This
photo shows 38 AWG micro-coaxial cable with a three-stage strip. This type
of cable is used in medical, telecom and consumer electronics
applications. Photo courtesy Schleuniger.
Increasingly, assemblers in the automotive industry are processing wire that is sized 26 AWG and smaller as they try to save weight and space in their products. Just how small is 26 AWG wire? Its conductor diameter is 0.405 millimeter, which is about five strands of human hair.
“We continue to see an increase of interest in our 26 gauge wire from all automotive OEMs,” says John Kightlinger, supervisor of advanced processes at Delphi Packard Electrical/Electronic Architecture’s technical center in Champion, OH. Delphi had been using 22 AWG wire for these applications, but, to save weight and space, switched to the thinner wire once they developed a way to give it the same mechanical strength as 22 AWG.
We used 22 gauge cable not because it was required for the current-carrying capability or the voltage drop, but because of its mechanical strength.” For this reason, says Kightlinger, until 2008, the smallest wire Delphi used in automotive wiring harnesses was 22 AWG cable.
By downsizing to 26 gauge wire, Delphi saves up to 60 percent in terms of mass and bundle size, without lessening product manufacturability, which is a big benefit to the customer, says Kightlinger.
Delphi has been producing 26 AWG wire since October 2008, and uses it on signal and low energy circuits for vehicle interiors,” says Kightlinger. The wiring set for the vehicle interior application consists of about 170 leads or wires, 90 of which are 26 AWG. This wire is installed by hand.
The company makes the extruded (seven strand) wire at several global sites based on each regional market they have the product in. Delphi covers the wire with an ultra-thin insulation (0.2 mm) that is halogen-free. Wire length ranges from one-half to five meters, with the average lead length being 1.5 meters.
Kightlinger says Delphi has put two more applications of the wire in production in different regions. The company currently is developing a sealing technique so the 26 AWG can be used for vehicle exteriors.
This halogen-free cable has been named a finalist for the 2010 Automotive News PACE (Premier Automotive Suppliers’ Contribution to Excellence) Awards, which honor superior innovation, technological advancement and business performance among automotive suppliers. The prestigious award is recognized around the world as the industry symbol of innovation.
PACE award finalists have come from [BB1] the U.S., Canada, Mexico, Brazil, Italy, Spain, France, Belgium, Luxembourg, Switzerland, Germany, Australia, Korea and Japan. The winning technologies will be announced in Detroit on April 12, 2010. Visit http://www.autonews.com for more information.
To process wire, Delphi both makes its own equipment and buys equipment from well-known suppliers. It also modifies the latter so it meets Delphi standards “to give us the technology advantage we want to have.”
Delphi buys and makes its own terminals to meet customer recommendations and specifications. In addition, the company has worked with internal and external suppliers to come up with ways to perform crimp force monitoring on very small wire.
“Right now, there is no application for 30 gauge and smaller in the automotive industry that Delphi’s aware of,” says Kightlinger. “There are a few applications with 28 AWG in the industry, such as a twisted jacketed shield assembly for a data cable similar to that which you might find on your computer.”
Nonetheless, for the past year, Delphi has been researching the development of 28 and 30 AWG wire. “It’s not necessarily in production but we’ve been looking at developing both the cable and the processing for about a year.”
One of the things Kightlinger sees as a challenge with this very small wire is developing its tensile and column strength so it equals that of 22 AWG wire.
“Even if we can develop the tensile strength using some kind of exotic cores or materials, the column strength may still not be there,” he says. “So we’re evaluating what we can do from automation and manufacturing standpoints to build these cables. I’d like to say it will be developed this year, but the industry is not ready to make the transition to 28 and 30 AWG yet.”
