1、BRITISH STANDARD AEROSPACE SERIES BS EN 3475-706:2005 Cables, electrical, aircraft use Test methods Part 706: Laser markability The European Standard EN 3475-706:2005 has the status of a British Standard ICS 49.060 BS EN 3475-706:2005 This British Standard was published under the authority of the St
2、andards Policy and Strategy Committee on 10 February 2006 BSI 10 February 2006 ISBN 0 580 47797 5 National foreword This British Standard is the official English language version of EN 3475-706:2005. The UK participation in its preparation was entrusted by Technical Committee ACE/6, Aerospace avioni
3、c electrical and fibre optic technology, to Subcommittee ACE/6/-/2, Aerospace Cables, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests
4、 informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referr
5、ed to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisi
6、ons of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 9 and a back cover. The BSI
7、 copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN3475706 October2005 ICS49.060 EnglishVersion AerospaceseriesCables,electrical,aircraftuseTest methodsPa
8、rt706:Lasermarkability SriearospatialeCbleslectriquesusage aronautiqueMthodesdessaisPartie706: MarquabilitlaserUV LuftundRaumfahrtElektrischeLeitungenfr LuftfahrtverwendungPrfverfahrenTeil706:UVLaser Markierung ThisEuropeanStandardwasapprovedbyCENon12September2005. CENmembersareboundtocomplywiththeC
9、EN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheCentralSecretariatortoanyCENmember. ThisEuropeanStandardexi
10、stsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheCentralSecretariathasthesamestatusast heofficial versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,Cyprus,CzechRepublic,
11、Denmark,Estonia,Finland,France, Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Slovakia, Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG
12、ManagementCentre:ruedeStassart,36B1050Brussels 2005CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN3475706:2005:EEN 3475-706:2005 2 Contents Page Foreword 3 Introduction4 1 Scope .4 2 Normative references .4 3 Terms and definitions.4 4 Requirements
13、6 EN 3475-706:2005 3 Foreword This European Standard (EN 3475-706:2005) has been prepared by the European Association of Aerospace Manufacturers - Standardization (AECMA-STAN). After enquiries and votes carried out in accordance with the rules of this Association, this Standard has received the appr
14、oval of the National Associations and the Official Services of the member countries of AECMA, prior to its presentation to CEN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2006, and conf
15、licting national standards shall be withdrawn at the latest by April 2006. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According t
16、o the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Lu
17、xembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. 4 Introduction UV laser wire marking is the aerospace industry standard method for marking identification codes on to the surface of electrical wires or cables. UV laser wir
18、e marking was developed in 1987 to provide a safe, permanent means of marking thin wall insulations in particular, as an alternative to hot stamp wire marking, which is considered to be an aggressive process. 1 Scope This standard specifies the test method to establish the ultra violet (UV) laser ma
19、rking performance of aerospace wire and cable for use in conjunction with UV laser wire marking systems in accordance with TR 4543 “UV laser wire marking systems for aircraft wire and cable identification” and EN 3475-100 “Aerospace series Cables, electrical, aircraft use Test methods Part 100: Gene
20、ral”. 2 Normative references The following referenced documents are indispensable for the application 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 3838, Aerospace s
21、eries Requirements and tests on user-applied markings on aircraft electrical cables. 1)EN 3475-100, Aerospace series Cables, electrical, aircraft use Test methods Part 100: General. EN 3475-705, Aerospace series Cables, electrical, aircraft use Test methods Part 705: Contrast measurement. TR 4543, U
22、V laser wire marking systems for aircraft wire and cable identification. 2)3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 laser laser is an acronym for Light Amplification by the Stimulated Emission of Radiation. Lasers are a source of inten
23、se monochromatic light in the ultraviolet, visible or infrared region of the spectrum. The “active” or lasing medium may be a solid, liquid or gas. The laser beam is generated by energising the active medium using an external power source, which is most commonly electrical or optical. 3.2 ultraviole
24、t (abbreviation UV) electromagnetic radiation in a wavelength range from approximately 200 nm to 400 nm 1) Published as AECMA Prestandard at the date of publication of this standard. 2) In preparation at the date of publication of this standard. EN 3475-706:20055 3.3 UV laser a laser that produces a
25、 beam of UV radiation 3.4 fluence the energy density, measured in J cm 2(Joules per square cm) of a single pulse of the laser beam, which, for the purposes of this document, is at the surface of the wire insulation or cable jacket 3.5 pulse length the time interval between the laser energy crossing
26、half the maximum energy on the rising and the falling edges of the pulse; referred to as FWHM full width half maximum. Pulse lengths are measured in nanoseconds, ns. 1 ns = 10 9s. 3.6 wavelength () wavelength is measured in nanometres, nm. 1 nm = 10 9m. = c/f where c is the velocity of light and f i
27、s the frequency 3.7 damage for the purpose of this document, damage is defined as an unacceptable reduction in the mechanical or electrical properties of a wires insulation, i.e. specifically a measurable reduction in the performance of the wire which is outside of its defined and acceptable specifi
28、cation Wire surface defects that are visible only through 10 magnification or greater, such as bubbles or flakes, should not be considered as damage unless they would affect marking performance (contrast, legibility, or other behaviour according to EN 3838) or other properties of the wire insulation
29、. 3.8 Nd (neodymium) neodymium is an elemental metal that forms the active laser material in the most common type of solid state laser. The neodymium is held in an optically transparent solid “host” material, and is energised by optical input, either from a flash lamp or from the optical output from
30、 a diode laser. The host material does not play a direct role, but can slightly influence the laser wavelength. Typical host materials are specialised crystal materials, such as Yttrium Aluminium Garnet (YAG) and Yttrium Lithium Fluoride (YLF). These lasers are commonly referred to as Nd:YAG or Nd:Y
31、LF respectively. The primary wavelength of Nd solid state lasers is in the infrared (IR) at a wavelength of approximately 1 064 nm. The IR output of such lasers can be conveniently reduced to lower wavelengths suitable for wire marking by use of harmonic generation (see 3.10). 3.9 excimer a gas lase
32、r deriving its name from the term “excited dimer”. The laser is energised by means of a gas discharge. Excimer lasers are available operating at a number of discrete wavelengths throughout the UV, the most common of which are 193 nm, 248 nm, 308 nm and 351 nm. The wavelength is dependant only on the
33、 gas mix used; 308 nm is commonly used for UV laser wire marking. 3.10 harmonic generation the use of non-linear optical processes to change the wavelength of a laser by frequency conversion. This enables the output of an infrared laser to be converted to shorter wavelengths. In the case of Nd laser
34、s this results in a frequency doubled output at 532 nm in the green and a frequency tripled output at 355 nm in the UV, which is used for wire marking. EN 3475-706:20056 4 Requirements 4.1 General 4.1.1 Preparation of wire samples Take a sample of the wire for marking. Before marking the wire ensure
35、 that the wire surface is clean and dry and free from dust and dirt. For initial production it should only be necessary to clean the wire with a dry cloth. However, in some situations, for instance if the wire is contaminated with oil or is very dirty, it may be necessary to wipe it clean using Prop
36、an-2-ol (Isopropyl alcohol). 4.1.2 Laser marking system A suitable laser must be used to mark the wire samples. Based on commonly used laser sources employed in UV laser wire marking systems within the aerospace industry, it is recommended that either one of the ultra violet (UV) laser types listed
37、in the following Table 1 is used for marking the wire samples. These are pulsed lasers that provide the very short pulse lengths and intense, high power pulses of UV light required for creating marks on aerospace wire insulation. The laser pulse length shall be within the range of 1 ns to 30 ns. Tab
38、le 1 Laser type Wavelength nm Pulse length ans Frequency tripled Q-switched Neodymium YAG, (Nd:YAG), solid state laser 355 4 to 20 Xenon chloride (XeCl) excimer gas laser 308 10 to 30 aThe pulse length ranges quoted are typical of commercially available lasers. IMPORTANT Other laser types may only b
39、e employed provided they comply with the requirements of TR 4543. To measure the marking performance of the wire it is necessary to measure the contrast of the mark made by the UV laser beam. The mark should be made using a laser and optical beam delivery system that incorporates a mask with a suita
40、ble cut out, e.g. in the shape of a square or rectangle, so that a clearly defined mark can be made on the wire surface for measurement. See Figure 1. To enable the mark contrast to be accurately measured, a well-formed mark with minimum dimensions of (1 1) mm is required, subject to the wire gauge
41、being large enough to accommodate this. See Figure 2. It is important that the intensity of that part of the laser beam used for marking the samples and subsequent contrast measurement should be uniform to within 10 % when projected on to a flat surface at the focal point of the beam delivery system
42、. This is to ensure that fluctuations in the mark contrast due to changes in the laser intensity within the marking field are kept to a minimum. To ensure that this is the case suitable, purpose designed test equipment must be used for the laser marking, or alternatively, appropriate diagnostic equi
43、pment must be used to confirm that the laser beam intensity is within the required limits. Figure 3 shows an acceptable laser beam profile. IMPORTANT The contrast achieved may vary for certain combinations of wire types and lasers, in particular wires with ethylenetetrafluoroethylene extruded insula
44、tions, whether cross linked or non-cross linked, are likely to exhibit a higher contrast with 355 nm Nd:YAG lasers than with 308 nm excimer lasers. It is therefore important to record the type of laser used in the tests. In general, wires with insulations made from polytetrafluoroethylene are unlike
45、ly to exhibit this tendency. EN 3475-706:20057 4.1.3 Laser marking fluence Marking should be carried out as follows: A marking fluence of (0,9 0,1) J cm 2should be used unless the wire type under test is specified for marking at a different fluence. This fluence level has been determined to be satis
46、factory for achieving the maximum contrast, or satisfactory contrast levels, on all common aerospace wire and cable types and is representative of the majority of equipment in use, albeit that some equipment does function with higher fluence levels. It should be noted that the fluence is specified h
47、ere for the purposes of defining the requirements for determining the laser markability of the wire only. The system used must ensure that the laser fluence delivered to the wire remains within the specified range for all markings. NOTE For marking on the smallest gauge wires in production situation
48、s, e.g. 24 and 26 gauge, it may be necessary with some wire types and equipment to utilise higher fluences at the wire centre. This is to ensure that the fluence at the edge of the mark remains above the minimum required to achieve the desired contrast while accommodating the geometric affects of the wire curvature, which reduces the fluence as the laser beam rolls off at the edges. WARNING Care must be taken that maximum permissible fluence is not exceeded in such cases: refer to
