The latest revision of the IPC-WHMA-A-620 standard for the acceptance of cable and wire harness assemblies was published in February.
Jointly developed by the Wiring Harness Manufacturers Association (WHMA) and the IPC—Association Connecting Electronics Industries, the standard debuted in 2002 and quickly became the most important process, materials and inspection document in the industry. Worldwide, more than 11,000 people are certified as either trainers of the standard or users of the standard (assemblers, testers and repair technicians).
The standard was revised for the first time in 2006 and again 2012. Now, revision C of the standard has just been released after 28 months of work. The standard was revised to include technical updates and make it easier to use.
“We looked at all the criteria,” says Teresa Rowe, director of assembly and standards technology at IPC. “If someone had issues with something in the standard, we reviewed the concern and added industry data [to back up our criteria.]”
As with previous updates, special emphasis was placed on the graphics to illustrate concepts in the standard.
“In many places, the criteria refer to a specific figure, so we spent a lot of time going over the figures, reviewing what users were looking for and what trainers were telling us,” says Rowe.
In some cases, IPC and WHMA sought to harmonize requirements in the A-620 standard with related criteria in other industry standards, such as J-STD-001 Requirements for Soldered Electrical and Electronic Assemblies and IPC-A-610 Acceptability of Electronic Assemblies. For example, the criteria for soldering gold cup terminals in J-STD-001 were adopted for A-620.
“Cable assemblies are different than electronic assemblies, but there is good information in those other standards that could be applied to A-620, particularly for those manufacturers that use all three documents,” says Rowe. “If you have to cross-train employees, it’s easier if the criteria are similar wherever it makes sense.”
Revision C of A-620 also includes entirely new sections covering safety wiring, safety cable, wire seals, grommets and raceways. In addition, the section on jack posts was improved significantly.
Built on Consensus
Since Revision B of A-620 was published five years ago, IPC and WHMA have received hundreds of comments and suggestions from users and trainers.
In drafting Revision C, IPC and WHMA relied on a task force of 130 industry professionals to assess, approve or reject any changes. To streamline the process, a special subcommittee—dubbed the “A Team”—culled through the comments. Simple changes (minor rewording or clarifications) were adopted right away. More complicated issues were referred to expert subcommittees for review before being presented to the entire task force for a vote.
“The standard was built on consensus,” says Rowe. “The meetings were very formal.”
The finished product, IPC-WHMA-A-620C, is 428 pages long and contains more than 700 full-color illustrations. The standard can be purchased digitally, in print form, or on CD-ROM. Spanish, Chinese, German, Danish, Polish and French versions will be released later this year, and a “red-line document” highlighting every change made to revision B was expected to be published at press time. The standard costs $190.
The A-620 standard is being followed by harness assemblers in 42 countries. More than 1,000 companies worldwide employ at least one person who is IPC-certified to train others in the use of the standard, and hundreds more employ at least one assembler who is certified in the use of the standard.
Trainers and assemblers who are currently certified will not need to get recertified now that revision C has been published. Their current certification will remain valid for the normal two-year period.
Alex Conley, training coordinator at Business Electronics Soldering Technologies (BEST), can attest to the growing popularity of the A-620 standard. Based in the Chicago suburb of Rolling Meadows, IL, BEST provides electronics assembly and rework services, as well as certification training for both operators and instructors in various IPC standards, including A-620.
BEST offers the three-day A-620 courses in facilities in Rolling Meadows; Auburn Hills, MI; Rosemount, MN; Cleveland; and Huntsville, AL. The company also offers the option of teaching the courses at a customer’s assembly plant.
“We’ve been teaching a lot more A-620 classes in the past two years,” says Conley. “It’s one of the top three classes we offer. The industry has really recognized that as their standard.”
Harness assemblers and OEMs are using the A-620 standard in several ways. The first is as a workmanship standard for operators. The standard provides hundreds of photos, sketches and diagrams of good and bad parts. Having a standard ensures that harnesses will not be accepted or rejected based on one individual’s opinion of what is good or bad.
Before the A-620 standard, there were a lot of different guidelines and references for cable and wire harness assembly, recalls Rowe. Today, the industry has truly embraced the standard. It’s a reference developed by the industry, for the industry.
“Revision C isn’t just acceptance criteria; it also has requirements and processing information. There’s a lot of good stuff in the document that harness and cable manufacturers can use to build their products,” she says.
The standard can also be used to train employees to spot, say, a faulty crimp or a poor solder joint, even if they don’t perform those particular processes themselves. By knowing the A-620 standard, downstream assemblers can act as quality inspectors of a sort, checking over cable or harness assemblies as they install them in the final product.
The A-620 standard can be incorporated into assemblers’ quality management systems, supporting ISO and regulatory requirements. Being able to document that staff have been trained and certified to the A-620 standard gives harness shops the ability to prove both personal and process effectiveness.
“Manufacturers are pushing the standard to their suppliers,” says Rowe. “They are making compliance with the standard a contractual requirement.”
The standard can also help assemblers achieve operational excellence. With consistent criteria, harness shop managers can categorize defects and monitor their operations’ internal and external quality. Armed with data, managers can then set goals for internal quality and track those results based on the defects they’re finding.
Finally, many harness shops use A-620 as a marketing tool. The three most important things to any OEM customer are quality, delivery and price. With tools such as the A-620 standard to enhance quality, harness shop owners will also influence delivery and cost.