Learn about the industry-adopted IPC standards that govern every step related to the design, assembly, inspection, testing, and documentation of printed circuit boards (PCBs).
What Are IPC Standards?
IPC is the official name of the association which produces PCB-related standards. The association was formerly called the Institute for Printed Circuits (hence the acronym "IPC"), but is presently called the Association Connecting Electronics Industries—even though it retains the IPC moniker.
IPC, itself, is an international industry association consisting of more than 4,000 member companies that make, use, specify, and design PCBs and assemblies, including:
- advanced microelectronics
- aerospace and military
- automotive
- computer
- industrial equipment
- medical equipment and devices
- telecommunications industry
IPC standards are the electronics-industry-adopted standards for design, PCB manufacturing, and electronic assembly. There's an IPC standard associated with just about every step of PCB design, production, and assembly (see Figure 1).
Figure 1. Listing of IPC standards. Image courtesy of Ipcassociation [CC BY-SA 3.0]
A Short History of IPC Standards
The Institute for Printed Circuits (IPC) was founded by six printed circuit board manufacturers in 1957.
In 1977, its official name was changed to the Institute for Interconnecting and Packaging Electronic Circuits, as a result of more electronic assembly companies becoming involved with the IPC association. And by 1998, because most people in the industry either could not remember the full name and/or didn't agree on what the words in the name meant, the association adopted IPC as the official name along with the tagline: Association Connecting Electronics Industries.
An Abbreviated Timeline of Major Events for IPC and Its Standards
1958 was an eventful year for IPC as it published and sold more than 25,000 copies of its book, How to Design and Specify Printed Circuits.
Figure 2. Book cover of IPC's first published book (1957). Image courtesy of ipc.org.
1964 was also an exciting year for IPC because, according to ipc.org, the first version of their IPC-A-600 standard was published. Known as the Acceptability of Printed Boards, the IPC-A-600 standard is still the main source of visual support for the bare board acceptability requirements contained in the IPC-6010 series, and has been revised and updated seven times since 1964.
In 1978 London, as one of its first major international events, IPC sponsored the First Printed Circuit World Convention (PCWC). This conference brought together Printed Wiring Board (PWB) associations from around the world, with sponsors of this event including:
- IPC
- EIPC (European Institute for Printed Circuits)
- ICT (Institute of Circuit Technology UK)
- JPCA (Japan Printed Circuit Association)
- Printed Circuit Group IMF (Institute of Metal Finishing UK)
1994 marked a major event in the history of IPC because, for the very first time, IPC offered their certification and training program based on IPC-A-610B, Acceptability of Electronic Assemblies. Again, according toipc.org, "Today, IPC-A-610 training is conducted in many languages around the world and has a user base of more than 10,000 instructor certifications. These instructors, in turn, have trained nearly 125,000 engineers, operators, inspectors, buyers and members of management teams. In addition, this certification program has spawned a number of other IPC certification efforts."
The year 2002 brought IPC's highly-received and their most widely-used standard: the IPC-A-620, Requirements and Acceptance for Cable and Wire Harness Assemblies. I, for one, can attest as to why this standard was received so well as I have used it often and find it very insightful.
Figure 3. Front cover of standard IPC-A-620.
Some of you, like myself, may have lived through the problems associated with the adoption of lead-free solder in 2008—ugh! During that same year, to address lead-free solder problems, IPC teamed up with Electronic Components Association (ECA) and Joint Electron Device Engineering Council (JEDEC) to develop the IPC-J-STD-075 standard known as the Classification of Non-IC Electronic Components for Assembly Processes.
Figure 4. In 2008, the IPC association helps address lead-free problems, such as these tin whiskers. Image courtesy ofJonathon Reinhart.
In 2017, celebrating their 60th anniversary, the IPC worldwide membership has climbed to an all-time high with more than 4,000 member sites in 79 countries. In celebration of 60 years, IPC has created their 60th Anniversary Celebration video:
Some of IPC's Terms and Definitions
"Shall" and "Should" ... does it matter which word is used? Yes, it does!!
Under their terms and definitions sections in their IPC-A-620 standard, IPC has selected the following definitions:
- Should: Reflects recommendations and is used to reflect general industry practices and procedures for guidance only.
- Shall or Must: Mean that the requirement or attribute discussed is mandatory for all Product Classes.
And speaking of Product Classes, IPC has adopted the following three classes:
- Class 1 – General Electronic Products: Includes products suitable for applications where the major requirement is the function of the completed assembly.
- Class 2 – Dedicated Service Electronic Products: Includes products where continued performance and extended life is required, and for which uninterrupted service is desired but not critical. Typically, the end-use environment would not cause failures.
- Class 3 – High Performance Electronic Products: Includes products where continued performance or performance-on-demand is critical, equipment downtime cannot be tolerated, and end-use environment may be uncommonly harsh, and the equipment must function when required, such as life support systems and other critical systems.
Some IPC Examples
When considering solder splices, according to the IPC-A-620 standard, "Using splices to repair broken or damaged conductors are not permitted for Classes 2 and 3 without end-user concurrence prior to the repair."
The IPC-A-620 standard calls out four acceptable methods for splicing conductors, which are:
- Mesh (see example below)
- Wrap
- Hook
- Lap
As shown in the figure below, IPC uses both words and images for describing the proper procedure, process indication, and defects for solder splicing.
Figure 5. Solder Splices – Mesh method. Image courtesy IPC-A-620. Click to enlarge.
With regards to the proper method for mounting DIP and SIP pins and sockets, IPC clearly—again using words coupled with images—explains what is acceptable (see figure below).
Figure 6. Proper mounting for DIP/SIP pins and sockets. Image courtesy of IPC-A-610C.
Where to Get IPC Standards
While IPC standards are not free, they can be purchased for a discount from the IPC store if you're an IPC member. There are other online stores, such as Soldertools.net, that sell them too.
No comments:
Post a Comment