Road vehicles -- Brake linings frictions materials -- Visual inspection

Friction linings are composite materials with complex structure. Due to their composition and their production process, visual appearance characteristics can occur which in a precisely defined design are to be regarded as specific to the product. ISO/PAS 22574:2007 defines visual aspect for the identification and assessment of such product characteristics in quality assurance, as well as a basis for commercial and technical agreements.

Véhicules routiers -- Matériaux de friction des garnitures de freins -- Inspection visuelle

General Information

Status
Published
Publication Date
09-Jan-2007
Current Stage
9092 - International Standard to be revised
Start Date
24-Sep-2020
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ISO/PAS 22574:2007 - Road vehicles -- Brake linings frictions materials -- Visual inspection
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PUBLICLY ISO/PAS
AVAILABLE 22574
SPECIFICATION
First edition
2007-02-01
Road vehicles — Brake linings frictions
materials — Visual inspection
Véhicules routiers — Matériaux de friction des garnitures de freins —
Inspection visuelle
Reference number
ISO/PAS 22574:2007(E)
ISO 2007
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ISO/PAS 22574:2007(E)
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© ISO 2007

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ii © ISO 2007 – All rights reserved
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ISO/PAS 22574:2007(E)
Contents Page

Foreword............................................................................................................................................................. v

Introduction ....................................................................................................................................................... vi

1 Scope ..................................................................................................................................................... 1

2 Characteristic features for friction materials..................................................................................... 1

2.1 Characteristic features for disc brake pads....................................................................................... 1

2.1.1 Gapping (between material and plate)................................................................................................ 1

2.1.2 Edge chipping ....................................................................................................................................... 2

2.1.3 Splits ...................................................................................................................................................... 2

2.1.4 Minor splits............................................................................................................................................ 3

2.1.5 Plucked and indented spigots............................................................................................................. 3

2.1.6 Poor consolidated spigot holes .......................................................................................................... 4

2.1.7 Excess adhesive on plate .................................................................................................................... 4

2.1.8 Material flash on plate .......................................................................................................................... 5

2.1.9 Abrasive coating................................................................................................................................... 5

2.1.10 Anti-noise coating runs........................................................................................................................ 6

2.1.11 Skin crazing........................................................................................................................................... 6

2.1.12 Underlayer distribution ........................................................................................................................ 7

2.1.13 Marking .................................................................................................................................................. 7

2.1.14 Unground material surface .................................................................................................................. 8

2.1.15 Paint on friction material surface........................................................................................................ 8

2.1.16 Surface blisters ..................................................................................................................................... 9

2.1.17 Surface indentations ............................................................................................................................ 9

2.1.18 Grinding marks on friction material surface.................................................................................... 10

2.1.19 Higher porosity area........................................................................................................................... 10

2.1.20 Poorly consolidated friction material ............................................................................................... 11

2.1.21 Surface contamination with foreign matter ..................................................................................... 11

2.1.22 Surface contamination with similar friction material...................................................................... 12

2.1.23 Friction surface structure .................................................................................................................. 12

2.2 Characteristic features for drum brake linings................................................................................ 13

2.2.1 Chipped edges/corners...................................................................................................................... 13

2.2.2 Edge splits........................................................................................................................................... 14

2.2.3 Drill hole chipping at lining ends ...................................................................................................... 14

2.2.4 Drill hole burrs inside the surface..................................................................................................... 15

2.2.5 Drill hole burrs outside the surface .................................................................................................. 16

2.2.6 Cracks radiating from the rivet hole ................................................................................................. 16

2.2.7 Paint on surface – Lining for riveting and bonding ........................................................................ 17

2.2.8 Surface cracks .................................................................................................................................... 17

2.2.9 Marking ................................................................................................................................................ 18

2.2.10 Moulding skin on inside radius surface – Linings for bonding and riveting................................ 18

2.2.11 Moulding skin on outside radius surface – linings for riveting or bonding ................................. 19

2.2.12 Surface blisters ................................................................................................................................... 19

2.2.13 Surface grind marks ........................................................................................................................... 20

2.2.14 Pitted surface (plucked surface) ....................................................................................................... 20

2.2.15 Surface structure ................................................................................................................................ 21

2.2.16 Poor consolidation ............................................................................................................................. 21

2.2.17 Inside surface indentations ............................................................................................................... 22

2.2.18 Outside surface indentations ............................................................................................................ 22

2.2.19 Concentration of self contained ingredients unless typical of the formulation .......................... 23

2.2.20 High porosity area .............................................................................................................................. 24

2.2.21 Metal wire or plastic reinforcement .................................................................................................. 25

2.2.22 Foreign matter friction surface inclusion......................................................................................... 26

© ISO 2007 – All rights reserved iii
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ISO/PAS 22574:2007(E)

2.3 Characteristics features for bonded lined shoes ............................................................................ 26

2.3.1 Lining overhang on shoe platform edge .......................................................................................... 26

2.3.2 Faulty shoes ........................................................................................................................................ 27

2.3.3 Restricted lever movement ................................................................................................................ 27

2.3.4 Stencilled information ........................................................................................................................ 28

2.3.5 Excess adhesive exudation over shoe platform edges .................................................................. 28

2.3.6 Excess adhesive exudation from lining ends .................................................................................. 29

2.3.7 Excess primer...................................................................................................................................... 29

2.3.8 Lining surface condition .................................................................................................................... 30

2.3.9 Gaps between linings and shoe platform......................................................................................... 32

iv © ISO 2007 – All rights reserved
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ISO/PAS 22574:2007(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the

International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

In other circumstances, particularly when there is an urgent market requirement for such documents, a

technical committee may decide to publish other types of normative document:

⎯ an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in

an ISO working group and is accepted for publication if it is approved by more than 50 % of the members

of the parent committee casting a vote;

⎯ an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical

committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting

a vote.

An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a

further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is

confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an

International Standard or be withdrawn.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO/PAS 22574 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 2,

Braking systems and equipment.
© ISO 2007 – All rights reserved v
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ISO/PAS 22574:2007(E)
Introduction

This Publicly Available Specification is based on the “Catalogue of characteristic features for friction materials”

of the “FEMFM-Federation of European Manufacturers of Friction Materials” issued the first time in 1980. The

FEMFM is a European organization of national associations formed by companies engaged in the

development and production of friction materials of various product forms. The description of the characteristic

features and their design was reviewed in 1996 when technological processes, especially safety aspects and

the demands made by the brake and automobile industry, were given careful consideration.

vi © ISO 2007 – All rights reserved
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PUBLICLY AVAILABLE SPECIFICATION ISO/PAS 22574:2007(E)
Road vehicles — Brake linings frictions materials — Visual
inspection
1 Scope

Friction linings are composite materials with complex structure. Due to their composition and their production

process, visual appearance characteristics can occur which in a precisely defined design are to be regarded

as specific to the product. This International Standard defines visual aspect for the identification and

assessment of such product characteristics in quality assurance, as well as a basis for commercial and

technical agreements. The sequence of the product characteristics represents no order of priority. The brake

linings are inspected in the “as supplied” condition, meaning unused. In some characteristic features, there

2 2

are differences between brake linings with an effective lining pad surface < 120 cm and W 120 cm . The

acceptance criteria within the International Standard do not allow any characteristics which could impair the

function and performance of brake linings and are applied unless there are other agreements between the

customer and the supplier.
2 Characteristic features for friction materials
2.1 Characteristic features for disc brake pads
2.1.1 Gapping (between material and plate)
The gap shown in Figure 1 is not acceptable.
Figure 1 — Gapping (between material and plate)
© ISO 2007 – All rights reserved 1
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ISO/PAS 22574:2007(E)
2.1.2 Edge chipping

In the case of a disc brake pad with a surface less than 120 cm a maximum of 1 % of the edge may chip.

In the case of a disc brake pad with a surface equal or more than 120 cm a maximum of 0,5 % of the edge

may chip.
Figure 2 — Edge chipping
2.1.3 Splits

Splits having a length of more than 30 mm or more than 10 mm on corners or deeper than 1,5 mm shall not

be accepted (see Figure 3).
Figure 3 — Splits
2 © ISO 2007 – All rights reserved
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ISO/PAS 22574:2007(E)
2.1.4 Minor splits

Splits having a length of less than 30 mm or less than 10 mm on corners or with a depth les than 1,5 mm may

be accepted (see Figure 4).
Figure 4 — Minor splits
2.1.5 Plucked and indented spigots

The disc brake pad shown in Figure 5 is acceptable on each spigot up to 50 % of area and 0,5 mm deep.

NOTE This definition also applies where spigots have been physically indented in the pad design.

Figure 5 — Plucked and indented spigots
© ISO 2007 – All rights reserved ROOF/ÉPREUVE 3
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