Aerospace series - Environmental testing - Test Xb: Abrasion of markings, letterings, surfaces and materials caused by rubbing fingertips and hands

Luft- und Raumfahrt - Umweltprüfung - Abrasiver Verschleiß von Bedruckungen, Beschriftungen, Oberflächen und Materialien verursacht durch die Reibung der Fingerkuppe oder der Hand

Série aérospatiale - Essais d'environnement - Essai Xb : Abrasion de marquages, inscriptions, surfaces et matériaux due au frottement des doigts et des mains

Le présent document fournit une série de méthodes d’essais standards permettant de déterminer la résistance à l’abrasion des marquages, inscriptions, surfaces et matériaux sur des surfaces planes ou courbes, qui peut par exemple survenir lors de la manipulation manuelle d’organes de commande, de boutons, de matériaux et de surfaces dans l’aérospatiale. La méthode convient aussi aux essais de résistance contre les fluides, les pâtes, les particules et autres matériaux, y compris lorsqu’ils sont combinés.

Aeronavtika - Okoljski preskusi - Preskus Xb: obraba oznak, črk, površin in materialov zaradi drgnjenja s prsti in dlanmi

General Information

Status
Not Published
Technical Committee
Current Stage
4060 - Closure of enquiry - Enquiry
Due Date
20-Aug-2020
Completion Date
20-Aug-2020

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SLOVENSKI STANDARD
oSIST prEN 4860:2020
01-julij-2020
Aeronavtika - Okoljski preskusi - Preskus Xb: obraba oznak, črk, površin in
materialov zaradi drgnjenja s prsti in dlanmi

Aerospace series - Environmental testing - Test Xb: Abrasion of markings, letterings,

surfaces and materials caused by rubbing fingertips and hands
Luft- und Raumfahrt - Umweltprüfung - Abrasiver Verschleiß von Bedruckungen,
Beschriftungen, Oberflächen und Materialien verursacht durch die Reibung der
Fingerkuppe oder der Hand

Série aérospatiale - Essais d'environnement - Essai Xb : Abrasion de marques, lettres,

surfaces et matériaux par cause de frottement de doigts et de mains
Ta slovenski standard je istoveten z: prEN 4860
ICS:
19.040 Preskušanje v zvezi z Environmental testing
okoljem
49.020 Letala in vesoljska vozila na Aircraft and space vehicles in
splošno general
oSIST prEN 4860:2020 en,fr,de

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

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oSIST prEN 4860:2020
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oSIST prEN 4860:2020
DRAFT
EUROPEAN STANDARD
prEN 4860
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2020
ICS
English Version
Aerospace series - Environmental testing - Test Xb:
Abrasion of markings, letterings, surfaces and materials
caused by rubbing fingertips and hands

Série aérospatiale - Essais d'environnement - Essai Xb : Luft- und Raumfahrt - Umweltprüfung - Abrasiver

Abrasion de marques, lettres, surfaces et matériaux par Verschleiß von Bedruckungen, Beschriftungen,

cause de frottement de doigts et de mains Oberflächen und Materialien verursacht durch die

Reibung der Fingerkuppe oder der Hand

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 4860:2020 E

worldwide for CEN national Members.
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oSIST prEN 4860:2020
prEN 4860:2020 (E)
Contents Page

European foreword ............................................................................................................................................ 3

1 Scope .......................................................................................................................................................... 4

2 Normative references .......................................................................................................................... 4

3 Terms and definitions ......................................................................................................................... 4

4 General description .............................................................................................................................. 4

5 Description of the test apparatus, test piston, test fabric and test media ........................ 4

5.1 General description .............................................................................................................................. 4

5.2 Motion of the test piston ..................................................................................................................... 5

5.3 Test piston ............................................................................................................................................... 5

5.4 Test fabric ................................................................................................................................................ 5

5.5 Test media ............................................................................................................................................... 6

6 Severity ..................................................................................................................................................... 7

7 Preconditioning ..................................................................................................................................... 7

8 Initial measurements .......................................................................................................................... 7

9 Testing ...................................................................................................................................................... 7

10 Intermediate measurements ............................................................................................................ 8

11 Recovery ................................................................................................................................................... 8

12 Final measurements............................................................................................................................. 8

13 Relevant information to be given in the test report ................................................................. 9

Annex A (informative) Schematic drawing of a test apparatus for test XB ................................. 10

Annex B (informative) Additional textiles for testing ........................................................................ 11

Annex C (informative) Cabin zones and test media in cabin ............................................................ 12

C.1 Cabin zones ............................................................................................................................................ 12

C.2 Test media in cabin ............................................................................................................................ 13

Annex D (informative) Fabric technical specification ........................................................................ 17

Annex E (informative) Standard evolution form .................................................................................. 18

Bibliography ........................................................................................................................................................ 19

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European foreword

This document (prEN 4860:2020) 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, prior to its presentation to CEN.
This document is currently submitted to the CEN Enquiry.
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oSIST prEN 4860:2020
prEN 4860:2020 (E)
1 Scope

This document provides a series of standard testing methods to determine the resistance of markings,

letterings, surfaces and materials on flat or curved surfaces against abrasion as may occur for example

by manually operating actuators, buttons, materials and surfaces in aerospace. The method is also

suitable to test the resistance against fluids, pastes, particles and other materials and also in combination.

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 60068-1:2014, Environmental testing - Part 1: General and guidance
3 Terms and definitions
No terms and definitions are listed in this document.

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/
4 General description

Marking and lettering on the product surface is a communication feature between the product and human

beings. This communication feature often affects its usability and diminishes the value of the product.

Therefore, testing of the abrasion resistance to the environmental load on the surface generated by

human physical contact is of great importance.
5 Description of the test apparatus, test piston, test fabric and test media
5.1 General description

A suitable test apparatus shall comprise all the parts and generate the motion which are described in the

drawing in Annex A.

A dynamic pneumatic drive shall move the test piston via a connecting rod towards the surface under test

and then over it. The tip of the test piston due to its viscoelasticity is deformed in such a way as to fit the

surface under test. This is to simulate the motion of human fingertip including its hand and arm muscles.

This motion shall be repeated cyclically. A viscoelastic test piston shall be used to simulate the

characteristics of the human fingertip, ball of a thumb and hand. The material property, hardness, the

shape and the surface topography of the test piston shall be chosen in such a way that the pressure and

friction executed by a human finger or by the ball of a thumb are simulated. To obtain reproducible

conditions for impact and friction, a piece of fabric is placed between the piston and the surface under

test (either as a cover of the piston or as a curtain, hanging between piston and surface). The test fabric

shall be chosen according to the real simulation condition. Depending on the relevant specification, this

fabric may either be dry (dry test) or wetted with a specified test liquid by means of an automatic

feedthrough if the test is intended to cover the influence of fluid contamination as may occur in normal

use (wet test).

The test specimen shall be positioned on a solid, rigid frame being able to hold a range of samples with

various dimensions and geometries and withstand all forces specified in this document. For non-rigid

test specimens, additional sample support shall be used.
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5.2 Motion of the test piston

A single cycle of the test piston shall comprise: movement of the piston towards the test specimen at an

angle of 45 ° ± 5 ° to the surface of the specimen and at a velocity of 60 mm/s ± 5 mm/s. After the test

piston impacts the surface of the specimen, it shall move parallel over the surface of the specimen for a

specified distance (referred to as the rubbing path). During this portion of the movement the test piston

shall apply a specified force and the longitudinal axis of the test piston shall remain normal to the test

specimen. The test piston shall then retract and separate from the surface of the specimen and return to

its start position. This motion shall be repeated cyclically as many times as prescribed by the relevant

specification and the duration of the cycle set so that the “piston pressing on the surface” and “piston

lifted times” are approximately equal. The period of each pressing unidirectional movement cycle is set

based upon the force applied by the test piston and the rubbing path. The length of the rubbing movement

shall be set to that specified in the relevant specification, which shall be between 4 mm and 40 mm.

The applied force shall be set to that specified in the relevant specification and shall be between 1 N and

20 N. The test specimen shall be firmly mounted on an adjustable, solid and rigid frame.

5.3 Test piston

The size and the type of the test piston shall be selected from Table 1 according to the shape and

dimension of the test specimen and the kind of lettering. The test piston shall consist of viscoelastic

material which shall be chemically inert against the test liquids and shall be characterized by a Shore-A-

hardness of 48 ± 5, measured on the flat side of the viscoelastic material.
Table 1 — Information about size of the test piston
Dimensions
Size
A B C D
±0,1 ±0,1 ±0,1 ±0,15
1 10 20 1 32
2 20 20 3 35
3 30 20 2 32

If necessary other dimensions for the test piston more suited to the test specimen may be chosen.

They shall then be prescribed by the relevant specification. The load-displacement charts shall be

documented by the manufacturer and provided upon request.

The test piston shall be replaced regularly to obtain the reproducible test results. The normal lifetime of

the test piston is no more than 1 (one) year or 2 000 000 test cycles, whichever occurs first. It could wear

out before reaching the maximum lifetime depending on the usage (e.g. test media, forces) which can

drastically change this behaviour. Wear signs include divergent hardness, loss of the contour of the

contact surface, damages on the surface, and discoloration and gloss change of the viscoelastic test piston

material. If one of the latter occurs, the test piston shall be replaced.
5.4 Test fabric

Between the test specimen and the test piston there shall be an easily replaceable piece of fabric which

also can be a cover for the test piston.

EN ISO 12947-1:1998, Table 1 gives an example of specifications of the test fabric.

Abrasion side, machine direction and cross direction of the fabric shall be specified. Additionally, they

shall be marked. The movement direction of the test piston shall be parallel to the machine direction of

the fabric to maintain reproducibility. To ensure this, a guide for the fabric is recommended. The fabric

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has to be free from folds, wrinkles and creases. Any post processing to remove those artefacts is not

permitted.

In case the test piston is covered by the fabric directly, an additional mark on the fabric is recommended

before the use.

Annex D gives a recommendation for technical specification of the fabric. For the “dry test”, the fabric

shall be changed or moved such as to bring an unused part of it into contact with the test specimen after

a maximum of 250 cycles in order to avoid wear of the fabric. The fabric feed can be realized automatically

or manually.

For the “wet test” (see 5.3), at the start of a new test and after a maximum of 250 cycles, the fabric shall

be renewed to avoid stray results due to encrustation and wear. The automatically moistening of the

fabric shall be repeated parallel to the fabric feed in order to wet the newly used areas of the fabric.

The fabric shall be fully wettened, especially on the area of the fabric facing the specimen. The moistening

can be achieved by a periodic dripping of the test media on to the fabric (Annex A).

If mentioned in the relevant specification, other test fabrics can be used. In Annex B, other suitable fabrics

are listed.

The abrasive dust produced during the test shall not influence the result of the test. Therefore, it shall be

removed periodically from the area between the test piston and the test specimen.

NOTE The accumulation of abrasive dust can be avoided by mounting the test surface vertically (the dust will

fall down) or by blowing it off by means of compressed air free of oil and any pollution at room temperature.

5.5 Test media

When a “wet test” is specified in the relevant specification the test media shall be specified.

Specified test media (e.g. particles, fluids and pastes) shall be added by an automatic feed due to a pump

from a closed container. The automatic dripping system will moisten the textile at the abrasion

point/area directly.
Specified test media may be:
a) artificial sweat;
b) oil and grease;
c) caffeine-containing liquid;
d) sun cream;
e) other relevant media.

A list of suitable test media can be found in Annex C. The media can be solid, liquid, pasty or mixed.

If more than one test media is specified, different specimens shall be used for each media unless

otherwise specified by the relevant specification.
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6 Severity

The load is given by the force with which the test piston acts on the specimen and by the number of cycles.

It shall be chosen from the following values. The chosen values shall be prescribed in the relevant

specification.

Force: 1 N ± 0,2 N; 2 N ± 0,4 N; 4 N ± 0,8 N; 5 N ± 1 N; 8 N ± 1,6 N; 10 N ± 2 N; 15 N ± 3 N; 20 N ± 4 N.

The rubbing path length shall be selected from the following values.

Rubbing path length: 4 mm; 5 mm; 10 mm; 15 mm; 20 mm; 25 mm; 30 mm; 35 mm; 40 mm.

Number of cycles: 101; 102; 103; 104; 105; 106; 107.
7 Preconditioning

The surface under test shall be in the condition of delivery after normal production. The relevant

specification may prescribe preconditioning (for example aging, dusting and cleaning).

8 Initial measurements

The specimen shall be submitted to a visual check and if prescribed by the relevant specification to

dimensional and functional checks. Additionally, an automated mobile 3D-scanning device can be used

to determine the topography including visual impression.
9 Testing

Testing shall only commence after the specimen, test apparatus, test media and test fabric are all

stabilized at the required ambient climatic conditions. Those conditions shall be maintained, with

specified tolerances, throughout the test.

Unless specified otherwise in the relevant specification, the test shall be conducted at one of the ambient

conditions set out in Table 2 (from EN 60068-1:2014, Table 1). The relevant specification may specify

alternative ambient temperatures, within a range of −40 °C to +85 °C.

The surface of the specimens shall be stressed in the test apparatus with the prescribed severity.

Table 2 — Standard ambient conditions for test
Temperature Humidity Air pressure
...

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