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Articles from 1995 In April

Application Digest

Application Digest

Fasteners that make the grade

John A. Buda, Product Line Manager, Unbrako Division, SPS Technologies

Design engineers use Grade 8 fasteners in many areas, including automotive, appliance, and light and heavy-duty industrial applications. Some fastener specifiers are under the impression that standard alloy-steel socket-head cap screws are Grade 8. This misperception is understandable, because Grade 8 connotes high strength. Specifications for Grade 8 fasteners appear in SAE J429, whereas ASTM A574 gives the requirements for a standard socket head cap screw (SHCS).

Technically, a Grade 8 fastener possesses an ultimate tensile strength (UTS) of 150 ksi, hardness of RC33 to RC39, and six radial lines marking the head.

In contrast, a standard SHCS has a UTS of 180 ksi through .50-inch diameter and 170 ksi in diameters greater than .50 inch. (SPS manufactures its standard SHCSs to a minimum UTS of 190 ksi through .50 inch and 180 ksi for larger diameters.) Socket head cap screw hardness ranges from RC39 to RC45 through .50 inch and RC37 to RC45 in diameters exceeding .50 inch. A standard SHCS can be made only in the SHCS configuration. Grade 8 socket head cap screws can be specially manufactured.

Substantial variations also exist among metric socket screws. Those manufactured overseas can fall into one of several strength categories. Property class 8.8 metric fasteners offer an 800 MPa (116 ksi) UTS for diameters less than M16 (16-mm-diameter, standard thread), and 830 MPa (120 ksi) for M16 and above. Class 10.9 are alloy steel with 1,040 MPa (151 ksi) UTS.

Metric property classes 8.8 and 10.9 offer cost options for applications not requiring maximum fastener strength. However, design practice with SHCSs in the U.S. traditionally used the inch ASTM A574 strength level or metric class 12.9. Inadvertent replacement of a high-strength 12.9 SHCS with a lower strength 8.8 or 10.9 product could cause problems.

To speak with an SPS applications engineer, call (800) 225-5777.

Programming Diverse Devices

John Swain, Director of Engineering, Bytek Corp.

Programming semiconductor devices is often challenging because of the wide range of package types and pinouts available. Instead of choosing the best device-programming technology, however, the type of programmer already in place often limits the choices.

A new device programmer efficiently customizes products that use programmable devices. The Model 2000 from Bytek Corp. programs embedded microcontrollers, E/EPROMs, PLDs, and other control elements.

Reprogrammable gate arrays allow the unit to handle a wide range of pinouts and package types, including DIP, PLCC, QFP, TSOP, SOIC, and others. It programs as many as 16 devices-8, 16, 32, or 64 bits wide-in block, interlace, block/interlace, or gang operation. It programs gangs of identical devices, sets, and even set-of-sets of devices where each contains unique data.

Multi-matrix technology permits changing device types on the fly without shutting down the machine. The unit operates either as a stand-alone unit or under a PC's control.

Rapid throughput complements operating flexibility. The unit comes with 2M bits of RAM, expandable to 128M bits. It can program, verify, and sumcheck sixteen 1M-bit E/EPROMs in 18 seconds, or sixteen 2M-bit parts in 34 seconds.

For application help on device programming, call Bob Sims, (407) 994-3520.

Fast but steady could win the race

Fast but steady could win the race

Berkeley Process Control, Inc., Richmond, CA, makes electronic machine-control products. In that business, it's one among many. Unlike many, it's grown by 40% a year for the last eight years. Its success hinges on two things: a stable of patents covering high-speed servo loops, and steady concentration on making control systems that people can actually use.

"From the start," explains BPC President Paul Sagues, "our focus was on making machines work, not on building boards." That focus is reflected in myriad ways, from controllers that haven't changed form factor while growing from 8- to 64-bit RISC architectures over the years, to consistent, simplified wiring schemes.

Most notable: source-code compatibility that's been maintained for more than ten years. Users can take a program written for a 16-bit BPC controller, load it unmodified on a 64-bit unit, and it will work. "It's a crucial element in gaining our customer's confidence," says Sagues.

Consistency, plus performance: According to Wayne Ferrari, BPC's marketing manager, the company's Bam(R) Series 64 controller offers sophisticated multiaxis servo control, compact distributed I/O for logic control, network communications, and operator interface control in one package. Simple connections to the company's touch-screen interface, I/O rack, and Universal Servo Amplifier, and single-cable servomotor connections complete the hardware configuration.

Prime example. The ELS-II Registration and Machine Control System developed by Dri-Tech, Inc., Milwaukee, WI, with cooperation from BPC, exemplifies the performance advantage of dedicated machine controls. ELS-II synchronizes multiple servomotors driving large rotating cylinders on high-speed commercial printing equipment.

Optical encoders on each axis signal the Bam(R) controller over the distributed I/O. By monitoring the signals, the controller can dynamically adjust each cylinder, regardless of speed, achieving printing accuracies of n 0.005 inch, comparable to mechanically synchronized printers. The controller also monitors web tension and multiple zone temperatures throughout the machine, reducing scrap production.

Machine commissioning went smoothly, largely due to BPC's QuickStart(TM) utility. Quickstart interrogates control network nodes, establishing device type and voltage level. It also performs auto-tuning, measuring motor and load characteristics to optimize servo-loop performance.

Compare this approach with others vying for machine-control business. PLC- and CNC-based schemes each have their limitations says Sagues. PLCs handle logic functions well, but "they're running out of steam, they can't do high-speed multi-axis servo control well." Alternatively, CNCs do yeoman work at controlling motors, but it's difficult to perform logic operations with them.

What's common to PLCs and CNCs that's kept them in the machine-control fight? Well-defined, well-maintained operating systems that plant-floor personnel can understand and use. Which brings up bus-based, "open" systems, the third major machine-control alternative.

An open question. As Berkeley people see it, open systems have some glaring disadvantages. First, assembling boards from different vendors for various machine-control functions and getting them to work together involves writing extensive application-specific software-and won't guarantee success. "Your desktop computer can crash with no harm done," Ferrari contends, "but that's unacceptable in a production machine."

The second shortcoming is the software itself. Ad hoc software is notoriously difficult to modify as machines are modified or redesigned. Data from the semiconductor-manufacturing industry, for example, shows that control-software costs skyrocket in the years after a machine's commissioning, as developers try to keep pace with changing customer needs.

Because the software for open systems reflects the programming styles of its writers, it's often difficult for others to decipher or make changes without unforeseen results. Lastly, changes in hardware can quickly render open-systems software obsolete. "Automation customers trade complex gears, belts, and cams for complex software," Sagues contends, "it's unfair to ask them to re-write it every time a new whiz-bang product comes along."

In short, Berkeley feels its approach to machine automation offers more reliability and more options, more easily, than so-called open systems. And, if ease of use and expandability is the real definition of openness, then the company feels its newest product-called Machine Works(TM) -provides the most open system of all.

A new approach. "Machine Works profoundly changes the way automation professionals approach multiaxis machines," says Sagues unabashedly. Instead of working on an idealized model offsite, then testing completed programs on the actual machine, Machine Works runs on the installed Bam controller, guiding automation-program development interactively with users over a touch-screen interface.

The system uses the previously described QuickStart utility to create a database of the machine's unique features. It asks users to define the individual tasks the machine has to perform, then define the sequence in which those tasks need to run. Users can have the system diagnose each separate task, then sequences, and then the completed control program for logical errors and component interference.

Because it contains an extensive library of machine operations, many applications will require no user-written software at all. Extensions to available routines-for example, custom cam-emulating tables-can be added easily, requiring a few lines, not a few thousand lines, to implement.

Although Machine Works was developed for relatively simple applications which had resisted automation because of the cost of conventional software development, it has proven valuable in running larger multitasking, multiaxis machines as well. In beta-site testing, it allowed plant-floor personnel to commission a 4-axis machine in just two days, saving some $25,000 in projected software development costs.

Sagues won't speculate on the eventual success of Machine Works. But discussing its place in his company's history of successful, workable automation products, he grins, saying, "It's the biggest thing we've ever done."

Water makes a comeback

Water makes a comeback

When a pork processing plant in Denmark recently installed a new hydraulic cutting machine, no one worried that hydraulic oil would leak into the meat. The company's seeming lack of concern over contamination wasn't misplaced, however. Its new machine doesn't use hydraulic oil. Instead, it operates off tap water.

For the machine's designer, the decision to go with water hydraulics, rather than more widely accepted alternatives, is at the cutting edge of a self-renewal trend. Throughout the long history of hydraulics, the oil vs. water debate has intermittently resurrected itself, most recently with the introduction of a raft of effective, new water hydraulics components.

In the past, water-based systems have earned only a grudging respect from the engineering community. During the last half century of its 200-year history, water hydraulics has been viewed mostly as a curiosity-an outdated technology driving creaky machinery.

No pork barrel. But advances in water-based components are changing that. At SFK Meat Systems in Denmark, the decision to go with water hydraulics was one based on new technical criteria, rather than traditional beliefs. The machine's engineers selected Danfoss' NESSIE water hydraulics system over more traditional alternatives, such as pneumatics or electric motors. "We moved away from air-driven machinery because of the cost of running it and the noise," explains Erik Petersen, manager for trade and service at SFK Meat Systems, designer of the new machine.

Pneumatic versions, Petersen explains, typically exhibited noise levels of 88-89 dBA, compared to as little as 80 dBA on the water hydraulic system. Similarly, SFK steered clear of electric motors, because of the large package size needed for the saw's 3-hp requirements.

Experts expect food processing to be one of the biggest new applications for water hydraulics. Unlike oil-based hydraulics, water systems present no potential for contamination of food. As a result, they also hold appeal for the pharmaceuticals industry.

The new hope for water hydraulics extends into a number of other areas. Hauhinco Maschineenfabrik, Sprockhovel, Germany, has sold water-based systems to a variety of new customers, including a German luxury-car manufacturer, which uses it in welding robots. Hytar Oy, Tampere, Finland, has applied its water-based systems to seawater ballast pumps, diesel emission-control systems, and water cutting power packs for the paper industry.

Water hydraulics fell out of favor early this century when engineers developed oil-resistant seals. From that point on, oil hydraulics dominated. Water, meanwhile, came to be thought of as a cost- ly alternative with inherent technical problems.

That was then. That characterization was accurate-at one time. Water presented a host of tough technical challenges for engineers. Among them: low viscosity, poor lubricity, corrosiveness, freezing, and fluid loss at high temperatures. As a result, component manufacturers found it difficult to maintain seal integrity. They also struggled to design state-of-the-art pumps and valves and to prevent erosion of internal surfaces. Though most of those problems were solvable, the cost of the solutions was, in many cases, three to four times as high as those of oil hydraulics.

That's why, for the past 40 years, water hydraulics has centered on a select few applications. Chief among them: steel mills, aluminum mills, mining, and oil drilling. Those industrial users have employed water because of fire-safety concerns. Until recently, these users were among the few willing to pay more for water hydraulics equipment.

Now, however, the tide is turning. Engineers are looking at water hydraulics with renewed interest, partially as a result of the environmental movement. Instead of viewing it with a jaundiced eye, many now see water hydraulics as environmentally friendly, non-flammable, inexpensive, clean, readily available, and easily disposable. Meanwhile, hydraulic oil leakage, merely an annoyance a decade ago, has become a potentially costly problem. Users of oil systems can no longer wash oil leaks down the drain. Instead, they must be collected and disposed of in an environmentally friendly manner.

"The oil-hydraulic industry presented a seemingly satisfactory solution to the problems of water hydraulics by offering new designs intended to eliminate leakage," says Ken Kirk, general manager for Schrupp, Inc., Bethel Park, PA. "However, these problems have persisted."

What's more, new noise legislation may lead some machine builders, already concerned about oil leakage and pneumatic noise, to seriously consider water hydraulics for the first time.

Dealing with leaks. Still, engineers have had to tackle some tough technical problems before water hydraulics could take a more prominent position in industry. Prime among those: leakage.

Engineers estimate that water's viscosity is about one-thirtieth that of hydraulic oil. In other words, its acceleration rate is higher, flow velocities are faster, and energy is greater.

Taken together, all of these characteristics translate to a greater potential for destruction. As a result, water systems have traditionally had problems with leakage. That's particularly true for pure tap-water systems, as opposed to those that employ a mixture of 95% tap water and 5% oil.

But manufacturers are dealing with the leakage and erosion problems through the use of new ceramic materials, such as aluminum oxides and zirconias. Hauhinco, for example, has introduced pilot valves-both ball and spool types-for leak-tight applications. The firm's ball valve uses a ceramic ball and a metal seat; its spool-style valve employs a ceramic spool. Spool leak-ages are said to fall into a range between 3 ml/min and 12 ml/min.

The advantage of the ceramic materials: They stand up better to high pressures, exhibit less permanent deformation, corrode less, and wear better under non-lubricated conditions. The result: less valve leakage. "You just do not have the wear on ceramics that you do on metals," notes Ladislaus Stromps of Hauhinco.

Danfoss' NESSIE system, designed for pure tap water, has dealt with leakage by employing a self-lubricating polymer on the moving surfaces of its pumps. Water, flowing over the moving surfaces, creates heat, which activates the polymer. NESSIE's axial piston pump uses the self-lubricating feature on all major contacting surfaces: between piston and cylinder bores, "slippers" and swash plates, and valve plates and the top of the cylinder block, for example.

The self-lubricating polymer also plays a major role in NESSIE's motor design. Danfoss engineers employed the polymer on all the motor's moving parts, as well. It paid dividends. The firm is currently the only one to offer a water hydraulic motor.

To further address leakage, engineers throughout the industry also have redesigned many water hydraulic components. They typically deal with water's lower viscosity by incorporating tighter part tolerances. Most pumps, for example, must now use clearances of 0.0001 inch, rather than the more common clearances of 0.0005 inch in oil hydraulics. To fight off corrosion, a host of parts, including pistons, cylinder blocks, swash plates, and valve plates, now consist of stainless steel. Housings, too, have been re-designed: Most now employ cast bronze. And some manufacturers use urethanes and reinforced plastic valve seats to reduce leakage.

For the most part, manufacturers have not dramatically changed the design of seals to accommodate water. But even there, subtle changes have surfaced. Many valve seats now use a high-nitrile BUNA-N rubber for sealing plungers and O-rings in valves. "Most erosion problems occur near seals, where you have very high velocities," notes Gary Bahner, vice president of engineering for The Oilgear Co., Milwaukee, WI. "All you need is a pinhole, and water will go through very fast."

Achieving proportional control. System manufacturers realize, however, that they won't break ground in new markets without state-of-the-art controls. That's particularly true in industries such as automotive, where users are accustomed to high-tech features. "To win customers in these areas, we have to produce equipment that's as easy to use as its oil equivalents," one engineer says.

That's one of the reasons why Hauhinco spent five years developing a ceramic spool valve. Traditionally, spool valves have failed to stand up to the rigors of water. But without spool valves, Hauhinco engineers believed they would be unable to build a proportional control system with the same characteristics as an oil-based system. Hence, the decision to introduce the ceramic valve spool.

Across the industry, manufacturers feel they should concentrate on proportional control over the next five years. To achieve gains in that area, engineers have worked to alleviate problems caused by the electrical conductivity of water. Unlike hydraulic oil, which has a low electrical conductivity, water can cause problems when used with servo valves.

Still, some firms have succeeded in developing proportional control systems. Others are close behind. Elwood Corp., Oak Creek, WI, now offers a water hydraulic valve commanded by an electrical pressure feedback signal from a closed-loop controller. Using a proportional/servo solenoid, it supplies fluid to, or relieves it from, the system. This step accurately controls system pressure and, therefore, load force.

Cost cutting the key. Despite these advances, engineers say more work is needed. Before water hydraulics seeps into a wider range of applications, it must:

Cut costs. Systems that use 95% water are roughly 20% more costly than oil hydraulics, but pure tap water systems are three to four times more expensive. Water hydraulics makers expect cost to drop as the market grows.

  • Eliminate bacterial growth. Bacterial growth inside the water is a problem that manufacturers are only starting to address with biocide programs.

  • Develop new pumps. Development of inexpensive, pressure-compensated pumps would eliminate the need for large and costly central accumulator systems. As a result, water hydraulics could move into applications now reserved for smaller systems.

Of the remaining work, however, the most important may be the reduction of system costs.

Still, some manufacturers report that customers are finding economic advantages in water hydraulics, despite the high initial costs. A German carmaker, after performing a cost analysis, reportedly selected water hydraulics over oil and pneumatics because of the lower overall costs. When considering operational costs, the carmaker said, water hydraulics can be a bargain.

Based on such appraisals, water hydraulics manufacturers are quite optimistic that they can recapture their former prominence.

Air Bearings Enable Micro-inch-Accuracy Stage

Air Bearings Enable Micro-inch-Accuracy Stage

Westboro, MA-The National Institute of Standards and Technology (NIST) defines accuracy, literally. Unsurprisingly, the organization has certain very special needs.

For a project requiring precision area measurement of minute standard apertures needed for defining still-smaller apertures for radiometry, NIST assembled a detailed specification for an ultra-high-accuracy positioning system. It consisted of an open-frame X-Y stage assembly on a granite base, and a Z-axis slide assembly on a granite bridge located directly above the stage. The X-Y stage would carry and position the aperture or other device to be measured over a 4 by 4-inch area. The Z axis would carry a high power microscope used for recording edge locations, and could carry the objective up or down for focusing and to accommodate varying part heights.

The most difficult requirement to meet: planar accuracy to plus or minus 0.5 aem over four inches of travel in both X and Y directions. "The specifications were beyond the capability of most mechanical stages," explains Steve Strandberg, a mechanical project engineer at Dover Instrument Corp. Drawing upon its extensive experience in designing and building high-precision stages and machine tools that incorporate frictionless air bearings, the company designed and assembled a solution in just eight weeks.

Because of certain other NIST requirements, primarily strict weight limits and microscope illumination through the bottom of the stage, Dover took a systems approach to the design. Its stage orchestrates five separate vacuum-preloaded air bearing surfaces, two brushless dc linear servomotors, a lead-screw/servomotor drive for the Z axis, and a laser interferometer feedback system for the stage's X and Y motions.

The laser interferometer and a high accuracy linear encoder on the Z axis provide position and velocity information for the company's DMM 2008 controller. In turn, the controller is responsible for DSP-based motion control for all three axes. Each axis exhibits straightness of less than four microinch/inch of travel, and delivers less than 0.5 arcsecond of yaw over its four inches of travel.

Before design work started, Strandberg, electrical engineer Jeff Lowe, and the rest of the project team constructed an error budget, a list of all the system's anticipated sources of error. These consisted of straightness of travel of the axes, roll, pitch, and yaw errors for each axis, squareness between X and Y, and servo stability. "The overall accuracy and traceability requirement dictated laser-interferometer feedback for the X-Y motions," says Lowe. "So we also had to consider the flatness of the system's mirrors and the alignment accuracy between them."

The team then set about minimizing each error source within the weight and motion constraints of the contract. Its design reflects each component working in harmony (see diagram). For example, the team chose an open-frame, single-plane configuration for the X-Y motion. Unlike a conventional stacked-axis stage, this approach allows unobstructed illumination from below. Also, it allows each axis motion to be referenced off the same plane (the granite base), reducing pitch, roll and Abbe errors.

Further, the planar X-Y stage allows alignment of the laser interferometer's beam path in a single plane with the stage motion at the same height as the workpiece to be measured. Placing the feedback plane at the work plane reduces Abbe offset error to virtually zero. The designers carefully laid out heat-generating components such as the motors and the laser away from the optical path, avoiding thermal gradients.

To further reduce the chance of thermally induced error, they included an optical wavelength compensator in their design that measures changes in the optical index of refraction of the ambient air. These changes, caused primarily by changes in temperature, pressure or humidity, are measured by the compensator and transmitted to the system controller for error correction.

Other Applications
  • Machine tools

  • Metrology equipment

  • Photolithography systems

As noted, the stage's base and bridge components are granite, chosen for its inherent stiffness and ability to be lapped to microinch flatness. Even so, the design uses custom manifolding for air and vacuum within the axis components to minimize stress from supply tubing.

Dover's DMM 2008 controller, augmented with a Delta Tau PMAC motion-control board, drives the stage. Using A-quad-B feedback from the laser interferometer and encoder, the controller coordinates all axis motion, performs valve sequencing, and supplies an operator host computer interface.

Additional details...Contact Michael Townsend, Dover Instrument Corp., 200 Flanders Rd., Box 200, Westboro, MA 01581, (508) 366-1456.

Smart Photoelectric Control Senses Lighting Problems

Smart Photoelectric Control Senses Lighting Problems

Mill Creek, WA-A common roadside feature, High Pressure Sodium (HPS) lamps exhibit a long life span-about 5 years. They eventually fail when the arc tube darkens and lamp voltages can no longer maintain a continuous arc within the bulb.

At that point, abnormal cycling takes place, and the lamp continually flashes or attempts to start. The condition can prove especially difficult to detect because of the infrequency of the cycling. If abnormal flashing continues for more than 2 to 3 months, the lamp's starter/ballast unit eventually becomes damaged. For a utility company, this means expensive replacement of the defective lamp as well as the starter/ballast unit.

The Dual Dome Anti-Cycling HPS Street Lamp Control turns lights on at night and off in the morning, and protects against cycling. It photoelectrically senses lamp cycling using a single PROM that performs all of the logic functions in the control. "Previous attempts to disconnect cycling street lamps from their power sources required complicated circuits," says designer Frederick Blake of F.H. Blake & Associates. "Their reliability was questionable, and their cost excessive."

Mounted on the top of a conventional street light, the Dual Dome counts the lamp's attempts to start. After three on-and-off cycles during the night, it cuts current to the ballast, and a red strobe light located on top of the unit flashes on to alert maintenance crews. "The PROM combined with Triac switching simplifies the circuit and gives trouble-free life to the control," explains Blake. "The load is always switched at a current zero so that no large in-rush current is switched on or off."

Fiber-optic cable extends between the anti-cycling controller and the lamp. The cable's distal end is so positioned that a portion of the light emitted by the lamp is transmitted along the cable to the controller. At the other end of the cable, a photocell generates an electrical signal that varies as light is transmitted, or not, through the cable. Input to the anticycling circuitry, this signal enables the controller to recognize abnormal lamp cycling.

Other Applications
  • Parking areas

  • Industrial lighting

  • Building wash lighting

Dual Dome's circuitry and power supply are mounted on a 23/8x 2-inch-wide PC board housed in the 3-inch high, shatterproof Lexan(R) dome. Its fiber-optic cable extends from the housing; a low-heat-conduction fitting connects it to the fixture's reflector.

Under a Dept. of Energy grant, 500 field-test units are currently in production; they will soon be sent to major utility firms.

Additional details...Frederick Blake, F.H. Blake & Associates, 3103 149th St. S.E., Mill Creek, WA 98012, (206) 337-5117.

Powered Grab Bar Offers Alternative to Chairlifts

Powered Grab Bar Offers Alternative to Chairlifts

Portland, OR-Elevators and chair lifts are important innovations for people who need help climbing stairs. But they're often too expensive and obtrusive for home use. And sometimes chairlifts represent overkill. Many people who need support going up and down stairs may still possess some leg mobility and upper-body strength.

The Stair Assist Bar and Guide Rail System offers a viable option for persons with a disability that requires them to have some additional support on stairs. Easy to use, the system takes up less space than a chairlift and reportedly costs .25 to .50 as much as conventional chairlifts. An added benefit: It employs neither rotating gears nor noisy levers.

To use the system, you hold onto a lightweight bar that runs along a guide rail mounted on the wall. After you activate simple controls with thumb or palm pressure, you are gently pulled along the stairway. Powered by a single-speed dc motor, the bar supports you throughout the climb or descent.

Use of the Stair Assist Bar and Guide Rail System is intuitive. "This is particularly important for people living with serious physical limitations," says David Knaub, a senior mechanical engineer at Ziba Design, the system's creator. "It gives users a feeling of independence and safety."

Weighing only six pounds, the Power Bar can support a 250-lb person, even at its tip. Its magnesium frame and a carbon-fiber-reinforced epoxy handle produce this strength-to-weight advantage. "The fibers are specifically oriented to maximize the handle's load-bearing capacity while minimizing its wall thickness," explains Knaub.

Made of heavy-duty, 12-gauge rolled steel, the 1.4-inch-deep Guide Rail has an internal positive-locking chain, so the Bar does not slip. The Power Bar is inserted into the Guide Rail via an enlarged entry-and-exit opening on the 8.5-inch-high track. According to the designers, the collar that surrounds the juncture of the handle into the Power Bar provides a resting place for a hand or arm. For safety's sake, the Power Bar stops advancing automatically at either end of the Guide Rail.

Design simplification is a priority, says Knaub. The Power Bar consists of only a few major components: a 4 x 8 x 5.5-inch die-cast magnesium frame, a single-speed electric motor, an instant self-locking worm gear braking system, forward and reverse buttons, and a 12V nickel-cadmium battery.

Ease of use is the key benefit. "You simply insert the Power Bar into the Guide Rail, then press the forward button on the Bar to go. Release the button and the Power Bar's positive-locking system stops it instantly and securely," says Jerry Findley, president of the manufacturing company, Stair Assist Corp., Beaverton, OR.

Other Applications
  • Materials handling

  • Physical therapy

Rechargeable batteries located inside the handle reduce its overall size for easy handling. Battery power permits 15 to 20 round trips between charges.

Additional details, design...Contact David Knaub, Ziba Design, 305 NW 21st Ave., Portland, OR 97209, (503) 223-9606.

Additional details, Stair Assist...Contact Jerry Findley, Stair Assist Corp., 7737 SW Cirrus Dr., Beaverton, OR 97005, (503) 526-8900.

MISSILES: Last Line of Defense

MISSILES: Last Line of Defense

Desert Storm and the war between Iran and Iraq demonstrated decisively that short-range and intermediate-range ballistic missiles and cruise missiles now occupy a prominent place in the armories of combatants. Ballistic and cruise-missile deployments will surely increase around the world during the next ten years. To deal with these emerging threats, the Ballistic Missile Defense Organization (BMDO) at the Department of Defense (DOD) has established a core Theater Missile Defense (TMD) program.

Three anti-missile systems comprise the TMD core program. They are: the Patriot Advanced Capability-3 (PAC-3); the AEGIS/Standard Missile-2 Block IVA (SM-2 Blk IVA); and the Theater High Altitude Area Defense (THAAD) system. According to the 1994 National Defense Authorization Act, the United States will develop these advanced theater missile defense systems for deployment, while continuing to comply with the 1972 ABM treaty.

All the TMD core programs will require considerable research and engineering work. In the near term, the enhanced Patriot Advanced Capability-2 (PAC-2), the AN/TPS-59 Radar, and the HAWK weapon system will provide an endoatomospheric defense against short-range ballistic missiles and cruise missiles.

Army TMD doctrine now calls for a defensive system that uses Patriot missiles and THAAD to create a two-layer defense in a theater of operations. During fiscal year 1998, the Army's 88 Patriot firing batteries will begin upgrading to the PAC-3 configuration. THAAD will go into service early in the next decade. Also, the THAAD program will develop a functional prototype system at the end of its Demonstration/Validation stage in 1997. According to BMDO, the prototype, called a User Operation Evaluation System (UOES), could be deployed to a combat theater.

The U.S. Navy intends to modify its AEGIS system to make the system effective against theater ballistic missiles (TBM). Called the Sea Based Area TBMD program, the Navy effort requires combat system modifications for AEGIS and the Standard Missile-2. Today, the AEGIS system uses the Standard Missile for air defense. After modification, the Standard missile will carry out what's called lower-tier (endoatmospheric) theater-wide intercepts. If contractors meet their schedules, a UOES prototype of the modified AEGIS system will be available in 1997.

Modifications to the HAWK weapon system and the TPS-59 radar will provide a TMD capability for the U.S. Marine Corps. Technical development and operational testing of the upgraded HAWK and TPS-59 will occur in fiscal year 1996, with the first operational units equipped late that year.

Modifications to the TPS-59 will allow detection of tactical ballistic missiles at ranges to 400 nautical miles and altitudes to 500,000 ft. A system called an Air Defense Communications Platform will provide a communications interface between the radar and the HAWK system. Under current plans, the USMC will retain one active duty HAWK battalion. It will consist of three batteries, each equipped with 12 launchers. Each launcher can carry three missiles. There will be a reserve HAWK battalion consisting of two batteries, each with eight launchers.

"We've improved the HAWK warhead and fuse, and incorporated software changes to provide greater capabilities against short-range tactical ballistic missiles," says Gail Hayes of Raytheon Corp. "Several countries have requested this upgrade, and we anticipate that others will as well."

New interceptors. There are two aspects to the enhanced-capability Patriot TMD system: A new, highly lethal hit-to-kill interceptor and an improved radar. Last year, after extensive tests, the Army selected the Extended Range Interceptor (ERINT) as the missile to be used for the PAC-3 program.

When the Patriot's radar detects a target, track information goes to a Fire Solution computer that calculates a predicted target acquisition point. It then electronically loads those coordinates into the missile. The interceptor flies to the acquisition point, acquires target update information from the ground-based radar, turns on its active seeker, and relies on its onboard systems to find the target.

Developed by the Loral Vought Div. of Loral Corp., Dallas, TX, ERINT/PAC-3 carries an on-board active Ka-band (GHz) seeker. Aerodynamic control vanes and impulse attitude control thrusters maneuver the missile for a hit-to-kill intercept. Honeywell Corp., Clearwater, FL, is responsible for the vehicle's inertial measurement unit, Rockwell International, Anaheim, CA for the millimeter-wave active radar seeker, Atlantic Research Corp. of Gainesville, VA, for the solid rocket motor and attitude control motors, and Lucas Aerospace, Aurora, OH for the aerodynamic maneuvering system.

ERINT represents the end product of some 30 years of work on non-nuclear anti-ballistic missiles. Engineers at the old Vought Corp., and then LTV Corp., developed the guidance concepts used in ERINT. Their work resulted in a project called FLAGE which, in 1987, demonstrated that hit-to-kill technology could work.

The PAC-3 is a hit-to-kill weapon designed to intercept tactical ballistic missiles at mid-endoatmospheric altitudes. Weighing 701 lbs (318 kg) at launch and 10 inches (255 mm) in diameter, the 16-ft (5.01m) long missile is inertially guided by aerodynamic fins toward a predicted impact point. In the terminal flight phase, the active, on-board radar seeker acquires the target and provides instantaneous data to the on-board guidance processor. The processor then calculates the endgame guidance commands that steer the missile to its target.

Two factors give the missile the agility it needs to close on a target: its small size and a set of attitude control motors located near the vehicle's nose. The PAC-3 fires these thrusters in flight to steer itself into the target. Loral Vought's Line Of Sight Antitank system (Design News 4-20-92) also employs this attitude control system.

PAC-3 will employ a lethality enhancer to improve its performance envelope against cruise missiles and high-performance aircraft. The lethality enhancer consists of a ring of tungsten fragments deployed pyrotechnically just before target intercept. It's located just aft of the PAC 3's attitude control motor module.

"Since the PAC-3 missile entered engineering and manufacturing development last October, we've been working to prepare the missile for full-scale production," says Sid Wells, vice president-air defense programs at Loral Vought. "We believe the missile is ideal for application to other missile defense systems because of its light weight, high performance, and ability to interface with different fire-control systems." In fact, Loral Vought believes the ERINT missile could provide theater ballistic missile defense aboard ships, and could be used with the HAWK system.

The ERINT missile will go through Developmental Test and Evaluation (DT&E) and flight tests using PAC-3 missile flight test software. DT&E will run from this year through 1998.

Radar upgrades will enhance the Patriot system. Benefits include: increased target detection range, positive target identification, more secure engagement of targets with small radar cross-sections, increased target-handling capability, and enhanced system survivability. Raytheon Corporation of Lexington, MA, will perform these upgrades.

Anchors aweigh. To enable the Navy's AEGIS system to destroy tactical ballistic missiles, SPY-1 radar computer programs and equipment will be modified to allow search at higher elevations and longer ranges. Doing so will allow the system to detect the missiles and track them.

Onboard a vessel carrying the modified AEGIS, the weapon control system will predict intercept points, fire missiles, and provide a data uplink to the missile as it flies out to attack the enemy's ballistic missile. AEGIS displays and all systems involved in attacking missiles will be updated to display missile tracks and to interface with off-ship sensors and other combat-system elements.

Now under development, the new SM-2 Block IVA missile will use an IR seeker to reduce miss distance. A new fuse will help ensure that the missile destroys its target. In addition to fighting ballistic missiles, the SM-2 Block IVA will retain its ability to combat aircraft and antiship cruise missiles.

Test and evaluation for sea-based TBMD includes early missile-hardware flight tests, IR seeker wind-tunnel and sled testing, and warhead development. Early testing at sea of prototype software and land-based development of AEGIS software and hardware will also take place. Sea tests will include multiple engagements, electronic countermeasures and other activities designed to test the system's robustness, according to BMDO.

Low-rate production of the new missile will begin in 1997. By the year 2000, some 90 missiles should be available to the Navy. The BMDO says that 35 missiles will be purchased for use with the Navy's UOES to deal with any potential contingencies. Early flight tests will begin this year-first at White Sands Missile Range, New Mexico, and then on an operational AEGIS ship. As of now, the DOD believes the first AEGIS theater missile defense system will enter service with the fleet in 1999.

At long range. The Army's THAAD system involves two programs aimed at solving separate, but closely linked, technical problems. They are the THAAD weapon system and the ground-based radar needed to direct the interceptor.

These elements will combine to engage targets at high altitudes and distances of more than 100 miles from the incoming missile's intended target. This long-range-intercept capability will minimize damage caused by debris generated above the target. Also, intercept will occur at a high enough altitude to ensure safe diffusion of chemical weapons. The THAAD system will receive cueing data from U.S. space-based sensors.

As for the interceptor, it's a single-stage, solid-fuel vehicle. The booster employs a thrust-vectoring nozzle to help stabilize and guide the missile, as well as a divert and attitude-control system. THAAD's booster provides initial thrust and acceleration. It also helps stabilize the vehicle by deploying a conical metal "flare" rather than fins. The flare deploys when the vehicle clears the Patriot-type launch canister. After several minutes of flight, the kill vehicle separates from the booster and maneuvers to the target.

Ground-based radar provides a predicted target intercept point and guidance data to the missile before launch. Able to receive in-flight data updates, the THAAD missile generates its terminal guidance data via a gimbal-mounted infrared seeker looking through a side-mounted, uncooled window. A shroud protects the seeker window prior to terminal homing, and separates from the missile as it closes in on the target.

Lockheed Missiles & Space Co. of Sunnyvale, CA, serves as prime contractor on THAAD. United Technologies Chemical Systems Div., San Jose, CA, has responsibility for the solid rocket booster motor, Rocketdyne Div. of Rockwell International in Canoga Park, CA, the kill-vehicle divert and attitude control system, Loral Infrared & Imaging Systems of Lexington, MA, the kill vehicle's infrared seeker, and Honeywell Space Systems Group Clearwater, FL, the missile avionics and navigation system.

Like the PAC-3, the THAAD missile is a hit-to-kill weapon. Unlike the PAC-3, it can perform intercepts either in the atmosphere (endoatmospheric intercept) or in space (exoatmospheric intercept).

THAAD's ground-based radar consists of five major elements: a single-faced, mobile, phased-array radar operating in the X-band (5200 to 11,000 MHz), and separate power generation, system cooling, equipment control, and operations control units.

The THAAD flight test program began last year at White Sands Missile Range. "The next major event in the program will be our first attempted intercept at White Sands this summer-and we expect a success," says Lockheed spokesman Eric DeRitis. Two test flights will precede the intercept. The first test flight of the full THAAD prototype is scheduled to take place before the end of June. System tests that are scheduled to follow the flight will demonstrate, in a step-by-step fashion, improved performance capability by the integrated missile, launcher, radar and C 3 I systems.

Defense authorities agree that U.S. military forces need some means of defeating tactical ballistic missiles. Leaving aside the non-technical (i.e. political) issues, interceptors of the sort described here represent a viable near-term method of accomplishing that objective.

Building the missiles, radar and support equipment for these systems will require spending billions of dollars. Clearly, the contracts can provide employment opportunities for many engineers and skilled workers employed by prime contractors and subcontractors.

Macsyma 2.0

Macsyma 2.0

Macsyma 2.0 has been enhanced in three major areas - User Interface, Matrices, and Graphics. Its Help system is structured in two ways - by command or by function. The former has hypertext type descriptions of nearly 2,000 commands; the latter contains all Macsyma's capabilities organized by menu.

Notebook documents. Macsyma's Front End (MFE) is a new menu system to help you make crisp documents and connect to Macsyma's number crunching engine. The new notebook approach lets the user organize math operations by inserting text and graphics into the document. Macsyma's notebook appears as a regular spiral bound book. Input and output is done in the same way as before: on the C-ommand line you type the expression to be analyzed and Macsyma responds with the answer on the Display line with the same number.

The notebook may consist of several combinations of C & D lines in sequence. To save time and avoid errors, you can reference a previous calculation by simply referring to its sequential number. As the document gets longer, you can select certain inputs, outputs, or graphics for review by having Macsyma's front end interface highlight any one with the Navigate tool.

With the added text between the input and output you can make whole sections that are clearly defined and labeled like chapters. The Navigator can take you to any section of your notebook based on the "table of contents' you build, or to the exact input or output line. It can also list all inputs or outputs at once to eliminate scrolling. If you open more than one notebook at a time, it combines all inputs or outputs and displays them for easier searching and comparison.

Version 2.0 lets you take models developed with previous versions of Macsyma and have them as a notebook or batch file. Converting an old model to the notebook format is as easy as typing "make_notebook (filename)'. The notebooks in Macsyma are re-executable. Once you make changes to a parameter and invoke the Re-execute command, the whole notebook is recalculated and all graphics are updated.

Capabilities. Macsyma has more linear algebra commands and numerical analysis utilities than most products I've seen. Enhancements include 180 new commands for matrix operations that are approached symbolically and/or numerically.

The matrix toolbox includes commands for Matlab users also. Only the matrix related commands of Matlab 3.0 are compatible and supported by Macsyma. You can import directly, translate Matlab functions into files, or interactively type Matlab commands while in Macsyma.

The numerical side has also been enhanced with the addition of numerical integration modules, data fitting routines for multivariable least square curve fits, and relatively simplistic routines on uni- or multi-variate statistics. The symbolic integration side can now handle integrals with error functions, elliptic integrals, or incomplete gamma integrals. Macsyma's 30 methods for first- and second-order differential equations have increased with the addition of routines for stiff systems of ordinary differential equations.

Graphics. With Macsyma's graphics engine, once you point to a graphic in the notebook, 11 new icons for editing, animation playing, and exporting of your graphics are attached to the existing menu system. An object-oriented graphics viewer offers you crisp graphs in 2, 3, or 4 dimensions. The 4th dimension is the time that is exploited with the animation tool. Up to 200 editable attributes can be accessed to adjust the graphics output.

With enhancements in its graphics and user interface, this powerful tool promotes mathematical thinking and knowledge in the hands of either a novice or an experienced user.

Spec Box

Macsyma 2.0
Macsyma is an integrated tool for symbolic and mathematical manipulations of problems in the engineering and scientific disciplines in the Windows environment. The program requires a 386 or better PC with 8M bytes of RAM, 18M bytes of hard disk space, and up to 20M bytes for swap file.

List Price: $349

Macsyma, Inc., 20 Academy St., Arlington, MA 02174, Phone: (617) 646-4550; Fax: (617) 646-3161.

A similar product:

Mathematica - Wolfram Research Inc, 100 Trade Center Dr., Champaign, IL 61820; ph: (217) 398-0700.

Defense isn't dead

Defense isn't dead

Kresa assumed his present position in 1994 after Northrop acquired Grumman Corporation. He held the same trio of titles at Northrop from 1990 to 1994, and was president of Northrop from 1987 to 1990. Kresa served in a series of other executive positions before becoming Northrop's president. He joined the company in 1975 as vice president and manager of the Northrop Research and Technology Center. Before coming to Northrop, Kresa served with DARPA, where he was responsible for broad applied R&D programs. From 1961 to 1968, he was employed by MIT's Lincoln Laboratory, where he worked on ballistic missile defense research and re-entry technology. Kresa holds a B.S., M.S. and E.A.A. from MIT, all in aeronautics and astronautics.

The defense industry is consolidating into a relatively small number of large, very capable firms. Northrop Grumman will surely be one of the survivors of this process, and Kent Kresa believes his company can look forward to an exciting future.

Design News-What are your goals for Northrop Grumman?

Kresa: Our acquisitions last year of Grumman and Vought put us in a much stronger position to achieve the strategic goals we've expressed repeatedly in the last few years. Those goals are to remain a key player in defense, to increase our position in commercial aerostructures, to leverage our core competencies into promising new areas, and to improve our performance to gain the financial strength to maximize value for our shareholders. We've consolidated our operations, and all five of our divisions were in place, on schedule, at the start of 1995: B-2, Military Aircraft, Commercial Aircraft, Electronics and Systems Integration, and Data System and Services.

Q: Can you please explain the concept of "core competencies" and their importance?

A: A core competency results from the integration of people, technology and capital to create competitive advantages in growth-oriented businesses. Core competencies are seen by customers as essential to a company's products; they are difficult to replicate elsewhere, and they contain the potential for new product development as well as enhancements to existing products. Northrop Grumman's core competencies are air vehicle design and systems integration; aircraft manufacturing; defense electronics; advanced composites; and applied acoustics.

Q: What sort of career prospects can the defense industry offer engineers now and in the foreseeable future?

A: In light of the changes and uncertainties in the defense industry over the last few years, we face a new challenge to convince young people that our work is just as exciting and important as it has ever been. The current struggle in the industry is to cut costs ahead of the expected sales reductions, as well as streamline operations. If we can succeed in that effort, then there is a future in defense-in electronics and systems integration, precision weapons, and military and commercial aircraft-even if it's filled with challenges.

Q: If today's defense engineering and production teams are broken up, how long would it take to replace them?

A: In the case of the B-2, the nation invested 15 years and $24 billion in technology, skilled personnel, facilities and equipment to design the B-2 and deliver the first operational aircraft-that's the kind of time and money involved. The industrial base that produced the most advanced aircraft in the world is a national asset. The thousands of men and women who have worked on that program possess talents and skills every bit as unique as the aircraft they build.

Q: How will Northrop Grumman manage to survive and succeed in this time of significantly reduced defense spending?

A: We feel strongly that we will not only survive, but continue to play a leading role in defense. Our core competencies are closely aligned with critical technologies identified by key U.S. military and civilian officials. Regional scenarios in the post-Cold War era considered likely by military planners will place a premium on surveillance, battle management, long-reach strike aircraft and precision weapons. When these systems are linked, the result is what we call a surveillance precision strike capability. Perhaps more than any other company, Northrop Grumman understands what surveillance precision strike systems are all about.

Q: What role does software play in the systems you've named, and other operations at Northrop Grumman?

A: Software is critical to virtually all business activities related to aerospace, from systems integration to defense electronics and battle management. Northrop Grumman is one of the nation's leading integrators of information systems, as is evident by our role as prime integrators for the B-2 and the Joint STARS surveillance and targeting system. The B-2 is the largest software development project in aircraft history. Joint STARS is another massive software-controlled system which uses some of the most sophisticated algorithms ever produced. We have a formidable software capability that provides information services and system solutions for our own programs as well as public and private customer.

Engineering News

Engineering News

Focus sharpens on high-definition TV

Paris-Even its biggest proponents can't deny that high-definition TV has had its problems.

First Japan invested heavily in an analog standard, but that's expected to be obsoleted by digital technology. In 1992, a European standards effort ran into problems with ground-based systems that couldn't handle HDTV-quality pictures. And in the U.S. that year, the Federal Communications Commission declined to adopt a standard among six that were proposed.

Today, HDTV is once again riding the crest of a wave of media attention. But things have changed. Rather than focusing on building an HDTV standard that would pack more pixels into a video image, the European community has turned its attention to developing a digital transmission standard. More than 130 companies, competing for digital business in Europe, have formed the Digital Video Broadcasting Group aimed at giving consumers a tremendous range of channels, based on standard television technology and digital services.

Considered a model of successful business communications, the DVB has agreed on a European digital transmission standard based on ISO-adapted Moving Picture Expert Group (MPEG)-2 standards as well as standards that address compression and multiplexing issues. Essentially, DVB compatibility will provide the key platform for multi-vendor interoperability in compression, channel coding, and modulation techniques. The first digital transmissions target cable and satellite applications.

For broadcasters, the opportunities are far-reaching-simulcasting the same service to facilitate a gradual transfer from analog to digital technology-or even simulcasting two different TV services in analog and digital format to target different audiences.

"The European community is focusing on the flexibility that digital transmission services can bring to the consumer," says Tony Wechselberger, executive vice president of TV-COM International, San Diego, CA, whose major business is in Europe, with centralized operations in Amsterdam. "It means getting many more TV channels and receiving all kinds of digital services."

The results of the effort are already showing up. In Paris, Eutelsat, the large European satellite consortium with operators in 44 countries, is simulcasting both analog and digital television signals in a single 36-MHz Eutelsat satellite transponder that does not require any extra cost to the broadcaster. And, already a number of European hardware firms including TV/COM International, Fuba, Nokia, Philips, Tandberg, and Thompson are designing decoders either for simulcast reception or for reception of a package of DVB digital television channels. Thousands of boxes are expected to be delivered throughout Europe by the end of this year.

Alliance sets the stage. In the U.S., the spotlight is focusing on the efforts of the digital HDTV Grand Alliance, formed after the FCC's Advisory Committee on Advanced Television Services (ACAT) encouraged digital HDTV groups to merge their best features into one system.

Since then, the Grand Alliance, consisting of industry giants AT&T, General Instrument Corp., Zenith Electronics Corp., the Massachusetts Institute of Technology, Thomson Consumer Electronics, Philips Consumer Electronics, and the David Sarnoff Research Center, has focused on a best-of-the-best digital HDTV system. It has successfully field-tested the transmission subsystem and constructed a prototype. Three years in the making, the final design-a new flexible, open architecture system-is undergoing tests at the ACAT. Experts predict that the prototype may well be adopted by the FCC as early as the end of this year. If it is accepted as the U.S. digital HDTV standard-test results may be available next month-actual sets could be on the market by 1997.

"Design engineers are going to have a ball," says James Carnes, president and CEO, of the David Sarnoff Center, Princeton, NJ. "The integrated circuit and device technology already exist to make it happen. There will be tremendous opportunities to make high quality video and audio products."

The prototype incorporates progressive scan transmission capability and square pixel capability, attributes that are extremely important for promoting interoperability with computers and telecommunications. Key features include:

Digital video compression technology based on proposed international standards. The compression system is based on MPEG-2 parameters, including the use of "B-Frames," a bi-directional motion compensation that improves picture quality.

  • High-performance digital modulation technology for broadcasters and cable operators. The modulation subsystem, 8-vestigial sideband (VSB) transmission technology, assures broad HDTV coverage, reduces interference with existing analog broadcasts, and provides immunity from interference into the digital signal. The higher-data-rate cable mode, 16-VSB, allows cable operators to transmit two full HDTV signals in a single 6-MHz cable channel.

  • Telecommunications-like packets of digital data based on proposed international standards.

  • Progressive scanning for computer interoperability. The system uses both progressive and interlaced scanning. The formats are 24- , 30-, and 60-frame-per-second progressive scan with a pixel format of 1280 x 720, and 24- and 30-frame-per-second progressive scan with a pixel format of 1920 x 1080. It will also be capable of 60-frame-per-second interlaced scan with a 1920 x 1080 format.

  • Compact-disc-quality digital surround sound. The prototype will use 5.1-channel Dolby AC-3 audio technology.

"The companies were so devoted to addressing compatibility and interface issues early on that equipment integration was reasonably clean," says John Mailhot, technical manager, AT&T, Murray Hill, NJ. "In fact, the biggest challenges were not technical, but getting the companies to communicate so that the components could be successfully integrated."

Because of the Grand Alliance system's interoperability between entertainment television and computer and telecommunications technologies, the digital HDTV standard is expected to play a major role in the establishment of the National Information Infrastructure (NII). Many analysts believe digital HDTV will be the engine that drives deployment of the NII by advancing the development of receivers with high-resolution displays and creating a high-data-rate path to the home for a multitude of entertainment, education, and information services.

What about a European digital HDTV standard? "It will happen, but realistically, after the turn of the century." says May Wilkhund, information manager at Nokia's headquarters in Finland.

Standards a big issue. Despite the tremendous support for the new U.S. HDTV proposal, there is the thorny problem of broadcast standards-or rather the lack of them.

The North America Digital Group (NADG), Washington D.C., newly formed in October, may head off such issues. Consisting of over 60 leading organizations representing the programming, satellite, cable, and consumer electronics manufacturing industries, NADG is launching an on-going process to reach consensus on digital compression standards for North America that will be built on the existing international ISO MPEG-2 standards.

"The NADG is taking a tip from the success of Europe's VBG," says MA/COM International's Tony Wechselberger, who spearheaded the formation of the group. "Simply being MPEG-2 compliant is not enough-it's merely the beginning."

In fact, digital HDTV is considered to be in general disfavor with the U.S. broadcasting industry-despite the fact that the FCC is willing to offer a second broadcast channel, an extra 6-MHz spectrum, free for conventional TV and HDTV to be broadcast simultaneously. "The broadcasters do not want to be told how to use that spectrum. They want the flexibility of using it for other services as well such as data transmission," says Paul Dykewicz, editor of the HDTV Report at Phillips Business Information, Inc., Potomac, MD. "At this point, the major obstacle that stands in the way of digital HDTV is politics."

Perhaps Japan's high-definition analog TV, NHK's Muse, currently broadcasting in almost 20,000 households, best exemplifies the havoc politics can play in technological commercialization. Many industry officials believe the Japanese have locked themselves out of this arena by investing hundreds of millions of dollars in an analog system that cannot play in an all-digital television world.

Lessons learned may prove to be the winning card to success in digital transmission and HDTV as the industry moves, this time with a little more wisdom, into the next era of telecommunications.

'Innovation with Teflon' award winners honored

Orlando, FL-Packard-Hughes Interconnect, Irvine, CA, walked off with the Grand Prize at the 1995 DuPont Plunkett Awards for Innovation with Teflon(R). The firm also captured first place in the Electrical/Electronic Category for its fully additive method of fabricating electrical circuitry using the fluoropolymer film. Award winners received their honors at a special awards ceremony at the Disney World Yacht Club Resort.

Packard-Hughes Interconnect's Gold Dot(TM) technology involves electroplating copper on a stainless-steel mandrel coated with Teflon FEP fluoropolymer resin. The mandrel has either a pattern of grooves filled with Teflon, or a surface pattern of the material that includes spaces for copper deposition. Raised contacts are formed as part of the plating process in depressions in the mandrels. After plating, the circuits are adhesive-laminated to DuPont's "Kapton" polyimide film. The Gold Dot contacts resulted in interconnect products for multichip modules.

This was the first time that the U.S. awards recognized winners in three categories -Electrical/Electronic, Chemical Process, and "All Other Uses."

W.L. Gore & Associates, Inc., Elkton, MD, took the top prize in the Chemical Category for its ONE-UP(R) pump diaphragms. Gore reports that the innovative, one-piece diaphragm design and manufacturing process results in a product that lasts up to six times longer than similar diaphragms for air-operated pumps. The patented construction is said to offer strength, increased flex life, and abrasion resistance for enhanced environmental protection, quality assurance, reliability, and cost reduction.

W.L. Gore also received the top honor in the All Other Uses category for its Glide(R) dental floss. Only two years after its introduction, the floss, made of expanded monofilament fibers of Teflon PTFE fluoropolymer resin, has captured the second leading sales spot in the U.S.

Special-recognition citations also were issued in the three categories.

Electrical/Electronic-Tensolite Co., St. Augustine, FL, for its Tufflite 20000(R) airframe wire.

  • Chemical Processing-Furon Co., Bunnell Plastics Div., Anaheim, CA, for its Ultrapure(TM) family of molded valves and regulators, as well as for its Molded Dual Containment Flare Fitting; and J.M. Clipper Corp., Nacogdoches, TX, for its ProTech(TM) labyrinth seal.

  • All Other Uses-Pilot Industries, Dexter, MI, for its P-TEC(R) fuel and fuel-vapor handling tube; and Textiles Coated International, Amherst, NH, for its "LFP" structural sheeting material.

Special awards also were presented to entries from Europe and Asia:

Europe-(first prize) Koch Konstruktive Membranen GmbH, Rinsling, Germany, for Velaflex(R) heavy fabrics of Teflon fiber for variable-geometry membrane constructions; (second prize) IFK Isofluor, Neuss, Germany, for a fluorescent lamp tube covered with a shrink-fit jacket of Teflon FEP that contains glass splinters in case of breakage; (third prize) La Tecnochimica S.r.l., Torino, Italy, for the Swan-Protector Duplex, a thin coating of Teflon on corks used to stopper wine bottles.

  • Asia-(tied for first) Tokyo Gas Group for a steel plate laminated with Teflon PFA film for table-top and built-in ovens; and Nippon Pillar Packing Co., Ltd. for its Super Type Pillarfitting with a safety-enhanced double-seal structure to secure a large flow; and (third place) Nippon Valqua Industries, Ltd. for a thin tube of Teflon PFA with an etched inner surface that adheres to pressure rolls.

Cray Research rolls out 'wireless' supercomputer

Eagen, MN-Engineers with a fat pocketbook and dire need for computing power may now have the ultimate analysis tool available to them. Cray Research has unveiled its long-awaited T90 family of supercomputers, a series of machines with a top speed of 60 billion calculations per second and a top price of $35 million.

The CRAY T90s are the fastest vector machines ever built by Cray Research, which has dominated supercomputing for the past 20 years.

Key to the T90s' high performance is a series of internally developed technologies. Those include no internal wiring, 50,000-gate chips, and 52-layer printed circuit boards.

The most startling design change is the machine's lack of internal wiring. In the past, supercomputers have typically housed thick bundles of wires that connect processor modules to memory. The CRAY C90, for example, used 36 miles of wiring.

In the new family of machines, engineers eliminated the need for copious amounts of wiring by replacing wires with electrically activated zero insertion force (eZIF) connectors. Each eZIF connector contains a pair of electrically-activated jaws. One set of jaws clamps onto a processor's pc board; the other attaches to a memory module. Four hundred contacts within each connector replace 800 wires that would ordinarily connect processor to memory. Each board employs five eZIF connectors, eliminating 4,000 wires per board.

The connectors were critical for the T90 design because otherwise, engineers would have needed to squeeze about 40 times as much wiring that exists in the older C90 into the new machine. Engineers say that the wireless design also enhances the machine's manufacturability and reliability because it simplifies the connection scheme.

The new machine's 52-layer boards are also an industry high, the firm says. Each incorporates a mile or more of interconnect wiring. Integrated circuits are mounted on both sides of pc modules, producing circuit densities of 800,000 gates within 2 nanoseconds' reach of one another.

The T90 family ranges from air-cooled single-processor systems to liquid-cooled, 32-processor systems. Prices start at $2.5 million.

Parallel vector supercomputers solve computationally intensive problems, such as fluid flow over an aircraft wing, or simulating complex manufacturing processes.

PTC to buy industrial design software

Waltham, MA-One of the youngest of the major CAE software companies will purchase part of one of the oldest in the industry.

Parametric Technology Corp. (PTC) has announced that it will buy the industrial design and visualization products of Salt Lake City-based Evans & Sutherland Computer Corp. Price: $34.5 million cash.

Specific Evans & Sutherland products to move under the PTC banner: the Conceptual Design and Rendering System (CDRS) and 3D Paint, tools used largely in industrial design for creating free-form surface models of automobiles, appliances, and sporting goods.

"This move indicates our desire to broaden our product line," says Amanda Radice, vice president of marketing services at PTC.

Even without the acquisition, users of PTC's Pro/ENGINEER software could import CDRS data via IGES transfer. Ultimately, says Radice, they would be able to do both industrial and mechanical design in the same system.

That has been difficult in the past. Software analyst Gisela Wilson of IDC says that industrial design has always been a stepchild, and its data hasn't been precise enough for detailed engineering. But, she says, the acquisition of CDRS and 3D Paint will help PTC sell more into its installed base of Pro/ENGINEER users.

Software speeds analysis of nuclear-storage tanks

Richland, WA-Westinghouse Hanford Company (WHC) recently used SDRC's I-DEAS Master Series software to develop and analyze safer, double-shell nuclear-storage tank designs for the clean-up of the Department of Energy's (DOE) Hanford site. WHC engineers say I-DEAS' interactive capabilities saved approximately $2 million by helping to drastcially cut down on analysis time. The software also allowed them to create and analyze more sophisticated designs, and helped establish safe operational limits.

With I-DEAS' interactive mode, on-screen graphics, and advanced display tools, fewer engineers developed and studied four complex tank models in just four months. Such a project previously took two years.

The I-DEAS-based tank models allowed Westinghouse to examine how liquid waste temperatures and various soil, liquid, or pressure loadings affect tank integrity and deformation. High temperatures, in particular, are a key concern since they can cause additional degradation of the outer, reinforced-concrete shell.

Westinghouse's new tank designs use two steel liners and a reinforced concrete outer structure to prevent radioactive waste leakage. ANSYS finite-element analysis software and Silicon Graphics, Inc. workstations were also used to model and analyze the DOE's long-term storage tanks.

Blade-maker cuts development time

Givat Shmuel, ISRAEL-Blades Technology has slashed product-development time up to 50 percent, thanks to CAD/CAM software that streamlines the process from design through production.

Blades Technology, formerly Iscar Blades, supplies turbines for companies including Pratt & Whitney, General Electric, and Rolls Royce.

"With turbine blades, it is essential that you create an accurate surface model," says Yacov Rubenstein, CAD/CAM supervisor. "The system we used previously was too complicated and lacked Cimatron's flexibility in surface modeling." In addition, engineers have not encountered data-translation problems, Rubenstein notes. "With Cimatron, we know we won't be held up by IGES."

Blades Technology takes a finished CAD model, scales it up two-fold, and creates tool paths for an epoxy model. That model is then scanned by laser, digitized, and scaled down 50 percent to generate toolpaths to mill a graphite electrode for the forging die (the electrode is not milled directly, because the softer epoxy is easier to work with). An exact computer model is crucial for this process.

Cimatron software is also used to test the blades. In one example, Blades Technology creates a plane section to obtain a theoretical curve for the blade. The actual blade is then measured using an electro-optic device, and the two are compared. If there is an error of more than 0.002 in, the blade is rejected.

Says Rubenstein: "Not only have we cut development and production time between 25 and 50 percent, we have cut costs and improved quality."

System watches drivers' blind spots

Cupertino, CA-Thirteen percent of vehicle collisions result from motorists' inability to see blind-spot objects while changing lanes, according to the U.S. Department of Transportation. The SideMinder(TM) crash-avoidance system invented by Autosense, Denver, CO, aims to help reduce this hazard. It uses infrared sensors and light-emitting diodes from Siemens Components' Optoelectronics Div. to alert drivers to blind-spot objects when they're negotiating congested freeways or city streets.

Blind spots are the areas on the left and right sides of a vehicle that the driver cannot see in the side-view mirrors. "The intent of the system is to reduce the need for over-the-shoulder, direct viewing of the blind spots, which takes the driver's eyes off the road ahead," says Autosense President and SideMinder inventor Warren Hyland. The system gives information only about the blind spots, so drivers will continue to use their peripheral vision and mirrors to see vehicles behind and next to them.

A driver activates SideMinder by engaging the turn signal. Sensor modules in the vehicle's tail-light assemblies include an IR transmitter, receiver, detection circuit, application-specific IC, and self-test circuitry. Beams from the transmitter reflect off objects in the blind spot, the detector receives them, and the IC processes the information. If the module detects an object, the LED arrays in or near the driver- and passenger-side mirrors flash.

Prototype vehicles using the SideMinder are currently on the road in the U.S. and Europe. Siemens estimates that the system will cost less than $50 in production quantities and should be available for 1997-model-year cars and trucks.

Critical ring material helps certify jet engine

East Hartford, CT-In a test rig, an explosive charge intentionally blows out the root of a jet engine's fan blade rotating at 3,000 to 4,000 rpm. To pass the test, the released blade must not penetrate the engine case, risking damage to the aircraft. Test engineers also must demonstrate that, after the release, the engine can be shut down safely with assurance that other structures in the engine can withstand the severe imbalance.

This worst-case scenario took place recently on high-thrust PW-4168 and PW-4084 jet engines at Pratt & Whitney's engine manufacturing plant. The 36-inch-long titanium fan blades, weighing more than 20 lbs each, fit into a slot in the fan disc in the front of the engine. The blade lock retention ring-30 inches in diameter, .75 inch wide, and 3/8 inch thick-hooks around the slot, acting like a large lock washer.

When P&W ran a blade-out test at red-line speed, using an AISI 4340 steel retention ring, the fan blade following the released blade punched through the lock ring like a "cookie cutter." The engine case ovalized from the impact, while following blades dug into the case wall.

Facing the need to do a redesign or find a new material, P&W project managers elected to try making the blade lock ring of AerMet(R) 100 alloy from Carpenter Technology Corp., Reading PA. The alloy consists of a nickel-cobalt steel strengthened by carbon, chromium, and molybdenum.

P&W engineers found that they could not break the AerMet 100 alloy blade lock. In fact, they discovered that the rings would withstand six times the force that broke the steel rings, and that they would do nothing more than deform under the impact.

Early in the investigation, P&W did not know how much improvement it could expect using the alloy retention ring. As a result, the engineers designed a blade catcher to use in the event the ring did not perform as desired. However, the ring held up so well that P&W eliminated the blade catcher. This translated into a weight savings of 25 lbs and $3,000 to $4,000 per engine.

With the alloy ring in place, P&W passed the critical FAA certification test, and, in the process, improved design, reduced weight, and lowered production costs. The P&W project team feels that test results have "clearly advanced the state-of-the-art in our understanding of blade-lock failure mode, method of loading, loads, energy, energy absorption, and design philosophy by a quantum leap." P&W has since used the alloy for blade locks in all of its large jet engines.

Subcontractor becomes first flow-sensor user

Plainville, CT-When Gems Sensors Division was developing the RF-2500 Series of RotorFlow(R) flow sensors, it used a subcontractor-Harkness Industries of Cheshire, CT-to form the polypropylene molded units.

While molding the bodies of the plastic versions, Harkness President Al Hoodboy saw that he had an application for the flow sensor. By installing several RotorFlow units into the cooling systems on his molding equipment, he found that he could more easily monitor the critical temperature control process.

"Within a couple of weeks we had them on our own equipment," says Hoodboy. "Tolerances are so critical that if proper core cooling isn't maintained, we need to stop and not make another part until the problem is fixed. RotorFlow gives us the warning we need."

RotorFlow sensors are available in three configurations: RFI, which provides a simple, visual indication of flow; RFO, for flow-rate monitoring or metering applications; and RFS, for specific flow setpoint switching.

Harkness uses RFI models now and is evaluating the RFS models for alarms and flow data. "A nice safety feature is that there are no buttons to push-you can walk along and glance at it," Hoodboy adds.

Electronic control synchronizes process line

Tar Heel, NC-When Carolina Food Processors Inc., a division of Smithfield Packing Co., opened its new 510,000 sq ft pork-processing plant, the physical size and layout of the building represented a major challenge. The problem: The company needed to synchronize the processing line.

"The plant has four overhead chain drive conveyors of different lengths diverging in different directions at different speeds," explains Henry L. Morris, executive vice president of Smithfield Packing. "But these separate conveyors must arrive at the inspection station simultaneously."

Carolina installed a conveyor system from Numark, Inc., Kenesaw, NE, that features an electronically geared synchronizer from Astrosystems, Inc., Lake Success, NY. The controller links multiple shafts to a single master without mechanical coupling.

Now, the four conveyors that bring parts to the inspection station are geared together at varying ratios. The overhead conveyor carrying the entire hog is the master. As it advances through the workstations, various parts are removed and placed onto conveyors that will parallel the master and arrive at inspection stations for simultaneous inspection as a single unit.

Another benefit of the new system: speed can be controlled by a single potentiometer on the master shaft. This allows continually adjustable control while maintaining synchronization. Changes can be made through simple keypad entries. Adds Morris, "The new system has given our operation additional flexibility."

SPARC-based workstation fits in a notebook package

San Diego-RDI Computer has designed an 8.5-lb SPARC-based portable notebook-sized workstation featuring an 85-MHz processor, 2.4 GBytes internal disk storage, and optional 1024 x 768 flat-panel color display.

The PowerLite 85 "provides the desktop-equivalent capabilities workstation users need to run computer- and graphics-intensive applications," says RDI President U.C. Moon. The system is powerful enough to run mechanical CAD software, he adds.

Can mechanical engineers now take their UNIX-based CAD applications on the road? Jim Brennan, senior director of Workgroup Technologies, Hampton, NH, says the technology already exists; what is lacking now is market acceptance.

"When I go on a plane, most people are using spreadsheets or word processing," he notes, not CAD. "Engineers are seemingly more conservative than other users. It may take longer."

However, he envisions engineers using a portable workstation like the PowerLite 85 in hotel rooms, or to take to other worksites when visiting suppliers or customers. RDI says one early user, at Ford Motor Co., carries his portable workstation to different buildings on the sprawling Ford campus, working with engineers to develop design software.

As portable UNIX workstations become more powerful and affordable, Brennan says they may become substitutes for conventional desktop machines- especially if they are designed to fit in desktop "docking stations." That way, they could be easily used with full-sized monitors, and then slipped out for portable use.

The PowerLite 85, which is bundled with the Solaris UNIX operating system, is rated at 64 SPECint92 and 54.6 SPECfp92 (measures of integer and floating-point performance, respectively). There are two display options: a 1024 x 768 flat-panel color display, or Colorplus 640 x 480 active-matrix LCD. Hard-drive options range from 520M to 4.4G internal, with additional external options; and memory from 32M to 96M. The system measures 2.2 x 12.75 x 11.2 inches; pricing starts at $11,995.

Sidekick aims at affordability

Newton, MA-With the release of the 1995 Sidekick, Suzuki seeks to capture the "affordable" end of the sport/utility market. The top-of-the-line, four-door JLX with four-wheel drive starts at $17,269; the more modest two-wheel-drive canvas-top JS with two doors lists at $11,699.

At $18,406, the four-door JLX hardtop Design News tested offered automatic transmission, air conditioning, and a built-in roof rack. Standard features on the JLX include rear-wheel anti-lock brakes, an alarm, locking spare tire, cruise control, and power outside mirrors, windows, and locks.

The Sidekick's 1.6-l, single-overhead-cam engine produces 95 horsepower at 5,600 rpm and 98 lb/ft of torque at 4,000 rpm. Although the engine posts EPA fuel efficiencies of 22 mpg city, 26 mpg highway, there is a performance penalty for the little four-cylinder. The engine labors in some off-highway conditions, such as hilly back roads. Overdrive and a lock-up torque converter in the four-speed automatic transmission help to compensate.

To further accommodate driving demands, Suzuki engineers gave the driver a choice of shift patterns in the automatic transmission. A two-position switch in the "two-mode preference" option package lets the driver choose between normal shift patterns for best fuel economy, or "power" mode. The boost, while not enormous, does improve pep.

Standing 66.5 inches tall, the JX and JLX models boast a generous 7.9-inch minimum running ground clearance. Engineers capitalized on the vehicles' height by giving the driver plenty of glass and a utilitarian instrument panel for outstanding overall visibility. The drawback: A high center of gravity and fairly stiff suspension make the vehicle feel top-heavy and somewhat unpredictable in turns, despite a curb weight of more than 2,800 lbs.

If your driving habits involve some rough roads, the Sidekick's interior pads and grab-bars should put your passengers at ease. Potholes and unpaved road surfaces are no threat to the suspension. In front, it uses MacPherson struts with coil springs, a stabilizer bar, and dual-action shock absorbers; the rear combines coil springs with trailing arms.

Remote-control lawnmower braves hazardous turf

Escondido, CA-Need to cut the grass in your yard, but afraid of excessive radiation exposure? Such concerns may seem the exclusive domain of paranoid landscapers. Yet until recently, workers at the Zimmer nuclear plant outside Cincinnati, OH, had to don hot, sweaty radiation suits to trim select acreage.

Now, thanks to a remote-control lawnmower designed by Remtron (Escondido, CA), cutting the grass at Zimmer may prove as easy as pushing a joystick.

The $45,000 unit consists of a large industrial mower, provided by eXmark, modified with a custom Remtron remote-control system. A radio transmitter equipped with two joysticks and a variety of knobs mimics the operation of most of the lawnmower's functions. It sends signals to a receiver/processor box mounted to the top of the mower. Inside, a standard Remtron remote-control board (the company's primary business is with overhead bridge cranes, locomotives, and backhoes) runs a custom program developed for the lawnmower.

Two linear trim servos, supplied by Menzimer Aircraft Components (Vista, CA), control the throttle and choke. ETI Systems (Carlsbad, CA), designed a second set of servos that pushes and pulls the hydraulic control arms to vary the speed of the drive wheels. Each of these larger servos outputs 20 in-lbs of torque at 1 rpm. Custom amplifiers, designed by engineers at Remtron, power the servos.

"The biggest challenge," says John Schooley, Remtron's president, "was to maintain the manual control capability of the mower while being able to convert it to remote control very easily." Ultimately, engineers developed a series of electrical and mechanical disconnects that allow workers to switch configurations in less than five minutes.

While the cost is a bit steep for suburban lawns, Schooley believes the company can cut the price to less than $25,000 in quantity.

Digital mock-ups slice jet design time

Belfast, Northern Ireland-The Shorts aerospace company has developed a digital mock-up for its latest project, the Learjet 45 corporate jet-a move that will help cut development time by an estimated two years.

"We've captured every single aircraft part in 3-D solid models, which means we've completely eliminated the need for traditional, wooden prototypes," says Willie Magill, CAD/CAM systems manager. Shorts-which won what it calls the world's first aircraft contract, to build six "Flyer" byplanes for the Wright Brothers in 1909-will be building the Learjet 45's fuselage and em-pennage. The Learjet is expected to go into flight testing in less than five years, compared to the usual seven.

When working on the coupe rail, for example-a curved, alloy component that forms a structural link between the plane's windscreen and cockpit roof-engineers traditionally test assembly of the design with a wooden prototype. With the Learjet 45 digital prototyping, though, the cockpit design team simply pieced together the coupe rail's different elements on the workstation screen. Engineers discovered six major "clashes" in the initial design, and ironed out the problems within two days.

Magill credits electronic data management software (EDM) for assisting that process. EDM helps ensure that the 300 to 400 engineers working on the project-including subconractors hundreds of miles away-all have the latest, correct versions of designs; it also tracks who is working on what task. The company uses Computervision CADDS CAD software and CV's Engineering Data Manager software running on networks of Sun workstations and servers. Short engineers also rely on packages from Patran, Nastran, Formtek, ICAD, and FrameMaker.

The system gives engineers more access to design data, Short officials say. Before, an engineer designing a hydraulic system would have a difficult time calling up design information on the layout of the structural area into which those components needed to fit. Obtaining a single file could take hours, even days. Now, engineers can tap into one of the 10,000 design models or drawings within seconds.

"We wanted to completely break down the wall between the design side of the house and the manufacturing side," Magill adds. "It's paid off handsomely for us."

Piston pump powers automatic clutch

Leamington Spa, UK-Engineers at the Oildyne division of Commercial Intertech Corp., Minneapolis, have developed a new hydraulic unit to power an automatic clutch system (ACS) for cars. The ACS, designed and developed by Automotive Products, is being used with a standard transmission for the "Twingo Easy" compact city car from French automaker Renault.

To actuate the manual clutch, the ACS uses a miniature piston pump with built-in relief and check valves and a 12V dc motor from Oildyne. In operation, a microprocessor signals the unit to actuate the clutch.

Because the ACS and the miniature piston pump operate with brake fluid, engineers had to address several challenges. To suit high under-hood temperatures and brake fluid's low viscosity, Oildyne engineers selected the model HP1000 piston pump. "We chose an all-steel construction for uniform thermal expansion properties and iron-nitride surfaces for lower friction," explains Oildyne's Director of Engineering Dave Mauch.

Engineers at Oildyne, Automotive Products, and Renault used a 525,000-cycle durability test as well as a 250-hour salt-spray/salt-mist test and vibration tests to qualify the ACS system. They also conducted thermal shock tests at -22 degrees F to 212 degrees F, and tested cold-starting at -22 degrees F.

The hydraulic power unit shows promise for ABS and other dynamic brake applications, says Mauch, because the multi-piston pump is quieter than the one- and two-piston pumps presently used. Oildyne engineers are developing a prototype parking brake actuation system using similar technology.

Design News releases directory on CD

Newton, MA-Engineers who are anxious to find a particular component or system as quickly as possible have one more resource to turn to. Design News has recently issued its OEM directory in CD-ROM format.

Like its print counterpart, the CD-ROM directory provides users with access to 7,000 suppliers and links to more than 2,300 products.

But because of the flexibility of this new media, says Vice President of Electronic Publishing Peter Urbach, the CD-ROM can offer more than just listings of supplier names and product numbers.

"Users can not only access product descriptions, but a number of product specifications, too," says Urbach. "And since this information is compiled in one source, users seem to find this feature most useful-not to mention the ease of search."

Users can locate a supplier, even if only a product trade name is known. A geographic locator is also included, allowing users to find suppliers by region, state, and zip code.

Other tools available on the disc include:

An industry reference tool with detailed IEEE, ANSI, NEMA, and National Fluid Power Association standards information.

  • A cumulative index of Design News articles from the past four years.

  • An electronic notebook to hold comments on suppliers and products.

  • A trade show reference index.

The OEM directory on CD-ROM, which is being distributed to 10,000 qualified engineers, is presently available in Windows 3.1 format only. Retail copies can be purchased for $97.