IEC 62739-1:2013

IEC 62739-1 ®
Edition 1.0 2013-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Test method for erosion of wave soldering equipment using molten lead-free
solder alloy –
Part 1: Erosion test method for metal materials without surface processing

Méthode d'essai de l'érosion de l'équipement de brasage à la vague utilisant un
alliage à braser sans plomb fondu –
Partie 1: Méthode d'essai d'érosion de matériaux métalliques sans traitement de
surface
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IEC 62739-1 ®
Edition 1.0 2013-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Test method for erosion of wave soldering equipment using molten lead-free

solder alloy –
Part 1: Erosion test method for metal materials without surface processing

Méthode d'essai de l'érosion de l'équipement de brasage à la vague utilisant un

alliage à braser sans plomb fondu –

Partie 1: Méthode d'essai d'érosion de matériaux métalliques sans traitement de

surface
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX R
ICS 31.190; 31.240 ISBN 978-2-83220-870-0

– 2 – 62739-1 © IEC:2013
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Test . 6
4.1 Overview . 6
4.2 Test equipment . 6
4.2.1 Test equipment description . 6
4.2.2 Configuration example of test equipment . 6
4.3 Specimen . 7
4.4 Test conditions . 9
4.5 Test method . 9
4.5.1 Test procedure . 9
4.5.2 Dross removal procedure . 10
5 Method of erosion depth measurement (focal depth method with optical
microscope) . 10
5.1 General . 10
5.2 Preparation of the specimen . 10
5.3 Measurement equipment . 10
5.4 Measurement procedure . 11
6 Items to be recorded in test report . 12
Annex A (normative) Specifications of test equipment & measurement equipment . 13
Annex B (informative) Method of estimation of maximum erosion depth by extreme
value statistical analysis . 15
Bibliography . 18

Figure 1 – Configuration example of test equipment . 7
Figure 2 – Shape of the specimen . 8
Figure 3 – Example of measurement equipment configuration for the focal depth
method using an optical microscope . 11
Figure B.1 – Example of section division of plate specimen . 15
Figure B.2 – Estimated maximum erosion depth for N = 8 . 17

Table 1 – Test conditions . 9

62739-1 © IEC:2013 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TEST METHOD FOR EROSION OF WAVE SOLDERING
EQUIPMENT USING MOLTEN LEAD-FREE SOLDER ALLOY –

Part 1: Erosion test method for metal materials
without surface processing
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
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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.
International Standard IEC 62739-1 has been prepared by IEC technical committee 91:
Electronics assembly technology.
The text of this standard is based on the following documents:
FDIS Report on voting
91/1092/FDIS 91/1106/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – 62739-1 © IEC:2013
A list of all parts in the IEC 62739 series, published under the general title Test method for
erosion of wave soldering equipment using molten lead-free solder alloy, can be found on the
IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication 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.
62739-1 © IEC:2013 – 5 –
TEST METHOD FOR EROSION OF WAVE SOLDERING
EQUIPMENT USING MOLTEN LEAD-FREE SOLDER ALLOY –

Part 1: Erosion test method for metal materials
without surface processing
1 Scope
This part of the IEC 62739 series provides an evaluating test method for the erosion of the
metallic materials without surface processing intended to be used for lead-free wave soldering
equipment as a solder bath and other components which are in contact with the molten solder.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 61190-1-3, Attachment materials for electronic assembly – Part 1-3: Requirements for
electronic grade solder alloys and fluxed and non-fluxed solid solder for electronic soldering
applications
IEC 60068-2-20:2008, Environmental testing – Part 2-20: Tests – Test T: Test methods for
solderability and resistance to soldering heat of devices with leads
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
erosion
phenomenon where a base material is dissolved and made thinner by coming into contact with
molten solder
3.2
lead-free solder
alloy that does not contain more than 0,1 % mass fraction of lead (Pb) as its constituent and
is used for joining components to substrates or for coating surfaces
[SOURCE: IEC 60194:2006, 75.1904 modified — "mass fraction" is used instead of "weight"]
3.3
dross
oxide and other contaminants that form on the surface of molten solder
[SOURCE: IEC 60194:2006, 75.0410]

– 6 – 62739-1 © IEC:2013
4 Test
4.1 Overview
The specimen is mounted to the rotation block of the test equipment which is driven by the
motor (may include gear unit) then immersed into molten lead-free solder and rotated to
simulate solder flow in the wave soldering equipment. The erosion depth is measured after
the block is rotated for a designated period of time.
4.2 Test equipment
4.2.1 Test equipment description
Test equipment shall include equipment that realises the test conditions specified in 4.3.
Component materials of the test equipment which come in contact with molten solder shall be
erosion resistant or processed to be erosion resistant.
Details of the specifications of the equipment are given in Annex A.
4.2.2 Configuration example of test equipment
An example of the configuration of the test equipment is shown in Figure 1.
The test equipment consists of a pot unit, rotation unit, and control unit.
a) The pot unit consists of a heater to melt the lead-free solder alloy and a pot in which a
specimen can rotate.
b) The rotation unit consists of a motor which rotates the specimen and a rotation block to
which the specimen is attached.
c) The control unit has functions to control the heater, using a temperature sensor, control
mechanism and motor rotation.
Since dross spreads during the test, it is preferable for the test equipment to have a
ventilatory function with an exhaust air duct.
Other test equipment can be used if its configuration and functions meet the above
requirements.
62739-1 © IEC:2013 – 7 –
Exhaust air duct
Rotation motor
Rotation unit
Rotation block
Specimen
Control unit
Heater
Solder
Temperature
sensor
Pot
Pot unit
IEC  1429/13
Figure 1 – Configuration example of test equipment
4.3 Specimen
A specimen of the following material and shape is used.
a) The material of the specimen shall be the same as that of the solder bath and its
components which come into contact with the molten solder.
b) The shape of specimen and the indication of the material designation shall be as shown in
Figure 2. The indication of the material designation shall be engraved.
c) The surfaces of the specimen to be evaluated shall be the surface with material indication
(face A) and its backside (face B), and from the lower edge to 50 mm above it.

– 8 – 62739-1 © IEC:2013
Dimensions in millimetres
4 2
2× ∅3,3
IEC  1430/13
Key
1 Laser engraved mark
Figure 2 – Shape of the specimen
8 6
62739-1 © IEC:2013 – 9 –
4.4 Test conditions
Test materials and test conditions are shown in Table 1.
Table 1 – Test conditions
Composition of test solder Sn96,5Ag3Cu,5 specified in IEC 61190-1-3 shall be used if not otherwise specified
alloy in individual standards.
Test flux Rosin flux with halide content of 0,2 % mass fraction shall be used.
Materials specified in Annex B of IEC 60068-2-20:2008, shall be used.
Solder temperature (at 350 °C ± 3 °C (the temperature is measured at a depth of 35 mm to 40 mm from the
measurement position) solder surface and at a distance of 20 mm to 30 mm from the specimen.).
Rotation speed of specimen
100 r/min ± 3 r/min
Rotation radius of specimen 6 mm to 8 mm (from the centre of the rotation block to the outer edge of the
specimen)
Dipping depth of specimen 65 mm to 70 mm
(from molten solder surface to the lower edge of the specimen)
a
Test duration A suitable test time needs to be set up in advance .
Frequency of removal of A minimum of once every 16 h
dross
a
Erosion generating time is different by specimen materials. The proper test duration at which the erosion depth
difference by material can be distinguished while the uneroded area which is used as the base of the erosion
depth measurement clearly remains, should be set up before performing the test. In case of stainless steel
(SUS316, SUS304 grade), 192 h correspond to it.

4.5 Test method
4.5.1 Test procedure
The test is conducted following the steps outlined below.
a) Clean the surface of the specimen with gauze or a paper towel.
b) Dip the cleaned specimen in a cleansing solution of, for example, ethanol for several
seconds and wipe the surface of the specimen with a new gauze or paper towel.
c) Repeat steps a) and b) twice.
d) Dip the cleaned specimen for several seconds in the test flux specified in 4.3 within 1 h of
completing step c).
e) After dipping the specimen, remove it from the test flux. Apply a paper towel to the bottom
of the specimen to remove excess flux from the specimen.
f) Suspend the specimen in the air for 5 min to10 min to dry it.
g) The erosion test needs to be commenced within 1 h of completing step c). Therefore, after
being cleaned as per step e) and dipped in the test flux and dried as in step f), the
specimen shall be attached again to the rotation block with face B touching the block,
without contacting the molten solder.
h) Remove the dross floating on the molten solder in the pot following the dross removal
procedure specified in 4.5.2. Dip the specimen attached to the rotation block into the
molten solder maintained at the specified temperature. The specimen should be dipped in
the molten solder to the depth specified in 4.4 and rotated by the rotation motor at the
rotation speed specified in 4.4. After the rotation is complete, commence measuring the
elapsed time of the test.
i) Remove the specimen from the molten solder within 2 h after the test duration reaches to
a specified value, and wipe off the solder completely from the specimen with a waste cloth.
j) The dross floating on the molten solder in the pot is removed at the frequency specified in
4.4.
– 10 – 62739-1 © IEC:2013
k) After the test duration specified in 4.4 passes, measure the depth of the erosion by the
method specified in Clause 5.
l) Do not remove the specimen from the molten solder until the elapsed time of the test
reaches the rated value, which includes the time for removing the dross and the
equipment down time during the nights.
4.5.2 Dross removal procedure
The dross floating on the molten solder in the pot is removed following the steps outlined
below.
a) Stop the rotation motor and use an appropriate jig (like a stainless steel ladle with many
holes) to remove the dross floating on the molten solder in the pot. Put the dross in a
sealed container.
b) Check the volume of the molten solder in the pot (to ensure the dipping depth as specified
in 4.4 is maintained). If the volume does not meet the specified requirements, supply
additional solder accordingly.
c) Dip the specimen into the molten solder, which is now free from dross, to the depth
specified in 4.4. Continue the test specified in 4.5.1.
5 Method of erosion depth measurement (focal depth method with optical
microscope)
5.1 General
After the test, the depth of the erosion of the specimen is measured following the steps
outlined below.
5.2 Preparation of the specimen
The specimen is prepared following the steps outlined below.
a) After the test has been conducted for the test duration specified in 4.4, continue dipping
the specimen in the molten solder until the rotation stops. Remove the specimen from the
solder when the rotation stops.
b) Remove the specimen by picking it up from the molten solder and detaching it from the
rotation block.
c) Dip each specimen again into the molten solder, heat it, and remove it from the solder.
Wipe the surface of the specimen to be evaluated immediately with a cotton cloth to
remove the solder.
If the solder has not been removed completely, repeat step c) until all solder has been
removed.
5.3 Measurement equipment
The measurement equipment shall consist of an optical microscope, digital micrometre, CCD
camera, and TV monitor and be able to measure focal depth. An example of the measurement
equipment is shown in Figure 3.

62739-1 © IEC:2013 – 11 –
Pole
Indicator
Indicator fixing
knob Zero adjustment
button
CCD camera
Lens slide
knob
TV monitor Microscope lens
Specimen
Measurement table
IEC  1431/13
Figure 3 – Example of measurement equipment configuration
for the focal depth method using an optical microscope
5.4 Measurement procedure
The specimen is measured following the steps outlined below.
a) Prepare the measurement equipment specified in 5.2. (If the equipment includes no CCD
camera, specimens shall be observed using normal or corrected vision.)
b) Visually observe faces A and B specified in 4.3 to find the seemingly deepest erosion area
in advance (more than 3 areas on each face).
c) Place the specimen on the measurement equipment and find the deepest erosion area by
multiplying the magnification of the microscope to its maximum setting. (The magnification
ratio is preferably 200 or higher.)
d) After identifying the deepest erosion area, focus the microscope’s lens on an uneroded
area within the view angle by rotating the lens slide knob.
e) Press the zero setting button of the digital indicator to reset the indicated value to zero.
f) Then, rotate the lens slide knob of the microscope to focus on the deepest erosion area.
g) Read and record the value indicated on the digital indicator.
h) It is preferable to take a photograph of the erosion area if possible.
i) The position where the erosion seems to be the deepest is measured at three places or
more on each face and the maximum value is adopted as erosion depth. To exclude the
influence of the erosion generated by dross, the evaluation area is limited to 50 mm from
the lower edge of the specimen. It is premised that the specified dipping depth is 65 mm
to 70 mm.
If maximum erosion depth estimation is needed, the extreme value statistical analysis in
Annex B should be used.
– 12 – 62739-1 © IEC:2013
6 Items to be recorded in test report
In the test report, each of the following items shall be included even if the descriptions in
Table 1 are satisfied:
a) date and time of the measurement;
b) test and measuring equipment manufacturer and equipment number;
c) specimen:
1) material and number;
2) thermal refining;
3) processing conducted (e.g. cutting, grinding);
4) surface condition;
d) solder material;
e) test conditions:
1) temperature of molten solder;
2) rotation speed;
f) presence/absence of erosion, depth of erosion;
g) condition of erosion (details of the erosion’s condition; photographs that indicate the
location of the erosion).
62739-1 © IEC:2013 – 13 –
Annex A
(normative)
Specifications of test equipment & measurement equipment
A.1 Overview
This annex provides specifications of the test equipment mentioned in 4.2.and measurement
equipment mentioned in 5.3.
A.2 Characteristics of the test equipment
A.2.1 General
The test equipment of this standard shall consist of a pot unit, rotation unit, and control unit,
each of which has the following characteristics.
A.2.2 Pot unit
a) The pot should be large enough to contain more than 5 kg of solder so that the specimen
can rotate inside of it and not to block the rotation of the specimen specified in 4.4.
b) The pot should be deep enough to dip the specimen to the specified depth.
c) If a steel pot is used, the pot surface should be processed to prevent erosion. No
particular specification is given to the surface processing.
d) The heater should be capable of melting the solder and heating the molten solder up to
400 °C.
e) If the heater needs to be dipped in the molten solder, the heater surface should be
processed to prevent erosion.
A.2.3 Rotation unit
a) The rotation unit has a motor that rotates the specimen.
b) The shaft of the rotation motor is provided with a rotation block to hold the specimen.
c) The specimen attached to the rotation block rotates in the solder at the depth specified in
4.4.
A.2.4 Control unit
a) The control unit has a temperature sensor and uses a temperature adjuster to control the
heater. The unit is capable of maintaining the temperature of the molten solder at
350 °C ± 3 °C.
b) If the temperature sensor needs to be dipped in the molten solder to the depth specified in
4.4, it is preferable that the sensor is surface processed.
c) The motor shall be controlled at a rotation speed of 100 r/min ± 3 r/min as specified in 4.4.
d) It is preferable that the elapsed time of the test specified in 4.4 can be automatically
recorded.
e) For safety reasons, it is preferable that the equipment has an interlock or other functions
to prevent overheating of the solder.
A.2.5 Ventilation
Since the specimen is rotated during the test, the dross and hot air would diffuse in the
surrounding air. It is therefore preferable that the test equipment has an exhaust air duct for
ventilation. The ventilation rate does not need to be specified if it does not affect the solder
temperature.
– 14 – 62739-1 © IEC:2013
A.3 Accuracy of the measurement equipment
A.3.1 General
The measurement equipment of this standard shall consist of an optical microscope, digital
indicator, CCD camera, TV monitor, and possess the following measurement accuracy.
A.3.2 Measurement accuracy
Measurement accuracy = depth of field + accuracy of digital indicator
a) Example of 100 times: 382 + 30 = 412 µm or less.
b) Example of 300 times: 38 + 30 = 68 µm or less.
c) Example of 600 times: 17 + 30 = 47 µm or less.

62739-1 © IEC:2013 – 15 –
Annex B
(informative)
Method of estimation of maximum erosion
depth by extreme value statistical analysis
B.1 Overview
This annex describes a method of estimating the maximum erosion depth by extreme value
statistical analysis mentioned in Clause 5 of this document.
B.2 Estimation method
B.2.1 Extreme value statistical analysis
Define N, measurement sections of the same condition on the specimen as shown in
Figure B.1. The maximum erosion depth in each section is measured experimentally and the
most probable maximum erosion depth of the specimen is estimated by using Gumbel
distribution.
Plate
specimen
n = 1
n = 2
n = 3
n = N × 1
n = N
IEC  1432/13
Figure B.1 – Example of section division of plate specimen
B.3 Estimation procedure
B.3.1 General
The measurement data is processed following the steps outlined below to conduct extreme
value statistical analysis.
B.3.2 Preparation of specimen
Use the specimen that has undergone the erosion test, and define erosion depth
measurement sections on the specimen. The measurement sections shall be those which
have undergone the test under the same conditions. Although the number of the sections is
not necessarily specified as long as the obtained data give a linear curve on a probability
paper, it is preferably eight or more.

Dipping test area
– 16 – 62739-1 © IEC:2013
B.3.3 Measurement of erosion depth
The measurement of the erosion depth is not explicitly specified herein. To obtain accurate
data, however, it is preferable to perform acid pickling to remove the solder and X-ray CT
scanning to measure the depth.
As for the measurement precision of the measurement equipment, the tolerance shall
be ± 5 µm from actual erosion depth.
B.3.4 Data arranging method
Data arrangement is carried out following the steps outlined below.
a) Define a Gumbel distribution.
The Gumbel’s maximum value distribution F(x) is obtained by Equation (B.1).
F(x) = exp[–exp{– (x–λ)/ α}] (B.1)
where x is the maximum erosion depth in the section;
λ is the position parameter;
α is the scale parameter.
b) Define y of Gumbel probability paper.
y is the standardization variable of the double exponential distribution (Gumbel
distribution) and is given by Equation (B.2) if combined with Equation (B.1). In this case, y
presents the vertical axis of the probability paper.
y = –ln{–lnF(x)} = (1/α) x– (λ/α) (B.2)
c) If plotted on a Gumbel probability paper (with the vertical axis y and the horizontal axis x),
the data give a straight line as shown in Figure B.2. x is λ when y = 0. 1/α is given by the
slope of the line Δy /Δx.
d) How to obtain the maximum erosion depth.
The return period T is defined by dividing the total area by the area of the sample section.
Here, the maximum value of x, x , can be obtained from Equation (B.3) as a function of
max
T, λ, and α.
x λ+αln{–ln(1–1/T)} ≈λ+αlnT (B.3
...