Custom enclosures are an example of value-added COTS

June 1, 2000
Much like the auto industry, enclosure and packaging designers find that most customers want to tweak their standard products differently depending on their needs.

By John McHale

Much like the auto industry, enclosure and packaging designers find that most customers want to tweak their standard products differently depending on their needs. However, mission- and life-critical requirements remain the same for rugged enclosures and packaging despite the onslaught of COTS.

If you think about it, the commercial-off-the-shelf (COTS) phenomenon is nothing new. Henry Ford dreamed up something like it about 90 years before former Defense Secretary William Perry issued his COTS edict, when Ford predicted "Ten Thousand autos for $400 apiece." A couple years later the Ford Motor Co. produced a standard off-the-shelf car, the Model T, each one the same, at a low price, and available right off the assembly line.

According to Ford's orders, the car had no special options like sunroofs or color choice. A telling slogan about Model Ts went "Any color so long as it's black." Ford even considered the electrical self-starter an unmanly luxury. Once, while he was vacationing in Europe, a few of his employees designed a new Model T prototype with a few minor enhancements. When Ford returned he dramatically showed his dismay by ripping the prototype apart piece by piece.

If one of today's electronics enclosure designers took the same approach that Ford took with his Model T, that company's competitors would tear it to shreds, which figuratively is what happened to Ford's Model T when automobile buyers became more affluent and wanted a little more out of a car. The market forced Ford to recognize a new trend in car shopping — men still bought the cars, but women chose them.

The same can be said of military electronics enclosures and packaging today — the government buys them, but systems integrators choose them.

Today's enclosure designers have a lot in common with modern automakers: customers rarely buy their products right off the shelf. Instead, customers usually want enclosure suppliers to tweak the original in some way. The reason for this is the customer wants a competitive advantage, and the supplier added value to bolster his profits. In the case of enclosures, it is common to see customers who ask the supplier to substitute convection cooling for conduction cooling, for example, or to add a door or two to their standard products.

The enclosure is no longer strictly COTS, but rather value-added COTS. In other words, off-the-shelf equipment listed in the catalog actually sells in slightly modified versions depending on the customer's wants and needs.

"We have a standard product we sell off-the shelf in our catalog," says Tom Schmedake, manager of enclosure engineering at AP Labs Inc. in San Diego. Yet while AP Labs engineers have sold less than a handful of that exact model, they have sold more than 250 slightly tweaked versions, he explains.

One of the AP Labs-tweaked standard products is the FS-8718 VME chassis, which houses the control and alarm monitoring system (CAMS) on the U.S. Navy Landing Craft-Air Cushion — better known as LCAC. AP Labs engineers worked with experts at LCAC prime contract Textron Marine & Land Systems in New Orleans to integrate fault-isolation software into the CAMS.

It is a type of "off-the-shelf custom or semi-custom," Schmedake adds. AP Labs designers may change the enclosure's power supply, its size, or even its color, depending on the customer, he explains.

At enclosure designer Elma Electronic Inc. in Fremont, Calif., all the components inside the subsystems that Elma engineers make are COTS, while the enclosures are customized to work with those components, explains Alfred Almeida, Elma's regional sales manager.

Elma's type 12R2, 6U CompactPCI system is installed below deck on a destroyer-type naval ship — Almeida would not specify which class of ship. The unit meets electromagnetic interference (EMI) requirements per MIL-S-461D. The 12R2 also uses military-grade electro-magnetic-compatibility line honeycomb filters, braided gasketing, and metal-impregnated gasket sheets to electronically seal off every external seam, he adds.

Government buyers rarely pay for research and development anymore, so suppliers must list a standard product, says Jim Walenda, director of marketing at Amco Engineering in Schiller Park, Ill. The customer then tells the supplier how he wants it, he explain. This can also be expensive for the customer, depending on what materials are requested, Walenda adds.

Amco produces heavy-duty EMI cabinets that meet some of the military's most demanding specifications for shielding, shock, vibration, and seismic requirements. The company's cabinets are available in a variety of standard sizes, colors, styles, and accessory options.

"I think the term COTS is more for procurement purposes," says Mark Clay, regional sales manager at APW Electronics Solutions in San Diego. There is not an open standard for all enclosures; each customer has different requirements, he adds.

A customized version of APW's RGD4 enclosure is part of the antisubmarine warfare suite aboard the U.S. Navy P-3 maritime patrol aircraft, Clay says. Each 6U enclosure has 20 VME slots, a 750-watt power supply, and a rugged one-eighth-inch aluminum-welded-seam construction.

Because many of the COTS components that the enclosures house become obsolete in a short time, enclosure designers build their products with a high degree of modularity.

Elma's enclosures, for example, have "a modular design similar to a jigsaw puzzle," Almeida says. The design is necessary, so customers can easily upgrade their boards and other products without replacing the chassis, he explains. "Enclosures don't really go obsolete" and modularity is the key, Walenda says. "We still sell a lot of our old products," he adds, yet customers still come in requesting drawings that are 30 years old.

Modular designs also make it relatively easy for systems designers to follow industry trends, such as from VME architectures to CompactPCI, says Ted Brewster, vice president of sales and marketing at Carlo Gavazzi Mupac Inc. Electronic Packaging in Brockton, Mass.

Elma's Almeida says he agrees. There is a definite interest in CompactPCI, but it has little influence on enclosures, since CompactPCI and VME are based on the Eurocard form factor, he explains.

The modularity and common requirements for shock and vibration also have military and telecommunications engineers looking in the same place for enclosures, says Frank Hom, new product development manager at APW. The industries are more alike than many originally thought, he adds.

Many industry experts also believe the push toward COTS is also causing prime contractors and subsystem manufacturers to subcontract out an increasing amount of their enclosure work to specialists like Carlo Gavazzi, Elma, and APW.

"Most of the primes definitely come to us," Brewster says. It is much more economical for them to contract out for their enclosures, he adds. However, a few board companies, such as DY 4 Systems in Kanata, Ontario, do design their own air transport racks (ATRs), Brewster adds.

DY 4 engineers design their own ATRs mostly for avionics and space applications, says Duncan Young, director of marketing at DY 4. Company engineers also customize the ATRs for each application, he adds. Occasionally, however, DY 4 designers do work with companies like Carlo Gavazzi for enclosures, Young says. One of DY 4's ATR chassis is on the BA-2 rocket from Beal Aerospace in Frisco, Texas.

Engineers at Vista Controls in Santa Clarita, Calif., a subsidiary of Lau Defense in Littleton, Mass., also produce rugged, conduction-cooled ATRs. One of Vista's chassis is flying on the Global Hawk unmanned aerial vehicle from Northrop Grumman/Ryan Aeronautical Center in San Diego, says Gorky Chin, vice president of technology at Vista.

Vista engineers also design their own enclosures, Chin says. The only things they do not do are processes such as metal working, he adds. Engineers at Vista's parent company, Lau Defense, also usually design their own enclosures whenever possible, Chin continues. It is usually cheaper and they have more control, he explains.

The same approach also goes for rugged computer manufacturer Computing Devices Canada in Nepean, Ontario. "We usually produce our enclosures in house for long production runs and large volume orders starting at a minimum of 200 to 300 systems," says Wade Cuthbertson, director of business development for ground tactical systems at Computing Devices. "Otherwise it would be too expensive. Sometimes outside enclosures cost $15,000, which is a nearly as much as one computer system."

For shorter tuns, engineers at Computing Devices do farm out their enclosures because the low volume cannot justify the cost of the casting, Cuthbertson explains.

Elma officials have seen a tremendous increase in requests for their 12R2 enclosures from many primes and companies like Mercury Computer Systems and Sky Computers — both located in Chelmsford, Mass., Almeida says.

Many of the primes that farm out their enclosure and other packaging work do so because it is often cheaper than keeping a full-time packaging staff, Brewster explains. This will happen more often as large defense manufacturers focus on their core competencies.

Harsh environments

Despite the fast-paced move toward the latest commercial technology, military requirements for shock, vibration, and severe temperatures remain for enclosures and other packaging.

The COTS mandate may have removed unique military specifications from the components, but subsystems still must work in harsh environments and the only way to accomplish that is with packaging that meets military specifications for mission- and life-critical environments, Brewster insists.

While military requirements for harsh environments still remain the same there are still differences between different applications.

U.S. Navy ship designers want the largest enclosures for their shipboard applications, and usually impose the toughest standards for shock and vibration, Brewster says. Airborne applications developers usually require a relatively small size and weight and are especially concerned with vibration, he explains. Ground vehicle builders also have mostly vibration requirements and their shock specifications are not as severe as the Navy's, Brewster adds.

Military designers are also looking at seismic enclosures able to survive earthquakes, Walenda says. Equipment that can survive an earthquake is very attractive to the military, he adds.

Protection from EMI and radio frequency interference (RFI) is also becoming more important as the government and the military continue into the digital age, says Wayne Martin, government sales manager at Lindgren RF Enclosures in Glendale Heights, Ill. Military program managers focus mostly on large shielded rooms to protect classified signals that may originate from applications such as teleconferencing, he explains.

The Navy has largely done away with computer metal shielding associated with meeting transient electromagnetic pulse emanations standards — better known as TEMPEST — because of its high cost. Still, systems designers must protect computers from EMI and RFI, Martin says.

Government officials today are mostly choosing welded rooms Martin says. These rooms must last at least 20 to 30 years because their buildings have the same lifespan, Martin explains.

Systems designers who must reduce electromagnetic emanations from their equipment spend most of their money in physical security.

Lindgren's products use a lightweight, RF, and acoustically enhanced shielding system based on Lindgren's patented double-electrically-isolate shielding design. The lightweight modular design meets or exceeds NSA 94-106 RF and NSA 65-5 acoustic requirements. Higher-performance systems are available.

Engineers at Vector Electronic Co. in North Hollywood, Calif., offer their series 400 specialized VME enclosures. Product options include a 9U 21-slot backplane with extra drive mounting and rear entry card options, and a 6U 21-slot enclosure.

Enclosure products from Vyckier Enclosure Systems in Houston come in wall-mounted and free-standing units, can be coupled in height, width, and depth, have a temperature resistance or -50 to 105 degrees Celsius.

Experts at Enidine Inc. in Orchard Park, N.Y. offer a highly damped elastomeric bushing, which protects military avionics from dangerous harmonics during flight.

Engineers at General Kinetics Inc. (GKI) Electronic Enclosure Division in Johnstown, Pa., provide enclosures that are adaptable for ground installation, mobile, or naval vessels (combatant or non-combatant) and are qualified to meet the various requirements of MIL-E-16400 such as MIL-S-901 shock and MIL-STD-167 vibration.

Aeroflex International designers in Plainview, N.Y., have designed a new helical wire rope isolator targeted at shipboard electronics/weapons systems, avionics trays, and other applications that use sensitive electronics in severe environments.

Engineers at Dawn VME in Fremont, Calif., produce enclosures that can function as a VME mainframe in either a tabletop or rack-mount environment or both. It can handle VME requirements up to 750 watts.

A recently designed battery cabinet from Pentair Electronic Packaging in Warwick, R.I., protects backup batteries from adverse indoor and outdoor environments.

Raytheon saves money on custom enclosure with DFMA tools

LEXINGTON, Mass. — Engineers at Raytheon Systems Co. working on the U.S. Army's Long Range Advanced Scout Surveillance System (LRAS3) saved about $2 million by using a product review design process from Boothroyd Dewhurst Inc. (BDI) in Wakefield, R.I., to design an enclosure for one of the LRAS3 sensors.

They used Boothryd's Design for Manufacture Assembly (DFMA) to develop the cover assembly for the LRAS3 global positioning system interferometer subsystem (GPSIS).

The Raytheon team went through seven design configurations for the cover using DFMA software tools — Design for Assembly (DFA) and design for Manufacture (DFM). BDI's DFA tool guides designers through a systematic analysis of products with the aim of consolidating parts and eliminating assembly difficulties. It simplifies products through parts reduction and quantifies assembly time and costs, BDI officials claim.

The DFM tool provides cost estimates for the manufacture of individual parts. It also uses cost-estimating analysis to enable design teams to weigh alternative designs and various production processes, quantify manufacturing costs, and make the necessary tradeoff decisions between parts consolidation and material/manufacturing costs, BDI officials explain.

The projected savings relative to the design of the GPSIS cover assembly exceed $2 million over the life of the program, BDI officials claim. The whole process resulted in a predicted production cost savings of 55 percent, Raytheon officials say. However, "the real benefit is defect avoidance," says Paul Zimmerman, lead systems producibility engineer at Raytheon. Reducing defects by 6.45 defects per unit decreased repair and rework by an estimated 97 percent.

Raytheon engineers also used an in-house Six Sigma methodology to improve quality by avoiding defects. "The major benefit of using DFMA with Six Sigma for this project was reducing the time and costs associated with repair and rework," Zimmerman says. "Defective parts can and will shut down the assembly line."

"The two GPSIS antennas require a flat ground plane with exact tolerances, which were difficult to achieve with traditional casting or sheet-metal processes," Zimmerman says.

The other requirements for the GPSIS cover included: thermal isolation of the circuit card assemblies from solar load, lightweight and rigid construction, an environmental seal on antennas and sight housing, a conductive ground plane to shield the system from electromagnetic interference and radio frequency interference, minimal tooling costs, and cost schedule conformance.

The original concept for the GPSIS cover consisted of a machined casting with insulation foam bonded to the bottom. Raytheon engineers recognized that the casting process would require a 16-week lead time and a hard-tool cost of approximately $50,000, which was too time-consuming and expensive to meet contract requirements, Raytheon officials say. The first design was also too heavy, weighing 5.8 pounds. Raytheon engineers were also concerned because the concept presented a direct solar load to the circuit card assemblies, and exposed foam introduced the possibility of foreign object debris entering into the system's optical equipment.

Raytheon engineers achieved their savings in the final GPSIS cover with the following recommendations:

  • use a foam core is a structural member of the composite cover with aluminum top and bottom skins, which provides rigidity and reduces weight;
  • make the cover flat to reduce tooling costs;
  • reduce the flanges with rubber plastic molding to minimize machining time and costs;
  • use off-the-shelf mounting hardware to mount the circuit card assemblies to the cover, reducing assembly time and cost;
  • use high-bond-strength tape to hold the flex cables that connect GPSIS antennas to the circuit card assemblies, which eliminates the need for screws; and
  • limit part marking to field-replaceable assemblies only to ease identification at the depot.

During design engineers reduced the weight of the assembly by three pounds and thermally isolated the circuit card assemblies (31-degree delta from top to bottom) without a solar shield. "A solar shield would have required far too many parts," Zimmerman says. "That's what drove us in the direction of the laminate design — to achieve isolation of the circuit card assemblies without getting foreign object debris in the optics."

The LRAS3 will replace obsolete surveillance systems and enable scouts to conduct 24-hour reconnaissance while remaining outside threat acquisition and engagement ranges The system bridges the gap between the Army's currently fielded systems and its planned Future Scout and Cavalry System.

LRAS3 will be deployed on the M1114 High-Mobility Multi-purpose Wheeled Vehicle in its mounted configuration and will be used on a tripod for dismounted missions. It is a multi-sensor system that will provide the scout with the real-time capability to detect, recognize, identify, and pinpoint far target locations. The system uses advanced second-generation forward-looking infrared (FLIR), a day video camera, an eyesafe laser rangefinder, and a GPS.

For more information on DFMA tools contact BDI by phone at 1-800-424-3362, by fax at 401-783-6872, by mail at BDI, 138 Main Street, Wakefield, R.I. 02879, by email at [email protected], or on the World Wide Web at — J.M.

Carlo Gavazzi designs chassis for Navy communication receivers

BROCKTON, Mass. — Engineers at Carlo Gavazzi Mupac Inc. Electronic Packaging recently redesigned the U.S. Navy next-generation Submarine Low Frequency/Very Low Frequency VMEbus Receiver (SLVR) chassis to meet the MIL-S-901D near-miss shock requirement.

The SLVR design uses an open-bus system architecture based on VME and VXI commercial-off-the-shelf (COTS) components, which reduced system development time and cost, Carlo Gavazzi officials claim. It uses a "militarized" chassis design provided by Carlo Gavazzi for protection of internal COTS components, they say.

The new system replaces four systems currently in use and will be installed on all classes of submarines as well as associated tender and shore installations. Carlo Gavazzi officials claim the VME COTS design and industry standard interfaces provide the Navy with a small, light system with reduced power requirements that reuses existing software. In short, the SLVR system provides expandability options and twice the capability of its predecessor in the same space, they say.

In addition to meeting MIL-S-901D Shock, the SLVR chassis are designed to meet other military standards for vibration, operating temperatures, relative humidity, altitude, fungus, ship motion up to 60 percent incline, electromagnetic compatibility, DC magnetic fields, airborne/structureborne noise, thermal requirements, and mean-time-between-failure.

For more information on Carlo Gavazzi Mupac, Inc., Electronic contact Caryn A. Banks by phone at 508-588-6110, by fax at 508-588-0498, by mail at Carlo Gavazzi Mupac, Inc., Electronic Packaging, 10 Mupac Drive, Brockton, Mass. 02301, or on the World Wide Web at — J.M.

Custom rubber isolator firm thrives in COTS world

BRIGHTON, Mass. - Engineers at Barry Controls, a subsidiary of APW, are finding their custom isolator business is just as secure as the enclosure market in an electronics industry dominated by commercial-off-the-shelf (COTS) technology. Their products continue to win spots on major programs such as U.S. Navy Aegis cruisers and destroyers, the U.S. Air Force F-22 jet fighter, and the U.S. Army's Joint Direct Attack Munitions program.

The Aegis ships use black rubber isolators based on the company's 2k products, says James Collins, defense/industrial engineering manager at Barry Controls. The series 2k isolators and systems have a vertical natural frequency of 6-8 Hz under vibratory conditions and meet MIL-STD-901 for shock.

COTS is definitely bigger than it used to be, Collins says. Customers are more sophisticated in what they want, he adds.

Custom used to mean designed from the ground up, and still does, but for many COTS applications customers will usually "pick a product from our catalog then ask us to tweak it a certain way," much like the enclosure market, Collins explains. Rubber products are available from scratch if a customer wants, he adds.

Usually customers design their isolators in at the front end for applications that have a lot of room such as shipboard applications, but a lot of Barry Control's business comes from programs that did not have a lot of room and thought they could get away without isolators, Collins says.

Rubber isolators use reflectance to absorb energy, but need a certain amount of room to allow for reflectance, Collins explains.

"If they could hard mount their electronics they wouldn't need us," Collins says. Usually these customers have strict weight, size, and price requirements and try to go without isolators, he explains. However, the price really only goes up when they request exotic materials, Collins notes.

The isolator industry also seems to be impervious to the obsolescence problems of COTS equipment, says John Hanlon, defense market manager for Barry Controls.

For example, Barry Controls recently had a request for an isolator they designed for Boeing about 30 years ago, Hanlon says. The device was used in the shuttle bay on the Space Shuttle and NASA engineers need to replace it but they cannot find any quality data, Hanlon explains. So they came to us looking for a new design, he adds.

The company has been in business for fifty years and keeps most of the drawings for its products, Hanlon says. Designers of isolators normally do not obsolete a product, he adds.

For more information on Barry Controls contact John Hanlon by phone at 617-787-1555, by fax at 617-782-8140, by mail at Barry Controls, 40 Guest Street, Brighton, Mass. 02135, by email at [email protected], or on the World Wide Web at — J.M.

Who's who in packaging

Aeroflex International,Plainview, N.Y.,

Amco Engineering,Schiller Park, Ill.,

AP Labs Inc.,San Diego,

APW Electronics Solutions,San Diego,

Barry Controls,Brighton, Mass.,

Carlo Gavazzi Mupac Inc. Electronic Packaging,Brockton, Mass.,

Dawn VME,Fremont, Calif.,

DY 4 Systems,Kanata, Ontario,

Elma Electronic Inc.,Fremont, Calif.,

Enidine Inc.,Orchard Park, N.Y.,

General Kinetics Electronic Enclosure Division,Johnstown, Pa.,

Lindgren RF Enclosures,Glendale Heights, Ill.,

Pentair Electronic Packaging,El Segundo, Calif.,

Tracewell Systems,Westerville, Ohio,

Vector Electronic Co.,North Hollywood, Calif.,

Vista Controls,Santa Clarita, Calif.,

Vyckier Enclosu°re Systems,Houston,

Voice your opinion!

To join the conversation, and become an exclusive member of Military Aerospace, create an account today!