PHT - MIL-DTL-28748 - Rectangular Connectors - Brochure

MIL-DTL-28748D11 June 2001SUPERSEDINGMIL-DTL-28748C7 July 1998DETAIL SPECIFICATIONCONNECTOR, PLUG AND RECEPTACLE,RECTANGULAR, RACK AND PANELSOLDER TYPE AND CRIMP TYPE CONTACTSGENERAL SPECIFICATION FORThis specification is approved for use by all Departmentsand Agencies of the Department of Defense.1. SCOPE1.1 Scope. This specification covers rectangular, rack and panel, electrical connectors, with nonremovable solder type contacts,and removable crimp type contacts, intended for use in electronic and electrical equipment (see 6.1).2. APPLICABLE DOCUMENTS2.1 General. The documents listed in this section are specified in sections 3 and 4 of this specification. This section does notinclude documents cited in other sections of this specification or recommended for additional information or as examples. Whileevery effort has been made to ensure the completeness of this list, document users are cautioned that they must meet all specifiedrequirements cited in sections 3 and 4 of this specification, whether or not they are listed.2.2 Government documents.2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and handbooks form a part of thisdocument to the extent specified herein. Unless otherwise specified, the issues of these documents are those listed in the issue ofthe Department of Defense Index of Specifications and Standards (DODISS) and supplement thereto, cited in the solicitation (see6.2).SPECIFICATIONSFEDERALQQ-P-416 - Plating, Cadmium (Electrodeposited).DEPARTMENT OF DEFENSEMIL-A-8625 - Anodic Coatings for Aluminum and Aluminum Alloys.MIL-C-22520 - Crimping Tools, Terminal, Hand or Power Actuated, Wire Termination, and Tool Kits, GeneralSpecification.MIL-W-22759 - Wire, Electrical, Fluoropolymer-Insulated, Copper or Copper Alloy.MIL-C-39029 - Contacts, Electrical Connector, General Specification.MIL-C-39029/34 - Contacts, Electrical Connector, Pin, Crimp Removal, (MIL-C-28748 Connectors).MIL-C-39029/35 - Contacts, Electrical Connector, Socket, Crimp Removal, (MIL-C-28748 Connectors).MIL-C-39029/36 - Contacts, Electrical Connector, Pin, Crimp Removal, (MIL-C-28748 Connectors).MIL-C-39029/37 - Contacts, Electrical Connector, Socket, Crimp Removal, (MIL-C-28748 Connectors).MIL-I-81969/18 - Installing and Removal Tools, Connector Electrical Contact, Type I, Class I, Composition C.MIL-I-81969/20 - Installing and Removal Tools, Connector Electrical Contact, Type I, Class I, Composition A.Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving thisdocument should be addressed to: Commander, Defense Supply Center Columbus, Attn: VAI, 3990 East Broad Street,Columbus, Ohio, 43216-5000 by using the Standardization Document Improvement Proposal (DD Form 1426) appearing at theend of this document or by letter.AMSC N/A FSC 5935DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.INCH-POUNDMIL-DTL-28748D2STANDARDSDEPARTMENT OF DEFENSEMIL-STD-202 - Test Method for Electronic and Electrical Component Parts.MIL-STD-889 - Dissimilar Metals.MIL-STD-1285 - Marking of Electrical and Electronic Parts.MIL-STD-1344 - Test Methods for Electrical Connectors.MS3197 - Gage Pin for Socket Contact Engagement Test.(Unless otherwise indicated, copies of the above specifications, standards, and handbooks are available from the StandardizationDocument Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.)2.3 Non-Government publications. The following documents form a part of this document to the extent specified herein. Unlessotherwise specified, the issues of documents which are DoD adopted are those listed in the issue DoDISS cited in the solicitation. Unless otherwise specified, the issues of documents not listed in the DoDISS are the issues of the documents cited in the solicitation(see 6.2).AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME)ASME B46.1-1982 - Surface Texture (Surface Roughness, Waviness and Lay).(Applications for copies should be addressed to the American Society of Mechanical Engineers, 11 West 42nd Street, 13TH Floor,New York, NY 10036.)AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)ASTM A342 - Standard Test Methods for Permeability of Feebly Magnetic Materials.ASTM A582 - Standard Specification for Free-Machining Stainless Steel Bars.ASTM B16 - Free-Cutting Brass Rod, Bar and Shapes for use in Screw Machines.ASTM B36 - Standard Specification for Brass Plate, Sheet, Strip, and Rolled Bar.ASTM B121 - Leaded Brass, Plate, Sheet, Strip, and Rolled Bar.ASTM B122 - Copper-Nickel-Tin Alloy, Copper-Nickel-Zinc Alloy (Nickel Silver), and Copper-Nickel Alloy Plate, Sheet,Strip, and Rolled Bar.ASTM B139 - Standard Specification for Phosphor Bronze Rod, Bar, and Shapes.ASTM B194 - Standard Specification for Copper-Beryllium Alloy Plate, Sheet, Strip, andRolled Bar.ASTM B196 - Standard Specification for Copper-Beryllium Alloy Rod and Bar.ASTM B197 - Standard Specification for Copper-Beryllium Alloy Wire.ASTM B633 - Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel.ASTM B488 - Standard Specification for Electrodeposited Coatings of Gold for Engineering Uses.ASTM D5948 - Standard Specification for Molding Compounds, Thermosetting.ASTM PS 2 - Provisional Standard Specification for Molding Plastics, Electrical, Thermoplastic.(Applications for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia,PA 19103-1187).MIL-DTL-28748D3ELECTRONIC INDUSTRIES ASSOCIATION (EIA)J-STD-004 - Requirements for Soldering Fluxes.J-STD-006 - Requirements for Electronic Grade Solder Alloys and Fluxed and Non-Fluxed Solid Solders forElectronic Soldering Applications.EIA-364-11 - Resistance to Solvents; Test Procedure for Electrical Connectors.EIA-364-56 - Resistance to Soldering Heat; Test Procedure for Electrical Connectors.EIA-557 - Statistical Process Control Systems.(Applications for copies should be addressed to the Electronic Industries Association, Engineering Department, 1722 Eye St. N.W.Washington D.C. 20006.)INTERNATIONAL STANDARD ORGANIZATION (ISO)ISO-10012-1 - Quality Assurance Requirements for Measuring Equipment.(Applications for copies should be addressed to the American National Standards Institute, 11 West 42nd Street, New York, NY10036.)NATIONAL CONERENCE OF STANDARDS LABORATORIES (NCSL)ANSI/NCSL 2540-1 - Calibration Laboratories and Measuring and Test Equipment, General Requirement.(Applications for copies should be addressed to the National Conference Standards Laboratories, 1800 30th Street, Suite 305B,Boulder, CO 80301-1032.)SOCIETY OF AUTOMOTIVE ENGINEERS (SAE)AMS-QQ-A-250/8 - Aluminum Alloy, 5052, Plate and Sheet.AMS-QQ-N-290 - Nickel Plating (Electrodeposited).AMS-QQ-P-35 - Passivation Treatments for Corrosion-Resist Steel.AMS-P-81728 - Plating, Tin-Lead (Electrodeposited).(Applications for copies should be addressed to the SAE World Headquarters, 400 Commonwealth Drive,Warrendale, PA 15096-0001.)(Non-Government standards and other publications are normally available from the organizations that prepare or distribute thedocuments. These documents also may be available in or through libraries or other informational services.)2.4 Order of precedence. In the event of a conflict between the text of this document and the references cited herein (except forrelated associated specifications or specification sheets), the text of this document takes precedence. Nothing in this document,however, supersedes applicable laws and regulations unless a specific exemption has been obtained.3. REQUIREMENTS3.1 Specification sheets. The individual item requirements shall be as specified herein and in accordance with the applicablespecification sheet. In the event of any conflict between the requirements of this specification and the specification sheet, the lattershall govern.3.2 Quality.3.2.1 Qualification. Connectors furnished under this specification shall be products that are authorized by the qualifying activity forlisting on the applicable qualified products list before contract award (see 4.5 and 6.3).3.3 Materials. Example reference materials are identified herein. However, when an example reference material is not identified,a material shall be used which will enable the connectors and accessories to meet the performance requirements of thisspecification. Acceptance or approval of a constituent material shall not be construed as a guaranty of acceptance of the finishedproduct.MIL-DTL-28748D43.3.1 Reference materials, plating, and processes. The identified reference material, plating, and processes have beenestablished to provide assurances that connectors manufactured to this specification will properly interface to similar industrystandard or government specified connector systems without problems of electrochemical contamination of critical electrical ormechanical interfaces or generation of incompatible mechanical interface surface wear products. The manufacturer of connectorssupplied to this specification are allowed to use alternate recognized industry standard materials, plating, and processes from thoseidentified in paragraph 3.3 of this specification. Alternate materials, plating and processes used must be coordinated with thequalifying activity as part of the qualification process. Use of alternates to those referenced guidance items by the supplier must not result in inferior short or long term performance or reliability of supplied connectors as compared with connectors manufactured usingthe referenced materials, plating, or processes. Short or long term failures or reliability problems due to use of these alternates shallbe the responsibility of the supplier.3.3.2 Nonmagnetic materials. All parts shall be made from materials which are classified as nonmagnetic.3.3.3 Metals and finishes. All exposed metal parts, other than electrical contacts, shall be manufactured with a corrosion-resistantmaterial or finished to resist corrosion. Noncorrosion-resisting metal parts shall be cadmium plated in accordance with QQ-P-416,type II, class 1 or class 2, or zinc plated in accordance with ASTM B633, type II, SC 3 or SC 4, except that a preliminary plating ofother metal is permissible. Aluminum alloy parts shall be anodized in accordance with MIL-A-8625, type I or II. Corrosion resistancesteel parts shall be passivated in accordance with AMS-QQ-P-35. Unless otherwise specified (see 3.3.1), all finishes shall beconductive, except anodized parts.3.3.3.1 Dissimilar metals. When dissimilar metals (as defined in MIL-STD-889) are used in intimate contact with each other,protection against electrolysis and corrosion shall be provided. The use of dissimilar metals which, in contact, tend toward activeelectrolytic corrosion (particularly brass, copper, or steel used in contact with aluminum and aluminum alloy) is not acceptable(see 3.3).3.3.3.2 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or environmentally preferablematerials should be used to the maximum extent possible provided that the material meets or exceeds the operational andmaintenance requirements, and promotes economically advantageous life cycle cost.3.3.4 Insert material. Insert material shall be diallyl phthalate conforming to ASTM D5948, type SDG-F, GDI-30F, GII-30F, or SIG-F, or thermoplastic polyphenylene sulfide compound conforming to ASTM PS2, type GST-40F (see 3.3.1).3.3.5 Solder type contacts. Solder type contacts shall of the nonremovable type (see 3.4.2.2). Materials shall be in accordancewith ASTM B36, ASTM B121, ASTM B16, ASTM B122 (C72500), ASTM B139, ASTM B194, ASTM B196, or ASTM B197. Crimptype contacts shall conform to MIL-C-39029. Manufacturers who are using crimp type contacts which are qualified, do not have tomeasure finish thickness specified in 4.7.19.1 and 4.7.19.2, or to perform the industrial gas test specified in 4.7.20.MIL-DTL-28748D5AREA X (I.D.) - ZONE OFTANGENCY +.02 MINMAX DIA PIN PERFIGURE 3APOINT B (O.D.) MAX DIA PIN(PER FIGURE 3)PRESSURE MEMBER SPRINGFPOINT C (O.D.)E +.000-.0203.3.5.1 Contact retaining clip. The contact retaining clip shall be of a material which will assure compliance with the contactretention requirements (see 3.5.4. Plastic contact retaining clips shall not be used.3.3.5.2 Contact finish (solder type).3.3.5.2.1 Overall finish (solder type). All parts of the contact shall be gold-plated in accordance with ASTM B488, type 2, code C,1.25µm for the socket spring and 0.50 µm for the socket sleeve. Finish for pin and socket contacts shall be over a nickel underplate,.000030 to .000150 inch thick (1.27 µm to 3.01 µm) in accordance with AMS-QQ-N-290. Silver shall not be used as an underplate.3.3.5.2.2 Localized finish.3.3.5.2.2.1 Contact mating area. The contact mating area shall be overall in accordance with ASTM B488 type 2, code C,1.27 µm, over a nickel underplate .000050 to .000150 inch thick, (1.27 µm to 3.81 µmm) in accordance with AMS-QQ-N-290. Thecontact mating area is as specified on figure 1.SOCKET CONTACTS WITH INTEGRAL PRESSURE MEMBERSE = LENGTH OF MAX ELECTRICAL CONTACT(WIPING) PLUS .020 (0.51 mm) INCH F = LENGTH OF MAXIMUM ELECTRICAL CONTACT WIPING PLUS .020 (0.51 mm) INCH MINIMUM WIPE SHALL BE EQUAL TO MAXIMUM E OF MATING PIN ENGAGEMENT MINUS THE SPHERICAL RADIUS.SOCKET CONTACTS WITH SEPARATE PRESSURE MEMBERSFIGURE 1. Areas of application of localized finish.3.3.5.2.2.2 Terminations. Terminations shall be gold in accordance with ASTM B488, type 2, code C, 1.27µm, class 1, over anickel underplate in accordance with AMS-QQ-N-290, class 2, .000050 to .000150 (1.27 µm to 3.01 µm) inch thick or tin-lead inaccordance with AMS-P-81728, .0001 inch minimum thickness (2.54 µm).3.3.5.2.2.3 Nonfunctional areas (crimp and solder contacts). Any portion of the contact other than the contact mating area ortermination area shall have a nickel plating in accordance with AMS-QQ-N-290, .000050 to .000150 inch thick(1.27 µm to 3.01 µm).3.3.6 Protective shells, connector shields and accessories. Unless otherwise specified, protective shells, connector shields, andother accessories shall be made of a high grade aluminum alloy conforming to AMS-QQ-A-250/8, temper H-32 or corrosion-resistantsteel conforming to ASTM A582, series 300 (nonmagnetic), or other material satisfactory to the Government. There shall be noassembly of protective shells, connector shields or other accessories made of different materials than specified herein.MIL-DTL-28748D6FRONT END MATING.108.103.490 MIN.315.305.075.073.080.075DIA ØSOCKET INSERT.494 MINPIN INSERT.103.083.202.172.130.12462°58°47°43°.119 MIN.126.122DIA.080.077DIA62°59°47°43°MATING F.062.059DIA.839 MIN.546.516.103.08347°43°.119 DIA MIN.126.122 DIA62°58°.106.103 DIA.130.124 DIA3.3.7 Connector assembly. No parts of the connector assembly shall be permanently displaced from their original, normal fittedposition at completion of the specified test (see 3.1).3.4 Connector interface and physical construction. Connectors shall be of the interface and physical construction specified (see3.1). The removable contact connector is intended to permit individual insertion and removal of the contacts with the insertion andremoval tools specified in 3.4.6. Wire conductors shall be attached to the contacts by crimping with the crimp tools specified in 3.4.7for removable contacts and soldered for nonremovable contacts.3.4.1 Insert interface. Inserts shall be of one-piece construction and shall be such that they will not crack, chip, or break in normalservice or assembly. Inserts glued or bonded together shall not be used. The insert dimensions shall be as specified (see 3.1). Theinsert hole configuration for the removable contacts shall conform to the dimensions shown on figure 2. Removable contacts, whenassembled, shall be recessed a minimum of 0.010 inch (0.254 mm) below the rear face of the insert.FIGURE 2. Insert hole configuration.MIL-DTL-28748D73.4.2 Contacts.3.4.2.1 Removable contacts. Removable contacts shall be qualified to MIL-C-39029. For shipments to the originalequipment manufacturers (OEM), or other suppliers, crimp contact connectors may be supplied without contacts(see 3.6 and 6.2).3.4.2.1.1 Pin contacts. Pin contacts shall be in accordance with MIL-C-39029/34 and MIL-C-39029/36.3.4.2.1.2 Socket contacts. Sockets contacts shall be in accordance with MIL-C-39029/35 and MIL-C-39029/37.3.4.2.1.3 Contact retaining clip. The contact retaining clip is furnished as part of the contact, assembled in the locationshown on MIL-C-39029/34, MIL-C-39029/35, MIL-C-39029/36, and MIL-C-39029/37. The design of the clip shall be designedto allow the contacts of being inserted and removed by the tools shown on MIL-I-81969/18 and MIL-I-81969/20.3.4.2.2 Nonremovable contacts. Nonremovable contact dimensions shall be as shown on figure 3 and shall meet the applicablerequirements of this specification.3.4.2.2.1 Contact pin. The contact pin shall be of the round pin type with a 60-degree included angle (conical tip configuration),allowing for a flat end not in excess of .015 inch (0.381 mm) in diameter for size 20 or larger and .008 inch (0.203 mm) for smaller.3.4.2.2.2 Socket contact. The socket contact shall have a circular cross-section and shall be machined. The entering end of thesocket contact shall be rounded or chamfered to allow for directing and centering of the entering pin. The socket contact shallprovide the spring action for maintaining the contact pressure between the pin and socket. The contact shall be of the closed entrydesign to exclude the entrance of a pin .005 inch (0.127 mm) larger than the allowable maximum diameter of the mating pin.3.4.2.2.3 Tinning solder cups. Where pretinned solder cups are required, the interior surface of solder cups shall be completelytinned over 100 percent of the full circle portion and for at least 50 percent of the remainder of the solder well area with solderconforming to composition Sn60 of EIA J-STD-004. Only fluxes meeting EIA J-STD-006, shall be used, any excess of which shall beremoved. Solder cup terminals shall be so constructed that liquid solder cannot leak through to the front of the socket and preventinsertion of the pin contact. No excess solder shall be on the exterior of the solder cup.3.4.2.3 Electrical characteristics. Contacts shall have the electrical characteristics as specified in table I.TABLE I. Current rating.Contact Wire size(AWG)Amperes(max)Solder162022Crimp16-1616-1616-1616-2016-2016-2020-2020-2020-20162022161820202224202224137.55.013107.57.55.03.07.55.03.0MIL-DTL-28748D8SPHERICAL ORCONICAL RADBA FA.010 PAD MAXG SEENOTE 7DECINSULATIONC DE SEE NOTE 6INSULATIONASPHERICAL CONICALASOLDER CUP SOLDER CUPDimensionsContactsizeAdia(mm)B±.015(0.38 mm)Cmin dia(mm)Dmin(mm)22 .030 ±.0005(0.76 ±.01) .145(3.69).034(0.86).065(1.65)20 .040 ±.001(1.02 ±.03).203(5.16).043(1.09).115(2.92)16 .0625 ±.001(1.58 ±.03).223(5.59).069(1.79).115(2.92)Configuration A - PinFIGURE 3. Contact assembly dimensions for nonremovable contacts.MIL-DTL-28748D9DimensionsContactsizeAdia(mm)Cmin dia(mm)Dmin(mm)Fmin dia(mm)Gmin(mm)22 .066(1.68).055(1.40).034(0.86).065(1.65).032(0.81).170(4.31)20 .072(1.83).064(1.62).043(1.09).115(2.92).0415(1.054).290(7.37)16 .106(2.69).099(2.51).069(1.79).115(2.92).064(1.63).290(7.37)Configuration B - SocketNOTES:1. Dimensions are in inches.2. Millimeters are in parentheses.3. Metric equivalents are given for general information only.4. Wall thickness shall be .005 min (0.13 mm) at any point.5. Dimensions are for finished parts after plating.6. E is 50-75% of D.7. Minimum bore depth of socket from connector mating surface.FIGURE 3. Contact assembly dimensions for nonremovable contacts - Continued.3.4.2.4 Contact identification and arrangement. The contact identification and arrangement shall be as specified (see 3.1). Letters or numerals shall be raised and clearly legible or shall appear in legible contrasting colors. Letters or numerals shall bearranged to avoid confusion between contacts. All letters or numerals shall appear on the front and rear faces of each insert. Lettering of the socket insert shall correspond with that of the mating pin insert.3.4.3 Polarization. Polarization of the plug with its receptacle shall be accomplished by mechanical means such as the shells,protective shell, bosses, guide pins, guide sockets, or jackscrews. Jackscrews and center jackscrew types shall conform as specifiedin the specification sheets, as applicable. Guidepins shall conform as specified in the specification sheets. Where jackscrews andjack sockets are required, lubrication is optional.3.4.4 Mating. Unless otherwise specified, connector plugs and receptacles shall be capable of being mated and unmated by handwithout the aid of special tools (see 3.1).3.4.5 Protective shell. The protective shell design shall be in accordance with the applicable military standard listed on thesupplement to this specification (see 3.1).3.4.6 Insertion and removal tools. Insertion and removal tools are used for easy assembly and disassembly of pin andsocket contact and permitted connectors to meet the performance requirements of this specification. Installing tools shall bein accordance with MIL-I-81969/18, and removal tools shall be in accordance with MIL-I-81969/20.3.4.7 Crimping tools. Crimping tools are specified on table II.MIL-DTL-28748D10TABLE II. Crimping toolsContacts Applicable toolBasic tool PositionerMIL-C-39029/34MIL-C-39029/35MIL-C-39029/36MIL-C-39029/37MIL-C-22520/1-01MIL-C-22520/1-01MIL-C-22520/1-01MIL-C-22520/1-01M22520/1-03M22520/1-03M22520/1-03M22520/1-03MIL-C-39029/34-40MIL-C-39029/35-41MIL-C-22520/2-01MIL-C-22520/2-01Buchanan 614412, Daniels K187or equivalentBuchanan 615695, Daniels K280or equivalent3.4.8 Operating temperature. The connectors shall be suitable for operation throughout a temperature range of -55°C to +125°C.3.4.9 Assembly. For shipments to the OEM or suppliers, connectors may be shipped unassembled. For shipments directly to theGovernment, all connectors shall be assembled except for the removable contacts.3.5 Performance. Connectors shall be designed to meet the performance requirements specified herein.3.5.1 Magnetic permeability. The relative permeability of the connector assembly or shield shall be less than 2.0 Mu (see 4.7.3).3.5.2 Insulation resistance. When the connectors are tested as specified in 4.7.4, the insulation resistance shall be not less than5,000 megohms.3.5.3 Dielectric withstanding voltage. When tested as specified in 4.7.5, connectors shall withstand the test voltage as specified intable III without flashover.TABLE III. Test voltages for dielectric withstanding voltage requirement.ContactsizeTest voltage, 60 Hz rms (sea level)Initial volts AfterconditioningvoltsSolder222016Crimp22-2216-2016-161,0001,2001,0001,0002,0002,0005006005005001,0001,0003.5.4 Contact retention. When tested as specified in 4.7.6, individual contacts shall withstand an axial load as shown in table IVwithout damage to the contact, insert, or contact retaining clip, if applicable.MIL-DTL-28748D11TABLE IV. Contact retention.Matingend sizePounds222016610203.5.5 Contact insertion and removal forces (removable contacts only). When tested as specified in 4.7.7, the axial forces requiredto insert and remove removable contacts shall not exceed 15 lbf (67 N).3.5.6 Temperature cycling. When the connectors are tested as specified in 4.7.8, there shall be no evidence of physical damage. Following temperature cycling, the dielectric withstanding voltage shall meet the requirements of 3.5.3.3.5.7 Humidity. When the connectors are tested as specified in 4.7.9, the insulation resistance shall be not less than 100megohms and the dielectric withstanding voltage shall meet the requirements of 3.5.3.3.5.8 Vibration. When the complete connector assembly, wired with the appropriate size wire, is tested as specified in 4.7.10,there shall be no cracking, breaking, or loosening of parts. There shall be no loss of electrical continuity of any contact circuits ofmore than 1 microsecond with 100 milliamperes minimum flowing in each contact circuit. After vibration test, the connector assemblyshall show no signs of loosening, fracture, or other deterioration (see 3.3.7).3.5.9 Shock (specified pulse). When tested as specified in 4.7.11, there shall be no evidence of failure of metallic or dielectricmaterials, nor shall the mated portions of the connector become disengaged. There shall be no loss of electrical continuity of any ofthe contact circuits of more than 1 microsecond with 100 milliamperes minimum flowing in each contact circuit.3.5.10 Insertion and withdrawal force (connector assembly). When tested as specified in 4.7.12, the force required to engage orseparate any pair of mated connectors (plug and receptacle) shall not exceed 1 pound times the number of contacts specified on theapplicable specification sheet or military standard (see 3.1).3.5.11 Durability. When connector assemblies are tested as specified in 4.7.13, there shall be no evidence of electrical ormechanical damage that impairs the normal operation of the connector.3.5.12 Contact resistance. When contacts in the mated condition are tested as specified in 4.7.14, the contact resistance shall beas specified in table V.TABLE V. Contact resistance.ContactsizeTest currentamperes(max)Initialvolts(max)Afterconditioningvolts (max)222016 5.0 7.513.0.060.055.050.070.065.0603.5.13 Salt spray (corrosion).3.5.13.1 Connectors. When connectors are tested as specified in 4.7.15, there shall not be sufficient corrosion to interfere withmating or unmating the connectors. Following the salt spray test, the dielectric withstanding voltage shall meet the requirements ofthe conditioning values specified in table III. Contact resistance shall not exceed the requirements of 3.5.12.3.5.13.2 Nonremovable contacts. When nonremovable contacts are tested as specified in 4.7.15, any corrosive productsresulting therefrom shall not cause exposure of base metal on the sets of pin and socket contacts.3.5.14 Low level circuit (for nonremovable contacts). When tested as specified in 4.7.16, the values of contact resistance shallnot exceed the potential drop in table VI.MIL-DTL-28748D12TABLE VI. Low level circuit.WiresizeawgInitialcontactresistance(max)(ohms)1/Initialpotentialdrop (max)(volts)Afterconditioningresistance(max)(ohms)1/Afterconditioningvoltage (max)(volts)16 5 m? 5 µV 60 m? 6 µV20 9 m? 9 µV 11 m? 11 µV22 15 m? 15 µV 17 m? 17 µV1/ Test current shall be .001 amperes.3.5.15 Resistance to test probe damage (for nonremovable contacts). When tested as specified in 4.7.17, socket contacts shallwithstand the bending moment and depth of test probe insertion without evidence of visible damage. In addition, socket contactsshall meet the requirements of 3.5.16.3.5.16 Contact separating forces (nonremovable contacts). When socket contacts are tested as specified in 4.7.18, the forcesrequired to withdraw the pins shall be in accordance with table VII.TABLE VII. Contact separating forces. 1/ContactsizeMaximum forceounces (Newton)Minimum forceounces (Newton)2220169.0 (2.50)16.0 (4.45)20.0 (5.56)0.5 (0.14)0.75 (0.75)2.0 (0.56)1/ Metric equivalents are given for general information only.3.5.17 Industrial gas. When tested as specified in 4.7.20, unmated contacts shall withstand industrial gas conditioning for 100hours and show no evidence of damage that would interfere with the mechanical or electrical performance.3.5.18 Solderability. Solderable, nonremovable contact terminations shall withstand the test specified in 4.7.21, unless solder cupterminations are specified. For solder cup terminations, individual contacts may be removed from the insulator or an alternatemethod using a hand iron may be used on the contacts in an assembled (non-removed) configuration.3.5.19 Resistance to soldering heat. When tested in accordance with 4.7.22, the connectors shall be visually inspected and shallshow no evidence of distortion or physical damage and shall meet the contact retention requirements of 3.5.4 and dimensionalrequirements of 3.3.5.3.5.20 Resistance to solvents. When tested in accordance with 4.7.23, the connectors shall be visually inspected and shall showno evidence of cracking, crazing, discoloration, distortion or bleeding out of any foreign matter from the material. Pitting shall not beallowed. The marking and color coding shall be legible.3.5.21 Contact pin strength. Contact pin strength shall be tested in accordance with 4.7.24, with the forces specified in table VIII.The force shall not produce a permanent set in excess of .005 inch (0.13 mm).MIL-DTL-28748D13TABLE VIII. Contact pin strength. 1/Mating end(contact size)Momentlb-in. (Newton)1620222.00 (8.90).53 (2.36).22 (0.98)1/ Metric equivalents are given for generalinformation only.3.6 Marking. Connectors and shields are to be marked in accordance with method I of MIL-STD-1285, and are to include the Partor Identifying Number (PIN)(see 3.1), the manufacturer's name or code symbol, and date code. For shipments of connectors withcrimp removable contacts, shipped separately, to the OEM or other contractors, the complete military PIN of the connector withcontacts to be loaded, shall be marked on the connector (see 3.4.2.1 and 6.2). For shipments of connectors without contacts to theOEM's or other contractors, the connector shall be marked with the complete military PIN of the connector "without contacts" (1Ldesignation). For field replacement purposes, the contact types used shall be specified in the OEM's technical data.3.7 Workmanship. Connectors, contacts, shields, jackscrews, and guide pins shall be processed in such a manner as to beuniform in quality and shall be free from defects that will affect life, serviceability or appearance. There shall be no evidence of poormolding, fabricating, cracking of insulator after molding or improperly assembled contacts, peeling or chipping of the plating or finish,nicks and burrs of metal parts surfaces, and no post molding warpage of connectors. The contacts shall be free from such burrs orsharp corners that would damage the plating of mating connectors.4. VERIFICATION4.1 Classification of inspection. The inspection requirements specified herein are classified as follows:a. Qualification inspection (see 4.4).b. Verification of qualification (see 4.4.4).c. Quality conformance inspection (see 4.5).4.2 Inspection conditions. Unless otherwise specified herein, all inspections shall be performed in accordance with the testconditions specified in the "GENERAL REQUIREMENTS" of MIL-STD-1344 and MIL-STD-202.4.2.1 Verification testing. The following identified tests and test methods assure socket integrity within typical operating conditionsand applications. Alternate commercial industry standard test methods are allowed, however when an alternate method is used, thealternate method must be coordinated with the qualifying activity prior to performance of the test. The test methods described hereinare proven methods and shall be the referee method in cases of dispute.4.2.2 Test equipment and inspection facilities. Test and measuring equipment and inspection facilities of sufficient accuracyqualify and quantity to permit performance of the required inspection shall be established and maintained by the contractor. Theestablishment and maintenance of a calibration system to control the accuracy of the measuring and test equipment (i.e. ANSI/NCSLZ540-1-1994, ISO 10012-1 part, or comparable standards) shall be required.4.2.3 Responsibility for compliance. All items shall meet all requirements of sections 3 and 4. The inspection set forth in thisspecification shall become a part of the contractor's overall inspection system or quality program. The absence of any inspectionrequirements in the specification shall not relieve the contractor of the responsibility of ensuring that all products or suppliessubmitted to the Government for acceptance comply with all requirements of the contract. Sampling inspection, as part ofmanufacturing operations, is an acceptable practice to ascertain conformance to requirements, however, this does not authorizesubmission of known defective material, either indicated or actual, nor does it commit the Government to accept defective material.MIL-DTL-28748D144.2.4 Assembly distributor. Assembly distributors must be listed on, or approved for listing on, the applicable qualified productslist. The qualified connector manufacturer shall certify that the assembly distributor is approved for the distribution of themanufacturer's parts. The assembly distributor shall use only piece parts supplied by the qualified connector manufacturer. Notesting other than visual examination is required of certified piece parts obtained from the qualified connector manufacturer, exceptwhen there is cause for rejection. All assemblies produced at the assembly distributor's plant shall be subjected to examination ofproduct to assure that the assembly process conforms with that established at the qualified manufacturing plant. Quality controlrequirements, including Government inspection surveillance, shall be the same as required for the qualified connector manufacturer.4.2.5 Statistical process control (SPC). A SPC program shall be established and maintained in accordance with EIA-557. Evidence of such compliance shall be verified by the qualifying activity as a prerequisite for qualification and retention of qualification.4.3 Materials inspection. Materials inspection shall consist of certification supported by verifying data that the materials, asspecified in 3.3 and on the specification sheets (see 3.1), used in fabricating the connectors, are in accordance with the applicablereferenced specifications or performance requirements prior to such fabrication (see 3.5, 4.7.2, and 6.2).4.4 Qualification inspection. Qualification inspection shall be performed at a laboratory acceptable to the Government (see 6.3)on sample units produced with equipment and procedures normally used in production. Use of alternate materials, plating, andprocesses shall be identified for inclusion in the product test documentation (see 3.3.1).4.4.1 Preparation of samples.4.4.1.1 Contacts. Preparation of samples; MIL-C-39029/34, /35, /36, and /37 contacts shall be wired using wire conforming toMIL-W-22759.4.4.1.2 Shields (if applicable). Shields shall be assembled.4.4.1.3 Connectors. Completely assembled plugs or receptacles, complete with guide pins, jackscrews, back-up plates, contacts,and shields (if applicable) shall be subjected to qualification inspection as follows.4.4.1.3.1 Connectors with nonremovable or removable contacts. The completely assembled plugs and receptacles (six each forcrimp terminations and eight for non-removable contacts), with the insert arrangement of the largest size connector in accordancewith the applicable military specification sheet, and two each completely assembled plugs and receptacles for all other connectorsizes for which qualification is desired shall be submitted.4.4.1.3.2 Nonremovable contacts. Forty sets of pin and socket contacts shall be subjected to qualification inspection.4.4.2 Inspection routine. The sample shall be subjected to the inspections specified in tables IX and X, as applicable, in the ordershown.4.4.2.1 Connectors. The six mating connector assemblies (for crimp contact terminations) or eight mating connector assemblies(for nonremovable contacts), shall be divided equally into three groups (for crimp terminations) or four groups (for nonremovablecontacts) of two units each for groups I, II, III, and V (group V is for solder terminations only) tests of table IX. Any two additionalmating connector assemblies shall be designated as group IV sample units of table IX.4.4.2.2 Nonremovable contacts. The sample shall be divided equally into two groups of 20 units each for groups I and II of tableIX and subjected to the inspection for their particular group. For salt spray test, 10 sets of contacts shall be unwired and unmatedand 10 sets shall be mounted as shown on figure 4.4.4.3 Failures. One or more failures shall be cause for refusal to grant qualification approval.MIL-DTL-28748D15B.50MAXLEAD SOLDERED TO WASHER3.50(88.9).50(12.7)CONTACTTEN ELECTRICAL CONTACTS(MATED PINS AND SOCKETS)PLACED AS SHOWN.75(19.1)PLASTIC MOUNTINGBASENOTES:1. Dimensions are in inches.2. Metric equivalents are given for general information only.3. Metric equivalents are in parenthesis.FIGURE 4. Test fixture for salt spray test.MIL-DTL-28748D16TABLE IX. Qualification inspection - connectors.NumberofsampleunitsRequirementparagraphTestmethodParagraphNumber of sample units to beinspectedConditionGroupsI II III IV V2 2 2 2 2Examination of productPermeabilityInsulation resistanceDielectric withstanding voltageContact retentionContact insertion and removal forcesTemperature cyclingDielectric withstanding voltageHumidityInsulation resistanceDielectric withstanding voltageVibrationShock (specified pulse)Insertion and withdrawal force (connector assembly)DurabilityContact resistanceSalt spray (corrosion)Dielectric withstanding voltageSolderabilityResistance to soldering heatResistance to solvents3.3, 3.4, 3.5, 3.6,and 3.73.5.13.5.23.5.33.5.43.5.53.5.63.5.33.5.73.5.23.5.33.5.83.5.93.5.103.5.113.5.123.5.133.5.33.5.183.5.193.5.204.7.2 4.7.34.7.44.7.54.7.64.7.74.7.84.7.54.7.94.7.44.7.54.7.104.7.114.7.124.7.134.7.144.7.154.7.54.7.214.7.224.7.23XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 2/X 2/XXX 1/X 3/X 3/XAllConnectorsMated or unmatedMatedUnmatedUnmatedUnmatedMatedUnmatedUnmatedUnmatedUnmatedMatedMatedMated or unmatedMated or unmatedMatedUnmatedMatedUnmatedUnmatedUnmated1/ This inspection is to be performed after "solderability” and "resistance to soldering heat".2/ Need not be monitored for electrical continuity during test.3/ Applicable for solder type termination connectors only.MIL-DTL-28748D17TABLE X. Qualification inspection - nonremovable contacts.Inspection RequirementparagraphTestmethodparagraphNumber ofsample units tobe inspectedGroup IExamination of productSalt spray (corrosion)Examination of productLow level circuitGroup IIExamination of productResistance to test probe damageContact separating forcesContact pin strengthIndustrial gas3.73.5.13.23.73.5.143.73.5.153.5.163.5.213.5.174.7.24.7.154.7.24.7.164.7.24.7.174.7.184.7.244.7.2020 1/201/ For salt spray test, 10 sets of contacts shall be unwired and unmated, and 10 sets shall bein accordance with figure 4.4.4.4 Verification of qualification. To retain qualification, the contractor shall verify in coordination with the qualifying activity thecapability of manufacturing products, which meet the performance requirements of this specification. Refer to the qualifying activityat any time that the inspection data indicates failure of the qualified product to meet the performance requirements of thisspecification.4.5 Quality conformance inspection.4.5.1 Inspection of product for delivery. Inspection of product for delivery shall consist of group A.4.5.1.1 Inspection lot. An inspection lot shall consist of all the connectors of the same PIN, produced under essentially the sameconditions, and offered for inspection at one time.4.5.1.1.1 Sample size, contact measurements. A total of 13 contact positions shall be measured per sample in each subgroup.For connectors with 13 or less contacts, all positions shall be measured. This shall apply to the requirements as specified in 4.7.2,4.7.5, 4.7.14, and 4.7.16.4.5.1.2 Group A inspection. Group A inspection shall consist of the examination and tests specified in table XI, in the ordershown.TABLE XI. Group A inspection.Inspection RequirementparagraphTestparagraphExamination of productDielectric withstanding voltageContact separating force (contacts)3.3, 3.4, 3.6,and 3.73.5.33.5.164.7.24.7.54.7.184.5.1.2.1 Sampling plan. Statistical sampling and inspection for the samples submitted for group A inspection shall be on alot by lot basis with sample sizes as listed in table XII. Any occurrence of a failure shall be considered as failure of the lot.MIL-DTL-28748D18TABLE XII. Lot and sample size.Lot size Sample size1 to 50 51 to 90 91 to 150 151 to 280 281 to 500 501 to 1200 1201 to 3200 3201 to 10000 10001 to 5 7111316192329354.5.1.2.2 Rejected lots. If an inspection lot is rejected, the manufacturer may rework it to correct the defects, or screen outthe defective units, and resubmit for reinspection. Resubmitted lots shall be inspected using the sample size of the nexthigher lot size specified in table XII and shall not thereafter be tendered for acceptance unless the former rejection orrequirement of correction is disclosed. Such lots shall be clearly identified as reinspected lots.4.5.1.2.3 Disposition of sample units. Sample units which have passed all the group A inspections may be delivered on thecontract if the lot is accepted and the sample units are still within the specification tolerances.4.5.1.3 Group B inspection. Group B inspection shall be performed every 6 months on sample units, which have passedgroup A inspections. Group B inspections shall consist of the examinations and tests specified in table XIII, in the ordershown, and the sample shall be selected from inspection lots that have passed group A inspection. Connector series may becombined for lot purposes during group B inspection and shall be in proportion to the number of connectors produced in eachseries.TABLE XIII. Group B inspection.Inspection RequirementparagraphTestparagraphExamination of productPermeabilityInsulation resistanceContact retentionInsertion and withdrawal force (connector assembly)3.3, 3.4, 3.5, 3.6,and 3.73.5.13.5.23.5.43.5.104.7.24.7.34.7.44.7.64.7.124.5.1.3.1 Sampling plan. Four sample pairs containing the largest number of contact positions with a full complement ofcontacts (not including the variation in terminal types) available at time of inspection should be selected at random from itemsproduced every 6 months. Where crimp type contacts are specified, that type shall be used in group B samples.4.5.1.3.2 Failures. If one or more sample units fail to pass group B inspection, the sample shall be considered to havefailed.4.5.1.3.3 Rejected lots. If an inspection lot is rejected, the contractor may rework it to correct the defects, or screen out thedefective units, and resubmit for reinspection. Resubmitted lots shall be inspected using tightened inspection. Such lots shallbe separate from new lots, and shall be clearly identified as reinspected lots.4.5.1.3.4 Disposition of sample units. Sample units, which have passed group B inspection, may be delivered on acontract or purchase order if the lot is accepted.MIL-DTL-28748D194.6 Group C inspection (periodic). Periodic inspection shall consist of a 12-month inspection and a 36-monthrequalification. Delivery of products, which have passed groups A and B inspections, shall not be delayed pending results ofthese periodic inspections. Upon passing this inspection two consecutive times, the supplier may select sample connectorsevery 36 months. If production of a particular PIN is not current, the periodic inspection tests shall take place at the timeproduction is resumed. The testing shall revert to the original schedule, which is applied to a newly qualified product.4.6.1 Group C inspection. Group C inspection shall consist of the examinations and tests specified in table XIV, in theorder shown. Group C inspection shall be made on sample units selected from inspection lots, which have passed the groupsA and B inspection.4.6.1.1 Sampling plan. Six mated pairs of the smallest, medium (exact middle or next higher), and largest insert for everydesign type. Forty sets of nonremovable pin and socket contacts shall be selected from current production after 200,000connectors of each PIN have been produced or once every 36 months, whichever occurs first.All sample units are to contain a proper mix of hardware for which the manufacturer has approval of sample units of each PINof connector. The six sets of connectors shall be divided into three groups and two pairs each shall be subjected to groups I,II, and III tests of table XIV. The 40 sets of nonremovable pin and socket contacts shall be divided into two groups for thetests of groups IV and V of table XIV.A design type is defined as a style represented per military specification sheet. Therefore, a company qualified to two slashsheets would test six mated pairs or 12 mated pairs if qualified to four slash sheets, etc.4.6.1.2 Noncompliance. If a sample fails to pass group C inspection, the contractor shall take corrective action on thematerials or processes, or both, as warranted, and on all units of product which can be corrected and which weremanufactured under essentially the same conditions, with essentially the same materials, processes, etc., and which areconsidered subject to the same failure. Acceptance of the product shall be discontinued until corrective action, acceptable tothe Government, has been taken. After the corrective action has been taken, group C inspection shall be repeated onadditional sample units (all inspection, or the inspection, which the original sample failed, at the option of the Government).Group A and B inspections may be reinstituted; however, final acceptance shall be withheld until the group C reinspection hasshown that the corrective action was successful. In the event of failure after reinspection, information concerning the failureand corrective action shall be made available to the cognizant inspection activity and to the qualifying activity.4.6.1.3 Defectives. Any failures of the samples tested in table XIV, the entire lot is considered to have failed.MIL-DTL-28748D20TABLE XIV. Group C inspection.Inspection RequirementparagraphTestmethodparagraphNumber ofsample units tobe inspectedConnectorGroup ITemperature cyclingDielectric withstanding voltageVibrationShock (specified pulse)HumidityInsulation resistanceDielectric withstanding voltageGroup IIDurabilityContact resistanceGroup IIISalt spray (corrosion)Dielectric withstanding voltage3.5.63.5.33.5.83.5.93.5.73.5.23.5.33.5.113.5.123.5.133.5.34.7.84.7.54.7.104.7.114.7.94.7.44.7.54.7.134.7.144.7.154.7.52 sets2 sets2 setsContactsGroup IVContact pin strengthResistance to test probe damageGroup VSalt spray (corrosion)SolderabilityExamination of productLow level circuit3.5.213.5.153.5.133.5.183.73.5.144.7.244.7.174.7.154.7.214.7.24.7.1620 sets20 sets4.6.1.4 Disposition of sample units. Sample units, which have been subjected to group C inspection, shall not be deliveredon the contract or purchase order.MIL-DTL-28748D214.7 Methods of inspection.4.7.1 Test methods. The following identified tests and test methods assure connector integrity within typical operatingconditions and applications. Alternate commercial industry standard methods are allowed, however when and alternatemethod is used, the qualifying activity must be notified prior to performance of the test. The test methods described herein areproven methods and shall be the referee method in cases of dispute.4.7.2 Visual and mechanical examination. Connectors and associated fittings shall be examined to verify that the design,construction, physical dimensions, marking and workmanship are in accordance with the applicable requirements (see 3.3,3.4, 3.5, 3.6, and 3.7).4.7.3 Permeability (see 3.5.1). The permeability of all parts of each connector assembly shall be measured with anindicator conforming to ASTM A342.4.7.4 Insulation resistance (see 3.5.2 and figure 5). Unmated connector assemblies shall be tested in accordance withmethod 3003 of MIL-STD-1344. The following detail shall apply: Duration of application of test voltage shall be one minuteminimum.4.7.5 Dielectric withstanding voltage (see 3.5.3 and figure 5). Unmated connector assemblies shall be tested inaccordance with method 3001 of MIL-STD-1344. The following details shall apply:a. Nature of potential: AC.b. Magnitude of test voltage: See table III.c. Points of application of test voltage: Between contacts alternately connected and between contacts and body.4.7.6 Contact retention (see 3.5.4).4.7.6.1 Nonremovable contacts. Axial loads shall be applied to individual contacts in unmated connectors. The load shallbe applied uniformly at a rate of one pound per second in one direction and then the other direction.4.7.6.2 Removable contacts (see 3.5.5). The contact shall be inserted and withdrawn 10 times from the same hole. Theaxial loads shall be applied to individual contacts in unmated connectors. The load shall be applied uniformly (in the normalremoval direction) at a rate of one pound per second. The axial load must be maintained a minimum of 30 seconds. Themaximum axial displacement is .015 inch (0.38 mm) after seating of the contact.4.7.7 Contact insertion and removal forces (see 3.5.5). Contacts shall be inserted and removed from the correspondingconnector inserts nine times by means of tools conforming to MIL-I-81969/18 and MIL-I-81969/20. The procedures andinstrumentation shall be capable of measuring the force applied parallel to the axis of the contacts. Measurements shall betaken on the first and ninth cycles.4.7.8 Temperature cycling (see 3.5.6). Mated connectors shall be tested in accordance with method 1003 of MIL-STD-1344. The following details and exception shall apply:a. Test condition A, except the high temperature shall be 125°C ± 3°C.b. Measurements after cycling: Following the temperature cycling test, dielectric withstanding voltage shall be tested asspecified in 4.7.5.MIL-DTL-28748D22HORIZONTAL ROWS+-mkTJAC ADAWAXBPCJCHBRVERTICAL ROWS-+ JDCBEACSCMCRCLCPCKCNCJHORIZONTAL ROWS VERTICAL ROWSFIGURE 5. Wiring diagram, typical suggested method for insulation resistancedielectric high potential and moisture resistance tests.MIL-DTL-28748D23POWERSUPPLYACABLECABLEVMILLIVOLT A-ASOLDERED4.7.9 Humidity (see 3.5.7 and figure 4). Unmated plugs and receptacles shall be tested in accordance with method 1002, type II,of MIL-STD-1344, except steps 7A and 7B are not required. The following details shall apply:a. Initial measurements: No measurements are required after initial conditioning, nor voltage applied toconnectors during exposure.b. Final measurement: After completion of step 6 of the final cycle, but no sooner than 1-1/2 hours and not later than 3hours while the sample is still in the chamber, insulation resistance shall be measured as specified in 4.7.4 Following theinsulation resistance test, dielectric withstanding voltage shall be tested as specified in 4.7.5, except the magnitude of testvoltage shall be in accordance with table III for a period of 5 minutes, applied between all contacts and the shell.4.7.10 Vibration (see 3.5.8). Complete mated connectors shall be tested in accordance with method 2005, test condition II of MIL-STD-1344.a. At the conclusion of this test, the connector assembly shall be visually examined for loosening, fracture,or other deterioration (see 3.3.7).4.7.11 Shock (specified pulse) (see 3.5.9). Complete mated connectors shall be tested in accordance with method 2004 of MIL-STD-1344. The following details shall apply:a. Mounting method: In accordance with the mounting fixture in method 2005 of MIL-STD-1344.b. Test condition I.c. Measurements: Contacts shall be monitored for electrical continuity during test and connectors shall beexamined for evidence of failure of metallic or dielectric materials and engagement of the mated portionsafter test.4.7.12 Insertion and withdrawal force (connector assembly) (see 3.5.10). Each connector, with full complement of contacts, shallbe mated and unmated. The insertion and withdrawal forces, applied gradually, shall be measured after three cycles.4.7.13 Durability (see 3.5.11). The complete connector assemblies shall be subjected to 500 cycles of insertion and withdrawal ata rate not to exceed 500 cycles per hour. Tests shall be conducted using normal engaging hardware. The insertions andwithdrawals shall be accomplished in a manner similar to that which the connectors shall be subjected in service.4.7.14 Contact resistance (see 3.5.12). The potential drop across each mated pair of pin and socket contacts shall be measuredat rated current as shown in table V. Potential drop readings shall be taken across the two points as shown on figure 6 (A-A). Measurements shall be taken after the temperature of the wire has stabilized and readings shall comply with the initial test valuesshown in table V.FIGURE 6. Voltage drop test wiring diagram.MIL-DTL-28748D244.7.15 Salt spray (corrosion) (see 3.5.13). The unmated plugs and receptacles, nonremovable contacts (unwired and unmated), andnonremovable contacts mounted in accordance with figure 4 shall be tested in accordance with method 1001 of MIL-STD-1344. Thefollowing details shall apply:a. Test condition B.b. Measurements after exposure: Immediately after exposure, the exterior surfaces of the connectors and of theindividual sets of pin and socket contacts shall be washed with tap water and the connectors and the individual setsof pin and socket contacts shall be dried for 12 hours maximum in a circulating air oven at a temperature of38°C ± 3°C (100°F ± 5°F). Following the salt spray test, the unmated plugs and receptacles shall be subjected tothe dielectric withstanding voltage test specified in 4.7.5, except the magnitude of test voltage shall be inaccordance with the "after conditioning" values of table III.4.7.16 Low level circuit (see 3.5.14). Nonremovable contacts shall be tested in accordance with method 3002 of MIL-STD-1344.4.7.17 Resistance to test probe damage (nonremovable contacts) (see 3.5.15). Non-removable contacts shall be tested inaccordance with method 2006.1 of MIL-STD-1344, and with the bending moment of table XV applied. The contact shall be suitablysupported to prevent bending, but the support shall not reinforce the pressure member. The test probe shall consist of a hardenedsteel pin having a diameter equal to the nominal dimension of the mating pin contact and a spherical radius tip. The test probe shallbe free and unsupported, and the socket contact shall be maintained in a horizontal position. For each specified depth, the contactshall be rotated one complete revolution at a uniform rate.TABLE XV. Bending moment for test probe damage test. 1/ContactsizeBend momentinch-pounds (kg)162022 2.0 (0.91) 0.5 (0.23) 0.125 (0.057)1/ Metric equivalents are given for general information only.4.7.18 Contact separating forces (nonremovable contacts) (see 3.5.16). Provisions shall be made for mounting socket contacts ina suitable position for applying gradually increasing loads during withdrawal of the minimum diameter hardened test pins. The depthof engagement shall be equal to the maximum length of the pin for the mating connector. Polished test pins as specified on figure 7with a maximum diameter, as shown on figure 7 table, shall be inserted into and withdrawn from each socket contact three times priorto measurement. Following this procedure, polished test pins as specified on figure 7 with a minimum diameter, as specified onfigure 7 table, shall be inserted into each socket contact. Withdrawal forces, applied gradually, shall then be measured.MIL-DTL-28748D25HANDLE SHOWN TYPICALRECOMMENDED LENGTH 1.0000MINIMUM DIAMETER TWICE “A” MAXSTAMP GAUGE WITHM28748-# OR MS 3197-#.500 MINRADII SHALL BE SMOOTHLYBLENDED INTO PIN DIAMETERABTest pins for measuring contact separating forces.ContactsizeA(mm)BanddashnumberMinimum diameter+.0001 (0.003)-.0000Maximum diameter+.0000-.0001 (0.003)Maxflat(mm)16X116Y120X120Y122X122Y10.0615 (1.56)---0.0390 (0.99)---0.0295 (0.75)---0.0635 (1.61)0.0410 (1.04)0.0305 (0.77).015 (0.38).015 (0.38).007 (0.18).007 (0.18).007 (0.18).007 (0.18)NOTES:1. Dimensions are in inches.2. Metric equivalents are given for general information only.3. Material: Gauge pin for contact sizes 22 and 20, tool steel or tungsten carbide, and for contact size 16, tungsten carbide.4. Finish: 6 to 10 microinches root mean square determined in accordance with ASME B46.1.5. No plating.6. These gauges are intended for use with electric connector socket contacts referenced in this document and in MIL-C-39029.FIGURE 7. Test pin.4.7.19 Finish thickness. Finish thickness of the plating and strikes shall be determined by any method which will give resultswithin ±.010 percent of the true thickness.4.7.19.1 Overall finish. Plating thickness shall be measured on the external surfaces of the contact body.4.7.19.2 Localized finish (see 3.3.5.2.2). Finished thickness shall be .00005 inch (0.00127 mm) minimum thickness of depositedgold. Measurements shall be made at point B or C (see figure 1) as applicable. However, the plating on non-significant surfaces,nonfunctional surfaces shall be sufficient thickness to ensure plating continuity and uniform appearance.4.7.20 Industrial gas (see 3.5.17). Unmated contacts shall be placed on a noncorrosive rack in a closed plastic or glass chamber(volume 2 cubic feet maximum) which contains a 10 percent solution of sulphurated potash NF in distilled water. Contacts shall notbe immersed in the solution but shall be exposed to the sulfide vapor for 100 hours.4.7.21 Solderability (see 3.5.18). Solder type contacts shall be tested in accordance with method 208 of MIL-STD-202.4.7.22 Resistance to soldering heat (see 3.5.19). All connectors with solder terminations shall be tested in accordance with EIA-364-56. The connectors shall be tested in accordance with procedure 1, unless otherwise specified (see 3.1).MIL-DTL-28748D26.0 3 0.0 8 LM INT O O L H E A D 3 0 °5 0 °P E R M A N E T S E T( .0 0 5 M A X )L F IX T U R E S H A L LS U P P O R T C O N T A C TO N T H IS D IA M E T E R.0 0 5.0 0 2 R4.7.23 Resistance to solvents (see 3.5.20). Connectors shall be tested in accordance with EIA-364-11. The solvents shall beclass 1. The connectors tested shall be fully assembled by normal assembly operations.4.7.24 Contact pin strength (see 3.5.21). Nonremovable contacts shall be mounted in a suitable fixture and a force (see table VIII)shall be applied to the end of the pin as shown on figure 8. The maximum rate of travel of the tool head of the testing machine shallnot exceed 1 inch per minute. The maximum loading time shall not exceed 1 minute. The permanent set shall be the differencebetween the initial and the final position of the extreme pin tip, immediately after load removal and shall not exceed the limitsspecified in 3.5.21.Inches mm.002.005.030.8 0.0510.1270.76220.32 NOTES:1. Dimensions are in inches.2. Metric equivalents are given for general information only.FIGURE 8. Contact strength.MIL-DTL-28748D275. Packaging.5.1 Packaging requirements. For acquisition purposes, the packaging requirements shall be as specified in the contract or order(see 6.2). When actual packaging of materiel is to be performed by DoD personnel, these personnel need to contact the responsiblepackaging activity to ascertain requisite packaging requirements. Packaging requirements are maintained by the Inventory ControlPoint's packaging activity within the Military Department or Defense Agency, or within the Military Department's or Defense Agency'sautomated packaging files, CD-ROM products, or by contacting the responsible packaging activity.6. NOTES(This section contains information of a general or explanatory nature that may be helpful, but is not mandatory.)6.1 Intended use. Connectors and contacts covered by this specification are intended for use in airborne, ground support, andshipboard electrical and electronic equipment.6.1.1 Insert material. The connectors covered by this specification are composed of an insert made of a suitable insulationmaterial into which are fixed either pins or sockets, with which electrical connections can be made. The specification also coversinserts, so that the units may be purchased separately as required.6.2. Acquisition requirements. Acquisition documents must specify the following:a. Title, number, and date of this specification.b. Title, number, and date of the applicable specification sheet and the complete military PIN (see 3.1).c. Level of preservation, packaging, packing and marking required (see section 5).d. Quantity of units per package, if other than one.e. Whether contacts are included (see 3.4.2.1 and 3.6).f. Insert material required (see 3.3.4).6.3 Qualification. With respect to products requiring qualification, awards will be made only for products which are at the time setfor opening of bids, qualified for inclusion in the applicable qualified products list whether or not such products have actually been solisted by that date. The attention of the contractors is called to this requirement, and manufacturers are urged to arrange to have theproducts that they propose to offer to the Federal Government tested for qualification, in order that they may be eligible to beawarded contracts or purchase orders for the products covered by this specification. The activity responsible for the qualifiedproducts lists is the Defense Supply Center Columbus (DSCC-VQP), 3990 East Broad Street, Columbus, Ohio 43216-5000.Application for qualification tests will be made in accordance with "Provisions Governing Qualification" (see 6.3.1).6.3.1 Provisions governing qualification. Copies of "Provisions Governing Qualification" may be obtained upon application toStandardization Document Order Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094.6.4 Definitions. For purposes of this specification, the following definitions shall apply.6.4.1 Connector assembly. A complete connector assembly consists of a mated plug and receptacle.6.4.2 Receptacle. A connector receptacle is that portion of the connector assembly which is normally "fixed", that is rigidlyattached to a supporting surface. It will be provided with pin or socket contacts.6.4.3 Plug. A connector plug is that portion of the connector assembly which is normally "removable". The plug will be providedwith pin or socket contacts.6.5 Interchangeability. All complete connectors, including their complement of pin or socket contacts, having the same PIN will becompletely interchangeable with each other with respect to installation (physical) and performance (function) as specified herein.Suitable evidence, such as dimensional data, may be required by the Government in order to assure that complete connectorassemblies will be interchangeable and meet the requirements of this specification.6.5.1 Removable contacts. All pins and sockets will be capable of being assembled in the molded inserts and be completelyinterchangeable with each other with respect to installation (physical) and performance (function) as specified herein (see 3.1). Toolswill be capable of properly inserting and removing the pin and socket contacts from the molded inserts. Suitable evidence such asdimensional data, may be required by the Government in order to assure that pins and sockets will be interchangeable and meet therequirements of this specification.MIL-DTL-28748D286.5.2 Plugs and receptacles. Plugs and receptacles of a given size and design manufactured by one source to the requirementsof this specification, will be capable of mating with associated plugs and receptacles manufactured to the requirements of thisspecification by other sources.6.6 Environmentally preferable material. Environmentally preferable materials should be used to the maximum extent possiblethat the material meets or exceeds the operational and maintenance requirements, and promotes economically advantageous lifecycle costs. Table XVI lists the Environmental Protection Agency (EPA) top seventeen hazardous materials targeted for major usagereduction. If any of these hazardous materials are required, it is recommended that it be used only when other materials cannot meetperformance requirements.TABLE XVI. EPA top seventeen hazardous materials.Benzene Dichloromethane TetrachloroethyleneCadmium and compounds Lead and compounds TolueneCarbon Tetrachloride Mercury and compounds 1,1,1 - TrichloroethaneChloroform Methyl Ethyl compounds TrichloroethyleneChromium and compounds Methyl Isobutyl Ketone XylenesCyanide and compounds Nickel and compounds6.7 Subject key word listing.Assembly distributorBerylliumContact pin strengthCopperDiallyl phthalateLeadLocalized finishNickelPolyphenylene sulfideShellsShieldsTin6.8 Changes from previous issue. Marginal notations are not used in this revision to identify changes with respect to the previousissue due to the extensiveness of the changes.CONCLUDING MATERIALCustodians: Preparing activity: Army - CR DLA - CC Navy - EC Air Force - 11 (Project 5935-4316) DLA - CCReview activities: Army - AR, AT, AV, CR4, MI Navy - AS, MC, OS, SH Air Force - 99STANDARDIZATION DOCUMENT IMPROVEMENT PROPOSALINSTRUCTIONS1. The preparing activity must complete blocks 1, 2, 3, and 8. In block 1, both the documentnumber and revision letter should be given.2. The submitter of this form must complete blocks 4, 5, 6, and 7, and send to preparing activity.3 The preparing activity must provide a reply within 30 days from receipt of the form.NOTE: This form may not be used to request copies of documents, nor to request waivers, or clarification of requirementson current contracts. Comments submitted on this form do not constitute or imply authorization to waive any portion of thereferenced document(s) or to amend contractual requirements.I RECOMMEND A CHANGE: 1. DOCUMENT NUMBERMIL-DTL-28748D2. DOCUMENT DATE (YYYYMMDD)200107113. DOCUMENT TITLE CONNECTOR, PLUG AND RECEPTACLE, RECTANGULAR, RACK AND PANEL SOLDER TYPE AND CRIMPTYPE CONTACTS4. NATURE OF CHANGE (Identify paragraph number and include proposed rewrite, if possible. Attach extra sheets as needed.)5. REASON FOR RECOMMENDATION6. SUBMITTERa. NAME (Last, First, Middle Initial) b. ORGANIZATIONc. ADDRESS (Include zip code) d. TELEPHONE (Include Area Code)(1) Commercial(2) DSN(if applicable)7. DATE SUBMITTED(YYYYMMDD)8. PREPARING ACTIVITYa. NAMEDefense Logistics AgencyDefense Supply Center, Columbusb. TELEPHONE (Include Area Code)(1) Commercial 614-692-0538(2) DSN 850-0538c. ADDRESS (Include Zip Code)DSCC-VAIP.O. Box 3990Columbus, Ohio 43216-5000IF YOU DO NOT RECEIVE A REPLY WITHIN 45 DAYS, CONTACT:Defense Standardization Program Office (DLSC-LM)8725 John J. Kingman Road,Suite 2533Fort Belvoir, Virginia 22060-6621Telephone (703) 767-6888 DSN 427-6888DD Form 1426, FEB 1999 (EG) PREVIOUS EDITION IS OBSOLETE. WHS/DIOR, Feb 99