Plastics — Joining of thermoplastic moulded components — Specification for quality levels for imperfections

This document specifies quality levels for imperfections in joints in thermoplastic moulded components due to the joining process. This document does not describe imperfections that can be generated either during service or present before joining, such as poor fit up. The correct preparation before joining is described in the relevant thermal joining process specification (TJPS), as defined in ISO 23512. Three quality levels are specified in order to permit application for a wide range of the following joining processes: a) ultrasonic welding; b) ultrasonic spot welding; c) infrared welding; d) hot gas convection welding; e) vibration welding; f) spin welding; g) laser welding; h) hot plate welding; and i) heat staking: hot air; electrical, infrared and ultrasonic. They are designated by symbols B, C and D, where B is the most stringent. The quality levels refer to production quality and not to the fitness for purpose of the manufactured product. NOTE Standards on joining of plastic pipes, fittings, valves and/or auxiliary equipment, and the assessment of the properties of the resulting joints are developed and maintained by ISO/TC 138.

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Status
Published
Publication Date
15-Sep-2022
Technical Committee
Current Stage
6060 - International Standard published
Due Date
23-Oct-2022
Completion Date
16-Sep-2022
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ISO 5623:2022 - Plastics — Joining of thermoplastic moulded components — Specification for quality levels for imperfections Released:16. 09. 2022
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INTERNATIONAL ISO
STANDARD 5623
First edition
2022-09
Plastics — Joining of thermoplastic
moulded components — Specification
for quality levels for imperfections
Reference number
ISO 5623:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 5623:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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© ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 5623:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

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

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Quality levels and requirements ........................................................................................................................................................ 2

Bibliography .............................................................................................................................................................................................................................17

iii
© ISO 2022 – All rights reserved
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ISO 5623:2022(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/

iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 61, Plastics.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
© ISO 2022 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 5623:2022(E)
Introduction

This document is intended to be used as a reference in the drafting of application specifications. It

contains a simplified selection of thermal joining process imperfections in thermoplastics based on the

designations given in EN 14728.

The purpose of this document is to define dimensions of typical imperfections which might be expected

in normal fabrication. It may be used within a quality system for the production of joints. It provides

three sets of dimensional values from which a selection can be made for a particular application. The

quality level necessary in each case is intended to be defined by the application specification or the

responsible designer, in conjunction with the manufacturer, user and/or other parties concerned.

The quality levels are expected to be prescribed before the start of production, preferably at the enquiry

or order stage. They provide basic reference data and are not specifically related to any particular

application. They refer to types of joint in fabrication and not to the complete product or component

itself. It is possible, therefore, for different quality levels to be applied to individual joints in the same

product or component.

It is normally expected that, for a particular joint, the dimensional limits for imperfections can all be

covered by specifying one quality level. In some cases, it may be necessary to specify different quality

levels for different imperfections in the same joint.

The choice of quality level for any application is expected to take account of design considerations,

subsequent processing, mode of stressing (e.g. static, dynamic), service conditions (e.g. temperature,

environment) and consequences of failure. Economic factors are also important and include not only

the cost of joining process but also of inspection and testing.

Imperfections are quoted in terms of their actual dimensions, and their detection and evaluation may

require the use of one or more methods of destructive and/or non-destructive testing. The detection

and sizing of imperfections are dependent on the inspection methods and the extent of testing specified.

This document is directly applicable to visual testing of thermal joints and does not include details of

recommended methods of detection or sizing by non-destructive means. These limits are not necessarily

applicable to non-destructive testing methods and might need to be supplemented by requirements for

inspection, examination and testing.

The values given for imperfections are for thermal joints produced using normal joining process

practice.
© ISO 2022 – All rights reserved
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 5623:2022(E)
Plastics — Joining of thermoplastic moulded components
— Specification for quality levels for imperfections
1 Scope

This document specifies quality levels for imperfections in joints in thermoplastic moulded components

due to the joining process.

This document does not describe imperfections that can be generated either during service or present

before joining, such as poor fit up. The correct preparation before joining is described in the relevant

thermal joining process specification (TJPS), as defined in ISO 23512.

Three quality levels are specified in order to permit application for a wide range of the following joining

processes:
a) ultrasonic welding;
b) ultrasonic spot welding;
c) infrared welding;
d) hot gas convection welding;
e) vibration welding;
f) spin welding;
g) laser welding;
h) hot plate welding; and
i) heat staking: hot air; electrical, infrared and ultrasonic.

They are designated by symbols B, C and D, where B is the most stringent. The quality levels refer to

production quality and not to the fitness for purpose of the manufactured product.

NOTE Standards on joining of plastic pipes, fittings, valves and/or auxiliary equipment, and the assessment

of the properties of the resulting joints are developed and maintained by ISO/TC 138.

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.

IEC 60812, Failure modes and effects analysis (FMEA and FMECA)
3 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 https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
© ISO 2022 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 5623:2022(E)
3.1
design failure mode effect analysis
DFMEA

application of the failure modes and effects analysis (FMEA) method specifically to product/service

design
3.2
failure modes and effects analysis
FMEA

step-by-step approach for identifying all possible failures in a design, a manufacturing or assembly

process, or a product or service
3.3
fitness for purpose

ability of a product, process or service to serve a defined purpose under specific conditions

3.4
quality level

description of the qualities of a weld on the basis of type and size of selected imperfections

4 Quality levels and requirements

The quality level necessary in each case shall be defined as set out in Table 1. The level shall be

prescribed before the start of production, preferably at the enquiry or order stage. The DFMEA severity

classes in Table 1 shall be determined in accordance with IEC 60812.

NOTE Table 1 defines three quality levels as B, C and D in order to permit application for a wide range of

thermoplastic components.
Table 1 — Quality levels for weld imperfections
Symbol Requirement
B (DFMEA Severity Class 9–10) Stringent
C (DFMEA Severity Class 6–8) Intermediate
D (DFMEA Severity Class 0–5) Moderate

Where additional requirements not covered by this document need to be prescribed for specific

applications, these additional requirements shall be defined as Quality Level A.

The quality level (B, C or D) selected from Table 1 shall be used to define the limits of imperfections

given in:
— Table 2 for ultrasonic welding;
— Table 3 for ultrasonic spot welding;
— Table 4 for infrared welding;
— Table 5 for hot gas convection welding;
— Table 6 for vibration welding;
— Table 7 for spin welding;
— Table 8 for laser welding;
— Table 9 for hot plate welding.
— Table 10 for staking: hot air, electrical, infrared and ultrasonic.
© ISO 2022 – All rights reserved
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ISO 5623:2022(E)

Different types of imperfection occurring simultaneously at any cross-section of the joint might need

special consideration and agreement should be sought between the contracting parties.

Any two adjacent imperfections separated by a distance less than the major dimension of the smaller

imperfection shall be considered as a single imperfection.

Measurements of imperfections can be carried out in accordance with EN 12814-5, EN 13100-1,

EN 13100-2 or EN 13100-3, as applicable. Other methods, such as computed tomography, active

thermography, terahertz spectroscopy and laser scanning, may also be suitable.

Where it is necessary to machine the completed weld, the weld shall be examined both before and after

machining.
© ISO 2022 – All rights reserved
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ISO 5623:2022(E)
© ISO 2022 – All rights reserved
Table 2 — Quality levels for ultrasonic welding
Quality level
Imperfection designa-
Number Description
tion
B C D
Break in continuity of the material Permissible: metric to be
1AAAA Cracks Not permissible Not permissible
either on surface or embedded agreed with customer

Permissible if sum of cavity Permissible if sum of cav- Permissible if sum of cavity

Cavity formed by evolution or en-

2BAAA Gas cavities diameter(s) ≤ 5 % of com- ity diameter(s) ≤ 10 % of diameter(s) ≤ 15 % of com-

trapment of gas(es)
ponent wall thickness component wall thickness ponent wall thickness
Inclusion of decomposition products
3KAAA Degraded polymer Not permissible Not permissible Not permissible
within the weld
No fusion across parts of weld
4BAAA Lack of fusion Not permissible Not permissible Not permissible
interface
Permissible:
Lack of penetration or Weld displacement is less than spec-
4CAAA Not permissible Not permissible
dimension to be agreed
incomplete penetration ified minimum value
with customer
Weld displacement is greater than Permissible: dimension to
4DAAA Excessive penetration Not permissible Not permissible
specified maximum value be agreed with customer
Incomplete fusion across weld
4WAAA Cold fusion Not permissible Not permissible Not permissible
interface
Permissible if ≤ 10 % of Permissible if ≤ 15 % of Permissible if ≤ 20 % of
5EIAA Misalignment The joint faces are not aligned
component wall thickness component wall thickness component wall thickness
Excessive deformation of the female
5MAAA “Belled” joint Not permissible Not permissible Not permissible
part of a shear joint
Overflow of melt/flash from the Permissible: metric to be
6BAAA Excess weld material Not permissible Not permissible
joint agreed with customer
Insufficient flash/upset Upset material smaller than the
6MAAA Not permissible Not permissible Not permissible
material specified value
Thermal damage out- Thermal damage to the component Permissible: requirement
7BAAE Not permissible Not permissible
side of welding outside specification to be agreed with customer
Mechanical damage to the compo-
9MAAA Diaphramming Not permissible Not permissible Not permissible
nent due to the oscillation energy
Permissible: require-
Mechanical damage to the compo- Permissible: requirement
9CAAA Tool mark Not permissible ment to be agreed with
nent due to tool or fixture contact to be agreed with customer
customer
NOTE The numbering system corresponds to that defined in EN 14728.
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ISO 5623:2022(E)
© ISO 2022 – All rights reserved
Table 3 — Quality levels for ultrasonic spot welding
Quality level
Imperfection designa-
Number Description
tion
B C D
Permissible:
Break in continuity of the material
1AAAA Crack Not permissible Not permissible
metric to be agreed with
either on surface or embedded
customer

Permissible if sum of cavity Permissible if sum of cav- Permissible if sum of cavity

Cavity formed by evolution or en-

2BAAA Gas cavity diameter(s) ≤ 5 % of com- ity diameter(s) ≤ 10 % of diameter(s) ≤ 15 % of com-

trapment of gas(es)
ponent wall thickness component wall thickness ponent wall thickness
Crack-like regions of micro-cavi-
Permissible:
tated material, caused by stress,
2DAAA Craze Not permissible Not permissible
metric to be agreed with
producing a local whitening of the
customer
material
Inclusions permissible Inclusions permissible Inclusions permissible

Foreign material trapped in the if sum of max. dimen- if sum of max. dimen- if sum of max. dimen-

3AAAA Solid inclusion

weld sion(s) ≤ 5 % of component sion(s) ≤ 10 % of compo- sion(s) ≤ 15 % of compo-

wall thickness nent wall thickness nent wall thickness
Inclusion of decomposition products
3KAAA Degraded polymer Not permissible Not permissible Not permissible
within the weld
No fusion across parts of weld
4BAAA Lack of fusion Not permissible Not permissible Not permissible
interface
Weld displacement is less than spec- Permissible: dimension to
4CAAA Incomplete penetration Not permissible Not permissible
ified minimum value be agreed with customer

4DAAA Excessive penetration Weld displacement is greater than Permissible: dimension to

Not permissible Not permissible
specified maximum value be agreed with customer
4WAAA Cold fusion Incomplete fusion across weld
Not permissible Not permissible Not permissible
interface
Deviation from the specified geome- Permissible: dimension to
5AAAA Imperfect shape Not permissible Not permissible
try of the weld be agreed with customer
Overflow of melt/flash from the Permissible: metric to be
6BAAA Excess weld material Not permissible Not permissible
joint agreed with customer
Insufficient upset ma- Upset material/flash smaller than
6MAAA Not permissible Not permissible Not permissible
terial the specified value
Thermal damage out- Thermal damage to the component Permissible: requirement
7BAAE Not permissible Not permissible
side of welding outside specification to be agreed with customer
NOTE The numbering system corresponds to that defined in EN 14728.
---------------------- Page: 10 ----------------------
ISO 5623:2022(E)
© ISO 2022 – All rights reserved
Table 3 (continued)
Quality level
Imperfection designa-
Number Description
tion
B C D
Permissible: require-
Mechanical damage to the compo- Permissible: requirement
9CAAA Tool mark Not permissible ment to be agreed with
nent due to tool or fixture contact to be agreed with customer
customer
NOTE The numbering system corresponds to that defined in EN 14728.
---------------------- Page: 11 ----------------------
ISO 5623:2022(E)
© ISO 2022 – All rights reserved
Table 4 — Quality levels for infrared welding
Quality level
Imperfection designa-
Number Description
tion
B C D

Permissible if sum of cavity Permissible if sum of cav- Permissible if sum of cavity

Cavity formed by evolution or en-

2BAAA Gas cavities diameter(s) ≤ 5 % of com- ity diameter(s) ≤ 10 % of diameter(s) ≤ 15 % of com-

trapment of gas(es)
ponent wall thickness component wall thickness ponent wall thickness

Permissible if sum of cavity Permissible if sum of cav- Permissible if sum of cavity

Small gas cavities opening out on

2MAAA Surface bubble diameter(s) ≤ 5 % of com- ity diameter(s) ≤ 10 % of diameter(s) ≤ 15 % of com-

the surface
ponent wall thickness component wall thickness ponent wall thickness
Inclusions permissible Inclusions permissible Inclusions permissible

Foreign material trapped in the if sum of max. dimen- if sum of max. dimen- if sum of max. dimen-

3AAAA Solid inclusion

weld sion(s) ≤ 5 % of component sion(s) ≤ 10 % of compo- sion(s) ≤ 15 % of compo-

wall thickness nent wall thickness nent wall thickness
Inclusion of decomposition products
3KAAA Degraded polymer Not permissible Not permissible Not permissible
within the weld
No fusion across parts of weld
4BAAA Lack of fusion Not permissible Not permissible Not permissible
interface
Weld displacement is less than spec- Permissible: dimension to
4CAAA Incomplete penetration Not permissible Not permissible
ified minimum value be agreed with customer
Weld displacement is greater than Permissible: dimension to
4DAAA Excessive penetration Not permissible Not permissible
specified maximum value be agreed with customer
Incomplete fusion across weld
4WAAA Cold fusion Not permissible Not permissible Not permissible
interface
Mechanical testing of
Deviation from the specified shape Mechanical testing of sam-
5CAAB Incorrect weld profile Not permissible sample welds recom-
of the weld bead/flash ple welds recommended
mended
Permissible if ≤ 10 % of Permissible if ≤ 15 % of Permissible if ≤ 20 % of
5EIAA Misalignment The joint faces are not aligned
component wall thickness component wall thickness component wall thickness
Mechanical testing of
Excessive variation of the weld bead Mechanical testing of sam-
5GAAB Irregular width Not permissible sample welds recom-
width along the joint ple welds recommended
mended
Excessive surface roughness or
5HAAF Irregular surface Not permissible Not perm
...

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