1、MIL-P-255186 93 = 9999906 0139225 T m /-43-0g MIL-P-255 18B 29 September 1981 SUPERSEDING MIL-P-B5 18A(ASG) 7 March 1961 MILITARY SPECIFICATION PLASTIC MATERIALS, SILICONE RESIN, GLASS FIBER BASE, LOW PRESSURE LAMINATED This specification is approved for use by all Departments and Agencies of the De
2、partment of Defense. 1. SCOPE 1.1 Scope. This specification covers glass fiber base, silicone resin, low pressure laminated plastic material used for airframe structural parts (including external parts) and other applications. 1.2 Classification. The laminated plastic materials shall be classi- fied
3、 by type, as below, and further identified by fabric number or mat as speci- fied in Table I. Type I - General purpose Type III- Radar frequency 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1.1 Specifications, standards and handbooks. Unless otherwise speci- fied, the following specifications
4、, standards and handbooks of the issue listed in that issue of the Department of Defense Index of Specifications and Standards (DoDISS) specified in the specification form a part of this specification to the extent specified herein. Beneficial comments (recommendations, additions, deletions) and any
5、 per- tinent data which may be of use in improving this document should be addressed to : Engineering Specifications and Standards Department (Code 93), Naval Air Engineering Center, Lakehurst, NJ 08733, by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appeari
6、ng at the end of this document, or by letter. ,-Y ri US. GOVERNMENTPRINTING OFFICE T981-505-022/7929 FSC 9330 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SPECIFICATIONS MILITARY MIL-C-9084 MIL-P- 9 400 MIL-R-25506 MIL-M-43248 STANDARDS MILITARY M
7、IX-STD-105 MIL-P-25518B -Cloth, Glass, Finished, For Resin Lamina tes -Plastic Laminate and Sandwich Con- struction Parts, Aircraft structural. -Resin, Silicone, Low Pressure Lamin- ating -Mats, Reinforcing, Glass Fiber -Sampling Procedures and Tables for Inspection by Attributes MIL-STD- 129 -Marki
8、ng for Shipment and Storage MIL-STD-794 -Parts and Equipment, Procedures for Packaging and Packing of (Copies of specif ications , standards, handbooks, drawings, and publications required by manufacturers in connection with specific acquisition functions should by obtained from the contracting acti
9、vity or as directed by the con- tracting officer,) 2.2 Other publications. The following documents form a part of this specification to the extent specified herein. The issues of the documents which are indicated as DoD adopted shall be the issue listed in the current DoDISS and supplement thereto,
10、if applicable. American Society for Testing and Materials (ASTM) AST1.I D 570 -Water Absorption of Plastics ASTM D 635 ASTM D 638 ASTM D 695 -Rate of Burning and/or Extent and Time of Burning of Self Supporting Plastics in a Horizontal Position. -Tensile Properties of Plastics -Compressive Propertie
11、s of Rigid Plastics Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-flIL-P-255LBB 73 = 777770b OLL7227 3 9 MIL-P-25518B American Society for Testing and Materials (ASTM) - Continued ASTM D 790 ASTM D 792 ASTM D 2520-77 -Flexural Properties of Plastic
12、s and Electrical Insulating Materials -Specific Gravity and Density of Plastics By Displacement -Complex Permittivity (Dielectric Constant) of Solid Electrical Insulating Materials at Microwave Frequencies and Temperatures to 165OOC (Applications for copies should be addressed to the American Societ
13、y for Testing and Materials, 1916 Race Street, Philadelphia) PA 19103. ) Uniform Classification Committee, Agent Uniform Freight Classification Rules (Applications for copies should be addressed to the Uniform Classification Committee, Room 1106, 222 South Riverside Plaza, Chicago, IL 60606.) (Indus
14、try association specifications and standards are generally available They are also distributed among technical groups for reference from libraries. and Federal agencies. ) 2.3 Order of precedence. In the event of a conflict between the text of this specification and the references cited herein, the
15、text of this specification shall take precedence. 3. REQUIREMENTS 3.1 First article. When specified, a sample shall be subjected to the first article inspection (See 4.3 and 6.2). 3.2 Materials. All materials shall be as specified below. There shall be no deviation from these materials without prior
16、 approval of the pro- curing activity. 3.2.1 Fabric. The glass fabric shall conform to Class 3 of MIL-C-9084. 3.2.2 Mat. - When mat laminate is specified, the mat shall conform to MIL-M-43248. 3.2.3 Resin. The resin shall conform to MIL-R-25506, Form A or B. The resin manufacturers curing instructio
17、ns shall be followed in the use of catalysts, curing, and post cure cycles except where the fabricator has deter- mined more suitable catalytic systems and curing cycles for a particular appli- cation. These systems and cycles shall be fully described in the fabricators process specification. 3.3 Pr
18、ocess specification. A detailed description of the manu- facturing and fabricating process and methods of control of manufacturing variables in the form of a titled, numbered, and dated process specification shall be prepared by the prime contractor (6.6.1), or obtained from a 3 Provided by IHSNot f
19、or ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-25518B b Thickness, inch (mm) 0.031 (0.787) to under ,0625 (1.58) 0.0625 (1.58) to under 0.125 (3.17) Over 0.25 (6.35) to 0.50 (12.7) 0.125 (3.17) to 0.25 (6.35) I subcontractor (see 6.6.2) and approved by the prime
20、contractor and submitted for approval to the procuring activity. The process specification shall comply with the requirements of this specification and MIL-P-9400, following that format as elocely as possible. The process specification shall be made available by the prime contractor at the commencem
21、ent of the production of material to which it applies and, thereafter, during the course of production for use by authorized Government inspectors in the facilities of the prime contractor, his subcon- tractors, or his vendors. It shall also be made available, on request, for review by engineers of
22、the procuring activity. The prime contractor represents that compliance with such process specifications will produce a laminate meeting all the contract requirements. The process specification shall not be changed during production without the approval of the procuring activity. The process specifi
23、cation shall also contain specific identification of all materials em- ployed and specific requirements for resin content, specific gravity, Barco1 hardness, allowable defects, reparable defects, nonreparable defects, and method of repairing any reparable defects (3.13). Approval of the fabricators
24、process specification shall constitute compliance only with minimum acceptable require- ments of this specification and does not obviate any additional requirements that may be specified in the contract, drawings, or detail specifications appli- cable to the procurement. 3.4 Foreign materials. Unles
25、s otherwise specified in the contract or order, there shall be no metal, paper or other foreign materials in the finished laminate. Permissible maximum % variation/36 inch (O .91m) dimension i/ 5.00 2.50 1.00 0.50 3.4.1 Fillers. Finely divided, inert, organic fillers shall be per- mitted in mat lami
26、nates only, 3.5 Gaps and laps. Unless specifically approved by the procuring activity, there shall be no gaps between pieces of glass fabricated in any lamination. When laps are necessary, they shall be laid up with a lap width of at Least 0.5 inch (12.7 mm) . No two laps shall be superimposed upon
27、each other in the plastic material. 3.6 Overlays, Unless otherwise specified, the laminated material shall not be made with a gel resin overlay (integrally molded or otherwise), with any thick resin surface, or any other surfacing material. 3.7 Warp or twist. The warp or twist of flat sheet laminate
28、s shall not exceed that shown in Table I. Percentage of warp is given in terms of length and width, and percentage of twist is given in terms of dimensions from one corner to the opposite corner. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NIL-P-
29、255LB 73 m 7777706 OLL7227 7 m MIL-P-25518B 3.8 Physical properties. 3.8.1 As specified properties. The minimum and maximum specific gravity, resin content and minimum barco1 hardness requirements shall be as specified by the contractor and become part of the process specification (3.3). Testing sha
30、ll be in accordance with Table VII. 3.8.2 Flammability, Flammability of the laminate determined as speci- fied in Table IV shall be 0.5 inch (12.7 mm) per minute, maximum. 3.8.3 Water absorption. Water absorption of the laminate when deter- mined as specified in Table IV shall not exceed 0.5 percent
31、. 3.9 Mechanical properties. Mechanical properties shall be in accor- dance with Tables II and III when tested as specified in Table IV. 3.10 Electrical properties (Type III only), Electrical properties for Type III laminates shall be determined at standard conditions (4.5.1) and after immersion (4.
32、5.5) in accordance with Table IV and 4.6.4. Requirements for both conditions shall be: Dielectric constant, max - 4.5 loss tangent, max - 0.025 3.11 Dimensions and tolerances. 3.11.1 Laminated flat sheets. 3.11.1.1 Thickness. Thickness requirements shall be as specified. Toler- ance requirements sha
33、ll be +_io% up to 0.25 inch (6.35 mm) , +-7% for thicknesses greater than 0.25 inch (6.35 mm) to 0.50 inch (12.7 mm) and 25% for all greater thicknesses. 3.11.1.2 Length and width. Length and width requirements shall be as Tolerance requirements shall be k0.5 inch specified by the procuring activity
34、. (12.7 mm). 3.11.2 Laminated parts. All dimensions and tolerances of laminated parts shall be as specified by the drawing, detail specification or the pro- curing activity. 3.12 Makeup of laminates. The number of plies, fabric number or mat, positioning and direction of the fabric, MIL-R-25506 type
35、 resin, and other specific-information relating to the makeup of laminated sheets and parts shall be as specfied in the appropriate drawings, specifications or the procuring activity . 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- e Provided by
36、IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a a Requirement Test Paragraph Method L/ MIL-P-255186 73 777770b OLL7233 7 No. of Average results Specimens rep0 r t ed to nearest z/ MIL-P-25518B 4.3.1 Prior approval. The first article approval procedures need no
37、t be repeated for subsequent contracts or orders for different parts. The supplier shall submit the previous first article test results and a certifi- cation that materials and processing techniques have not been changed. However, the procuring activity shall have the right to require the performanc
38、e of any of the tests at any time it is deemed necessary to determine the conformance of the laminate to the requirements of this specification. 4.3.1.1 Contractor Certification. When specified (6.2), the contractor may submit a certificate of compliance for the electrical requirements of 3.10 . for
39、 type III procurements. 4.3.2 First article sample. The first article sample shall consist of a suitable number of laminate sheets 0.125 2. 0.010 inch (3.17 i 0.25 mm) thick, having a minimum area of 4 square feet (.35 square meter). When specified, an additional 4 by 8 inch (10 by 20 cm) sample at
40、least 0.75 inch (19.0 mm) thick shall be supplied for electrical tests. The first article sample shall be fabricated from the. predominant material specified for the end item, and pro- cessed in the equipment intended to produce that item. When specified, the sheets shall be cut to produce the numbe
41、r of specimens required for testing. Property Physical and Mechanical Specific gravity Resin content Barco1 hardness Flammability Water absorption Tensile strength Compressive Flexural strength Initial modulus of strength elasticity Tensile strength Compress ive Flexural strength Initial modulus of
42、strength elasticity . 3.8.1 3.8.1 3.8.1 3.8.2 3.8.3 Table II Table II Table II Table II D 792 4.6.2 4.6.3 D 635 D 570 c/ D 638 D 695 41 D 790 51 D 790 z/ TESTED WET - AFTER IMMERSI Table II Table II Table II Table II D 638 D 695 5/ D 790 ?/ D 790 5/ i (See 4.5.2) 9 0.01 unit 1% 1 unit .O1 in/min (O.
43、 25 mm/min) 10 psi o. 81% 10 3 psi 10 3 psi 5 10 psi 3 10 psi 10 3 psi 3 10 psi 10 5 psi Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-255 18B F Property Requirement Test Physical and Paragraph Method i-/ Mechanical No. of Average results Spe
44、cimens rep o rted to nearest 2/ Tensile stength Compressive strength Flexural strength Initial modulus of elasticity Flexural strength Table III D 790 5/ Initial modulus of Table III D 790 s/ elasticity ELEXTRICAL 3/ Dielectric constant Table IV D 2520, 4.6.4 Loss tangent Table IV D 2520, 4.6.4 Tabl
45、e III Table III Table III Table III 3 5 10 psi 5 5 10 psi 3 O. 1 unit 3 0.001 unit D 638 D 695 +/ D 790 5/ D 790 g/ 3 lo3 psi 10 psi 3 5 10 psi 10 psi - i/ - 2/ - 3/ - 4/ - 5/ Methods other than paragraph numbers are ASTM methods. Test reports shall include all individual values. Electrical tests sh
46、all be conducted at standard conditions and after immersion (see 4.5.4). Three specimens for each condition. Compression specimens tested edgewise. Flexural specimens tested flatwise. 4.3.2.1 Manufacturers data. Along with the first article sample, the manufacturer shall submit, for approval, the fo
47、llowing data: a. Two copies of proposed process specification b. Certification stating that all materials conform to paragraph 3.2 of this specification. c. Two copies of preliminary test report showing the laminates submitted conform to the requirements of this specification. Included shall be the
48、contrac- tor “as determined“ values for specific gravity, resin content and barco1 hardness. 4.4 Quality conformance. 4.4.1 Lot formation. Unless otherwise specified, a lot shall consist of all the laminated sheets or parts fabricated from the same materials under an approved process specification a
49、s part of one contract or order. 4.4.2 Sampling and inspection. 10 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-2553B 73 m 9797706 0339235 2 MIL-P-25518B 4.4.2.1 Visual. Prior to the application of any coating or finish, each molded part or sheet shall be visually inspected in accordance with Table V and the approved process specification. Criticality
