《BS-EN-60068-2-44-1995 IEC-60068-2-44-1995.pdf》由会员分享，可在线阅读，更多相关《BS-EN-60068-2-44-1995 IEC-60068-2-44-1995.pdf（22页珍藏版）》请在三一文库上搜索。
1、BRITISH STANDARD BS EN 60068-2-44: 1995 IEC 68-2-44: 1995 Environmental testing Part 2: Tests Guidance on Test T. Soldering The European Standard EN 60068-2-44:1995 has the status of a British Standard Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 09 06:07:33 GMT+00:00 2006, Uncontrolled Copy,
2、 (c) BSI BS EN 60068-2-44:1995 This British Standard, having been prepared under the direction of the Electrotechnical Sector Board, was published under the authority of the Standards Board and comes into effect on 15 December 1995 BSI 01-2000 The following BSI references relate to the work on this
3、standard: Committee reference GEL/50 Draft for comment 94/209929 DC ISBN 0 580 24865 8 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee GEL/50, Environmental testing of electrotechnical products, upon which the following b
4、odies were represented: Federation of the Electronics Industry Gambica (BEAMA) Ltd. Ministry of Defence Society of Motor Manufacturers and Traders Limited Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 09 06:07:33 GMT+00:00 2006, Uncontro
5、lled Copy, (c) BSI BS EN 60068-2-44:1995 BSI 01-2000i Contents Page Committees responsibleInside front cover National forewordii Foreword2 Text of EN 60068-2-443 List of referencesInside back cover Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 09 06:07:33 GMT+00:00 2006, Uncontrolled Copy, (c)
6、 BSI BS EN 60068-2-44:1995 ii BSI 01-2000 National foreword This Part of BS EN 60068 has been prepared by Technical Committee GEL/50 and is the English Language version of EN 60068-2-44:1995 Environmental testing. Part 2: Tests Guidance on Test T: Soldering, published by the European Committee for E
7、lectrotechnical Standardization (CENELEC). It is identical with IEC 68-2-44:1995 Environmental testing Part 2: Tests Guidance on Test T. Soldering, published by the International Electrotechnical Commission (IEC), including the corrigenda of May 1995 and August 1995. This standard supersedes BS 2011
8、-2.2T:1981 which is withdrawn. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-refe
9、rences Publication referred toCorresponding British Standard BS 2011 Environmental testing Part 2.1 Tests HD 323.2.20 S3:1988 (IEC 68-2-20:1979) Part 2.1T:1981 Test T. Soldering HD 323.2.54 S1:1987 (IEC 68-2-54:1985) Part 2.1Ta:1989 Test Ta. Soldering. Solderability testing by the wetting balance me
10、thod HD 323.2.58 S1:1991 (IEC 68-2-58:1989) Part 2.1Td:1990 Test Td. Solderability, resistance to dissolution of metallization and to soldering heat of surface mounting devices (SMD) EN 60249 seriesBS EN 60249 Base materials for printed circuits HD 313 S1 series (IEC 249 series) BS 4584 Metal-clad b
11、ase materials for printed wiring boards IEC 326-2:1990BS 6221 Printed wiring boards Part 2:1991 Methods of test Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 16, an inside back cover and a back cover. This standard has be
12、en updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 09 06:07:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE N
13、ORM EN 60068-2-44 March 1995 ICS 19.040Supersedes HD 323.2.44 S1:1988 Incorporates corrigendum May 1995 Descriptors: Electricity, components, equipment, soft soldering, procedures, components specifications writing English version Environmental testing Part 2: Tests Guidance on Test T: Soldering (IE
14、C 68-2-44:1995) Essais denvironment Partie 2: Essais Guide pour lessai T: Soudure (CEI 68-2-44:1995) Umweltprfungen Teil 2: Prfungen Leitfaden fr die Prfung T: Lten (IEC 68-2-44:1995) This European Standard was approved by CENELEC on 1995-03-06. CENELEC members are bound to comply with the CEN/CENEL
15、EC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CE
16、NELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official version
17、s. CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardi
18、zation Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1995 Copyright reserved to CENELEC members Ref. No. EN 60068-2-44:1995 E Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 09 06:07:33 GM
19、T+00:00 2006, Uncontrolled Copy, (c) BSI EN 60068-2-44:1995 BSI 01-2000 2 Foreword The text of document 50(CO)265, future edition 2 of IEC 68-2-44, prepared by TC 50, Environmental testing, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60068-2-44 on 1995-03-06. Thi
20、s European Standard supersedes HD 323.2.44 S1:1988. The following dates were fixed: Annexes designated “normative” are part of the body of the standard. In this standard, Annex ZA is normative. Annex ZA has been added by CENELEC. Contents Page Foreword2 Section 1. General3 1Scope3 2Normative referen
21、ces3 Section 2. General principles3 3Introduction3 4Solderability of components and wettability of their terminations3 5Place of solderability in environmental testing4 6Solderability tests5 7Wettability tests5 8Explanations of the test conditions8 9Requirements and the statistical character of resu
22、lts10 Section 3. Guide to the use of the wetting balance for solderability testing11 10General11 11Characteristics of test apparatus11 12Examples of representative force-time curves13 13Parameters to be measured from the force-time trace13 Annex ZA (normative) Other international publications quoted
23、 in this standard with the references of the relevant European publications16 Figure 18 Figure 214 latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement(dop) 1996-03-01 latest date by which the national standards confli
24、cting with the EN have to be withdrawn(dow) 1996-03-01 Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 09 06:07:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 60068-2-44:1995 BSI 01-20003 Section 1. General 1 Scope The purpose of this International Standard is to provide background information
25、 and recommendations for writers of specifications containing references to IEC 68-2-20, IEC 68-2-54 and IEC 68-2-58. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of IEC 68. At the time of public
26、ation of this standard, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on this part of IEC 68 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. Members of
27、 IEC and ISO maintain registers of currently valid International Standards. IEC 68-2-20:1979, Environmental testing Part 2: Tests Test T: Soldering Amendment 2 (1987). IEC 68-2-54:1985, Basic environmental testing procedures Part 2: Tests Test Ta: Soldering Solderability testing by the wetting balan
28、ce method. IEC 68-2-58:1989, Environmental testing Part 2: Tests Test Td: Solderability, resistance to dissolution of metallization and to soldering heat of Surface Mounting Devices (SMD). Series IEC 249, Base materials for printed circuits. IEC 326-2:1990, Printed boards Part 2: Test methods. Secti
29、on 2. General principles 3 Introduction The conditions on which the ease of making and the reliability of a soldered joint depend may be classified in three groups as follows: a) The joint design, determined by the choice of the two metallic elements to be joined (their shape, size, composition, etc
30、.) and of the assembly method (relative position, initial fastening, etc.). b) The wettability of the surfaces to be joined. c) The conditions adopted for the soldering operation (temperature, time, flux, solder alloy, equipment etc.). The choice of conditions of classes a) and c) concerns the manuf
31、acturer of equipment or subassemblies, who shall know the importance of each of the conditions and the limits of their variation. Condition b) depends for the most part on the component manufacturer, except in cases of unusual handling or storage conditions by the equipment manufacturer. The wettabi
32、lity of surfaces needs to be defined with whatever degree of precision is necessary to allow the equipment manufacturer to choose conditions of classes a) and c) appropriate to that wettability. On the other hand, components of satisfactory surface quality will not necessarily prevent rejectable joi
33、nts arising from faults in joint design or joining conditions. This often complex overlapping of responsibility between component manufacturers and equipment manufacturers creates a need to be able to define with considerable precision the wettability of component terminations or, more generally, th
34、e solderability of components. 4 Solderability of components and wettability of their terminations It is not sufficient that an electronic component should have terminations that are suitable for soldering (capable of being wetted by molten solder). For mass-soldering operations it shall fulfil thre
35、e other requirements: a) it shall possess thermal characteristics (“thermal demand”) small enough for a temperature sufficiently higher than the liquidus of the solder alloy used, to be reached and maintained for the length of time for wetting to occur; b) it shall withstand without short-term or lo
36、ng-term change the thermal stresses associated with the soldering cycle (including rework and possible repair by soldering iron); c) it shall withstand without short-term or long-term damage the mechanical and chemical stresses accompanying cleaning operations for the removal of flux residues. Clean
37、ing considerations are not emphasized in this Guide. Thus certain electronic components containing lubricated mechanical parts (e.g. switches), or being unsealed are sensitive to contamination (e.g. relays, potentiometers), or containing a plastics material with poor heat resistance (e.g. certain ca
38、pacitors with thermoplastic dielectric), shall be excluded from mass-soldering operations because of their inability to withstand one or more of the stresses associated with the process. Licensed Copy: sheffieldun sheffieldun, na, Thu Nov 09 06:07:33 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 600
39、68-2-44:1995 4 BSI 01-2000 For these reasons careful distinction must be made between the solderability of the component, which refers to the total suitability for industrial soldering, and the wettability of the termination, which refers only to the ease of coating the termination with solder. Unfo
40、rtunately, these concepts are often confused in ordinary language, and such confusion can prevent smooth running of production. Furthermore, unsuitability of a component for soldering under the general conditions specified (see clause 6) does not mean that its terminations cannot be soldered to a pr
41、inted circuit board or other support; it means only that it is necessary to take special precautions depending on the condition it does not satisfy, such as having thermally-sensitive insulation, or incompatibility with some or all solvents. Only defective wettability of the terminations prevents th
42、e use of soldering for mounting the component; this quality is of prime importance, but does not exclude consideration of the others. The standardized tests referred to here are all directed to simulating some part of the effects of this set of conditions. The appropriate choice of a group of these
43、tests, in conjunction with electrical and mechanical measurements, allows one to answer the question, “Is this component solderable by the methods normally used in electronics?”. This is one of the questions which the equipment manufacturer shall ask himself before putting a component on a soldering
44、 line. The principle of each standardized test and the degree of information it supplies are defined in clause 5. In this way the component specifier can, in full knowledge of the reasons, select the number and type of tests needed to establish the behaviour of the component during soldering; and th
45、e requirements that he will lay down in every case reflect the general requirements of the method of manufacture. Similarly, the person conducting the tests will appreciate the degree of information they will give him. 5 Place of solderability in environmental testing In previous sections the exact
46、significance of the tests has been examined to show how they may be used to answer the question, “Is this component solderable in practice by normal methods?”. The reply can be as discriminating as necessary; the tools for making the necessary distinctions exist. But this question, however important
47、, is never the only one. Solderability is but one element in the characterization of a component; performance, robustness, expected life, etc., also play a part. If the sequence of tests is not specifically covered in solderability test specifications, the result can be influenced by the conditions
48、the component has encountered during previous tests. Therefore, it is necessary to be very careful in placing the solderability tests in the test sequence. Neglect of this may produce false results for solderability, and may equally falsify the results of other tests on component characteristics. EX
49、AMPLES: if, in a sequence of tests, a long-term damp heat or corrosion test is required before a wettability test, a component could be rejected even if, had it been tested as received, the wettability would have been perfectly acceptable. Certainly, in practice, electronic components are always soldered in place in the equipment before experiencing the environments simulated by damp heat or salt spray; conversely, if the resistance to soldering heat Test Tb is applied before the robustness of terminations test, intended quite correctly