1、INCH-POUND IMIL-I-2476825 Februaty 1992SUPERSEDING(See section 6)MILITARY SPECIFICATIONINSULATION, PLASTICS, LAMINATED, THERMOSEITING;GENERAL SPECIFICATION FORThis specification is approved for use by all depaments and agencies of theDepament of Defense.10 SCOPE1.1 Scope. This specification covers t
2、hermosetting plastic laminated insulation materials formechanical and electrical militaty applications.1.2 Classifkation. The form and type of insulation shall be as specified in the applicablespecification sheet (see 3.1 and 6.2.1).1.2.1 Types. The types of insulation grouped according to the base
3、material used, shall be asfollows:a. Cotton Fabric Base, Phenolic-Resin BinderFBE Cotton Fabric Base, Phenolic-Resin, Electrical GradeFBG Cotton Fabric Base, Phenolic-Resin,FBI Cotton Fabric Base, Phenolic-Resin,FBM Cotton Fabric Base, Phenolic-Resin,General PurposeMachining ApplicationsMechanical G
4、radeBenetieial comments (recommendations, additions, deletions) and any pertinent data which may be of use inimproving thii document should be addressed to: Commander, Naval Sea Systems Command, SEA 55Z3,Department of the Navy, Washington, DC 20362-5101 by using a self-addressed Standardization Docu
5、mentImprovement Proposal (DD Form 1426) appearing at the end of this document or hy letter.AMSC WA Fsc 5970DISTRIBUTION STATEMENT A, Approved for public release; distribution is unlimited.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I-24768b.
6、Glass Fabric, Base, Epoxy-Resin BinderGEE Glass Fabric Base, Epoxy-Resin, Electrical GradeGEB Glass Fabric Base, Epoxy-Resin, High Temperature Electrical GradeGEE-F Glass Fabric Base, Epoxy-Resin, Flame Resistant, Electric-al GradeGEB-F Glass Fabric Base, Epoxy-Resin, High Temperature, Flame Resista
7、nt,Electrical Gradec. Glass Fabric Base, Melamine-Resin BinderGME Glass Fabric Base, Melamine-Resin, Electrical GradeGMG Glass Fabric Base, Melamine-Resin, General Purposed. Glass Mat Base, Polyester-Resin BinderGPO N-1 GPO N-2 GPO N-3 GPO N-1P GPO N-2P GPO N-3P Glass Mat Base, Polyester-Resin, Mech
8、anical GradeGlass Mat Base, Polyester-Resin, Low Flammability and Self-extinguishingProperties, General PurposeGlass Mat Base, Polyester-Resin, Track Resistance, Low Flammability andSelf-extinguishing Properties, General PurposeGlass Mat Base, Polyester-Resin, Mechanical Grade, PunchingCharacteristi
9、csGlass Mat Base, Polyester-Resin, Low Flammability, Self-extinguishingProperties, Punching CharacteristicsGlass Mat Base, Polyester-Resin, Track Resistance, Low Flammability,Self-extinguishing Pr (DODadopted)Standard Method of Testing Rigid Sheet and Plate Materials Used forElectrical Insulation; (
10、DOD adopted)Standard Test Methods for Impact Resistance of Plastics and ElectricalInsulating Materials; (DOD adopted)Standard Test Methods for D-C Resistance or Conductance of InsulatingMaterials; (DOD adopted)Standard Methods of Testing Rigid Tubes Used for Electrical InsulationStandard Laminated R
11、ound Rods Used for Electrical InsulationStandard Test Methods for Thickness of Solid Electrical InsulationStandard Test Method for High-Voltage, Low-Current, Dry ArcResistance of Solid Electrical Insulation; (DOD adopted)Standard Test Method for Water Absorption of Plastics; (DOD adopted)Standard Me
12、thods of Conditioning Plastics and Electrical InsulatingMaterials for Testing (DOD adopted)Standard Methods of Measuring Dimensions of Rigid Rods and TubesUsed for Electrical InsulationStandard Test Methods for Specific Gravity, Relative Density andDensity of Plastics by Displacement; (DOD adopted)S
13、tandard Test Method for Dielectric Breakdown Voltage of InsulatingLiquids Using Disk Electrodes; (DOD adopted)5Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I-24768D 3951 Standard Practice for Commercial Practice; (DOD adopted)D 2303 Standard T
14、est Method for Liquid-Contaminant, Inclined-Plane Trackingand Erosion of Insulating MaterialsD 2304 Standard Method for Thermal Evaluation of Rigid Electrical InsulatingMaterialsG 21 Standard Recommended Practice for Determining Resistance ofSynthetic Polymeric Materials to Fungi; (DOD adopted)(Appl
15、ication for copies should be addressed to the American Society for Testing and Materials,1916 Race Street, Philadelphia, PA 19103.)UNIFORM CLASSIFICATION COMMITTEE AGENTUniform Freight Classification Ratings, Rules and Regulations(Application for copies should be addressed to the Uniform Classificat
16、ion Committee Agent,Room 1106,222 South Riverside Plaza, Chicago, IL 60606.)(Nongovemment standards and other publications are normally available from the organizations whichprepare or distribute the documents. These documents also maybe available in or through librariesor other informational setvic
17、es.)2S Order of precedence. In the event of a conflict between the text of this document and thereferences cited herein (except for associated detail specifications, specification sheets orMS standards), the test of this specification shall take precedence. Nothing in this document,however, shall su
18、persede applicable laws and regulations unless a specific exemption has beenobtained.3. REQUIREMENTS3.1 Specification sheets. The individual item requirements shall be as specified herein and inaccordance with the applicable specification sheets. In the event of any conflict betweenrequirements of t
19、h specification and the specification sheets, the latter shall govern.3.2 First article. When specified (see 6.2) a sample shall be subjected to first article inspection(see 4.5 and 6.5).33 Material. The material shall be as specified herein and in accordance with the applicablespecification sheets
20、(see 3.1).33.1 Sheets. Sheets shall cmsist of a base or filler, properly impregnated withresin compound or binder, and processed to ecmform to the specification sheets.6a thermosetting-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I-247683.3.2
21、Rods. Rods shall be composed of laminations of impregnated sheet material which havebeen molded in cylindrical molds under high pressure and temperature and then ground to size.33.3 Tubes. Tubes shall be formed by rolling impregnated sheet material upon mandrels betweenheat pressure rolls and then e
22、ither oven-baking for rolled tubes or pressing the material in a heatedmold for molded tubes until the curing or setting of the resin into the infusible form is completed.3.3.4 Recovered materials. Unless otherwise specified herein, all materials incorporated in theproducts covered by this specifica
23、tion shall be new and maybe fabricated using material producedfrom recovered materials to the mtimum extent practicable without jeopardizing the intended use.The term “recovered materials” means materials which have been collected or recovered from solidwaste and reprocessed to become a source of ra
24、w materials, as opposed to virgin raw materials. Noneof the above shall be interpreted to mean that the use of used products is allowed under thisspecification unless otherwise specified.3.4 Physical Characteristics. The insulation material shall be of the construction and dimensions,and have the pr
25、operty values specified herein and in the applicable specification sheet (see 3.1).3.4.1 Machinability. The laminated material shall be such that it can be drilled, tapped, sawed,and machined in all directions without cracking, splitting or otherwise impairing the material forgeneral use. The nature
26、 of laminated materials necessitates special precautions when drilling ortapping parallel to laminations.3.4.1.1 Fine machining applications. The laminated materials FBI and FBE shall be suitable forfine machining applications requiring close tolerances.3.4.2 Color. Unless otherwise specified (see 3
27、.1 and 6.2), laminated materials designated GSG,FBQ FBG, FBI, FBM, and NPG shall be natural in color, which may vary from white to light brown.Natural color is the color produced by a combination of a natural undyed base or filler and the resinused. The brown color due to heat treatment of glass fib
28、ers maybe streaked or mottled, provided itcan be shown that a nonuniform color does not impair the performance characteristics of thematerial. The color for the other materials shall conform to MIL-STD-104 if rated above 2000 volts,and natural color if used below 2000 volts.3.4.3 Uniformity. All mat
29、erial of any lot shall be uniform in texture, finish, and specifiedproperties.3.4.4 Surface finish.3.4.4.1 Laminated sheets. Unless otherwise specified (see 6.2), the surface finish of laminatedsheets shall be semigloss as produced by the laminating process.3.4.4.2 Laminated tubes and rods. Unless o
30、therwise specified (see 6.2), tubes shall be furnishedin the following finishes.7Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I-247683.4.4.2.1 Ground. Ground finish is applied by a tine grinding wheel or belt and is free from anypronounced scr
31、atches.3.4.4.2.2 Buffed. Buffed finish is somewhat more glossy than the ground finish and is obtainedby buffhg the tube or rod immediately after grinding, using a small amount of shellac or otherpolishing compound on the buffer.3.4.4.23 Varnished. Varnished finish is obtained by coating the rod or t
32、ube with varnish and thenair-drying or baking. Due to the operations involved with a varnished finish, the physical and electricalproperties may change greatly. -3.4.S Surface defects.3.4.5.1 hminated sheets. Sheets shall be free from internal and external blisters, wrinkles, orcracks and other smal
33、l defects such as scratches, dents, or heat marks. If the insulation materialcontains a glass fabric, differential coloration of various wrap or filler threads of the glass fabric orthe filament of the nonwoven parallel alignment fibers may cause streaks.3.4.5.2 Laminated tubes and rods. Laminated t
34、ubes shall be free from blisters, pronouncedmandrel scores, loose layers, resin pockets, voids, and heat marks. Rolled tubes shall be free fromwrinkles. Molded tubes shall be free from seam cracks. Rods shall be free from blisters, mold seamcracks, voids, and resin pockets. Tubes with a wall thickne
35、ss greater than 0.500 inch or rods with adiameter greater than 1.000 inch may show checks or cracks between the laminations on machinedor sawed edges. Edges, drilled holes, and machined, milled or ground faces of laminated rods andtubes shall be smooth and shall present a neat appearance.3.4.6 Warp
36、or twist3.4.6.1 Standard 36 by 36 inches laminated sheets. The warp or twist of material as delivered,shall not exceed the values of table 1. Percentage of warp is given in terms of lateral dimensions(length and width) of the material and percentage of twist is given in terms of dimensions from onec
37、orner to the opposite comer.TABLE L Wa or wk.lMckness (inches) Maximumvariation (percent)0.031 to 0.061 5.000.062 to 0.124 2.500.125 to 0.250 *.X)10.251 to 0.750 0.500.751 to max. 0.25%he value for qqx GSG shall be 1.5 percent.8Provided by IHSNot for ResaleNo reproduction or networking permitted wit
38、hout license from IHS-,-,-MIL-I-247683.4.6.2 Non-standard sheets. The warp or twist of laminated sheets other than 36 inches shallbe determined using the following formula:DX . h (36)2where:DX =D3 =.Permissible deviation -from straight edge in inches for the given lengthPermissible deviation in inch
39、es for 36 inch lengthsThe given length in inches.3.4.6.3 Laminated tube and rods. The warp material furnished in the tube or rod form, asdelivered, shall not exceed the values specified in table II. Percentage of warp is specified in termsof a 36-inch length of material. Measurement of warpage shall
40、 be as specified in ASTM D 668.TABLE II. WaqnOutside diameter (inch) Masimum variation (percent)0.12s to 0.250 2000.251 to 0.750 .10.751 to max. 0.50lThe value for type GSG shall be 1.5 percent.3.4.7 Length and width.3.4.7.1 Laminated sheets. Unless otherwise specified (see 3.1), the contractors sta
41、ndard sizesbetween 18 and 50 inches in width and 36 and % inches in length will be acceptable. The length andwidth of sheets may vary * one inch from the contractors standard size. Nonuniform standard sheetdimensions caused by cutting specimens for tests required by this specification shall not be c
42、ause forrejection, unless particular dimensions are specified. When particular sheet dimensions are specified(see 6.2), the permissible variation from specified length or width shall be as shown in table III.3.4.7.2 Laminated tubes and rods. Unless otherwise specified (see 6.2), tubes and rods shall
43、 befurnished in mntractors standard lengths, with a tolerance of * one inch.3.4.7.2.1 Tubes. When specified (see 6.2), the tubes shall be furnished cut to length, circular-sawed, within the tolerances shown in table IV. Dimensions shall be measured as specified inASTM D 668.3.4.7.2.2 Rods. When spec
44、ified (see 6.2), rods shall be furnished cut to length within thetolerances shown in table V. Dimensions shall be measured as specified in ASTM D 668.9Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Thickness (inches)up to 0.2500.251to 0.5000.501 to
45、1.0001.001to 1.5001501 to 3.5CM)MIL-I-24768TABLE HI. Permissible variations in length or wzdth.PermiAble variation (A inch)6 inches and under 6.001 to 23.999 inches 24 inches and wer0.010 0.015 0.0310.012 0.017 0.0310.015 0.020 0.0310.018 0.030 0.0620.022 0.040 0.062TABLE IV. Tolerances of cut round
46、 tubes.Tolerances( inch)Tube length (inches) Outside dmmeter (iches)Min. to 2.OIX) 2.001 to 4.000 4.001 to 8.OtM 8.001 to max.Min. to 3.000 0.010 0.010 0.0303.001 to 6.000 0.010 0.015 0.0306.001 to 12000 0.015 0.020 0.03012001 to 48.000 0.031 0.031 0.04748.001 to 72000 0.062 0.078 0.094 0.18872001 t
47、o %.(MO 0.094 0.094 0.125 0.250TABLE V. Tolerances of cut rods.I Tolerances (A inch)Rod length (inches)Outside diameter0.125 to 1.9S9inches 2 to 4 inchesMin. to 3.000 0.010 0.0103.001 to 6.000 0.010 0.0156.001 to 12000 0.015 0.02012.001to 48.m 0.030 0.0313.4.8 Thickness and diameter.3.4.8.1 Laminate
48、d sheets. Sheets shall be furnished in the nominal thickness as specified (see 3.1and 6.2). At least 90 percent of the area of the sheet shall be within the variations specifi no special conditioningHumidity conditioningImmersion conditioning in distilled waterImmersion conditioning in distilled wat
49、er following temperatureconditioning (E-1/105)Temperature conditioning.14Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-I-2476S43.2.2 Designation. Conditioning procedures shallfollowing:be designated in accordance with thea. A capital letter indicating the general condition of the specimen to be tested. Condition maybe as received, or conditioned to humid
