SIST EN 4650:2023

Aerospace series - Wire and cable marking process, UV Laser

This document is applicable to the marking of aerospace vehicle electrical wires and cables using ultraviolet (UV) lasers.
This document specifies the process requirements for the implementation of UV laser marking of aerospace electrical wire and cable and fibre optic cable to achieve an acceptable quality mark using equipment designed for UV laser wire marking of identification codes on aircraft wire and cable subject to EN 3475-100, Aerospace series - Cables, electrical, aircraft use - Test methods - Part 100: General. Wiring specified as UV laser markable and which has been marked in accordance with this document will conform to the requirements of EN 3838.
This document is applicable to the marking of airframe electrical wires and cables using ultraviolet (UV) lasers. The laser process practices defined in this document are mandatory.

Luft- und Raumfahrt - Leitungs- und Kabelkennzeichnungsverfahren durch UV-Laser

Série aérospatiale - Procédé de marquage des fils et câbles au laser UV

Le présent document est applicable au marquage des fils et des câbles électriques de véhicules aérospatiaux par lasers ultraviolets (UV).
Ce document spécifie les exigences relatives au procédé de mise en oeuvre du marquage au laser UV des fils et câbles électriques ainsi que des câbles de fibres optiques pour l’aérospatiale, en vue d’obtenir une marque de qualité acceptable en utilisant des équipements conçus pour le marquage au laser UV de codes d'identification sur les fils et câbles à usage aéronautique relevant de l’EN 3475-100, Série aérospatiale - Câbles électriques à usage aéronautique - Méthodes d'essais - Partie 100 : Généralités. Les câblages spécifiés comme marquables au laser UV et qui ont été marqués conformément au présent document seront conformes aux exigences de l'EN 3838.
Le présent document est applicable au marquage des fils et câbles électriques de cellules par lasers ultraviolets (UV). Les pratiques liées au procédé laser définies dans le présent document sont obligatoires.

Aeronavtika - Postopek označevanja žic in kablov z UV-laserjem

General Information

• Status: Not Published
• Public Enquiry End Date: 31-Oct-2020
• ICS: 49.060 - Aerospace electric equipment and systems
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 09-Mar-2023
• Due Date: 14-May-2023
• Ref Project: EN 4650:2023 - Aerospace series - Wire and cable marking process, UV Laser

Relations

• Revised: SIST EN 4650:2010 - Aerospace series - Wire and cable marking process, UV Laser
• Effective Date: 19-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN 4650:2020
01-oktober-2020
Aeronavtika - Postopek označevanja žic in kablov z UV-laserjem
Aerospace series - Wire and cable marking process, UV Laser
Luft- und Raumfahrt - Leitungs- und Kabelkennzeichnungsverfahren durch UV-Laser
Série aérospatiale - Procédé de marquage des fils et câbles par laser UV
Ta slovenski standard je istoveten z: prEN 4650
ICS:
49.060 Letalska in vesoljska Aerospace electric
električna oprema in sistemi equipment and systems
oSIST prEN 4650:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 4650:2020
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oSIST prEN 4650:2020
DRAFT
EUROPEAN STANDARD
prEN 4650
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2020
ICS Will supersede EN 4650:2010
English Version
Aerospace series - Wire and cable marking process, UV
Laser

Série aérospatiale - Procédé de marquage des fils et Luft- und Raumfahrt - Leitungs- und

câbles par laser UV Kabelkennzeichnungsverfahren durch UV-Laser

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee ASD-

STAN.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations

which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other

language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC

Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 4650:2020 E

worldwide for CEN national Members.
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Contents Page

European foreword ............................................................................................................................................ 4

Introduction .......................................................................................................................................................... 5

1 Scope .......................................................................................................................................................... 6

2 Normative references .......................................................................................................................... 6

3 Terms, definitions, symbols and abbreviations ......................................................................... 6

3.1 Terms and definitions ......................................................................................................................... 6

3.2 Symbols and abbreviations ............................................................................................................. 11

4 Requirements ....................................................................................................................................... 11

4.1 UV laser wire marking requirements .......................................................................................... 11

4.2 Design construction file .................................................................................................................... 11

4.3 Process requirements ....................................................................................................................... 11

4.3.1 Laser wavelength ................................................................................................................................ 11

4.3.2 Mask based laser marking systems (see Clause 8) ................................................................. 11

4.3.3 Scanner laser marking systems (see Clause 8) ........................................................................ 12

4.3.4 IR radiation ........................................................................................................................................... 13

4.4 System requirements ........................................................................................................................ 13

4.4.1 Laser type ............................................................................................................................................... 13

4.4.2 Laser output control .......................................................................................................................... 13

4.5 Quality requirements – General .................................................................................................... 14

4.5.1 Insulation Damage .............................................................................................................................. 14

4.5.2 Legibility and permanence .............................................................................................................. 14

4.5.3 Mark contrast ....................................................................................................................................... 14

5 Quality assurance provisions ......................................................................................................... 14

5.1 Responsibility for inspection .......................................................................................................... 14

5.1.1 General .................................................................................................................................................... 14

5.1.2 Test equipment and inspection facilities ................................................................................... 14

5.2 Quality conformance inspection .................................................................................................... 14

5.2.1 General .................................................................................................................................................... 14

5.2.2 Inspection conditions ........................................................................................................................ 14

5.3 Verification insection ........................................................................................................................ 15

5.4 Quality conformance inspection .................................................................................................... 15

6 Test methods ........................................................................................................................................ 15

6.1 Design construction file .................................................................................................................... 15

6.2 Laser wavelength (see Clause 8) ................................................................................................... 15

6.3 Laser pule length (see Clause 8) .................................................................................................... 15

6.4 Applied laser fluence ......................................................................................................................... 16

6.4.1 Mask Based Marking System ........................................................................................................... 16

6.4.2 Scanning Laser Marking System .................................................................................................... 16

6.5 Laser dot overlap in Scanning Laser Marking Systems ......................................................... 17

6.6 IR radiation ........................................................................................................................................... 17

6.7 Laser type ............................................................................................................................................... 18

6.8 Laser output control .......................................................................................................................... 18

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6.9 Insulation damage .............................................................................................................................. 18

6.10 Legibility and permanence .............................................................................................................. 18

6.11 Mark contrast measurements ........................................................................................................ 18

7 Packaging ............................................................................................................................................... 18

8 Notes ........................................................................................................................................................ 18

8.1 Principle of the marking process .................................................................................................. 18

8.1.1 General ................................................................................................................................................... 18

8.1.2 Mask-based laser marking systems ............................................................................................. 18

8.1.3 Scanning laser marking systems ................................................................................................... 18

8.2 Markability of wire constructions ................................................................................................ 19

8.3 Properties of UV laser-marked insulation materials............................................................. 19

8.3.1 General ................................................................................................................................................... 19

8.3.2 Mark depth ............................................................................................................................................ 20

8.3.3 Mark permanence............................................................................................................................... 20

8.3.4 Mark colour ........................................................................................................................................... 20

8.3.5 Polymer insulation background colour ...................................................................................... 20

8.3.6 Fungus ..................................................................................................................................................... 21

8.4 Laser wavelength ................................................................................................................................ 21

8.5 Pulse length ........................................................................................................................................... 21

8.6 Pulse repetition rate .......................................................................................................................... 21

8.7 Laser type .............................................................................................................................................. 22

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oSIST prEN 4650:2020
prEN 4650:2020 (E)
European foreword

This document (prEN 4650:2020) has been prepared by the Aerospace and Defence Industries

Association of Europe — Standardization (ASD-STAN).

After enquiries and votes carried out in accordance with the rules of this Association, this Standard has

received the approval of the National Associations and the Official Services of the member countries of

ASD-STAN, prior to its presentation to CEN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 4650:2010.
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Introduction

Ultraviolet (UV) laser wire marking was developed in 1987 to provide a safe, permanent means of

marking thin wall insulations; it is now the aerospace industry standard method for marking wire

identification codes on to the surface of electrical wires and cables. It provides a simple, convenient,

environmentally friendly, cost effective means of marking and identifying wires and jacketed cables.

While a few larger airframe manufacturers have developed process standards and specifications for their

own use during the introduction of this technology, there has been variability in the issues covered within

these specifications and there has been no comprehensive standard process document developed for

general use. The intended use of this document is to serve directly as a process standard for use by laser

wire marking concerns. It can also serve as a model set of comprehensive requirements for use by

organizations who intend to develop in-house laser marking process specifications or serve as a means

for evaluating the adequacy and completeness of such specifications by procuring activities.

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1 Scope

This document is applicable to the marking of aerospace vehicle electrical wires and cables using

ultraviolet (UV) lasers.

This document specifies the process requirements for the implementation of UV laser marking of

aerospace electrical wire and cable and fibre optic cable to achieve an acceptable quality mark using

equipment designed for UV laser wire marking of identification codes on aircraft wire and cable subject

to EN 3475-100, Aerospace series ― Cables, electrical, aircraft use ― Test methods ― Part 100: General.

Wiring specified as UV laser markable and which has been marked in accordance with this document will

conform to the requirements of EN 3838.

This document is applicable to the marking of airframe electrical wires and cables using ultraviolet (UV)

lasers. The laser process practices defined in this standard are mandatory.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 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

EN 3475-706, Aerospace series - Cables, electrical, aircraft use - Test methods - Part 706: Laser markability

EN 3838, Aerospace series - Requirements and tests on user-applied markings on aircraft electrical cable

EN ISO 10012, Measurement management systems - Requirements for measurement processes and

measuring equipment (ISO 10012)
3 Terms, definitions, symbols and abbreviations
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• ISO Online browsing platform: available at http://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/
3.1.1
cable

electrical cable, unless noted as a fibre optic cable. 2 (two) or more insulated conductors, solid or

stranded, contained in a common covering, or 2 (two) or more insulated conductors twisted or molded

together without common covering, or one insulated conductor with a metallic covering shield or outer

conductor

Published as ASD-STAN Standard at the date of publication of this document by AeroSpace and Defence

industries Association of Europe — Standardization (ASD-STAN), http://www.asd-stan.org/

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3.1.2
component

for the purposes of this document this shall be an electrical wire or multi-conductor cable or fibre optic

cable
3.1.3
contrast

measurement relating to the difference in luminance of the mark and its associated background according

to a precise formula
3.1.4
damage

for the purpose of this document, with reference to wire and cable, damage is defined as an unacceptable

reduction in the mechanical or electrical properties of the insulation (i.e., specifically a measurable

reduction in the performance of the wire or cable that is outside of its defined specification or is otherwise

unacceptable)
3.1.5
dot overlap

dot overlap for scanning laser systems is defined in relation to the diameter, D, of the laser beam at the

surface of the wire at the 1/e point, and the distance, d, between the centres of the adjacent dots

Note 1 to entry: The percentage overlap = (1-(d/D)) x 100 %
3.1.6
excimer
gas laser deriving its name from the term “excited dimer”

Note 1 to entry: The laser is energized by means of an electrical discharge in a specialized mixture of rare gases

and halogens. 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 gas mix

used; 308 nm is commonly used for UV laser wire marking.
3.1.7
fibre optic cable

cable that is designed to transmit light waves between a light transmission source and a receiver

Note 1 to entry: In signal applications, the transmitter and receiver include devices that are used to convert

between optical and electronic pulses. Typical cables include a glass or plastic core, a layer of cladding having a

lower refractive index to refract or totally reflect light inward at the core/cladding boundary, a buffer, strength

members and jacketing to protect the inner cable from environmental damage.
3.1.8
fluence

energy density, measured in joules per square centimetre (J/cm ), of a single pulse of the laser beam,

which is at the surface of the wire insulation or cable jacket
3.1.9
font
defining shape and style of a character set for printing or marking
3.1.10
gauge

wire size specified for a wire in a wire harness assembly by the wire harness assembly drawing

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3.1.11
harmonic generation

use of non-linear optical processes to change the wavelength of a laser, enabling the output of an infrared

laser to be converted to shorter wavelengths

Note 1 to entry: In the case of Neodymium (Nd) lasers 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.

3.1.12
harness

assembly of any number of wires, electrical/optical cables and/or groups and their terminations which

is designed and fabricated so as to allow for installation and removal as a unit
Note 1 to entry: A harness may be an open harness or a protected harness.
3.1.13
infrared

IR electromagnetic radiation in the wavelength range from approximately 700 nm to in excess of

10 000 nm
3.1.14
insulation

outer polymer covering of an electrical wire or multi-conductor cable or fibre optic cable

3.1.15
IR laser
laser that produces a beam of radiation in the IR range
3.1.16
jacket
outer protective covering for a cable
3.1.17
laser

laser is an acronym for Light Amplification by the Stimulated Emission of Radiation. Lasers are a source

of intense 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 energizing the active

medium using an external power source, which is most commonly electrical or optical

3.1.18
laser average power
optical power, measured in Watts (W), delivered by the laser source
3.1.19
laser pulse energy
optical energy, measured in Joules (J) contained in each laser pulse
3.1.20
laser pulse length

time interval between the laser energy crossing half the maximum energy on the rising and the falling

edges of the pulse; referred to as FWHM – full width half maximum
Note 1 to entry: Pulse lengths are measured in nanoseconds (ns). 1 ns = 10 s.
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3.1.21
laser pulse rate

number of laser pulses delivered per second, measured in Hertz (Hz). Also referred to as the laser pulse

frequency or repetition rate
3.1.22
legibility
properties of a mark that enable it to be easily and correctly read
3.1.23
luminance

quantitative measurement of the visible light reflected from a surface, in this case the wire or cable

insulation
3.1.24
mark

meaningful alphanumeric or machine readable mark applied to the surface of a wire or cable jacket

3.1.25
markability

markability of a wire construction to be marked to provide legible identification marks of a specified

contrast when marked in accordance with this document
3.1.26
neodymium Nd

elemental metal that forms the active laser material in the most common type of solid-state laser

Note 1 to entry: The neodymium is held in an optically transparent solid “host” material, and is energized by

optical input, either from a flash lamp or from the optical output from a diode laser. The host material does not play

a direct role but can slightly influence the laser wavelength. Typical host materials are specialized crystal materials,

such as Yttrium Aluminium Garnet (YAG), Yttrium Lithium Fluoride (YLF) and Yttrium Vanadate (YVO4). These

lasers are commonly referred to as Nd:YAG, Nd:YLF and Nd:YVO4 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.

3.1.27
purchaser
activity that can issue a purchase order or contract
3.1.28
q-switched laser

laser that retains and circulates the laser energy internally within the laser until a signal is sent to open

the “Q-switch”, usually an electro-optic component. The Q-switch acts like a gate that when opened allows

the trapped laser beam to exit on a nanosecond timescale. This technique is routinely used on long pulse

solid state lasers to create short laser pulses such as those required for UV laser wire marking

3.1.29
quality conformance

tests performed on production samples at a specified frequency to ensure that the requirements of this

document are met
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3.1.30
quality conformance inspection

process that includes measurements, non-destructive tests, analysis, and associated data that will

provide verification that a particular individual component continually conforms to the requirements

defined in the standard
3.1.31
supplier

original equipment manufacturer (OEM) or a value-added manufacturer which has design and

production control of the processes used to produce the final product in accordance with the standard

3.1.32
ultraviolet

electromagnetic radiation in the wavelength range from approximately 200 nm to 400 nm

3.1.33
UV laser
laser that produces a beam of radiation in the UV range
3.1.34
verification inspection

process that demonstrates that a product is capable of fully conforming to all the requirements defined

in a standard

Note 1 to entry: Verification Inspection includes definition of the measurements, tests, analysis, and associated

data that provides consistent rationale for acceptance of a particular supplier's design as meeting the standard

requirements typically prior to acquisition by the purchaser.
3.1.35
wavelength λ

distance between repeating units of a wave pattern, e.g. the distance between the crest of 1 (one) wave

and the crest of an adjacent wave
Note 1 to entry: Laser wavelength is typically measured in nanometres (nm).
Note 2 to entry: λ = c/f
where
c is the velocity of light;
f is the frequency.
3.1.36
wire

single metallic conductor of solid, stranded or tinsel construction, designed to carry current in an electric

circuit, but not having a metallic covering, sheath or shield

Note 1 to entry: For the purpose of this specification, “wire” refers to “insulated electric wire”.

3.1.37
wire code

wire circuit identification number or code assigned to a specific wire in a wire harness assembly and

marked on the insulation surface
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3.2 Symbols and abbreviations
nm: nanometre, 10 m;
ns: nanosecond 10 s;
ETFE: ethylenetetrafluoroethylene;
PFA: perfluoroalkoxy fluoropolymer;
PTFE: polytetrafluoroethylene;
PVDF: polyvinylidene difluoride / polyvinylidene fluoride.
4 Requirements
4.1 UV laser wire marking requirements
The laser requirements for marking aerospace wire and cable are grouped under:

a) Process Requirements, i.e. those characteristics that affect the marking process in terms of the mark

characteristics and quality; and

b) System Requirements, i.e. those characteristics that affect the performance of equipment in terms of

its operational use.
4.2 Design construction file

The equipment supplier shall create a Design Construction File that records the relevant design details of

the equipment and demonstrates clearly how all the requirements of Clause 4 are met. A copy of this

Design Construction File shall be maintained and made available to purchasers as required.

4.3 Process requirements
4.3.1 Laser wavelength

Short wavelength UV laser light, in the range 240 nm to 380 nm only shall be used for marking

(see Clause 8). Long wavelength infrared (IR) laser radiation shall not be used for the direct marking of

aerospace electrical or fibre optic wire and cable.
4.3.2 Mask based laser marking systems (see Clause 8)
4.3.2.1 General

Laser marks generated by mask-based processes shall be formed by a single pulse of the laser and shall

not overlap. Only laser beams with a uniform top hat profile shall be employed for mask marking.

WARNING — Multiple overlapping marks may cause wire insulation damage, particularly on

extruded ETFE and PVDF materials.
4.3.2.2 Laser pulse length (see Clause 8)
Lasers with pulse lengths between 3 ns and 35 ns shall be used for marking.
4.3.2.3 Applied laser fluence (see Clause 8)

The equipment supplier shall be responsible for designing the system to ensure that the equipment

delivers the required fluence to achieve the optimum mark contrast and quality without impairing the

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wire characteristics. The user shall be responsible for ensuring that the equipment is maintained and

calibrated to continue to deliver the required fluence.

The fluence shall be taken as the average value across the mark. The equipment shall be set to mark at a

−2 −2

fluence in the range 0,8 J/cm to 1,3 J/cm . The specified fluence shall be the fluence measured at the

top centre of the wire surface, as marked. These marking fluences shall be used unless the wire type under

test is specified for marking at a different fluence.

The laser fluence delivered to the wire shall remain within the specified range under all standard

operating conditions at all times during the entirety of the marking process and for all different font sizes;

this shall be inclusive of any pulse to pulse variations in laser energy.

In ensuring that the equipment delivers and operates within the required fluence at all times the supplier

shall design the equipment taking into account:
a) the laser shot to shot pulse energy variation;
b) short to long term drift in laser power output;

c) the laser beam intensity profile, ensuring that that part of the beam used for marking the wires shall

be of sufficiently uniform intensity and without any hot spots that would result in the maximum

fluence being exceeded within the beam profile when projected on to a flat surface at the focal point

of the beam delivery system.

Laser markers set to operate in the specified fluence range will produce the maximum mark contrast on

any given aerospace wire or cable. It is NOT possible to increase the mark contrast by increasing the

fluence above t
...