ImageVerifierCode 换一换
格式:PDF , 页数:195 ,大小:8.54MB ,
资源ID:427879      下载积分:10000 积分
快捷下载
登录下载
邮箱/手机:
温馨提示:
快捷下载时,用户名和密码都是您填写的邮箱或者手机号,方便查询和重复下载(系统自动生成)。 如填写123,账号就是123,密码也是123。
特别说明:
请自助下载,系统不会自动发送文件的哦; 如果您已付费,想二次下载,请登录后访问:我的下载记录
支付方式: 支付宝扫码支付 微信扫码支付   
验证码:   换一换

加入VIP,免费下载
 

温馨提示:由于个人手机设置不同,如果发现不能下载,请复制以下地址【http://www.mydoc123.com/d-427879.html】到电脑端继续下载(重复下载不扣费)。

已注册用户请登录:
账号:
密码:
验证码:   换一换
  忘记密码?
三方登录: 微信登录  

下载须知

1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。
2: 试题试卷类文档,如果标题没有明确说明有答案则都视为没有答案,请知晓。
3: 文件的所有权益归上传用户所有。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 本站仅提供交流平台,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

版权提示 | 免责声明

本文(AIR FORCE MIL-HDBK-349-1994 MANUFACTURE AND INSPECTION OF ADHESIVE BONDED ALUMINUM HONEYCOMB SANDWICH ASSEMBLIES FOR AIRCRAFT《飞机铝蜂窝夹层结构粘合剂粘结制造及检验》.pdf)为本站会员(brainfellow396)主动上传,麦多课文库仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知麦多课文库(发送邮件至master@mydoc123.com或直接QQ联系客服),我们立即给予删除!

AIR FORCE MIL-HDBK-349-1994 MANUFACTURE AND INSPECTION OF ADHESIVE BONDED ALUMINUM HONEYCOMB SANDWICH ASSEMBLIES FOR AIRCRAFT《飞机铝蜂窝夹层结构粘合剂粘结制造及检验》.pdf

1、1 INCH POUND 1 MIL-HDBK-349 30 September 1994 MILITARY STANDARDIZATION HANDBOOK MANUFACTURE AND INSPECTION OF ADHESIVE BONDED, ALUMINUM HONEYCOMB SANDWICH ASSEMBLIES FOR AIRCRAFT This military handbook is approved for use by all Departments and Agencies of the Department of Defense. Beneficial comme

2、nts (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to SA-ALCPIILDD, Kelly AFB, TX 78241-5000, by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this docum

3、ent or by letter. AMSC: NIA FSC: 1560 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-349 m 9999970 OL9507L 258 MIL-HDBK-349 Table of Contents Paragraph Page 1

4、.0 GENERAL INFORMATION . 1-1 1.1 Introduction . 1-1 1.2 Purpose . 1-2 1.3 Scope 1-2 1.4 Use of Handbook and Limitations 1-2 1.5 Approval Procedures . 1-3 2.0 APPLICABLE DOCUMENTS 2-1 2.1 Government Documents 2-1 2.1 . 1 . 1 Specifications 2-1 2.1.1 Specifications and Standards 2-1 2.1.1.2 Standards

5、. 2-1 2.1.1.3 Handbook 2-2 2.2 Non-Government Publications . 2-2 2.3 Order of Precedence 2-3 3.0 DEFINITIONS OF TERMS AND ACRONYMS . 3-1 4.0 GENERAL REQUIREMENTS 4-1 4.1 Introduction . 4-1 4.1.1 Sandwich Construction 4-1 4.1.2 Materials Selection and Fabrication . 4-2 4.2 Face Skins . 4-3 4.2.1 Func

6、tion and General Description 4-3 4.2.2 Aluminum Face Skin 4-4 4.2.3 Fiberglass Face Skin 4-4 4.3 Sandwich Cores (Aluminum) . 4-4 4.3.1 Function and General Description 4-4 4.3.2 Types of Core . 4-4 4.3.2.1 Hexagonal 4-4 4.3.2.2 Corrugated or Over-Expanded . 4-4 4.3.2.3 Waffle-Type . 4-5 ii Provided

7、by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. Paragraph 4.4 4.4.1 4.4.1.1 4.4.1.2 4.4.1.3 4.4.1.4 4.4.1.5 4.4.1.6 4.4.2 4.4.2.1 4.4.2.2 4.4.3 4.4.3.1 4.4.3.2 4.4.3.3 4.4.4 4.4.4.1 4.4.4.2 4.4.5 4.5 4.5.1 4.5.2 4.5.3 4.5.4 4.6 4.6.1 4.6.1.1 4.6.1.2 4.6.1.3

8、 4.6.2 4.6.2.1 4.6.2.1.1 4.6.2.1.2 4.6.2.1.3 4.6.2.1.4 4.6.2.1 . 5 4.6.2.1.6 4.6.2.1.7 4.6.2.2 4.6.2.2.1 4.6.2.2.2 MIL-HDBK-349 Table of Contents Page Adhesives 4-6 Function and General Description 4-6 Products Given Off During Curing 4-6 Bonding Pressure 4-7 Fillet Forming 4-7 Adaptability . 4-7 Bo

9、nd Line Control . 4-7 Toughness 4-7 Phenolic . 4-8 Neoprene Elastomer-Phenolic . 4-8 Nitrile Elastomer-Phenolic . 4-8 EPOXY 4-8 Epoxies Modified with Nylon or Other Polyamide Polymers 4-8 Nitrile Modified Epoxies 4-9 Phenolic-Epoxy . 4-9 Other Organic Systems 4-9 Urethanes . 4-9 Other Polyimides, Th

10、ermoplastics, and Highly Specialized Adhesives . 4-9 Adhesive Primers 4-10 Auxiliary Manufacturing Materials 4-10 Solvents 4-10 Sealants/Aerodynamic Smoothers . 4-10 Bagging Materials 4-10 Potting Compounds . 4-10 General Requirements . 4-10 Personnel . 4-10 Skill Level 4-10 Classification/Certifica

11、tion . 4-11 Tool Qualification . 4-11 Manufacturing Facilities and Equipment . 4-11 Storage and Handling 4-11 Raw Materials . 4-11 Adhesives, Potting Compounds, Sealants, and Paints 4-11 Aluminum Honeycomb Core . 4-12 Consumables 4-13 Detail Parts and Skins 4-13 Subassemblies . 4-13 Finished Assembl

12、ies . 4-13 Lay-Up Room 4-14 Controlled Areas . 4-15 Equipment . 4-15 iii Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-349 Table of Contents Paragraph 4.6.2.2.3 4.6.2.2.4 4.6.2.2.5 4.6.2.3 4.6.2.3.1 4.6.2.3.2 4.6.2.3.2.1 4.6.2.3.2.2 4.6.2.

13、3.2.3 4.6.2.3.2.4 4.6.2.4 4.6.2.4.1 4.6.2.4.2 4.6.2.4.3 4.6.2.5 4.6.2.6 4.6.2.6.1 4.6.2.6.2 4.6.2.6.3 4.6.2.6.4 4.6.2.6.4.1 4.6.2.6.4.2 4.6.2.6.5 4.6.2.6.5.1 4.6.2.6.5.2 4.6.2.6.6 4.6.2.6.7 4.6.2.6.8 4.6.2.7 4.6.2.8 4.6.2.9 4.6.2.9.1 4.6.2.9.2 4.6.2.9.3 4.6.2.9.4 4.6.2.9.5 4.6.2.9.6 4.6.2.9.7 4.6.2.

14、9.8 4.6.2.9.9 4.6.2.1 O Page Operating Conditions 4-16 Maintenance . 4-17 Personnel . 4-17 Surface Treatment Facilities and Related Equipment . 4-17 Nonbondable Surfaces 4-17 Bondable Surfaces 4-17 Aluminum (Except Core) 4-17 Stainless Steel 4-19 Titanium . 4-19 Aluminum Honeycomb Core 4-19 Adhesive

15、 Primer Application Facilities and Equipment 4-19 Adhesive Receiving Acceptance Tests . 4-19 Equipment Requirements 4-20 Primer Application Area . 4-20 DryingKuring Ovens 4-20 Core ManufacturingAWachining Equipment . 4-21 Core Manufacturing . 4-21 Sawing 4-22 Expanding 4-23 Rigidizing . 4-23 Using P

16、olyethylene Glycol . 4-23 Ice Chucking . 4-24 Honeycomb Core Carving (Machining) . 4-24 Equipment 4-24 Facilities . 4-25 Splicing 4-25 Stabilizing (Stiffening. Rigidifying) . 4-26 Potting 4-26 Autoclaves 4-26 Platen and Cavity Presses . 4-27 Bonding Fixtures 4-28 Tooling Requirements 4-28 Metal Tool

17、 Fabrication . 4-28 General Requirements 4-28 General Design Criteria . 4-29 Removable Tool Components 4-32 Fairing Bars . 4-32 Pressure Bars and Mandrels . 4-33 Vacuum Blanket Support Details 4-34 Handling Provisions . 4-35 Prefit Fixtures 4-35 . iv Provided by IHSNot for ResaleNo reproduction or n

18、etworking permitted without license from IHS-,-,- MIL-HDBK-349 m 9999970 0195034 Tb7 MIL-HDBK-349 Table of Contents Paragraph Page 4.6.2.11 4.6.2.1 2 4.6.2.12.1 4.6.2.12.2 4.6.2.12.3 4.6.2.12.3.1 4.6.2.12.3.2 4.6.2.12.3.3 4.6.2.12.3.4 4.6.2.12.3.5 4.6.2.1 2.4 4.6.2.12.5 4.6.2.13 4.6.2.14 4.6.3 4.6.3

19、.1 4.6.3.2 4.6.4 4.6.4.1 4.6.4.2 4.6.4.3 4.6.5 4.6.5.1 4.6.5.1.1 4.6.5.1.2 4.6.5.1.3 4.6.5.2 4.6.5.3 4.6.5.4 4.6.5.5 Equipment for Material Acceptance. Process Control and Destructive Testing . 4-35 Nondestructive Inspection Equipment . 4-37 Visual . 4-37 Tapping 4-37 Ultrasonic 4-39 Low Frequency 4

20、-40 Resonance 4-47 Acoustics Holography 4-47 Acoustic Emission 4-47 Radiography . 4-48 Optical Holography . 4-48 Environment Measuring and Recording Devices 4-48 Leak Test Equipment . 4-48 HighFrequency . 4-39 Supplier Requirements . 4-49 Approval of Materials and Processing Procedures . 4-49 Depart

21、ures From the Standard Procedure . 4-49 Traceability of Material 4-49 Identification of Assemblies 4-49 Required Documentation 4-49 Record Keeping . 4-49 Safety Considerations . 4-49 Special Notes Concerning the Use of Solvents . 4-49 Health Hazards 4-49 Personal Exposure 4-50 Fire Hazards . 4-50 Ad

22、hesives, Potting Compounds, Sealants 4-51 Autoclaves, Platen Presses, Cavity Presses . 4-51 Disposal of Hazardous/Toxic Waste . 4-51 Nonsolvent Surface Preparation Materials or Solutions 4-51 5.0 DETAILED REQUIREMENTS 5-1 5.1 Introduction 5-1 5.1.1 Process Flow Chart 5-1 5.2 Fabrication Operations 5

23、-1 5.2.1 Aluminum Honeycomb Core . 5-1 5.2.1.1 Sawing 5-1 5.2.1.1.1 Unexpanded Aluminum Core Block 5-5 5.2.1.1.2 Core Slice 5-5 5.2.1.2 Expanding 5-7 V Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Paragraph 5.2.1.3 5.2.1.3.1 5.2.1.3.2 5.2.1.3.3 5.

24、2.1.3.4 5.2.1.4 5.2.1.4.1 5.2.1.4.2 5.2.1.5 5.2.1.6 5.2.1.7 5.2.1.8 5.2.2 5.3 5.3.1 5.3.2 5.4 5.4.1 5.4.1.1 5.4.1.2 5.4.2 5.4.2.1 5.4.2.2 5.4.3 5.4.3.1 5.4.3.2 5.4.3.3 5.4.4 5.4.4.1 5.4.4.1.1 5.4.4.2 5.4.4.2.1 5.4.4.3 5.4.5 5.5 5.5.1 5.5.2 5.5.3 MIL-HDBK-349 9999970 0395075 9T3 m MIL-HDBK-349 Table

25、of Contents Page Rigidizing/Stiffening/Rigidifying/Stabilizing . 5-8 Rigidizing Core for Machining . 5-8 Stiffening 5-8 Rigidifying Local Areas 5-8 Stabilizing Crushed Core Areas . 5-10 Milling . 5-10 Unexpanded Core Block . 5-12 Cutting . 5-12 Potting . 5-12 Splicing 5-14 Aluminum Alloy Skins and D

26、etail Parts . 5-17 Expanded Core 5-12 Sanding 5-14 Prefit . 5-17 Mechanical 5-18 Impression (Overlay) 5-20 Surface Preparation . 5-20 Bond Fixtures 5-20 Application of Mold Release . 5-20 Removal of Adhesive Flash . 5-21 Single-multiple-Stage Bonding 5-21 Single-Stage Bonding . 5-21 Multiple-Stage B

27、onding 5-21 Aluminum Honeycomb Core 5-22 Removal of Polyethylene Glycol Rigidizing Materials . 5-22 Vapor Degreasing (With Perchloroethylene) 5-22 Removal of Oil Contamination . 5-23 Details . 5-23 Vapor Degreasing . 5-24 Spray Cleaning Procedure 5-25 Anodizing . 5-25 Phosphoric Acid Anodizing . 5-2

28、6 Precured Glass-Reinforced Plastic Details 5-27 Process Control Coupons (Panels/Specimens) 5-27 Aluminum Alloy Skins and Detail Parts and Precured Glass Reinforced Plastic Priming and Adhesive Application . 5-28 Application of Primer 5-29 Application of Film Adhesives . 5-30 Application of Foam Adh

29、esives . 5-31 Vi Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- MIL-HDBK-349 W 9999770 0395076 83T m MIL-HDBK-349 Table of Contents Paragraph Page 5.6 5.6.1 5.6.2 5.6.2.1 5.6.2.2 5.6.3 5.6.3.1 5.6.3.2 5.6.3.3 5.6.4 5.6.5 5.6.6 5.6.7 5.6.7.1 5.6.7.2

30、 5.7 5.7.1 5.7.1.1 5.7.1.1.1 5.7.1.1.2 5.7.1.1.3 5.7.1.1.4 5.7.2 5.7.3 5.7.4 5.7.5 5.7.6 5.7.7 5.8 5.8.1 5.8.2 5.8.2.1 5.8.2.2 5.8.2.3 5.8.2.4 5.8.2.4.1 5.8.2.4.2 5.8.2.4.2.1 5.8.2.4.2.2 5.8.3 5.8.3.1 5.8.3.2 5.8.3.2.1 Assembly and Curing 5-32 Lay-Up 5-32 Vacuum Bagging (When Curing in an Autoclave)

31、 . 5-35 Bagging with a Rubber Blanket . 5-37 Ragging Multiple Fixtures 5-38 Curing 5-38 Curing in an Autoclave 5-38 Curing in a Platen Press . 5-39 Curing in a Cavity Press . 5-40 Secondary Bonding 5-40 Post Bond Cleaning . 5-41 Visual and Dimensional Inspection 5-41 Rework 5-41 Part Trimming . 5-42

32、 Replacement of Fasteners and Missing Sealant . 5-42 Final Processing . 5-42 Sealant/Aerodynamic Smoother Application . 5-42 Application Procedures for Specific Types of Sealing or Smoothing . 5-44 Faying Surface Sealing 5-44 Butt Joint Sealing . 5-44 Fillet Sealing . 5-44 Aerodynamic Smoother Appli

33、cation . 5-44 Leak Testing . 5-44 Nondestructive Testing . 5-44 Corrosion Protection 5-45 Identification . 5-45 Packaging . 5-45 Disposition of Defective and/or Damaged Parts . 5-45 Quality Assurance 5-46 Quality Assurance Plan and Administration . 5-46 Quality Assurance . 5-46 Administration . 5-46

34、 Defect and Damage Assessment . 5-47 Honeycomb Core . 5-47 Assemblies . 5-50 External Damage to Assemblies . 5-50 Internal Damage to Assemblies . 5-51 Mechanical Testing 5-52 Mechanical Test Types 5-52 Lap Shear Strength 5-54 Specimens From Test Panels . 5-54 Introduction 5-46 Receiving Inspection a

35、nd Acceptance 5-47 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-flIL-HDBK-3LI9 m 9999970 0395077 776 9 MIL-HDBK-349 Table of Contents Paragraph Page 5.8.3.2.2 5.8.3.2.3 5.8.3.2.4 5.8.3.2.5 5.8.3.3 5.8.3.3.1 5.8.3.3.2 5.8.3.3.3 5.8.3.3.4 5.8.3.4 5.

36、8.3.4.1 5.8.3.4.2 5.8.3.4.3 5.8.3.5 5.8.3.5.1 5.8.3.5.2 5.8.3.5.3 5.8.3.6 5.8.3.6.1 5.8.3.6.2 5.8.3.7 5.8.3.7.1 5.8.4 5.8.4.1 5.8.4.2 5.8.4.2.1 5.8.4.2.2 5.8.4.2.3 5.8.4.3 5.8.4.3.1 5.8.4.3.2 5.8.4.3.3 5.8.4.3.3.1 5.8.4.3.3.2 5.8.4.3.3.3 5.8.4.3.3.4 5.8.4.3.3.5 5.8.4.3.3.6 5.8.4.3.3.7 5.8.4.3.3.8 5.

37、8.4.3.4 5.8.4.3.4.1 5.8.4.3.4.2 5.8.4.3.4.3 5.8.4.3.4.4 Specimens From Assemblies 5-54 Specimen Alignment . 5-54 Test Temperature . 5-54 Test Procedure 5-56 Wedge Crack . 5-56 Test Panel Preparation 5-58 Specimens from Test Panels 5-58 Interpretation of Results . 5-58 T-Peel (for Metal-to-Metal) . 5

38、-58 Test Procedure 5-58 . Test Panel Preparation 5-59 Specimens from Test Panels 5-59 T-Peel Test Procedure 5-59 Honeycomb Climbing Drum Peel 5-59 Test Panel Preparation 5-59 Specimens from Assemblies . 5-60 Test Procedure 5-60 Honeycomb Flatwise Tensile Strength . 5-61 Test Specimens 5-61 Test Proc

39、edure 5-62 Beam Shear Strength 5-62 Test Specimen Preparation . 5-62 Nondestructive Inspection 5-62 Selection of ND1 Techniques 5-63 Manufacturing Inspection 5-63 Post-Repair Inspection 5-66 Inspection Standards . 5-67 Visual Inspection of Assemblies 5-68 Tapping 5-70 Ultrasonic . 5-71 Through-Trans

40、mission 5-71 Pulse Echo 5-71 Noncontact Methods . 5-72 HighFrequency . 5-72 Low Frequency 5-72 Resonance Type Instruments 5-73 Acoustic Holography . 5-74 Acoustic Emission 5-74 Radiography . 5-75 X-Ray and Gamma Radiography 5-75 Low Voltage Radiography (25-50 kv) . 5-81 Radiation Sources 5-85 Radiat

41、ion Beam Geometry 5-85 Detection of Manufacturing and Fabrication-Induced Defects 5-63 Nondestructive Inspection of Core, Skins and Detail Parts 5-68 viii Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-349 m 9999970 0195078 bo2 m MIL-HDBK-3

42、49 Table of Contents Paragraph Page 5.8.4.3.4.5 5.8.4.3.4.6 5.8.4.3.4.7 5.8.4.3.4.8 5.8.4.3.4.9 5.8.4.3.4.10 5.8.4.3.5 5.8.4.3.6 5.8.4.3.7 5.8.4.3.8 5.8.4.3.9 5.8.4.4 5.8.4.5 5.8.4.5.1 5.8.4.5.2 5.8.4.5.3 5.8.4.5.4 5.8.4.6 5.8.4.6.1 5.8.4.6.2 5.8.4.6.2.1 5.8.4.6.2.2 5.8.4.6.3 5.8.4.6.3.1 Radiographi

43、c Equivalence Factors Relative to Aluminum 5-85 Film and Film Processing . 5-85 Penetrameters 5-86 Screens. Backing. and Masking 5-87 X-Ray Potential . 5-87 Viewing Facilities and Illuminators 5-87 Image Processing and Other Enhancement Methods . 5-88 Leak Test 5-89 Optical Holography . 5-90 Eddy Cu

44、rrent 5-90 Dielectric Measurements 5-91 ND1 Set-up and Calibration Methods . 5-91 ND1 Procedures . 5-95 Radiographic ND1 5-95 Ultrasonic ND1 . 5-95 Tapping . 5-95 Rejection . 5-95 ND1 Personnel Qualification and Certification 5-95 Government and Air Force Standards . 5-96 Industry Standards . 5-96 A

45、STM E94-Standard Guide for Radiographic Testing 5-96 American Society for Nondestructive Testing SNT-TC-1 A . 5-97 Company Standards . 5-97 (Ref 16) . 5-97 The McDonnell Douglas Corporation, Process Specification 21 240 6.0NOTES 6-1 6.1 Intended Use . 6-1 6.2 Subject Terms (Keywords) Listing . 6-1 R

46、EFERENCE R-1 INDEX 1-1 ix Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Figure MIL-HDBK-3Y9 m 9999970 0195079 5Y7 m MIL-HDBK-349 FIGURE 3(a) FIGURE 3(b) FIGURE 3(c) FIGURE 3(d) FIGURE 3(e) FIGURE 3(9 FIGURE 3(g) FIGURE 3(h) FIGURE 3(i) FIGURE 3(j)

47、FIGURE 3(k) FIGURE 3(1) FIGURE 3(m) FIGURE 4.1. I (a) FIGURE 4.1.1 (b) FIGURE 4.3.2.1 FIGURE 4.3.2.2(a) FIGURE 4.3.2.2(b) FIGURE 4.3.2.3 FIGURE 4.6.2.2 FIGURE 4.6.2.3.2 FIGURE 4.6.2.4.3 FIGURE 4.6.2.5 FIGURE 4.6.2.6.3 FIGURE 4.6.2.7 FIGURE 4.6.2.9.2(a) FIGURE 4.6.2.9.2(b) FIGURE 4.6.2.9.2(c) FIGURE

48、4.6.2.9.2(6) FIGURE 4.6.2.9.6(a) FIGURE 4.6.2.9.6(b) FIGURE 4.6.2.9.7 FIGURE 4.6.2.9.8 FIGURE 4.6.2.9.9(a) FIGURE 4.6.2.9.9(b) FIGURE 4.6.2.9.9(c) FIGURE 4.6.2.12.2 FIGURE 4.6.2.12.3.1 (a) FIGURE 4.6.2.12.3.1 (b) List of Figures Page Blown core 3-2 Buckled core . 3-3 Honeycomb core designations 3-4

49、Compressed core for contoured part . 3-4 Condensed core 3-5 Crushed core . 3-6 Double foil 3-7 Mismatched nodes . 3-10 Nested cells . 3-11 Node separation . 3-12 Ruptured core 3-14 Shifted core . 3-15 Core splice . 3-16 The elements of a honeycomb sandwich structure are as follows: (1) two rigid. thin. high strength facings; (2) one thick. low density core; and (3) on adhesive attachment which fo

copyright@ 2008-2019 麦多课文库(www.mydoc123.com)网站版权所有
备案/许可证编号:苏ICP备17064731号-1