The origin and status of international norms
Both supply and demand in each of the circuit board quality inspection of the written standard, usually the most hard-board widely used by global industry about three types of international norms; that the U.S. army to MIL-P-55110, IEC-326-5/-6 and IPC- RB-276 and so on.
MIL-P-55110 has published more than 30 years, the earliest series circuit boards are also the most credibility and influence in the formal specification. E 1993, the latest version of its content is very interesting, important for the industry must-read documents, but unfortunately in recent years, the pace of the gradual loss of color behind the times.
IEC-326 "International Electrotechnical Commission" (IEC) launched by the PCB for a total of 11 series specifications. Its bones are dominated by the assault Island people for the global consultations with Member States to vote under the product content is also less stringent provisions are comprehensive, except for a few more with no one hitting business outside the general reference.
IPC formerly of the United States Institute of Printed Circuit short, only six when the founding group members. After years of growth and absorption of foreign members of the group has grown to six thousand members of the large-scale international academic organizations, and renamed "The Institute for Interconnecting and Packaging Electronic Circuits". Published its board of various quality, technology, research, and market research and other documents in large numbers for the global electronics industry relies on the downstream. However, many of its wonderful set of standards and documents, is mostly from a number of large U.S. electronics company, appears to be evolving into a set of "open justice" of the data, in fact, to facilitate the implementation of American culture in the world, namely, practical new IPC standard One of the reasons.
IPC relating to the quality of rigid circuit board norms, the original single-double of the IPC-D-250, and multilayer IPC-ML-950 and other two, after twenty years, several versions of the amendment until 1992 March was then integrated into a single system, IPC-RB-276. November 1994 276 original launch after partial revision Amendment 1, actually in the text does not appear before the revision of the 276A, ventured to the new designation is not a long time to be generally good 276 system Jing-line abandoned, but new kitchen opened up brand new IPC -6011 and IPC-6012, a considerable violation of ethical norms, the reason is that too difficult for the outsiders.
the new regulations
Hard finished before the IPC Board of official goods seized documents IPC-RB-276, Department released in March 1992, and gained considerable industry attention. Between July 1996 has been split into the IPC-6011 and IPC-6012 specification as the two new successor.
6011 of the former entitled "Overview of the circuit board performance specification" describes only a number of grading, tolerance, SPC, Quality Assurance Executive, the provisions of sampling plans in principle, did not address the practical test PCB. The latter 6012 entitled "Rigid board of accreditation and performance testing norms," Department of rigid plates for all practical quality specifications and to set Acceptable detection methods. The new specification now clearly changed the content described below:
2.1 IPC-6011:
2.1.1 The new 6011 and 6012 two specifications seem to wish to avoid the original "U.S. military rules" provisions out of the impact of military regulations. As in 6011 in the note section 1.2 of the classification, that is intentionally similar provisions from the three panels will be "Military" words removed. Another section 3.1 in 6011, also quoted in the original military specifications in Group A and Group B is deleted, its real cause is unknown, but may be obvious who is advanced PCB are no longer hope that the impact of military regulations. The complete genetic characters, however still very ambiguous word wordy, obscure mystery and feared by his best, is not off Army regulations simplified and bureaucratic stereotype.
2.1.2 The new 6011 3.6 pairs of "accreditation" has to be more clearly defined, subject to IPC-MQP-1710 list of the contents of the careful engineering capabilities PCB producers, production equipment, quality control practices detailed investigation. To do than the old standard only requires a few pieces to play model (such as IPC-A-100047, etc.) do many practical, vendor capability advantages and disadvantages of how to establish sub-clear evidence.
2.1.3 The new section 6011 of 3.6.3.3, in addition to the position of supply and demand sides, but also the independence and impartiality of the "third reviewer," such as ISO, CSA, IECQ, etc. into. Even in 3.7 also the standard of civilization that ISO -9000 Quality Assurance System. An anti-American past, consider themselves the best, turn a blind eye to the assault Chau industry mentality, this is probably a "European style" set up the market outlook, the impact of drinking places in command bar.
2.2 IPC-6012:
2.2.1 The new 6012 has a number of items seized items were not clear that the conditions (Default), also took the most widely used in the specified conditions, and is gradually shown in Table 1.1. If the next line width is limited to 4mil, Acceptable test of solder can be accessed by J-STD-003 for Catagory 2 then 6012 will be cited in the IPC-TM-650 to actually do a number of test methods, the translator also according to the latest version (1997.8 ) outlined the steps the data, so that readers can quickly obtain specific practical ideas. Please pay special attention to the industry here, many of the common test at the scene had been from time to time you may not know. In order to keep up with this translation can be outlined for the IPC-TM-650 latest version, you can compare that with the amendment.
2.2.2 The new 6012 will be in the 3.2.7 section referred to as bare copper OSP Organic Solderability Preservatives approach for the first time included in the official specification.
2.2.3 The new 6012 table 3.2 in the plating of copper on "thickness", have been major changes in the general Class 2 board (such as computer products are) the surface of copper and copper hole "average thickness" has been reduced to 0.8 mil 1mil ; lower and more reduced to 0.7mil. This is popular because of deep holes, hole copper thickness requirements difficult to meet due. Over the years the taboo has finally been broken military rules also break away from constraints of the proof, the industry will have a major impact. For the process to shorten, automatic transmission level Rise copper are very favorable terms. Class 2 of the table or on the board category of blind holes (Blind Via) the average thickness of copper, but also relax 0.6mil, lower limit can be thin to 0.5mil. Small and thin multilayer class is indeed very good news. Another copper layer in 3.11.8 on demanding stipulated that in 99.5%, the tensile strength of not less than 36000 PSI; extension rate not less than 6%. The Table 3.2 on the finger of the other end of the thickness of nickel dropped from the 0.2mil 0.1mil (Class 2 and Class 3 category were also relax the two plates).
2.2.4 The new section 6012 in 3.3.2.5 has been clear that the inner plate surface of the "black oxide" are often the spots and color, when such flaw total floor area of not more than the black of space with 10 % should be rejected. But the fact is that a reasonable change, it was difficult to see the truth behind the appearance of the customers accepted.
2.2.5 New in 3.4.4 section 6012, on the plate bending Alice also cancel the original upper limit of 1.5% of the outdated, and the other to SMT board class for years form the upper limit of 0.75% of all official languages. In fact, this merely reflects the fact that assembly of the status of compliance only, not the original flat type plug tightening of scale.
2.2.6 The new 6012 notes in its 3.6.2.14, expressly noted that its thinnest multilayer thin dielectric layer can be thin has to 1mil (276 of 3.9.2.6 in the original provision can not be less than 2mil), also goes to some reaction the fact sheet (such as some of the six board PCMCIA only 18mil thick). Also the new rules of section 3.7.2, more clearly pointed out many times on the through-hole soldering and de soldering plug the "analog Heavy" reliability test should only be for a through-hole soldering the board and do not in difficult SMT or BGA solder the board and other non-plug type of.
2.2.7 New in 3.8 in 6012 on the masking requirement, than the original IPC-RB-276 is more detailed in 3.11, also underscored the importance of masking. Also in section 3.8.1 in the special provisions of paragraph f.1, masking intentional or accidental climbing stick or BAG SMT square pad when the round pad, where the pitch (Pitch) in 50mil or more, the climbing stick The width of no more than 2mil; foot climb in less than 50mil who stick their width must be less than 1mil. The second paragraph of the original 276 in 3.11.1.f than allowed by strict 4mil many. The masking thickness requirements, 6012 and IPC-SM-840C also relaxed, no longer insists on the Class 2 category 4mil minimum thickness of the plate. But pointed out that when customers need to measure thickness, then the should from the.
2.2.8 and 3.9.1 the new 6012 "dielectric voltage" within the text, for 3mil following ultra-thin dielectric layer, to test voltage is reduced from the 500 Vdc 250 Vdc; For more than 3mil dielectric layer is still maintained Pressure of the original 500 Vdc.
2.2.9 of the original RB-276 will be "hot shock Thermal Shock" provision under section 313 in 3.12.2 environmental testing. It will be the new 6012 series in the section 3.11.9 is a "specific request" of the category, may feel more reasonable.
2.2.10 of the original RB-276 in 3.12.2.1 on connectivity (Continuity) requirements, such as Class 2 board type of resistance value is not more than 50 ohmic. The new 6012 is another in 3.9.2.1 in accordance with IPC-ET-652's provisions, rather than listing specific values. The isolation of the other 3.9.2.2 is also quasi-forth.
2.2.11 The new 6012 in its section 4.2 and 4.2.1 mentioned in the so-called C = 0 sampling plan and a list of 4.2 stipulated that the number of samples. The integrity of the quality standard, the sample seems to be an integral part; but PCB has always been 100% of the full inspection, the customer is difficult to accept but missed due to sampling problems board, unfortunately, this new specification is still that can not afford to throw such a meaningless burden.
Conclusion
Both supply and demand for some items to be seized are set in consultation with acceptance criteria, however fairly frequently stand and drinking places because of different views on differences or disputes from time to time. The latest IPC-6011 and IPC-6012, should be neutral as a powerful reference and evidence, is an important industry must-read document.
