When is a standard not a standard? Not all standards are equal.

Common use of the word "standard," implies a document that provides direction. A "specification" includes measurable criteria (numbers and dimensions). Dictionaries, such as IPC-T-50 Terms and Definitions for Interconnecting and Packaging Electronic Circuits, define such terms. Simply put, I'm asking the reader to broaden his or her definition of a standard.

The front cover of most documents published by IPC feature a simple line: "A standard developed by IPC." For many years, these words have been included on any document that is developed following the American National Standards Institute (ANSI)-approved standard development process. In reality, the IPC publishes a broad range of support documents that do not feature specific requirements and do not use words such as shall/shall not or must/must not. Such documents, usually identified in the title as guides or handbooks, are a form of a standard.

Cleanliness Testing Guidelines

One of the industry's most popular series of handbooks and guides is related to cleaning and cleanliness testing. IPC-CH-65 Guidelines for Cleaning of Printed Boards and Assemblies, revised in 1999, is the largest of the cleaning support handbooks and provides a broad view of cleaning processes and comparisons of those processes. Three other handbooks are included in the series. The first, IPC-AC-62 Post Solder Aqueous Cleaning Handbook, addresses aqueous cleaning of electrical/electronic parts and application tools after soldering and also provides a basic understanding to users, or prospective users, of aqueous cleaning technology, allowing selection or improvement of aqueous cleaning processes.

The second handbook, IPC-SC-60 Post Solder Solvent Cleaning Handbook, was also revised in 1999 and features information on solvent cleaning materials. The third process-specific handbook, IPC-SA-61 Post-Solder Semi-Aqueous Cleaning Handbook, revised in 2002, features the most up-to-date cleaning documents available to the industry today.

Some facilities determine cleanliness by referring to IPC-9201 Surface Insulation Resistance Handbook, but, with new assembly materials in use, extended discussions are needed to decide if the document is a meaningful cleanliness measurement. The Electronics Manufacturing Productivity Facility (EMPF), operated by the American Competitiveness Institute, performed extensive studies in the mid-1990s on the meaning of ionic cleanliness and published EMPF-RR-0013. The report, boasting more than 200 pages, is full of tables and research data. The report has been republished, by permission, as IPC-TR-583, An In-Depth Look At Ionic Cleanliness Testing. Other facilities use technical papers, such as IPC-TP-1115, Selection and Implementation Strategy for a Low-Residue No-Clean Process, to bypass the cleaning process once and for all.

Handbooks to Explain Standards?

IPC-HDBK-001, Handbook and Guide to Supplement J-STD-001, originally published in 1998, was developed to help users decipher what ANSI/IPC-J-STD-001B meant by using the words must and shall in relation to Class 1, 2 or 3 hardware, and whether or not the words expressed a requirement (if Table 11-1 did not define nonconformance as a defect). Fortunately for users, in addition to eliminating conflicts to IPC-A-610C, IPC/EIA J-STD-001, Revision C made the requirements much easier to understand. The HDBK-001 committee was not to be outdone--if the standard could be improved, the handbook could be improved as well!

When IPC/EIA J-STD-001C was published, the handbook was revised to help users transition from revision B to C of J-STD-001. The handbook provides extensive cross-reference tables and explanations of all changes. Several of the appendices in J-STD-001B were moved to the handbook, with expanded explanations. At 164 pages, and with graphs and additional illustrations, the information was so helpful that the Training Technical Committee added the handbook as a reference document for the J-STD-001 Training and Certification Course. Other widely used support documents for J-STD-001 users are: 1) IPC-TP-1114, The Layman's Guide to Qualifying a Process to J-STD-O01 and 2) IPC-7530, Guidelines for Temperature Profiling for Mass Soldering (Reflow & Wave) Processes.

Conformal Coatings

The industry's two newest handbooks, published in September 2002, are IPC-HDBK-830, Guidelines for Design, Selection and Application of Conformal Coatings and IPC-HDBK-610, Handbook and Guide to IPC-A-610 that includes IPC-A-610B to C Comparison. The conformal material qualification standard IPC-CC-830, Qualification & Performance of Electrical Insulating Compound for Printed Board Assemblies has been in use since 1984 (revision B released in August 2002) and features a number of assembly standards addressing coverage requirements. HDBK-830, at over 80 pages, brings together the knowledge of experts on when and how to select coatings, which coatings to use and available methodology for applying different types of coatings. The EMPF also performed extensive research on the performance of conformal coatings versus no-clean flux residue. The research, originally published as EMPF-PP-0014 and EMPF-PP-0015, is included, by permission, as appendices to the new handbook.

Assembly Acceptance Standard

IPC-HDBK-610, at 120 pages, includes explanations on why the committee set certain criteria and helps readers understand the requirements of the most widely used assembly acceptance standard in the industry. The handbook also includes an extensive discussion of the differences between IPC-A-610 versions B and C, cross-reference tables of the two versions, an explanation of minimum electrical clearance, a copy of the U.S. Department of Defense adoption notice and a printed copy of Amendment 1 to IPC-A-610C.

Balloters included representatives from U.S. Army and Navy engineering activities, North American and European satellite and space agencies, the avionics industry, the automotive industry, original equipment manufacturers (OEMs), and global electronics manufacturing services (EMS) providers.

Conclusion

Intentionally, none of the documents described here contain binding acceptance criteria/requirements. Is each document a standard? Most certainly! So, when is a standard not a standard? Only when the document does not have consensus of acceptance!

Jack Craw ford is director of assembly, standards and technology with IPC, Northbrook, IL; [phone]; e-mail: [e-mail]