Harness Standard
Effort Expands

WHMA-IPC 3710 started
as one document but now is a library

By Jennifer Read

Over the past several years a group of Wire Harness Manufacturers Association members have met with representatives of the IPC to develop an Acceptability Standard for wire harness manufacturers. While the work on that document is well underway, the committee has decided to address a number of other issues as well.

The standard originally was intended to be a collection of visual quality acceptability requirements for wire and harness assemblies. It is being prepared through a joint effort between the WHMA and the Product Assurance Committee of the IPC. The Committee has met six times so far and will continue to have four to six meetings a year. Other items planned for the collection of documents include a handbook, design document, and a glossary of terms and definitions.

The standard will be available as a stand-alone document for purchasing products, however it does not specify frequency of in-process inspection or frequency of end product inspection, and no limit is placed on the number of process indicators or the number of allowable repair/rework of defects. Such information should be developed with a statistical process control plan. The purpose of the acceptability document is to describe criteria for determining acceptable crimped, mechanically secured, or soldered interconnections and the associated lacing/restraining criteria associated with cable and harness assemblies. It is not the intent of the committee or the document to exclude any acceptable procedure used to make the electrical connection; however, the methods used must produce completed assemblies that conform to the acceptability requirements described in the document.

The acceptability document follows a standard format. There is a written description of what is required along with a picture or drawing of a "target condition." Following are pictures or drawings of "acceptable conditions" along with word descriptions. Finally, there will be pictures or drawings showing "unacceptable conditions" along with a description. This is the format IPC follows for its documents.

The committee's kick-off meeting was held at IPC headquarters in Northbrook, Illinois, just outside of Chicago. Other meetings have been set to coincide with IPC meetings, and the Chicago ATE show. In addition, the committee has met at the WHMA convention meeting, where interested WHMA members were invited to attend.

IPC contributes the technical support in the document production process, while WHMA members provide the technical expertise to write the content. IPC and WHMA will both disseminate the material once it is completed. The acceptability document will include sections on connectorization, terminations, cables and wire preparation, labels/marking; molding/potting/ encapsulation, shields and shielding, protective coverings, packaging, handling and testing.

There will be a final approval process whereby the committee arrives at a draft they find acceptable; then they publish the document and send it out to interested parties for their review and comment. The committee then reviews the industry comments and discusses them. When all the agreed upon changes have been implemented, a notice is sent out that the final document is available for review and it is then sent out to those who request it, along with those who responded to the first issue. This process is continued until all comments have been addressed.

Vernon Judy, president of Qualastat Electronics, is co-chair of WHMA's Industry Technical Guidelines Committee. He estimates that a total of 30 people have become involved in the production of this standard. He believes that once it is completed, the standard will contribute to the overall status of the wire harness industry. "Having a standard that can be used to establish guidelines for acceptable wiring harnesses and cable assemblies will show users we are serious about quality and reliability. While there are no plans at the present time to require any type of certification process, the document does state that personnel manufacturing to the spec must be proficient in the processes used. This will be the definitive reference source for quality control managers. It is intended to bring a higher level of quality to the industry as a whole. We also hope it will be used universally, in all applications, but we realize that there are some markets where standards exist already that aren't going to change. Our desire is to have our customers accept this document as their standards, allowing manufacturers to make harnesses to one specification."

Other individuals who have played a key role in WHMA-IPC 3710 include Ray Sweeney, operations manager, Unlimited Services; Brett Miller, manufacturing engineer, USA Harness; Richard Francis, senior quality engineer, Carlyle, Inc.; Troy Agner, engineering manager, ESI; Lowell Nutter, engineering manager, Sine Systems; and John Mastroianni, president and CEO of Intercon, Inc. Jack Crawford of IPC has coordinated that organization's involvement.

The IPC is a US-based trade association dedicated to the competitive excellence and financial success of the nearly 2,600 member companies which represent all facets of the electronics interconnection industry, including design, printed wiring board manufacturing and electronics assembly IPC is a member-driven organization and leading source for industry standards, training, market research and public-policy advocacy. The IPC is headquartered in Northbrook, Illinois, and can be reached at 847-509-9700, or at their website, http://www.ipc.org.