1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2014 SAE International All rights reserved. No part of this p
3、ublication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AIR6291 AEROSPACE INFORMATION REPORT AIR6291 Issued 2014-07 Guidelines for Repair
5、 Process Evaluation of Aluminum Bonded Structure RATIONALE This document is intended to satisfy the need for a checklist of best practices in implementation of tooling, process steps, and quality controls that help to make sure that a previously substantiated repair design and process requirements a
6、re met. TABLE OF CONTENTS 1. SCOPE 4 1.1 Purpose . 4 2. APPLICABLE DOCUMENTS 4 2.1 SAE Publications . 4 2.2 Other References 5 3. DEFINITIONS . 5 4. GENERAL . 7 4.1 Overview . 7 4.2 Process Flows . 7 4.2.1 Process Flows Overview . 7 4.2.2 Process Flows Role of Quality Personnel . 7 4.2.3 Process Flo
7、ws Recommended Steps . 7 4.3 Preparation Steps Prior To Repair Accomplishment 9 4.3.1 Determine the Part Characteristics . 9 4.3.2 Determine if the Part Requires Removal 10 4.3.3 Assess the Damage 13 4.3.4 Remove the Part if Necessary 13 4.3.5 Identify the Part Construction 14 4.3.6 Make Sure Facili
8、ties Are Satisfactory . 14 4.3.7 Make Sure Personnel Are Qualified . 14 4.3.8 Remove the Damage 15 4.3.9 Inspect the Part for Corrosion . 17 4.3.10 Confirm Damage is Removed - Select NDI Method . 19 4.3.11 Confirm Damage is Removed - Make Sure NDI Equipment is Acceptable 20 4.3.12 Confirm Damage is
9、Removed - Do the NDI Inspection 20 4.3.13 Select Applicable Repair Method 20 4.3.14 Assess Facilities 22 4.3.15 Procure Materials / Parts / Consumables . 25 4.3.16 Inspect the Materials / Parts . 28 4.3.17 Tooling Quality Check . 33 4.3.18 Schedule Repair Activity . 36 4.4 Repair Accomplishment 37 S
10、AE INTERNATIONAL AIR6291 Page 2 of 73 4.4.1 Repair Accomplishment General Steps 37 4.4.2 Prepare Surfaces for Bonding . 38 4.4.3 Bond-Tool Preparation 43 4.4.4 Bond line Check/Dry Fit Check . 43 4.4.5 Staging of Time and Temperature Sensitive (TATS) Materials 49 4.4.6 Lay Up of Repair . 50 4.4.7 Lay
11、up of Witness Coupons . 52 4.4.8 Bag and Cure of Repair 53 4.5 Post Repair Actions and Finishing Sequences . 55 4.5.1 Post Repair Actions and Finishing Sequences General Steps 55 4.5.2 Remove from Heat Source, Debag and Inspect . 55 4.5.3 NDI and Mechanical Testing . 57 4.5.4 Accomplish Finish Seque
12、nce to Bond Assembly . 58 4.5.5 Reassemble Subcomponent Details and Apply Finish to Assembly 59 4.5.6 Perform Dimensional and Fit Check . 60 4.5.7 Accomplish Weight and Balance Procedures . 60 4.5.8 Fire/Heat protection 60 4.5.9 Acoustic Procedures . 62 4.5.10 Identify Repair and Prepare Records . 6
13、2 5. NOTES 63 APPENDIX A REPAIR TOOLING DIMENSIONAL REPORT EXAMPLE . 64 APPENDIX B THERMAL AND PRESSURE REPORT EXAMPLE . 66 APPENDIX C STANDARD LEAK TEST EXAMPLE 69 APPENDIX D ALUMINUM WITNESS COUPON SUMMARY . 71 FIGURE 1 ROLE INDICATOR KEY FOR MAJOR FLOWCHART SECTIONS . 8 FIGURE 2 REPAIR PREPARATIO
14、N DECISION FLOW 8 FIGURE 3 PART REMOVAL DECISION FLOW. . 10 FIGURE 4 A THERMAL CAMERA IDENTIFIES HEAT ABSORPTION AND CONSEQUENT TEMPERATURE DIFFERENCES BETWEEN LARGE FITTINGS AND ADJACENT BONDED STRUCTURE. . 11 FIGURE 5 EXAMPLE OF A FITTING THAT IS ASSEMBLED TO A WEDGE ASSEMBLY AFTER THE WEDGE IS IN
15、ITIALLY FABRICATED. 12 FIGURE 6 EXAMPLE OF OVERHEATING DURING SKIN REMOVAL 16 FIGURE 7 EXAMPLE OF CORRODED CORE/WEAK BOND/GOOD BOND AREAS . 17 FIGURE 8 EXAMPLE OF CORRODED CORE/WEAK BOND/GOOD BOND AREAS . 18 FIGURE 9 EXAMINING PEELED SKIN AND RESIDUAL CORE FOR EVIDENCE OF CORROSION 19 FIGURE 10 FOAM
16、ING OF ADHESIVE DUE TO THE IMPROPER APPLICATION OF VACUUM PRESSURE. . 20 FIGURE 11 AUTOCLAVE PROCESSED TEST COUPON (LEFT) SHOWS IDEAL ADHESIVE BONDING CONDITION. VACUUM PROCESSED TEST COUPON (RIGHT) SHOWS FAILURES DUE TO FOAMING OF FILM ADHESIVE. 21 FIGURE 12 FACILITIES DETERMINATION PROCESS FLOW. .
17、 22 FIGURE 13 CATASTROPHIC FAILURE OF A FLIGHT CONTROL WEDGE ASSEMBLY THAT WAS REPAIRED USING ALTERNATE (AND INAPPROPRIATE) SURFACE PREPARATION PROCEDURES . 24 FIGURE 14 NON-PAA ALUMINUM HONEYCOMB CORE FOUND DISINTEGRATED AFTER LESS THAN 2 YEARS FLIGHT TIME 27 FIGURE 15 PARTS CHECK PROCESS FLOW. . 2
18、8 FIGURE 16 TOOLING CHECK PROCESS FLOW. . 33 FIGURE 17 EXAMPLE OF A THERMOCOUPLE DIAGRAM 34 FIGURE 18 USAGE OF PLACARDS TO KEEP TRACK OF INSPECTION INTERVALS IS A VISIBLE METHOD OF ENSURING COMPLIANCE TO INSPECTION REQUIREMENTS . 35 FIGURE 19 REPAIR SCHEDULING PROCESS FLOW. . 36 FIGURE 20 REPAIR IMP
19、LEMENTATION DECISION FLOW 37 FIGURE 21 PREPARE SURFACES FOR BONDING FLOW 38 FIGURE 22 FIT CHECK PROCESS FLOW . 44 FIGURE 23 EXAMPLE OF NON-UNIFORM CORE IMPRINT . 45 FIGURE 24 EXAMPLE OF A VERIFICATION FILM TEST CURED OUT AND CIRCLED THICKNESS INDICATIONS IN AREAS THAT APPEAR DARK WHEN EXPOSED TO A L
20、IGHT SOURCE . 46 FIGURE 25 TUNNEL VOIDS SHOWN AT THE INTERFACE BETWEEN A TOOL SIDE SKIN AND SPAR FLANGE FOR A WEDGE ASSEMBLY . 47 SAE INTERNATIONAL AIR6291 Page 3 of 73 FIGURE 26 DESTRUCTIVE ANALYSIS OF A FLAP VANE ASSEMBLY SHOWING THE CURED FILM ADHESIVE BETWEEN THE OUTER SKIN AND INTERNAL CORE AND
21、 DOUBLER . 48 FIGURE 27 CONTAMINATION CONTROL PROCESS FLOW . 50 FIGURE 28 TYPICAL BAGGING SCHEDULE FOR ALUMINUM BONDED REPAIRS 53 FIGURE 29 EXAMPLE OF A THERMOCOUPLE FAILURE DURING REPAIR CURE . 54 FIGURE 30 POST REPAIR ACTIONS AND FINISHING DECISION FLOW . 56 FIGURE 31 EXAMPLE OF CONTINUOUS ADHESIV
22、E FLASH ALONG A BOND LINE EDGE . 57 FIGURE 32 DETAIL OF AN AJ BEING USED TO CHECK FOR ALIGNMENT OF AN ATTACH FITTING FOR A FLIGHT CONTROL ASSEMBLY. . 61 SAE INTERNATIONAL AIR6291 Page 4 of 73 1. SCOPE This SAE Aerospace Information Report (AIR) is intended to be used as a process verification guide
23、for evaluating implementation of key factors in repair of metal bond parts or assemblies in a repair shop environment. This guide is to be used in conjunction with a regulatory approved and substantiated repair, and is intended to promote consistency and reliability. 1.1 Purpose This SAE Aerospace I
24、nformation Report (AIR) is intended to be used as a guide for regulatory and Customer personnel during the evaluation process of a substantiated repair submitted to the aforementioned parties by a repair station acting on behalf of a Customer to carry out a repair to aluminum bonded structure. This
25、AIR is also intended to be used as a supplement to AS7118 during an audit to evaluate repair station processes. This document may be used as a reference for a Customer to understand some key considerations that should be taken into account during the repair process. This document is intended for sho
26、p level repairs; however, all of the procedures given within this document can also be used to evaluate repairs accomplished on-wing. This document is NOT intended to be a design handbook for repair stations that wish to substantiate repairs that extend beyond the size limits of an OEM approved repa
27、ir manual, such as a CMM, SRM, AMM, etc. 2. APPLICABLE DOCUMENTS The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purcha
28、se order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1 SAE Publications Available fr
29、om SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. AIR4844 Composites and Metal Bonding Glossary ARP4916 Masking and Cleaning of Epoxy and Polyester Matrix Thermosetting Composite Materials AR
30、P5089 Composite Repair NDT/NDI Handbook ARP5143 Vacuum Bagging of Thermosetting Composite Repairs ARP5144 Heat Application for Thermosetting Resin Curing ARP5256 Mixing Resins, Adhesives and Potting Compounds AIR5431 Repair Tooling AS7118/2 Nadcap Requirements for Metal Bonding AS7118/3 Nadcap Requi
31、rements for Core Processing AMS-STD-401 Sandwich Constructions and Core Materials; General Test Methods Armstrong, K.B., Cole, W., and Bevan, G., “Care and Repair of Advanced Composites, Second Edition,“ Society of Automotive Engineers, Inc., Warrendale, PA, ISBN 978-0-7680-1062-6, 2005, doi:10.4271
32、/R-336. SAE INTERNATIONAL AIR6291 Page 5 of 73 2.2 Other References AC 43-214 Repairs and Alterations to Composite and Bonded Aircraft Structure ASTM C297 Standard Test Method for Flatwise Tensile Strength of Sandwich Constructions ASTM D1002 Standard Test Method for Apparent Shear Strength of Singl
33、e Lap Joint Adhesively Bonded Metal Specimens by Tension Loading (Metal to Metal) ASTM D1781 Standard Test Method for Climbing Drum Peel for Adhesives ASTM D3167 Standard Test Method for Floating Roller Peel Resistance of Adhesives ASTM D3762 Standard Test Method for Adhesive-Bonded Surface Durabili
34、ty of Aluminum (Wedge Test) ASTM D3933 Standard Guide for Preparation of Aluminum Surfaces for Structural Adhesives Bonding (Phosphoric Acid Anodizing) MIL-C-7438 Core Material, Aluminum, for Sandwich Construction SAMPE Volume 47, Bk 1 Factors Influencing Durability of Sol-Gel Surface Treatments in
35、Metal Bonded Structures Boeing Commercial Airplanes,Renton, WA , Metal Bond Repairs: The Impact of Vacuum Level, Adhesive Type, and Repair Size (L. Cadwell Stancin and P. J. Van Voast) 3. DEFINITIONS Refer to AIR4844 for a more complete composite and metal bonding glossary. New terms that appear in
36、this document are defined, below: AJ: Assembly Jig. When assembling fittings, leading edge skins, latches, or any other part that requires alignment to a theoretical datum, such as a hinge axis or a contour line, an AJ may be necessary equipment during accomplishment of a repair. AMM: Aircraft Maint
37、enance Manual. Sometimes referred to as “MM” or “OEM MM”. ASM: Assembly Mandrel. It is sometimes necessary to use a light weight tool that is neither dimensionally controlled nor dimension tolerance critical. An ASM is any intermediate tool used during original manufacture or during repair to struct
38、ure that does not have critical effect on the integrity of the final assembly or any of its subcomponent details. BAJ: Bonded Assembly Jig. During high pressure and temperature cycles (autoclave or vacuum assisted oven cure), on original production or during repairs to metal bond structure, BAJs are
39、 necessary to define and/or maintain appropriate contour of the part being manufactured or repaired. CAA: Chromic Acid Anodize. CCA: Controlled Contamination Area. An area that ensures levels of dirt, dust, oils, lubricants, and other containments are controlled for acceptable structural bonding. CM
40、M: Component Maintenance Manual. Sometimes referred to as “MM” or “OEM MM”. CUSTOMER: The Customer may be an owner or an operator of the airplane, or the Customer may be a holder of a spare component. When the component is being repaired at an outside maintenance facility, the Customer is responsibl
41、e for regulatory oversight of the repair station. A repair station must have a regulatory approved certificate. Repairs are approved and coordinated with the OEM or submitted to the regulatory agency whenever repairs are accomplished outside of an OEM provided repair documentation (i.e., CMM, SRM or
42、 AMM). SAE INTERNATIONAL AIR6291 Page 6 of 73 ENGINEERING: Organizations or individuals responsible for providing part-specific repair documentation, and all other supporting documentation such as material and process specification, tool design, inspection criteria, etc. Engineering departments at a
43、irlines also have the responsibility to determine acceptability of repair documents and of repaired parts to ensure there is no conflict with the airlines maintenance program, configuration, reliability program, and interactions with systems. Engineering is responsible to coordinate with OEM, Regula
44、tory Authorities, or other experts when repairs are outside their area of expertise and/or previous experience. Engineering has the responsibility to make sure that the repair as correctly implemented satisfies all regulations for airworthiness. FAI: First Article Inspection. The first time a repair
45、 part is fabricated by a particular supplier, an FAI should determine if the product meets acceptance requirements and quality control requirements. Key characteristics should be identified, in advance, by Engineering, prior to accomplishing an FAI. FCS: Fatigue Critical Structure. Airplane structur
46、e that is susceptible to fatigue cracking, which could contribute to a catastrophic failure. Also includes both FCBS (Fatigue Critical Baseline Structure) as defined by the OEM and FCAS (Fatigue Critical Altered Structure) as defined by the operator. MM: AMM or CMM NDI: Non-Destructive Inspection ND
47、T: Non-Destructive Testing NHA: Next Higher Assembly NTM: Non-Destructive Testing Manual OEM: Original Equipment Manufacture OML: Outer Mold Line PAA: Phosphoric Acid Anodize PSA: Phosphoric Sulfuric Acid Anodize PSE: Principal Structural Element. An element that contributes significantly to the car
48、rying of flight, ground, or pressurization loads, and whose integrity is essential in maintaining the overall integrity of the airplane. PSE structures are defined as such by the OEM. QUALITY: Organizations or individuals responsible for either Quality Assurance (QA) and/or Quality Control (QC) func
49、tions. QA functions typically make sure systems and procedures are in place to ensure all organizations perform as required by documents and policies. QA functions are responsible for making sure documents are up to date, repair technicians are current on training, and equipment is calibrated. QA functions are also responsible for identifying any corrective action that may be required if a defect is identified during a repair. QC functions a
