Original Date: 02/19/2007
Revision Date: / /
Best Practice : Wire Assembly Work Directors
Raytheon’s Network Centric Systems Manufacturing Center in Largo, Florida, has made changes to its wire/cable harness operations that greatly reduce the build errors and subsequent rework, resulting in lower overall cost and higher reliability. With the changed method of building and testing wiring harnesses concurrently, the company has been able to virtually eliminate rework due to wiring errors and reduce build cycle times by a factor greater than 4.
The building of cable and wiring harness assemblies is an exacting and time-consuming process. Any errors in the build process are not normally discovered until the completed harnesses are subjected to test and then must be sent back to the assembly area for repair/correction. This added “regressive flow” or rework contributes to added costs and possible added cable failures due to handling. Raytheon’s Network Centric Systems (NCS) Manufacturing Center in Largo, Florida, has made changes to its wire/cable harness operations that greatly reduce the build errors and subsequent rework, resulting in lower overall cost and higher reliability.
Many wiring harness manufacturers will typically determine the approximate length, type, and color of each wire in a harness; cut and mark the wire; terminate one end of the wire with crimp or solder pins; bundle all of the wires into a wire bundle; and pass this bundle on to an assembly person to complete the harness. Using assembly aids such as wiring harness boards, wiring tables, from-to paper wiring lists, and other aids, the assembly individual will then build the cable harness. Terminated wires are installed into one connector of the harness; wire numbers or other identifications are located on each wire; and that wire is prepared, terminated, and installed into the proper location of the connector at the end of the harness. This method is extremely labor-intensive and lends itself to many errors.
Raytheon Largo has changed the method that it uses to manufacture many of its wiring harness assemblies to improve quality and reduce errors, rework, and cycle time. By using a commercially available PC-based Cirris system, Raytheon Largo has been able to replace many of the old assembly aids with a highly reliable and accurate process for the assembly build operators. The new system, coupled with a mechanical interface, allows the operator to search a prepped wire bundle for wires through body conductance in lieu of visually looking for wire marking or identification. The operator then receives an initial visual and audible prompt that the correct wire has been selected followed by a second audible and visual prompt that the wire has correctly been terminated at its other end. This process is a “verify-as-you-go” approach that provides real-time feedback at each incremental level of harness assembly. This system uses wiring instructions guided by electronic media with enhanced graphics. The operator can see the proper wire termination point on the screen and is guided by color coding of the proper point, receiving audible verification that the wire is installed into the proper connector pin location.
Since implementing the Cirris system in 2003, Raytheon Largo has seen first-pass yields grow from approximately 82% to 98%, typical harness build cycle times have decreased by a factor greater than 4, and regressive flow due to missed wires has been virtually eliminated. All of this has yielded significant cost reductions for the company in the cable and wiring harness along with increased quality. By not having to handle the harness assemblies to test for continuity, test times are reduced and handling-induced wire breakage is eliminated.
For more information see the
Point of Contact for this survey.