvery important that accurate records be prepared of all physicaldata pertaining to those materia
24、ls for later identification. Inaddition, the specific characteristics of the film used with thecushion shall be recorded. Care must be taken to ensure thatsamples are of representative quality. It is recommended thatall samples be allowed to cure and stabilize after being pouredfor a minimum period
25、of 24 h before they are tested.7.2 SpecimensIf any of the requirements of Sections 7and 8 are not met, the container and cushioning material shallbe discarded and the procedure repeated with new material.Fig. 1 shows a typical specimen assembled and ready for test.8. Preparation of Test Specimens8.1
26、 Modified Free-Rise Bottom Cushion Fabrication (Op-tion 1):8.1.1 Dispense a layer of the foam-in-place cushioningmaterial into the bottom of the box. Place the barrier film overthe foam; then position the test block such that the foam willrise to a depth equal to the thickness to be tested. Alternat
27、ively,a dummy test block jig referenced to the top of the box may beused to ensure the correct position of the test block. The sidesof the foam cushion shall be 3 in. (76 mm) thick and shouldcome up about half of the depth of test block. Care must betaken to dispense a proper amount of foam in order
28、 that thecushion samples are of representative quality, are not overlydensified, and are free of large voids. See Fig. 3.8.2 Premolded Bottom Cushion Fabrication (Option 2):8.2.1 The bottom cushion may be premolded outside of theouter container by using a wooden mold having the insidedimensions of t
29、he outer container, and including an insert in thebottom that duplicates the size and shape of the test block. Thesides of the foam cushion shall be 3 in. (76 mm) thick andshould come up to half of the depth of the test block. Care mustbe taken to dispense a proper amount of foam in order that thecu
30、shions are of representative quality and have the desiredmolded density. (See 12.3.2 and Fig. 4)9. Test Machine9.1 Shock Test Apparatus Set-Up:9.1.1 Calculate the required carriage velocity change usingthe following equation:DV 5 =2 gh (1)where:DV = required velocity change, in./s (m/s),g = accelera
31、tion of gravity, in./s2(m/s2), andh = desired equivalent freefall drop height, in. (m).9.1.2 Following the recommendations of the shock machinemanufacturer, adjust the machine to produce a shock pulse ofnot greater than 3 ms total duration and a velocity change equalto that calculated in 9.1.1.9.1.3
32、 Rigidly mount an accelerometer or velocity-measuring instrumentation such as optical sensors on thecarriage to measure this velocity change.9.1.4 Secure the test specimen to the shock table carriage insuch a way to ensure a flat impact of the test specimen.NOTE 1Instrumentation to mesaure the veloc
33、ity change of the shocktable is required. This may be a device that integrates the area electroni-cally under the shock pulse wave form. Alternatively, it can be measuredby photodiode-type devices that measure shock table impact and reboundvelocity. Calculation that assumes the shock pulse to be a p
34、erfectgeometric figure is usually grossly inaccurate and should not be used. SeeAnnexes A1 and A2 of Test Method D 3332 for a more completediscussion.NOTE 2Equivalent drop height determined in 9.1.1 for the shock testFIG. 3 Bottom Cushion FabricationD 4168 95 (2008)e13machine will not be necessarily
35、 the same as free-fall drop height. For amore complete discussion of the relationship, refer to Test MethodD 3332.10. Conditioning10.1 Condition test specimens prior to test for a sufficientlength of time to essentially achieve and maintain equilibriumin accordance with any requirements. In the abse
36、nce of otherrequirements, use standard conditioning atmosphere of 23 62C (73.4 6 3.6F) and 50 6 2 % relative humidity.10.2 Conditioning ApparatusIn those cases where specialatmospheric conditions may be required, provide adequatefacilities for conditioning the test specimens to the desiredhumidity a
37、nd temperature prior to test.11. Procedure11.1 Test Specimen Assembly:11.1.1 Assemble the test block with the weight adjusted toachieve the desired static load.11.1.2 Insert the test cushion into the corrugated container.11.1.3 Place the test block into the cavity of the test cushionwith care.11.1.4
38、 Add the top cushion.11.1.4.1 For Option 1, modified free-rise bottom cushion,add a layer of plastic film, then dispense the foam-in-placecushioning material to form the top cushion. The sides of thetop cushion should extend down about one half of the depth ofthe test block to mate with the sides of
39、 the bottom cushion.11.1.4.2 For Option 2, premolded bottom cushion, the topcushion shall also be premolded as discussed in 8.2.11.1.5 Close the box securely. See Fig. 1.11.1.6 Take proper care to ensure that the accelerometerleads are arranged so as not to interfere with a free fall.11.2 Test Metho
40、d A Free-Fall Drop Test:11.2.1 Set the release mechanism to support the test speci-men at the desired drop height.11.2.2 Place the test specimen on the release mechanismsupport. The center of gravity of the supported face shall becentered on the supporting mechanism.11.2.3 Operate the machine in acc
41、ordance with the manu-facturers instructions to produce a flat drop within 62 asdefined in Test Method D 5276.11.2.4 Repeat for a total of five drops at the chosen testconditions with the box positioned so that the weight rests onthe test cushion as shown in Fig. 1 throughout the entire test.11.2.4.
42、1 There shall be a minimum of 1 min between thesequential drops.11.2.4.2 The time interval between the drops shall not beexcessive in order not to affect adversely the test specimenpreconditioning.11.2.5 The maximum number of drops to be conducted withone sample of the cushioning material is five. I
43、f more tests areto be run at different drop heights or static loadings, forexample, use new samples.11.3 Test Method B, Shock Test :11.3.1 Securely fasten the properly prepared test specimento the carriage of the shock test machine. Attach the inputpulse-monitoring accelerometer to the carriage as c
44、losely aspossible to the outer container. Properly connect the test blockacceleration measuring channels.11.3.2 Operate the machine in accordance with the manu-facturers instructions to produce the acceleration versus time,pulse, as determined in 9.1.11.3.3 Monitor the carriage accelerometer output
45、to verifythat the proper pulse is being obtained.FIG. 4 Bottom Cushion FabricationD 4168 95 (2008)e1411.3.4 Repeat for a total of five drops at the chosen testconditions with the box positioned so the weight rests on thetest cushion, as shown in Fig. 1, throughout the entire test.11.3.4.1 There shal
46、l be a minimum of 1 min between thesequential drops.11.3.4.2 The time interval between the drops shall not beexcessive in order not to affect adversly the test specimenpreconditioning.11.3.5 The maximum number of impacts to be conductedwith one sample of the cushioning material is five. If more test
47、sare to be run at different impact heights or static loadings, forexample, use new material.11.4 Foam Specimen Weight:11.4.1 To determine the foam density when Option 2(premolded bottom cushion) is used (see 12.3.2), the weight ofthe bottom cushion is required.At the conclusion of the drop orimpact
48、sequence, carefully remove the barrier film from thetest cushion and weigh the foam to within 1 % accuracy inpounds (or kilograms).12. Calculation12.1 Drop Height:12.1.1 For Test Method A, measure drop height, in inches(or metres).12.1.2 For Test Method B, calculate equivalent free-falldrop height a
49、s h = DV2/2g, in inches (or metres).12.2 Static LoadingCalculate the weight of the test blockin pounds (or kilograms) divided by the surface area of thebottom face of the test block in square inches (or squaremetres).12.3 Density:12.3.1 For Option 1, modified free rise foam-in-place bot-tom test cushion, determine the free rise core density of arepresentative foam sample in pounds per cubic foot (kilo-grams per cubic metre).12.3.2 For Option 2, pre-molded bottom cushion:12.3.2.1 Measure the inside dimensions of the mold used tofabricate the bottom cushion to
