1、AECMA STANDARD NORME AECMA AECMA NORM prEN 4533-001 Edition P 1 April 2005 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES - STANDARDIZATION Gulledelle 94 - B-1200 Brussels - Tel. + 32 2 775 8110 - Fax. + 32 2 775 8111 - www.aecma-stan.orgICS: 49.060 Descriptors: ENGLISH VERSION Aerosp
2、ace series Fibre optic systems Handbook Part 001: Termination methods and tools Srie arospatiale Systmes des fibres optiques Manuel dutilisation Partie 001 : Mthodes des terminations et des outils Luft- und Raumfahrt Faseroptische Systemtechnik Handbuch Teil 001: Verarbeitungsmethoden und Werkzeuge
3、This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECMA-STAN (The European Association of Aerospace Industries - Standardization). It is published for the needs of the European Aerospace Industry. It has been technically approved by the experts of the concerned Domain
4、 following member comments. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physically or functionally, without re-identification of the standard. After examination and review by users and formal agreemen
5、t of AECMA-STAN, it will be submitted as a draft European Standard (prEN) to CEN (European Committee for Standardization) for formal vote and transformation to full European Standard (EN). The CEN national members have then to implement the EN at national level by giving the EN the status of a natio
6、nal standard and by withdrawing any national standards conflicting with the EN. Edition approved for publication 30 April 2005 Comments should be sent within six months after the date of publication to AECMA-STAN Electrical Domain Copyright 2005 by AECMA-STAN Copyright Association Europeene des Cons
7、tructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Page 2 prEN 4533-001:2005Foreword This standard was reviewed by the Domain Technical Coordinator of AECMA-STANs Electrical Domain. After inquir
8、ies and votes carried out in accordance with the rules of AECMA-STAN defined in AECMA-STANs General Process Manual, this standard has received approval for Publication. Contents Page Foreword 3 1 Scope 4 1.1 General 4 1.2 Need for high integrity terminations. 4 2 Normative references. 4 3 Component
9、selection . 5 3.1 Elements . 5 3.2 Fibre optic cables. 5 3.3 Primary coating materials. 6 3.4 Aramid yarn versus fibreglass strength member 7 3.5 Fibre optic connectors 7 4 Health and safety aspects. 11 4.1 General 11 4.2 Chemicals 11 4.3 “Sharps” 11 5 Termination process . 12 5.1 Objective. 12 5.2
10、Cable preparation. 12 5.3 Removal of secondary coating(s) 16 5.4 Removal of primary coating . 17 5.5 Adhesives 26 5.6 Connector preparation 31 5.7 Sleeves, boots and backshells 32 5.8 Attachment of fibre to connector 32 5.9 Adhesive cure. 34 5.10 Excess fibre removal 36 5.11 Polishing. 39 5.12 Inspe
11、ction 50 Bibliography. 52 Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Page 3 prEN 4533-001:2005Foreword a) The handbook This handbook draws on the
12、work of the Fibre Optic Harness Study, part sponsored by the United Kingdoms Department of Trade and Industry, plus other relevant sources. It aims to provide general guidance for experts and non-experts alike in the area of designing, installing, and supporting multi-mode fibre-optic systems on air
13、craft. Where appropriate more detailed sources of information are referenced throughout the text. It is arranged in 4 parts, which reflect key aspects of an optical harness life cycle, namely: Part 001: Termination methods and tools Part 002: Test and measurement Part 003: Looming and installation p
14、ractices Part 004: Repair, maintenance and inspection b) Background It is widely accepted in the aerospace industry that photonic technology offers a number of significant advantages over conventional electrical hardware. These include massive signal bandwidth capacity, electrical safety, and immuni
15、ty of passive fibre-optic components to the problems associated with electromagnetic interference (EMI). To date, the latter has been the critical driver for airborne fibre-optic communications systems because of the growing use of non-metallic aerostructures. However, future avionic requirements ar
16、e driving bandwidth specifications from 10s of Mbits/s into the multi-Gbits/s regime in some cases, i.e. beyond the limits of electrical interconnect technology. The properties of photonic technology can potentially be exploited to advantage in many avionic applications, such as video/sensor multipl
17、exing, flight control signalling, electronic warfare, and entertainment systems, as well as in sensing many of the physical phenomena on-board aircraft. The basic optical interconnect fabric or optical harness is the key enabler for the successful introduction of optical technology onto commercial a
18、nd military aircraft. Compared to the mature telecommunications applications, an aircraft fibre-optic system needs to operate in a hostile environment (e.g. temperature extremes, humidity, vibrations, and contamination) and accommodate additional physical restrictions imposed by the airframe (e.g. h
19、arness attachments, tight bend radii requirements, and bulkhead connections). Until recently, optical harnessing technology and associated practices were insufficiently developed to be applied without large safety margins. In addition, the international standards did not adequately cover many aspect
20、s of the life cycle. The lack of accepted standards thus lead to airframe specific hardware and support. These factors collectively carried a significant cost penalty (procurement and through-life costs), that often made an optical harness less competitive than an electrical equivalent. c) The fibre
21、-optic harness study The Fibre-Optic Harness Study concentrated on developing techniques, guidelines, and standards associated with the through-life support of current generation fibre-optic harnesses applied in civil and military airframes (fixed and rotary wing). Some aspects of optical system des
22、ign were also investigated. This programme has been largely successful. Guidelines and standards based primarily on harness study work are beginning to emerge through a number of standards bodies. Because of the aspects covered in the handbook, European prime contractors are in a much better positio
23、n to utilise and support available fibre optic technology. Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Page 4 prEN 4533-001:20051 Scope 1.1 General
24、 This Part of EN 4533 examines the termination aspects of fibre optic design for avionic installations. By termination is meant the mechanism used to interface from one component (usually a fibre) to another. This is normally performed by a connector, which aligns the fibre with another component (u
25、sually another connector) to a sufficient accuracy to allow continued transmission of an optical signal throughout the operational envelope. This Part will explain the need for high integrity terminations, provide an insight into component selection issues and suggests best practice when terminating
26、 fibres into connectors for high integrity applications. A detailed review of the termination process can be found in clause 4 of this part and is organised broadly in line with the sequence of a typical termination procedure. The vast number of cable constructions and connectors available make defi
27、ning a single termination instruction that is applicable to all combinations almost impossible. Because of the problems of defining a generic termination instruction, this handbook has concentrated on defining best practice for current to near future applications of fibre optics on aircraft. This ha
28、s limited the studies within this part to currently available avionic silica fibre cables and adhesive filled butt-coupled type connectors. Many of the principles described however would still be applicable for other termination techniques. Other types of termination are considered further in the re
29、pair part of this handbook. 1.2 Need for high integrity terminations In order to implement a fibre optic based system on an aircraft it is vital to ensure that the constituent elements of the system will continue to operate, to specification, over the life of the system. An important aspect of this
30、requirement is the need for reliable interconnection components. This is often expressed as the need for reliable connectors, but in reality it is the need for a reliable cable to connector termination process. The essence of this requirement is the need to assure reliable light transmission through
31、 each optical connector throughout the operational envelope. This needs to be achieved through a robust process that enables a high level of optical performance over the lifetime of the terminations. Many factors can contribute to an optical connectors in-service performance, such as basic connector
32、 design, choice of optical fibre, cable, operating and maintenance environment etc. However, one of the main factors governing in-service connector performance is the quality of the cable to connector termination. 2 Normative references The following referenced documents are indispensable for the ap
33、plication of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 4533-002, Aerospace series Fibre optic systems Handbook Part 002: Test and measurement. 1) 1) Published as AE
34、CMA Prestandard at the date of publication of this standard. Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Page 5 prEN 4533-001:20053 Component selec
35、tion 3.1 Elements It is important to recognize that a fibre optic termination, while appearing straightforward, is in fact a complex interaction of the constituent elements such as: fibre coatings, connector design, cable strength member anchorage method, adhesive type and cure regime (where used),
36、material properties and so on. Each of these elements will have an impact on the termination, in terms of reliability, integrity and process complexity. 3.2 Fibre optic cables 3.2.1 General One of the main aspects to be addressed is the implication of choosing one cable construction over another. Th
37、ere are various types of fibre optic cable on the market ranging from loose tube to tight jacket construction, containing a single fibre or an array of many fibres; however, at the time of publication of this handbook the range of options available to aerospace users is somewhat limited. Most of the
38、 possible cable types are only suitable for telecommunication applications due to environmental capability limitations, with avionic solutions being generally limited to single fibre, tight jacket constructions. 3.2.2 Cable construction Although the design of fibre optic cable for use on aircraft is
39、 fairly similar from one manufacturer to another there are important differences between cables. The two main areas of difference are fibre coatings and cable strength member materials. Each has its own positive and negative attributes in the context of termination procedures. Avionic fibre optic ca
40、bles are typically constructed as follows, see Figures 1 and 2. Key 1 Outer jacket 2 Buffer 3 Cladding 4 Core 5 Primary coating 6 Strength member Figure 1 Typical avionic fibre optic cable construction 1 2 6 5 4 3 Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by
41、IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Page 6 prEN 4533-001:2005Figure 2 Examples of typical avionic fibre optic cables 3.2.3 Fibre choice From the perspective of termination there is little difference between small and larger c
42、ore optical fibres. The main fibre issues that impact upon the termination process relate to cladding and primary coating materials. Current generation of avionic fibre sizes tend to be larger than the standard high volume fibres such as those used in the datacomm/telecomm market and so have an asso
43、ciated cost and availability penalty. 3.2.4 Cladding materials Most avionic fibres employ an “all silica” fibre, i.e. both the core and the cladding are made from glass and may be treated as a single glass filament. Some designs use non-glass materials for the cladding e.g. plastic (acrylate) or epo
44、xy. These fibres are referred to as Plastic Clad-Silica (PCS) and Hard Clad-Silica (HCS) respectively. Although these fibres have been used in a number of aircraft applications they are somewhat limited in thermal endurance capabilities and thus tend to be confined to the more benign environmental a
45、pplications. The termination processes described in this handbook refer to all-silica fibres. 3.3 Primary coating materials 3.3.1 Function The major function of the fibre buffer coating 1 is to protect the fibre from abrasive and environmental damage. Many materials have been used for the primary co
46、ating of optical fibres but the most widely known and used of these are, acrylate, polyimide and silicone. The pros and cons of each are briefly described below. It should be noted that most fibres use an acrylate type material for the primary coating other materials can be encountered however, such
47、 as silicone, proprietary polymers and even metal, such as Gold or Aluminium (although these are somewhat specialised and will not be considered here). 3.3.2 Acrylate This is perhaps the most common of optical fibre primary coating materials and is relatively easy to remove with hand tools. The coat
48、ing is usually a UV cured acrylate that is translucent and typically is the same thickness as the fibre. Acrylates have a limited temperature performance of up to approximately 100 C therefore, for high temperature applications other additional coatings are also applied. Copyright Association Europe
49、ene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Page 7 prEN 4533-001:20053.3.3 Polyimide This coating has a higher temperature range than UV cured acrylates and can be used in temperatures up to approximately 350 C. Although useful for high temperature applications polyimide coatings are difficult
