Surface mounting technology - Part 3-1: Standard method for the specification of components for through hole reflow (THR) soldering – Guidelines for through hole diameter design with solder paste surface printing method

IEC TR 61760-3-1:2022(E) supplements IEC 61760-3 to describe examples of solder paste supply methods, the relationship between the terminal position tolerance and the through hole diameter, and provides guidelines for the design of printed circuit boards with solder paste surface printing method, including specific examples.

General Information

Status
Published
Publication Date
16-Jun-2022
Current Stage
PPUB - Publication issued
Completion Date
17-Jun-2022
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IEC TR 61760-3-1:2022 - Surface mounting technology - Part 3-1: Standard method for the specification of components for through hole reflow (THR) soldering – Guidelines for through hole diameter design with solder paste surface printing method
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IEC TR 61760-3-1
Edition 1.0 2022-06
TECHNICAL
REPORT
colour
inside
Surface mounting technology –
Part 3-1: Standard method for the specification of components for through hole
reflow (THR) soldering – Guidelines for through hole diameter design with solder
paste surface printing method
IEC TR 61760-3-1:2022-06(en)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC TR 61760-3-1
Edition 1.0 2022-06
TECHNICAL
REPORT
colour
inside
Surface mounting technology –
Part 3-1: Standard method for the specification of components for through hole

reflow (THR) soldering – Guidelines for through hole diameter design with solder

paste surface printing method
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.190 ISBN 978-2-8322-3928-5

Warning! Make sure that you obtained this publication from an authorized distributor.

® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 3 ----------------------
– 2 – IEC TR 61760-3-1:2022  IEC 2022
CONTENTS

FOREWORD ........................................................................................................................... 4

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

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

3 Terms and definitions ...................................................................................................... 6

4 Solder paste application methods .................................................................................... 6

4.1 General ................................................................................................................... 6

4.2 Through hole filled method ...................................................................................... 8

4.2.1 Overview ......................................................................................................... 8

4.2.2 Advantages ..................................................................................................... 9

4.2.3 Disadvantages ................................................................................................. 9

4.3 Solder paste surface printing method ...................................................................... 9

4.3.1 Overview ......................................................................................................... 9

4.3.2 Advantages ..................................................................................................... 9

4.3.3 Disadvantages ................................................................................................. 9

5 Solder paste printing stencil aperture design guidelines................................................. 10

5.1 General ................................................................................................................. 10

5.2 Amount of solder paste ......................................................................................... 10

5.2.1 Needed amount of solder paste ..................................................................... 10

5.2.2 Printing volume of solder paste ...................................................................... 11

5.2.3 Designing amount of printing solder paste ..................................................... 13

6 Influence of terminal position tolerance on through hole diameter and stencil

aperture design guidelines ............................................................................................. 13

6.1 Terminal position tolerance ................................................................................... 13

6.2 Relationship between terminal position tolerance and through hole diameter ........ 14

6.2.1 General ......................................................................................................... 14

6.2.2 Terminal position tolerance of 0,40 mm ......................................................... 14

6.2.3 Terminal position tolerance of 0,30 mm ......................................................... 15

6.2.4 Terminal position tolerance of 0,20 mm ......................................................... 15

6.3 Circuit board though hole diameter design guidelines for THR components .......... 16

6.3.1 Circuit board though hole diameter design ..................................................... 16

6.3.2 Relationship through hole diameter and solder paste supply .......................... 17

Annex A (informative) Calculation method for solder fillet volume of the round terminal ....... 21

Annex B (informative) Calculation method for metal volume of the printed solder paste ....... 24

Bibliography .......................................................................................................................... 26

Figure 1 – Solder paste application method ............................................................................ 7

Figure 2 – Through hole filled method (bottom side view) ....................................................... 8

Figure 3 – Solder paste fallen inside the reflow oven (through hole filled method) ................... 8

Figure 4 – Solder paste state of solder paste surface printing method..................................... 8

Figure 5 – Conceptual view of solder wetting of component terminals after reflow

soldering ............................................................................................................................... 10

Figure 6 – Single area printing .............................................................................................. 12

Figure 7 – Slit printing ........................................................................................................... 13

Figure 8 – Terminal position tolerance 0,40 mm, through hole diameter 1,40 mm (one

side clearance 0,20 mm) ....................................................................................................... 14

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IEC TR 61760-3-1:2022  IEC 2022 – 3 –

Figure 9 – Terminal position tolerance 0,30 mm, through hole diameter 1,40 mm (one

side clearance 0,20 mm) ....................................................................................................... 15

Figure 10 – Terminal position tolerance 0,20 mm, through hole diameter 1,30 mm (one

side clearance 0,15 mm) ....................................................................................................... 16

Figure 11 – Circuit board through hole diameter and component terminal

diameter/diagonal line dimension .......................................................................................... 17

Figure 12 – Through hole diameter and solder paste supply amount (printing area) for

round terminal ....................................................................................................................... 18

Figure 13 – Through hole diameter and solder paste supply amount (printing area) for

square terminal ..................................................................................................................... 19

Figure 14 – Through hole diameter and solder paste supply amount (printing area) for

rectangular terminal .............................................................................................................. 20

Figure A.1 – Solder joint region cross section ....................................................................... 21

Figure A.2 – Solder fillet approximated by a truncated cone .................................................. 22

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– 4 – IEC TR 61760-3-1:2022  IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SURFACE MOUNTING TECHNOLOGY –
Part 3-1: Standard method for the specification of components for
through hole reflow (THR) soldering – Guidelines for through hole
diameter design with solder paste surface printing method
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international

co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and

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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

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

IEC TR 61760-3-1 has been prepared by IEC technical committee 91: Electronics assembly

technology. It is a Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
91/1734/DTR 91/1773/RVDTR

Full information on the voting for its approval can be found in the report on voting indicated in

the above table.
The language used for the development of this Technical Report is English.
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IEC TR 61760-3-1:2022  IEC 2022 – 5 –

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in

accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available

at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are

described in greater detail at www.iec.ch/standardsdev/publications.

A list of all parts in the IEC 61760 series, published under the general title Surface mounting

technology, can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under webstore.iec.ch in the data related to the

specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it

contains colours which are considered to be useful for the correct understanding of its

contents. Users should therefore print this document using a colour printer.
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– 6 – IEC TR 61760-3-1:2022  IEC 2022
SURFACE MOUNTING TECHNOLOGY –
Part 3-1: Standard method for the specification of components for
through hole reflow (THR) soldering – Guidelines for through hole
diameter design with solder paste surface printing method
1 Scope

This Part of IEC 61760 supplements IEC 61760-3 to describe examples of solder paste supply

methods, the relationship between the terminal position tolerance and the through hole diameter,

and provides guidelines for the design of printed circuit boards with solder paste surface printing

method, including specific examples.
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 61760-3:2021, Surface mounting technology – Part 3: Standard method for the
specification of components for through-hole reflow (THR) soldering
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 61760-3 and the

following apply.

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

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
stencil aperture
stencil opening
opening area for solder paste printing in the stencil
4 Solder paste application methods
4.1 General

The amount of solder paste required for through-hole reflow soldering is much greater than for

surface mount. In the industry marketplace, various methods to supply the solder paste are

utilised. All these methods have specific advantages and disadvantages and are depending

upon the board lay-out, the solder material to be used, the trough-hole components to be

inserted. Other points to be considered are production efficiency, cost and quality requirements.

---------------------- Page: 8 ----------------------
IEC TR 61760-3-1:2022  IEC 2022 – 7 –

The most common method used is printing solder paste into plated through-holes and over the

pad surface during normal surface mount paste printing (solder paste surface printing method,

see 4.3). The size of the aperture in the solder paste stencil may be adjusted to allow paste to

fill the hole, cover the pad or extend over the surface of the solder mask to obtain the solder

volume required.

Another method is the solder paste surface printing method (through hole vacant method),

see 4.3.
Refer to Figure 1 to Figure 4 for comparison of both methods.

In this document, the features (advantage and disadvantage) of the solder paste surface

printing reflow technology are introduced from the following two perspectives:
• Solder paste printing stencil aperture design guidelines (see Clause 5);

• Influence of position tolerance between component terminals and through holes on through

hole diameter and stencil aperture design guidelines (see Clause 6).
Through hole filled method Solder paste surface printing method
key
1 top side (assembly side)
2 solder paste
3 Land
4 circuit board
5 through hole
6 bottom side
t solder paste thickness
H solder paste protrusion height
Figure 1 – Solder paste application method
---------------------- Page: 9 ----------------------
– 8 – IEC TR 61760-3-1:2022  IEC 2022
Figure 2 – Through hole filled method (bottom side view)
Reflow oven side view Reflow oven top view

Figure 3 – Solder paste fallen inside the reflow oven (through hole filled method)

a) After print b) After reflow (top side) c) After reflow (bottom side)
Figure 4 – Solder paste state of solder paste surface printing method
4.2 Through hole filled method
4.2.1 Overview

As the name indicates, the through hole filled method is a method of filling the through hole

with the required amount of solder paste using a printing method or a dispenser.
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IEC TR 61760-3-1:2022  IEC 2022 – 9 –
4.2.2 Advantages

The advantage of this method is that it is applicable in cases where the solder paste surface

printing method does not provide enough space for solder printing, such as when the distance

between adjacent through holes or between through holes and adjacent component electrodes

is close.
4.2.3 Disadvantages

A disadvantage of this method is that the solder paste can drop down during the surface

mounting process. The reason for this is that the solder paste filled in the through hole is

...

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