1、 A-A-5244b 9999974 0364229 812 1 METRIC 1 A-A- 5 2 446 March 10, 1994 SUPERSEDING MIL-S-62502 (AT) 15 December 1987 COMMERCIAL ITEM DESCRIPTION SHEET MOLDING COMPOUND: LOW SHRINKAGE (METRIC) The General Services Administration has authorized the use of this commercial item description (CID) as a rep
2、lacement for MIL-S-62502(AT) which is canceled. ABSTRACT This CID covers requirements for a high strength, low shrinkage, sheet molding compound (SMC) and molded plastic parts yade therefrom. The low shrinkage property imparts dimensional stability to the molded parts. Items made from this material
3、are primarily used for nonappearance, high strength body panels that are not painted. SALIENT CHARACTERISTICS a. Materials. The SMC material covered by this CID shall posses high strength, low shrinkage characteristics and shall be reinforced with 32.5 + 2.5 percent (%) by weight of glass fiber rovi
4、ngs chopped into lengths not less-than 23 millimeters (mm). The SMC material shall be formulated with appropriate types and amounts of additives, such as, calcium carbonate filler, zinc stearate mold release, catalyst, thickener, and pigment, as required to meet the salient characteristics of this C
5、ID. The use of recovered material made in compliance with regulatory requirements is acceptable provided all the requirements of this CID are met (see Note d). b. Design and construction. Parts molded from this SMC material shall be designed and constructed in accordance with the applicable engineer
6、ing drawing (AED) (see Note b). i Beneficial comments, recommendations, additions, deletions clarifications, etc. /and any other data which may improve this document should be sent by letter to: 1U.S. Army Tank-Automotive Command, ATTN: AMSTA-GDS, Warren, MI 48397-5000. 1 l FSC 9330 AMSC N/A DISTRIB
7、UTION STATEMENT A. Approved for public release; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-A-A-524Lib W 9999974 0364230 534 A-A-52446 c. Properties of SUC material. The SMC material shall be molded into test plaques to
8、 verify conformance to the physical and mechanical properties specified herein. The test plaques shall be 2.5 - + 0.1 mm thick and shall be molded using the same cure cycle, mold temperature, and mold pressure as is used to mold the production items (parts). conform to the conditions specified in fi
9、gure 1, unless the combination of SMC sheet weight and plaque mold dimensions make this impossible. The charge pattern used to mold the test plaques shall CROSS SECTION Legend : I l l I i 0.85 b I i OF CHARGE PLAN VIEW OF TEST PLAQUE L = Longitudinal dimension of mold. T = Transverse dimension of mo
10、ld. a = Indicated is the longitudinal direction of the SMC in charge no. 1 b = Indicated is the longitudinal direction of the SMC in charge no. 2. (sometimes referred to as the machine direction of the SMC). FIGURE 1. Charge pattern conditions. 1. Physical and mechanical properties. The physical and
11、 mechanical properties of the SMC material shall be as specified in table I. d. SMC molded parts. The properties and performance requirements of CMC molded parts shall be as follows: 1. Properties of SMC molded parts. The physical and mechanical properties of CMC molded parts and verification of sam
12、e shall be as specified in table I (for parts thicker than 2.5 mm use 0.5 mm offset for second modulus). The part or specimens made from the part, as appropriate, shall be used for this purpose. For glass fiber content, at least five specimens shall be taken at random from the part. 2. Performance/e
13、nvironmental requirements. (a) Dimensional stability. The SMC molded parts shall maintain their dimensions and tolerances, as specified in the AED, before and after exposure to 150C for 90 minutes. Also, the parts shall not blister or show any other deleterious effects after exposure. 2 Provided by
14、IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-A-A-5244b 9999974 0364233 470 Property A-A- 52 44 6 Minimum ASTH value teet required method Notes (b) Environmental conditions. The SMC molded parts shall be capable of withstanding exposure to the following high a
15、nd low temperature and humidity conditions without showing evidence of any functional/visual degradation or embrittlement: (1) (2) (3) Relative humidity, as ollowa: High temperature of 70 + 3OC for 168 hours. Low temperature of -40+-3OC for 4 hours. Step 1. Gradually raise the internal chamber tempe
16、rature and RH from room ambient to 6OoC and RH to 95 + 5% for a period of two hours minimum. Step 2. Maintain the conditions of Step 1 for a period of six hours minimum. Step 3. Reduce and maintain RH at 85% minimum and gradually reduce the internal chamber temperature to 3OoC in eight hours. Step 4
17、. increase RH to 95 - + 5% and maintain temperature at 3Ooc for an additional eight hours. Step 5. Repeat steps 1 through 4 for a total of 10 cycles and not less than 240 hours. Step 6. Near the end of the fifth and tenth cycle, while still at - Tensile strength at 23OC Flexural strength at 23OC Ifl
18、exural modulus at 23OC I Water absOrptLOn t Glass fiber content 3Ooc and 95% RH, visually and functionally check the 85 ma 11 I D638 - 2/ hi y 0790 - 3/ 6 6/ D790 - 41 6 i/ 169 ma 8000 ma 0.8% max D570 30 to 35% by weight (average) 5/ 25 to 40% by weight per - epecimene item. Provided by IHSNot for
19、ResaleNo reproduction or networking permitted without license from IHS-,-,-A-A-52446 = 74 OLb4232 307 = A-A- 5 2 44 6 e. f. Finish color. Unless otherwise specified (see Note b), the SMC molded g. Identification and markinq. Unless otherwise specified in the AED, Body sealer. The SMC material shall
20、be compatible with body sealer. Sealer shall not contain any chlorofluorocarbon (CFC). part shall be integrally colored black. identification and marking of the SMC molded parts shall be permanent and legible 1 and shall include, as a minimum, the AED part number, the manufacturers CAGE code, and wh
21、en specified, the molders identification marking (see Note b). QUALITY ASSURANCE PROVISIONS a. Responsibility for inspection. The contractor is responsible for the b. First article inspection. When specified (see Note b), a first article performance of all inspections (examinations and tests). sampl
22、e shall be inspected to verify conformance to the Salient characteristics in this CID. Approval of the first article sample by the Government shall not relieve the contractor of the obligation to supply items that are fully representative of those inspected a8 a first article sample. c. Contractor c
23、ertification. The contractor shall certify and maintain substantiating evidence that the product offered me+s the salient characteristics of this commercial item description and that the product conforms to the producers own drawings, specifications, workmanship standards, and quality assurance prac
24、tices. Items with known defects shall not be submitted for Government acceptance. The Government reserves the right to require proof of such conformance prior to the first delivery and thereafter as may be otherwise provided for under the provisions of the contract. PRESERVATION, PACKAGING, PACKING,
25、 LABELING, AND MARKING Preservation, packaging, packing, labeling, and marking for the desired level shall be as specified in the contract or order (see Note b). NOTES (This section contains information of a general or explanatory nature that may be helpful, but is not mandatory.) a. Addresses for o
26、btaining copies of referenced documents. Copies of ASTM D570 “Standard Test Method for Water Absorption of Plastics“; ASTM D638 “Test Method for Tensile Properties of Plastics“; and ASTM D790 “Test -Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Mat
27、erials (Metric),“ can be obtained from the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103-1187 b. Ordering data. Acquisition documents must specify the following: 1. Title, number, and date of this commercial item description. 2. Issue of DODISS to be cited in t
28、he solicitation and, if required, the 3. AED and revision letter, and part number. 4. Molders identification marking, if required. 5. First Article, if required. 6. Selection of applicable level and packaging requirements. 7. Color, if other than as specified. specific issue of individual documents
29、referenced 1 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-A-A-5244b = 4 0164233 243 A-A-52 44 6 c. Cross-reference data. SMC material that conforms to this CID are interchangeable/substitutable with material conforming to MIL-S-62502(AT) and AMG
30、 157 Revision D, dated 24 August 1905. d. Regulatory requirements. The offeror/contractor is encouraged to use 1 recovered materials in accordance with Public Law 94-580 to the maximum extent practicable. MILITARY INTERESTS: custodian Army - AT Review activity DLA - GS CIVIL AGENCY COORDINATING ACTIVITY: GSA - FSS PREPARING ACTIVITY: Army - AT (Project 9330-1268) c Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
