Environmental testing for electric and electronic products--Part 2:Test methods--Test XA and guidance:Immersion in cleaning solvents
Some standard content:
GB/T2423.30—1999
This standard is equivalent to IEC68-2-45 (1980 1st edition) "Basic environmental test procedures Part 2: Test methods Test XA and Guide: Immersion in cleaning agents" and the first amendment in 1993. This standard is a revision of GB/T2423.30-1982 "Basic environmental test procedures for electric and electronic products Test XA: Immersion in cleaning agents" and GB/T2424.18-1982 "Basic environmental test procedures for electric and electronic products Guide for immersion in cleaning agents". In the 1982 edition of the national standard, the appendix of IEC68-2-45 was formulated as a guideline standard. During this revision, it was still merged into one standard according to the principle of equivalent adoption. This standard was first issued in 1982, revised for the first time in August 1999, and implemented on March 1, 2000. From the date of implementation of this standard, GB/T2423.30-1982 and GB/T2424.18-1982 will be replaced at the same time. Considering the harmful effects of F113 on the environment, this standard has been revised to add provisions for restricting its use. Appendix A and Appendix B in this standard are both standard appendices. This standard is proposed by the Ministry of Information Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Environmental Conditions and Environmental Tests for Electrical and Electronic Products. The drafting unit of this standard is China Electronics Technology Standardization Institute. The main drafter of this standard is Han Ruifu.
GB/T2423.30-1999
IEC Foreword
1) The formal resolutions or agreements of the International Electrotechnical Commission (IEC) on technical issues are formulated by technical committees with the participation of representatives of national committees that are particularly concerned about the issue, and they express the international consensus on the issue as much as possible. 2) These resolutions or agreements are in the form of recommended standards for international use and are accepted by national committees in this sense. 3) In order to promote international unification, the International Electrotechnical Commission hopes that all national committees should adopt IEC recommended standards as their national standards when conditions permit. Any differences between IEC recommended standards and corresponding national standards should be clearly stated in the national standards as much as possible.
This standard was developed by IEC Technical Committee 50 (Environmental Testing). IEC standards referenced in this standard:
IEC653: General considerations for ultrasonic cleaning.
National Standard of the People's Republic of China
Environmental testing for electric and electronic products
Part 2: Test methodswww.bzxz.net
Test XA and guidance: Immersion in cleaning solvents1 Scope
GB/T2423.30-.1999
idt IEC 68-2-45:1993
Replaces GB/T 2423.30
GB/T 2424.18
This standard applies to test procedures in which the test specimens are immersed in a cleaning solvent at a specified temperature and for a specified time. If required by the relevant specification, the test specimens should be wiped with absorbent cotton or tissue paper after immersion and drying. Guidance for this test is given in Appendix A.
2 Purpose
To determine the extent to which electronic components (including assemblies, etc., the same below) or other parts mounted on a printed circuit board are affected by the cleaning agent specified below when immersed in the cleaning agent.
Note: This test does not simulate the impact of assembly. 3 Types of test solvents and test conditions
3.1 Solvents
This test specifies three commonly used cleaning solvents. Note: Good test results according to this test method do not mean that other solvents can be tolerated. 3.1.1 A mixture of 70%±5% of 1.1.2 trichlorotrifluoroethane and 30%±5% isopropyl alcohol by mass. Industrial pure grade should be used. Note: The components of trichlorotrifluoroethane are harmful to the environment. Therefore, do not use this solvent when the solvent specified in 3.1.2 is applicable. Note
11.1.2 Trichlorotrifluoroethane is called F113 in my country, and R113 according to IS0/R817:1974. 2 The above mixture has been sold as a finished chemical product. 3.1.2 Industrial isopropyl alcohol. Whenever possible, this solvent should be used. Note: This solvent has been sold as a finished chemical product. 3.1.3 Soft water or distilled water with a resistivity of not less than 500 Q·m (equivalent to a conductivity of 2mS/m.). Note: In the case of technical appraisal, when the relevant specifications have provisions, other solvents with similar activity to the specified solvent can be used. 3.2 Test conditions
3.2.1 Solvent temperature
For the solvent specified in 3.1.1, one of the following temperatures should be selected: 23C±5C48.6C~~50.5C (boiling point temperature). Note: The temperature of 48.6℃～50.5℃ is the boiling point of the mixture of F113 and isopropanol at the limit ratio under the pressure of 101.3kPa after one reflux. The normal boiling point is 49.2℃.
GB/T2423.30—1999
For the solvents specified in 3.1.2, the test temperature is 23℃±5℃. For the solvents specified in 3.1.3, the temperature used is 55℃±5℃. Note: For other solvents (see the note in 3.1.3), the temperature is 23℃±5℃ or the boiling point temperature specified in the relevant specifications. 3.2.2 The duration of immersion
is 5min±0.5min in each case. 4 Initial Testing
If this test is conducted to determine the effect on the surface of the marking, encapsulation or coating, the test sample shall be visually inspected. If this test is conducted to determine the effect on the performance of the test sample, the relevant specification may require the measurement of electrical and/or mechanical properties. 5 Conditional Testing
The relevant specification shall specify the use of one of the following methods. 5.1 Method 1 (wiped)
The test sample shall be completely immersed in a solvent specified in 3.1 at a temperature specified in 3.2.1 for the time specified in 3.2.2.
After removing the test sample from the solvent, let the test sample dry for at least 5 minutes, then wipe the marking area with absorbent cotton or thin roll paper to determine the durability of the marking. The relevant specification shall specify the wiping material used. Wipe a total of 10 times, five times in each direction in opposite directions. Wipe the marking area with a force of 5N ± 0.5N over an area of approximately 1cm2, and the wiping rate shall be 2 times per second. The recommended wiping device is shown in A2.3 of Appendix A. A new cotton wool or thin roll of paper should be used for each test sample.
Note: Commercially available cotton wool, such as medical cotton wool, can be used. In this standard, "thin roll of paper" refers to thin, soft and relatively tough paper, which is usually used to package fragile items. Its unit mass is between 12g/m2 and 25g/m2. Soft cotton paper sold on the market can also be used. 5.2 Method 2 (without wiping)
The test sample should be completely immersed in a solvent specified in 3.1 at a certain temperature specified in 3.2.1 and for the time specified in 3.2.2.
6 Recovery
After the test sample is removed from the solvent, if the final electrical properties and (or) mechanical properties measurement is required, the test sample should be kept under standard test atmospheric conditions for not less than 1h and not more than 2h, or for the time specified in the relevant specifications. 7 Final test
If the purpose of the test is to determine the marking , packaging, coating, etc., the test sample should be visually inspected. If the purpose of the test is to determine the impact on the working performance of the test sample, the relevant specifications may also require the measurement of electrical properties and (or) mechanical properties.
8 Provisions to be made in the relevant specifications
When the relevant specification stipulates that this test should be carried out, the following details should be given as far as possible whenever applicable: a) Solvent used (see 3.1);
b) Temperature of the solvent (see 3.2.1);
c) Initial inspection (if any) (see Chapter 4);319
GB/T2423.30—1999
d) Condition test, method 1 or method 2 (see Chapter 5); e) Wiping material (absorbent cotton or thin roll paper) (see 5.1); f) recovery time (if not 1h~2h) (see Chapter 6); g) final inspection (see Chapter 7);
h) acceptance criteria:
surface influence;
electrical and (or) mechanical performance parameters. 320
A Overview
GB/T2423.30--1999
Appendix A
(Standard Appendix)
Guidelines for Test XA
Many components or parts mounted on printed circuit boards are subject to solvent cleaning. In order to simulate the effects of this cleaning operation and to identify the solvent resistance of components or parts, Test XA should be used. Test XA includes two aspects:
a) Determine the effects on the surface of markings, packaging, coatings, etc.; b) Determine the effects on the performance of the test sample. The test sample can only be tested after at least 48 hours of printing and the ink has solidified. A2 Cleaning
A2.1 Basic Considerations (Test Methods and Solvents) Printed circuit boards with components soldered to them (i.e., printed circuit boards plus components) may be cleaned in various ways. In many cases, it is necessary to immerse the entire printed circuit board in a specified solvent, in which case the components on the board must be subjected to a short immersion in the relevant cleaning agent. The cleaning agent normally used will depend on the flux selected. A2.1.1 Printed Circuit Boards Fluxed with Rosin-Based Fluxes These boards may be effectively cleaned with a mixture of fluorocarbons and alcohols. To remove the flux and flux residues, the printed circuit boards are usually: immersed in a cold (room temperature) solvent, immersed in a boiling solvent, or immersed in a series of cold and boiling solvents. A2.1.2 Printed Circuit Boards Fluxed with Water-Soluble Fluxes These printed circuit boards are cleaned by spraying with warm water or by immersion in warm water. A2.2 Selection of Test Solvents and Test Conditions A2.2.1 Solvents
In order to remove rosin-based flux and flux residues, many different types of organic cleaning agents are used in practice, but some of them are highly corrosive, flammable or toxic. Many tests conducted in industry have shown that relatively mild solvents based on a mixture of F113 and alcohol can achieve good cleaning results while having no effect on most types of components and parts. Note: When testing or cleaning in halogenated solvents, rubber-sealed components (such as electrolytic capacitors) may be damaged or even fail because these solvents penetrate into the rubber seals.
Three solvents can be selected as test solvents because they are well matched with the main types of flux and have been widely used. These three solvents are:
a) a mixture of 70%±5% F113 and 30%±5% isopropyl alcohol by mass; b) industrial isopropyl alcohol;
c) soft water or distilled water, whose conductivity is ≤2mS/m. The mixture of F113 and isopropyl alcohol has the characteristics of low toxicity, non-flammability, stability and good cleaning function. It was used most in the past, but because F113 is harmful to the environment, its use has been gradually restricted. Note 1: If the solvent is kept within the specified concentration or boiling point range, it is non-flammable, but if excessive evaporation or boiling makes the concentration of alcohol in the remaining solvent high enough, it may cause fire or explosion hazards. 321
GB/T2423.30—1999
In the case of technical appraisal, when the relevant specifications stipulate, other solvents with similar activity to the specified solvent can be used. Note 2: Other organic solvents, such as some hydrocarbons (petroleum, benzene, toluene, etc.) or fluorinated solvents (trichloroethane, trichloroethylene, perchloroethylene, methyl monoxide, etc.), are not recommended for use in cleaning processes due to toxicity hazards, combustion hazards, insufficient stability, and excessive corrosion damage to many components and materials.
A2.2.2 Test conditions
For practical considerations and to limit the types of product cleaning conditions, the test conditions in Table A1 should be used. Table Al
a) Mixture of F113 and isopropyl alcohol
b) Industrial isopropyl alcohol
c) Water
Solvent temperature, °C
Boiling temperature
(48. 6~50.5)
Immersion time, min
Mechanical treatment
Wipe if necessary
Wipe if necessary
Wipe if necessary
Hot wipe if necessary
Note: In case of dispute, fresh solvent must be used for each test. Since this test procedure does not simulate the effects of ultrasonic energy. Therefore, ultrasonic energy is not used while immersing in the solvent. For ultrasonic cleaning issues, see IEC653.
The test temperature is selected based on the commonly used cleaning procedures. Contact of F113 and isopropyl alcohol with the skin must be avoided because, like contact with other organic solvents, it can cause skin defatting and lead to skin diseases. Generally speaking, the actual cleaning treatment is to immerse the printed circuit board in a solvent for 0.5min to 2min. For enhanced treatment, the immersion time is selected to be 5min
The temperature of the solvent must be measured during the immersion of the components or parts in the solvent, the temperature must be kept within a given range, and the boiling mixture of F113 and isopropanol must be kept boiling.
Due to evaporation, the composition of the mixture of F113 and isopropanol will change, and the concentration of isopropanol will increase, making the solvent flammable. When using 23℃±5℃ conditions, the composition of the solvent should be checked by measuring the density with an accurate hydrometer at the beginning and end of the test. The density range is shown in Table A2.
Density range, g/cm2
1.17~1.26
1.16~1.25
1. 14~1.23
When boiling point temperature is used, the composition shall be checked continuously during the test by measuring the boiling point. The boiling point shall be kept within the range of 48.6℃50.5℃, see Table A3
To avoid composition changes during the test, a simple condenser shall be used to prevent excessive loss of F113 components (two examples are given in Appendix B).
Isopropyl alcohol, %
Boiling point at 101.3kPa pressure, C
A2.3 Wiping
GB/T 2423.30—1999
In fact, after the printed circuit board is immersed in the cleaning agent, it should be wiped or scrubbed on the soldering side to remove insoluble residues or certain impurities and contaminants.
For this reason, if the relevant specifications require it, wipe the dry surface, because wiping on a wet surface may lead to irreproducible effects. Wiping is only to show that the markings on the printed circuit board remain clearly legible after the cleaning procedure. In order to obtain a wiping method with good reproducibility and independence from the operator, a suitable wiping device must be used. A recommended device is a simulated "fingertip" consisting of a rubber disc of 11.3 mm diameter (approximately 1 cm2), 5 mm thick, and 3040 Shore hardness, mounted on the back of a hard (metal or plastic) disc or rod. The rubber disc is covered with a cotton wool or soft tissue paper pad which, when pressed with a specified pressure, has a thickness of approximately 1 mm. This assembly is fixed to a pressure spring balance force measuring instrument. A pressure spring balance with a reading of approximately 10 N (approximately 1 kg) is particularly suitable.
For small components, a scaled-down modified wiping device can be used, with the top diameter reduced to 5 mm (approximately 0.2 cm2) and the force applied being approximately 1 N.
For good reproducibility, the cotton wool and tissue paper should be selected (see 5.1) of the best possible specifications. If considered necessary and permitted by the size of the test specimen, a wiping length of approximately 10 mm is recommended. A3 Practical considerations
When using cleaning solvents, relevant safety precautions should be observed. When testing the same type of components or parts under different test conditions or methods, different test samples should be used for each test. Components with insulating sleeves (such as shrinkable plastic tubes) or components with hairline cracks in their housings may produce long-term effects due to the long-term retention of absorbed solvents. Different types of components may be tested at the same time. During the soaking, the components should not contact each other or the printed circuit board to avoid mechanical effects or solution retention effects that cannot be reproduced. When conducting the test, the components can be mounted on the printed circuit board or connected to a section of wire. When mounting the components on the printed circuit board, appropriate space should be left between the components and the board and between the components. 323
Type 1:
Type 2:
Water flow
Water flow
Heating jacket
GB/T 2423.30—-1999
Appendix B
(Standard Appendix)
Apparatus for the boiling solvent test
Thermometer
Boiling phosphine solvent
Water outflow
Water outflow
Thermometer
Stagnant solvent
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