1、Designation: D 3896 07Standard Practice forRubber From Synthetic SourcesSampling1This standard is issued under the fixed designation D 3896; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in par
2、entheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice, intended for referee purposes, covers auniform procedure for sampling lots of solid synthetic rubbers.Raw synthetic rubber generally
3、 is marketed in bales or pack-ages of various sizes.1.2 A procedure for determining the acceptability of lots ofsynthetic rubber is given. This procedure is based on avariables sampling plan.1.3 The sample size is based on the assumption of a visuallyhomogeneous material. If obvious heterogeneity ex
4、ists, thenumber of samples shall be increased.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility
5、of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ANSI Standard:Z1.9 Sampling Procedures and Tables for Inspection byVariables for Percent Defective23. Significance and
6、 Use3.1 The sampling plan is intended for referee purposes onlyin establishing the properties or quality of a lot or shipment ofsynthetic rubber.4. Sampling4.1 Number of SamplesThe number of samples to beselected to represent the lot shall be determined by the size ofthe lot as indicated in Table 1.
7、 A sample bale or package isselected randomly from the lot for each sample required.NOTE 1The sampling plan is more efficient for large lots. The risk forthe producer and consumer decreases as the sample size increases.4.2 Removal of Test Portions:4.2.1 BalesFrom each sample bale selected, cut one 6
8、00to 1500-g test portion of rubber, depending on the tests to bemade. Each test portion is tested separately. Cut the test portionthrough the entire bale, normal to the bale surfaces of thelargest area without the use of lubricant. Remove polyethylenefilm, paper, talc, or other extraneous surface ma
9、terial prior totesting. Unless the test portion is to be tested immediately,place it in an airtight container of not more than twice thevolume of the test portion, or wrap it tightly in two layers ofaluminum foil until tested.4.2.2 PackagesFrom each sample package selected, re-move between 600 and 1
10、500 g of rubber depending on the teststo be made. The rubber should be selected randomly from thepackage and should be as free of surface material as practical.Unless the sample is to be tested immediately, place it in anairtight container.5. Lot Acceptability5.1 Each property of the lot is evaluate
11、d separately. Therequirements of these tests are of two types: (1) those having asingle limit such as a minimum or maximum and (2) thosehaving double limits, that is, a minimum and a maximum. Aquality index is calculated for each property tested, and fromthis index, an estimate is made of the percen
12、t of the lot that isdefective. If this percentage does not exceed the allowablevalues shown in Table 1, the lot is considered acceptable.1This practice is under the jurisdiction of ASTM Committee D11 on Rubber andis the direct responsibility of Subcommittee D11.23 on Synthetic Rubbers.Current editio
13、n approved March 1, 2007. Published April 2007. Originallyapproved in 1980. Last previous edition approved in 2001 as D 3896 85 (2001).2Available from the American National Standards Institute, 25 W. 43rd St., 4thFloor, New York, NY 10036.TABLE 1 Sampling PlanNOTE 1The sampling plan is based on Insp
14、ection Level III, ANSIZ1.9, and an Acceptable Quality Level of 2.5 %.Lot Size, kg (lb)Number ofSamplesQ Value,minAAllowablePercentDefective,maxB300 to 4000 (660 to 8800) 3 1.12 7.64001 to 6500 (8801 to 14 300) 4 1.17 10.96501 to 10 100 (14 301 to 24 200) 5 1.24 9.810 001 to 18 000 (24 201 to 39 700)
15、 7 1.33 8.418 001 to 30 000 (39 701 to 66 100) 10 1.41 7.330 001 to 50 000 (66 101 to 110 200) 15 1.47 6.650 001 to 80 000 (110 201 to 176 400) 20 1.51 6.2AMinimum value of Q for quality characteristics having single specification limit.BMaximum allowable percent defective for quality characteristic
16、s having bothupper and lower specification limit.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Quality Index Calculations:5.2.1 For a requirement having a maximum limit, calculatethe quality index as follows:Q 5U 2 X!/S (1)wher
17、e:Q = quality index,U = maximum value permitted by the specification,X= mean of values obtained for the test portion, andS = standard deviation of the samples.5.2.2 For a requirement having a minimum limit, calculatethe quality index as follows:Q 5X2 L!/S (2)where:Q, X, and S = same as those for max
18、imum value, andL = minimum value permitted by the specifica-tion.5.3 Acceptability:5.3.1 For a quality characteristic having a single specifica-tion limit, a lot is acceptable if the quality index equals orexceeds the minimum quality index shown in Table 1 for theapplicable lot and sample size.5.3.2
19、 For a quality characteristic having both an upper andlower specification limit, estimate the percentages of the lotabove the upper limit and below the lower limit from Table 2using the appropriate sample size and quality index valuescalculated in 5.2. A lot is acceptable if the sum of the twopercen
20、tages does not exceed the maximum allowable percentdefective shown in Table 1 for the lot size being evaluated.6. Precision and Bias6.1 Precision and bias statements are not directly applicableto this sampling practice, but they are pertinent to individualtest methods that will use this sampling pra
21、ctice.7. Keywords7.1 sampling; synthetic rubberASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights,
22、and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revi
23、sion of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you
24、shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be o
25、btained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 2 Estimate of Lot Percent DefectiveNumberofSamples:3 4 5 7 101520Q Value Estimated Percent of Lot Above or Below Limit0.95 19.3
26、18.3 17.9 17.5 17.3 17.2 17.21.00 16.7 16.7 16.4 16.1 16.0 15.9 15.91.05 13.7 15.0 14.9 14.8 14.7 14.7 14.71.10 9.8 13.3 13.5 13.5 13.5 13.5 13.51.15 0.3 11.7 12.1 12.3 12.3 12.4 12.41.20 . 10.0 10.8 11.1 11.2 11.3 11.41.25 . 8.7 9.7 10.2 10.4 10.5 10.61.30 . 6.7 8.2 8.9 9.2 9.4 9.51.35 . 5.0 7.0 7.
27、9 8.3 8.5 8.61.40 . 3.3 5.9 7.0 7.4 7.7 7.81.45 . 1.7 4.8 6.1 6.6 6.9 7.01.50 . . 3.8 5.3 5.9 6.2 6.31.55 . . 2.9 4.5 5.2 5.5 5.71.60 . . 2.0 3.8 4.5 4.9 5.11.65 . . 1.3 3.2 4.0 4.4 4.51.70 . . 0.7 2.6 3.4 3.8 4.01.75 . . 0.2 2.1 2.9 3.4 3.61.80 . . . 1.7 2.5 2.9 3.11.85 . . . 1.3 2.1 2.6 2.81.90 . . . 0.9 1.8 2.2 2.41.95 . . . 0.6 1.4 1.9 2.12.00 . . . 0.4 1.2 1.6 1.82.10 . . . 0.1 0.7 1.2 1.32.20 . . . . 0.4 0.8 1.02.30 . . . . 0.2 0.5 0.72.40 . . . . 0.1 0.3 0.52.50 . . . . . 0.2 0.32.60 . . . . . 0.1 0.22.70 . . . . . 0.1 0.12.80 . . . . . . 0.12.90 . . . . . . .D3896072
