ASSEMBLY magazine is celebrating its 50th anniversary this year. To mark the occasion, we are publishing a series of articles examining the past, present and future of various assembly technologies.
When ASSEMBLY debuted in the late 1950s, integrated circuits had just been invented and computers were new-fangled devices housed in big, mysterious boxes. An article in the May 1959 issue of the magazine examined computer assembly techniques at Autonetics (Downey, CA), which built products for engineering and scientific applications.
It explained how “some 8,347 wires leading to a possible 11,121 pin locations and connecting approximately 20,000 electronic components are assembled neatly into a space 16 inches wide, 3 feet high and 2 feet long.” Ironically, today’s wireless, handheld devices contain much more computing power, features and memory-in only a small fraction of that space.
By investing in automation, computer manufacturers were able to dramatically boost wire processing productivity and slash costs. For instance, a cover story in July 1965 revealed how IBM Corp. (Armonk, NY) used automated wire-wrap machines at several of its plants to assemble computers.
At a rate of 1,000 terminations per hour, complete computer back panels were wired automatically in 2 hours. The article explained how “each panel uses an average of 1,000 wires or approximately 2,000 termination points. The pins are connected by 24 gage wire according to intricate circuitry patterns that vary from panel to panel.”
Computers, automobiles, appliances, aircraft and other products were much simpler back in the good old days. For example, cars didn’t require miles of electrical wiring to support numerous entertainment and safety features. Power windows, clocks and radios were considered luxury items.
“Many technologies didn’t exist 50 years ago, such as satellite radio, GPS navigation, DVD video entertainment systems, anti-lock brakes, air bags, remote start and remote entry,” says Pete Doyon, vice president of product management at Schleuniger Inc. (Manchester, NH). “All of these devices require additional wire and cable. Even so-called ‘wireless’ devices require cables for antennas.”
“Cars used to have three wire circuits controlling basic circuits such as wipers, headlights and the engine starter,” notes Jim Shandersky, director of business development for the global application tooling division of Tyco Electronics Corp. (Harrisburg, PA). “Now, there are dozens of computers and hundreds of sensors throughout the vehicle that control everything from braking and pollution to stability control and crash avoidance.”
Today, many wires and hard connections have been replaced by printed circuit boards and wireless networks. “[However], almost all products in all industries have more sensors, switches, motors and other components, which are interconnected with more wire and cable than ever,” claims Doyon.
“Fifty years ago, the main application of terminated wires was carrying power,” adds Shandersky. “Control was done by switches in the power circuit. Today, signal level current is common to all applications. The wire termination process now has to handle extremely low voltage and low power applications. High frequency circuits are essential for data transmission.”
To handle this added complexity, a new generation of terminations has evolved. With those new termination devices have come an entirely new level of wire processing technology to meet those demands.
“The slightest aberration in the termination may corrupt those low-level or high-frequency signals,” Shandersky points out. “Termination machines have had to evolve to handle those demands that have increased by at least an order of magnitude.”
Wire itself has also evolved over the years. In the past, whenever anyone talked about wire processing, they were usually referring to round, coated copper wires cut to varying lengths, plus the addition of electrical connectors and seals, and the final shaping of the resulting circuits into a harness assembly. Today, wire is still round, but it’s also much smaller and sometimes even flat.
“Fifty years ago, wire insulation was usually soft PVC,” says Dave Eubanks, president of Eubanks Engineering Co. (Ontario, CA). “Today’s wire tends to be harder and thinner, which makes it more difficult to process.”
“New wires and cables have been developed with smaller sizes, new insulation materials and better electrical performance,” adds Doyon. “Insulations are thinner and wire sizes are typically smaller than in the past. [New] insulation materials, such as cross-linked PVC and halogen-free type materials, are more difficult to strip than insulations used in the past.”
Flexible flat cable was developed by aerospace engineers in the 1960s to minimize weight and space requirements. Flexible printed circuits take the technology a step further. By using automated equipment, it’s now possible to process copper foil into flexible printed circuits with parallel running copper conductors, complete with jumper connections, into as many as eight harnesses in less than 90 seconds.
New connector systems, such as RAST and other insulation displacement connections (IDC), have recently been developed as an economical alternative to traditional crimping. In contrast to a crimped connector, an IDC connector incorporates preloaded internal contacts that cut through insulation without having to strip the wire first.
“[These] new interconnection standards make it easier to install the harness into the final product,” says Doyon. “But, it requires high levels of assembly automation to derive the full benefit.”
Before the late 1950s, automatic wire strippers and other types of equipment were mechanical machines that used cams, gears and levers to dereel and measure lengths of wire. “Fully automatic, programmable cut, strip and terminate machines did not exist,” explains Doyon. “Typically, wires and cables were cut to length and stripped on one machine and taken to semiautomatic crimping presses to be terminated or tinned and assembled into the final product.
“Ink jet and laser markers did not exist, nor did machine vision,” says Doyon. “Changing something as simple as the overall wire length, stripping lengths or stripping diameters required mechanical adjustments to the equipment.”
According to Shandersky, the variety of wire processing has changed over the last few decades. “Crimping and soldering used to be the main stay,” he explains. “Now, there are termination alternatives such as IDC, resistance welding, ultrasonic welding, press fit and insertion. Plus, the complexity of the process has increased. [In addition to basic wire termination, the process now] includes many additional items that were once secondary operations, such as marking, adding seals, twisting and real-time quality monitoring.”
Automation that was developed during the 1960s and 1970s dramatically simplified wire processing and made it possible for manufacturers to assemble wire harnesses more cost-effectively. For example, a table published in the December 1977 issue of ASSEMBLY noted that the annual cost of manual vs. automatic harness forming was $490,022 vs. $138,802.
By investing in automation, engineers at Amphenol Interconnect Products Corp. (Endicott, NY) claimed to have achieved a “60 percent reduction in forming board preparation time, a 75 percent reduction in wiring labor, reduced wire usage, plus significant decreases in testing time and minimized rework.”
During the last 30 years, wire processing has become much more automated. “Today, almost all adjustments can be programmed and stored into memory and recalled for future use,” Doyon points out. “Programmability, program memory storage, PCs, software, networking and touchscreen displays have made newer equipment easier to set up and quicker to change over for different jobs.”
Wire processing is now easier and more productive, because machines are less demanding and more flexible. “Controls have advanced significantly,” notes Tyco’s Shandersky. “We have gone from AC motors, to DC motors, to stepper motors, to servomotors; each one making wire processing more flexible and easier.”
Computers have also played a key role in improving wire processing over the years. “Computer technology has been a huge influence,” says Joe Stacy, national sales manager at AmTech (Danbury, CT). “It allows us to have sophisticated control and greatly enhances the interface between the operator and the equipment.”
“Thanks to the use of microprocessors, wire processing machines now provide programmable control of parameters such as strip depth and strip length,” adds Eubanks, who says programmable wire strippers were unheard of 50 years ago.
The aerospace industry was an early adopter of computers for wire processing applications in the 1960s and 1970s. For instance, an article in the June 1967 issue of ASSEMBLY explained how Lockheed Missiles & Space Co. (Sunnyvale, CA) harnessed computer power to boost productivity by more than 50 percent. Engineers used a wiring documentation system to improve accuracy, reduce production time and eliminate errors associated with complex harness assembly operations. It tracked critical information, such as type of wire to be used, connector pin designations and jacket requirements.
A May 1971 news item reported on how engineers at Boeing Commercial Airplanes (Renton, WA) used a computer to print more than 500,000 wiring harness labels for use in 707, 727 and 737 passenger jets. “The new labels are made of a pressure-sensitive adhesive coated material that meets FAA requirements for flammability,” the article pointed out. “They replace vinyl plastic labels produced semiautomatically in stamping machines.”
“Labeling has come a long way from the simple preprinted vinyl cloth labels,” says Tim Ziegler, product manager for automated assembly solutions at Brady Corp. (Milwaukee). “Materials are now diversified, such as self-laminating, self-extinguishing, high temperature and chemical resistance, low halogen and repositionable adhesives.
“The printing technology has developed from dot matrix to thermal transfer print technology,” adds Ziegler. “Large, slow, low-resolution benchtop printers are a thing of the past. Current benchtop and portable printers show drastic improvements in print resolution, permanence and resistance technology.”
Boeing engineers also experimented with wire harness forming machines in the early 1970s. The devices were 10 to 20 times faster than human operators. By 1974, Boeing was using a second-generation machine to improve productivity and lower costs on harnesses assembled for use in the 747 jumbo jet.
An article in the December 1977 issue of ASSEMBLY explained how the computer-controlled harness maker automatically prepared the software required to operate a large X-Y forming table equipped with interchangeable drilling and forming heads, in addition to a bulk wire dereeler and feeder stations.
“Today, there’s a move toward networking,” says Tim MacAlpine, director of sales at Komax Corp. (Buffalo Grove, IL). “Manufacturers want to be able to link multiple wire processing machines to one central scheduling location.
“The focus used to be on how may pieces per hour that you could produce on a piece of equipment,” adds MacAlpine. “But, now, the emphasis is on machines that can handle multiple types and sizes of wire and different applications. With smaller, shorter production runs today, the focus is on quick changeover, seamless transition and reduced downtime.”
In the future, manufacturers will continue to demand increasingly more automated wire processing equipment. For instance, there may be more applications that use lasers to help guide operators in the identification and placement of wires.
Brian Dorich, OEM manager at Panduit Corp. (Tinley Park, IL), expects to see more robots used in wire processing applications. “End-of-arm robotics with the ability to function on the X, Y, Z axes are replacing operators, due to consistency as well as increased speed to apply cable ties,” he points out. Dorich also expects to see more fiber optic cabling used in the future, especially for automotive applications.
“Wire processing equipment will become even easier to use,” predicts Schleuniger’s Doyon. “All equipment will be networked and work orders will be sent in ‘paperless’ fashion over the network. Equipment will be more flexible and allow quicker changeovers than ever before. This will allow smaller batch sizes, higher throughput, reduced work in process, and increased efficiency in future wire processing operations.
“Higher volume jobs will be done on fully automatic machines, even in low-cost labor countries,” Doyon believes. “This is necessary to ensure quality and repeatability, and to reduce labor costs as much as possible.” A