1、 CHECK THE MASTER LISTVERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE at https:/repository.msfc.nasa.gov/docs/multiprogram/MSFC-SPEC-3659 MSFC-SPEC-3659 National Aeronautics and BASELINE Space Administration EFFECTIVE DATE: February 8, 2012 George C. Marshall Space Flight Center Marshall Space Fl
2、ight Center, Alabama 35812 ES42 MSFC TECHNICAL STANDARD PROCESS SPECIFICATION FOR ELECTRICAL BONDING Approved for Public Release; Distribution is Unlimited Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MSFC Technical Standard ES42 Title: Process Sp
3、ecification for Electrical Bonding Document No.: MSFC-SPEC-3659 Revision: Baseline Effective Date: February 8, 2012 Page 2 of 13 CHECK THE MASTER LISTVERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE DOCUMENT HISTORY LOG Status (Baseline/ Revision/ Canceled) Document Revision Effective Date Descrip
4、tion Baseline 2/8/2012 Baseline Release; document authorized through MPDMS. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MSFC Technical Standard ES42 Title: Process Specification for Electrical Bonding Document No.: MSFC-SPEC-3659 Revision: Baseli
5、ne Effective Date: February 8, 2012 Page 3 of 14 CHECK THE MASTER LISTVERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE at https:/repository.msfc.nasa.gov/docs/multiprogram/MSFC-SPEC-3659 TABLE OF CONTENTS 1.0 INTRODUCTION 4 1.1 Scope 4 1.2 Purpose . 4 1.3 Applicability 4 2.0 APPLICABLE DOCUMENTS .
6、 4 3.0 REQUIREMENTS . 5 3.1 Manufacturing Facility. 5 3.2 Materials and Equipment . 6 3.3 Process Flow 6 3.4 Surface Preparation 7 3.4.1 Cleaning . 7 3.4.1.1 Cleaning Method Selection Criteria 9 3.4.2 Protective Finishes . 9 3.4.3 Refinishing . 9 3.5 Bond Jumpers or Straps . 9 3.6 Completion of the
7、Bond .10 4.0 VERIFICATION10 4.1 Process Qualification .10 4.2 Product Acceptance .10 4.3 Inspection .10 4.4 Tests .11 4.5 Records, Reports, and Forms .11 4.6 Personnel Training and Certification .11 5.0 PACKAGING .11 6.0 NOTES 12 6.1 Implementation 12 6.2 Safety Precautions and Warning Notes 12 APPE
8、NDIX A .13 DEFINITIONS AND ACRONYMS .13 FIGURE 1. Electrical Bonding Process Flow 8 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MSFC Technical Standard ES42 Title: Process Specification for Electrical Bonding Document No.: MSFC-SPEC-3659 Revision
9、: Baseline Effective Date: February 8, 2012 Page 4 of 13 CHECK THE MASTER LISTVERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE 1.0 INTRODUCTION 1.1 Scope This document establishes criteria for the processes involved in electrical bonding of semi-permanent, metal-to-metal joints (joints held togeth
10、er by bolts, rivets, clamps, etc.) and indirect bonds for equipment and elements manufactured at the Marshall Space Flight Center (MSFC). There are two types of electrical bonds: direct and indirect. Direct bonds are metal-to-metal joints provided by welding, riveting or bolting. Indirect bonds are
11、connected through a strap or jumper. Joints formed by welding, brazing or sweating are inherently bonded provided that proper procedures are followed to ensure no impurities or imperfections are incorporated in the joint. 1.2 Purpose This document has two purposes: 1. To provide a minimum set of pro
12、cess control requirements to be used in implementing electrical bonds. 2. To provide a specification for callout on mechanical drawings. 1.3 Applicability This document applies to in-house and contract activities and should be cited in program and contract documents as a technical requirement. All p
13、rime contractors and subcontractors performing activities to the requirements of this document shall be on-site audited and approved by NASA as to their quality management system and process controls as specified herein. Individual provisions of this document may be tailored based on application spe
14、cific experience and sufficient technical rationale. This document may be cited by other NASA centers or Industry. This document is applicable to all new, used, or repaired flight hardware that is within its scope. 2.0 APPLICABLE DOCUMENTS The following documents are called out as an extension of th
15、e requirements given in this specification: DOCUMENT NO. TITLE NASA-STD-4003 Electrical Bonding for NASA Launch Vehicles, Spacecraft, Payloads, and Flight Equipment Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MSFC Technical Standard ES42 Title: P
16、rocess Specification for Electrical Bonding Document No.: MSFC-SPEC-3659 Revision: Baseline Effective Date: February 8, 2012 Page 5 of 13 CHECK THE MASTER LISTVERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE NASA-STD-6016 Standard Materials and Processes Requirements for Spacecraft MIL-C-81302 Cle
17、aning Compound, Solvent, Trichlorotrifluoroethane MWI 3410.1 Personnel Certification Program 2.1 Reference Documents The following documents are cited as references to guide the user in the application of this specification. DOCUMENT NO. TITLE EPA SNAP list U.S. EPAs Significant New Alternatives Pol
18、icy (SNAP) Program SAE-AMS-S-8802 Sealing Compound, Temperature Resistant, Integral Fuel Tanks and Fuel Cell Cavities, High Adhesion SAE-AMS3276 Sealing Compound, Integral Fuel Tanks and General Purpose, Intermittent Use to 360 Deg. F (182 Deg. C) SAE-AMS3277 Sealing Compound, Polythioether Rubber,
19、Fast Curing Integral Fuel Tanks and General Purpose, Intermittent Use to 400 Mdf (204Mdc) MIL-S-81733 Sealing and Coating Compound, Corrosion Inhibitive MSFC-SPEC-164 Cleanliness of Components for Use in Oxygen, Fuel, and Pneumatic Systems, Specification for MIL-PRF-16173 Performance Specification C
20、orrosion Preventive Compound, Solvent Cutback, Cold-Application 3.0 REQUIREMENTS 3.1 Manufacturing Facility The manufacturing facility should include as a minimum the following resources: a. Adequate lighting and a temperature/humidity controlled ventilation system. b. Adequate space for safe operat
21、ion of cleaning and corrosion control equipment. c. Operating instructions for each piece of equipment. d. All hazardous Material Safety Data Sheets (MSDS) for materials used. e. Safety equipment and protective personal equipment as required by local, state, and federal ordinances. Provided by IHSNo
22、t for ResaleNo reproduction or networking permitted without license from IHS-,-,-MSFC Technical Standard ES42 Title: Process Specification for Electrical Bonding Document No.: MSFC-SPEC-3659 Revision: Baseline Effective Date: February 8, 2012 Page 6 of 13 CHECK THE MASTER LISTVERIFY THAT THIS IS THE
23、 CORRECT VERSION BEFORE USE f. Personnel trained in the recognition of corrosion. g. Personnel trained in the safe and proper operation of support equipment. h. Quality assurance inspectors trained in the operational characteristics and restrictions of each piece of support equipment. 3.2 Materials
24、and Equipment Materials used in the electrical bonding process shall meet the requirements of NASA-STD-6016. In some cases, special consideration may be required to resolve situations where material selection criteria conflicts with electrical bonding requirements. Deviations from the requirements i
25、n NASA-STD-6016 associated with electrical bonding shall be approved by the NASA program/project authority with technical inputs from the responsible Materials and Processes (M otherwise, the paint may seep under the edges of the bonded components and impair the quality of the connection. Gold, nick
26、el, chromium, rhodium, tin-lead alloys or sufficiently thick platings of these metals are satisfactory without additional protection or treatment other than buffing or cleaning. 3.5 Bond Jumpers or Straps Bonding jumpers should be made as short as practicable. The jumper should not interfere with eq
27、uipment operation, and conversely, equipment operation should not result in damage to the bonding jumper. Basically, the interface between the lug on the bonding jumper or strap and the Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MSFC Technical S
28、tandard ES42 Title: Process Specification for Electrical Bonding Document No.: MSFC-SPEC-3659 Revision: Baseline Effective Date: February 8, 2012 Page 10 of 13 CHECK THE MASTER LISTVERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE mating surface shall meet the same requirements as for direct bondin
29、g interfaces. It is preferable to not use a washer under the fastener head for securing the lug of the bonding jumper or strap. When a washer must be used in order to have a good mechanical joint, the material of the washer shall be chosen to prevent galvanic corrosion to the greatest extent possibl
30、e. When a galvanic couple still exists, the entire joint should be sealed against the entrance of moisture as defined in Section 3.6. 3.6 Completion of the Bond After cleaning of the mating surfaces, the bond members should be assembled or attached within 30 minutes if possible. If delays beyond 2 h
31、ours are necessary between cleaning and assembly in a corrosive environment, a temporary protective coating, such as MIL-PRF-16173, grade 4 or other approved sealant, shall be applied. This coating shall be removed before completing the bond. Cleaned and treated surfaces should not be handled by the
32、 bare hand. The bond surfaces shall be kept dry before assembly and, when called for on the engineering drawings, the completed bond shall be sealed against the entrance of moisture into the mating region. Various conductive compounds and paints may serve as acceptable sealants, such as those confor
33、ming to SAE-AMS-S-8802, SAE-AMS3276, SAE-AMS3277, or MIL-S-81733. Nothing in this specification should be interpreted as preventing implementation of advancing technology or use of state-of-the-art materials. 4.0 VERIFICATION 4.1 Process Qualification Electrical bonding procedures shall be qualified
34、 prior to acceptance of bond installations on production parts. Qualification shall consist of documented evidence that the procedures are capable of meeting all the requirements of this specification and NASA-STD-4003. 4.2 Product Acceptance Acceptance of electrical bond installations shall be base
35、d upon evidence of compliance with the procedures used for qualification and with requirements of the Engineering Drawing. 4.3 Inspection An in-progress inspection shall be conducted at each step in the process to check installation procedures, methods, and materials to determine compliance with req
36、uirements. After the completion of each bond, a final inspection shall be made. This inspection shall be in accordance with approved procedures to determine that all requirements of this specification and NASA-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from
37、IHS-,-,-MSFC Technical Standard ES42 Title: Process Specification for Electrical Bonding Document No.: MSFC-SPEC-3659 Revision: Baseline Effective Date: February 8, 2012 Page 11 of 13 CHECK THE MASTER LISTVERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE STD-4003 have been met. Unless otherwise spe
38、cified in the contract or purchase order, the supplier is responsible for the performance of all inspections, prior to delivery. For MSFC contracts, the supplier may utilize his own facilities or any other commercial laboratory acceptable to MSFC. The MSFC reserves the right to perform any of the in
39、spections deemed necessary to assure supplies and services conform to prescribed requirements. 4.4 Tests A limited number of resistance measurements, made as partial proof of satisfactory bonding, shall be conducted on at least two bonds of each type. Spot checks shall be made to verify the process
40、and workmanship are still acceptable. Testing of every bond is neither required nor desirable unless specifically noted by the procuring agency. The electrical bond measurements shall be performed using a four-terminal micro-ohm resistance meter. Bonding measurements often require the protective fin
41、ish to be penetrated with the ohmmeters electrical probes in order to obtain good electrical contact. Care should be taken so that a corrosion problem is not introduced by surface scars created during the measurement. Caution: Do not perform electrical bond checks in a hazardous atmosphere. Meter pr
42、obes can produce sparks. 4.5 Records, Reports, and Forms Standard manufacturing records, reports and forms shall be used. Records shall be maintained to provide evidence that all production and inspection/verification operations have been completed as planned, or as otherwise documented and authoriz
43、ed. 4.6 Personnel Training and Certification Personnel performing electrical bonding shall be qualified through training or experience and certified, as required by MWI 3410.1, to perform the task or operation required to conduct the process. 5.0 PACKAGING The requirements of Section 5 are not appli
44、cable to this specification. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MSFC Technical Standard ES42 Title: Process Specification for Electrical Bonding Document No.: MSFC-SPEC-3659 Revision: Baseline Effective Date: February 8, 2012 Page 12 of
45、13 CHECK THE MASTER LISTVERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE 6.0 NOTES 6.1 Implementation When using this document as a technical requirement, engineering drawings shall identify the surfaces to be bonded, the Class of bond, and the allowed dc resistance per NASA-STD-4003. The followin
46、g are examples of electrical bonding notes on engineering drawings: THE RESISTANCE ACROSS THIS JOINT SHALL BE LESS THAN XX OHMS TO MEET THE ELECTRICAL BOND REQUIREMENTS OF NASA-STD-4003, CLASS X. THE BOND RESISTANCE BETWEEN FN XX AND FN YY SHALL BE LESS THAN ZZ MILLIOHMS TO MEET THE BOND REQUIREMENT
47、S OF NASA-STD-4003, CLASS X. This process specification shall be called out using the following drawing note: PERFORM SURFACE PREPARATION AND JOINING IN ACCORDANCE WITH MSFC-SPEC-3659. 6.2 Safety Precautions and Warning Notes Appropriate safety precautions shall be documented in the detailed process
48、 instructions for implementing this process specification. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MSFC Technical Standard ES42 Title: Process Specification for Electrical Bonding Document No.: MSFC-SPEC-3659 Revision: Baseline Effective Date: February 8, 2012 Page 13 of 13 CHECK THE MASTER LISTVERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE APPENDIX A DEFINITIONS AND ACRONYMS DEFINITIONS Aqueous - Made from, with, or by water. Bond Classifications per NASA-STD-4003: CLASS C for intentional current return through structure CLASS
