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Articles from 1997 In February


Designer's Corner

Designer's Corner

Binary cylinder

To provide mid-stroke positioning of a lever arm at 16 equally spaced points, an engineer devised this configuration of pneumatic cylinders. It produces quick response and a large force output.

It consists of a series of two-state devices, each successive device providing half the stroke of its neighbor. When actuated in appropriate combinations, the output rod assumes one of 16 positions. Its inventor claims the configuration is not limited to equal spacing. He also states that, using a six-cylinder device, this approach could position a load within 0.050 inch anywhere in a three-inch total stroke.

Ken Hardman, P.E., 1607 North 390 East, Pleasant Grove, UT 84062.


LED status indicator

Incandescent lamps provide 360-degree output but don't do well in environments that subject them to vibration. Also, in most applications the life of an incandescent is limited to about 2,000 hours. Conventional LEDs offer extended life, but a limited field of visibility.

LitestakTM delivers 360-degree visibility and the 100,000-hour life typical of LEDs. It consists of an array of LEDs positioned in six columns around a cylinder with a standard bayonet base. Areas of high-intensity light from each LED column intersect to fill the chamber of a signal light.

As light reaches the chamber's exterior walls, lenses diffuse it for greater visibility.

Linda Carlisle, Federal Signal Corp., 2645 Federal Signal Drive, University Park, IL 60466, (708) 534-3400.

Value to customers means survival

Value to customers means survival

To excel, says Biach, companies need to respect employees and provide clear leadership on values.

Design News:How can a specialized company like Biach Industries survive today?

Biach: It's important to have an organization that has the contacts and access to find out what you can offer that's of high value to a focused group of customers. I'm not so much concerned about competition with other consultants as I am about competition with much larger companies. Larger companies are trying to find ways to justify various smaller segments of their organizations. And they're trying to address the smaller or more specialized projects that companies like us historically lived on. In the long term we will win out, because we can do a better job.

Q: Speaking as a supplier, what future do you see for the nuclear power industry?

A: I've seen the morale and attitudes of operating people in the nuclear power industry improve considerably over the past few years. As we start facing the end of the lifetimes of a lot of these plants, I'm concerned that there's going to be a change in attitude. There'll be less investment in capital improvements and less investment in im-proving the operation of the plants. They're depending more on outside people to come in and do the work. We can offer services to supplement the loss of staff. And we can help the industry determine how to get the remaining staff better trained and more up to speed.

Q: How valuable is computer-aided visualization to a firm like yours?

A: For us it's very valuable. A lot of the equipment that we develop is sold into markets that are not big enough to allow us to build things in volumes. So if we have a concept for a new idea, we can't prototype it. A prototype might cost a million dollars, and we can't afford to do that. So we need a way to demonstrate the principles and concepts of our idea and engage in a dialogue with our customers to see whether this is the right thing for them. Certainly as a sales tool visualization gives customers a sense of what they can gain from utilizing our services or our product. It's a communication tool more than anything else.

Q: What applications do you see for such innovations as neural networks?

A: We need to be more and more creative in the types of services and the nature of the products that we sell. We need to be able to bring the best technology to bear on any problem. Neural networks are a very effective way of implementing a solution to a problem where it's difficult to quantitatively model what you need. But neural networks aren't the only kind of technologies that are useful. A big part of our organization is devoted to exploring new technologies and seeing how they can be applied to process industries, and to improvements in product design.

Q: What must management do to persuade tough-minded employees like engineers that attempts to change corporate culture are serious?

A: There are people who are going to accept change and be energized by it, there are some people who follow along, and there are some people who resist change, believing that it's not necessary. Any company, if it intends to remain competitive and continue to grow and flourish, needs to have the best people available. And those people need to be on board with your values. They need to be enthusiastic about being flexible and addressing change. The best that you can do in workshops is to show employees the systemic reasons why changes are necessary.

When you try to make a change, if you try to change components of the system, the system is going to find a way to spring back, to go back into the position it was before. Unless you make a very organic change in the system itself that reinforces the behavior you're looking for, the change is not going to happen.

Q: How important is trust in the relationship between managers, engineers, and other personnel?

A: It's critical in all directions. Certainly managers have to trust all employees--engineers, production people, and everyone else. They have to trust them to be dealing on an open and above-board basis, and to accept that they are mature human beings. Employees in turn have to trust that managers are going to be there to support them and to give them the opportunity to do their best. And employees must trust managers to have some idea about how they're going to make the company continue to thrive.

Engineering Productivity Kit - Electronics

Engineering Productivity Kit - Electronics

Electronics tame airbag deployment

Newton, MA--No one will argue that airbags save lives and, in fact, have saved many more lives than they have taken.

The National Highway Traffic Safety Administration (NHTSA) estimates that airbags have saved more than 1,500 lives in the U.S. since 1987. However, the agency also says there have been 52 automobile airbag-related deaths since 1991. Of those killed, 32 have been children sitting in the passenger seat or strapped into a rear-facing child seat on the passenger side--against safety guidelines. Many of the other deaths involved small adults.

Siemens Automotive, Auburn Hills, MI, already has a system on the market to prevent deployment of a passenger-side airbag into a rear-facing child seat. Called BabySmart, it debuted on the Mercedes Benz 1997 SLK model in January. A specially equipped child seat, made by Britax and available through Mercedes Benz dealerships, is part of the system.

Designed jointly by Siemens and IEE USA, the system senses if a child safety seat is present and determines its orientation. If the seat faces the rear, the system automatically deactivates the passenger airbag and prevents it from inflating in a collision. The system also prevents airbags from deploying into an unoccupied seat, thus saving car owners the $1,500 to $2,500 airbag replacement cost.

The system works like this: A pressure-sensitive foil integrated in the passenger seat detects the presence of a passenger. Similarly, the child safety seat detectors are integrated into the seat. They detect the presence of two resonators affixed to the safety seat's base. The position of the resonators, with reference to the location of the antennae in the vehicle's passenger seat, determines whether the child seat is rear facing, forward facing, or out of position.

Did you know...
Of those engineers surveyed who useembedded processors, 41.1% use them in industrial control applications.
Source: Design News Market Beat survey.

The U.S. is primed for this type of passive safety system, notes Siemens Automotive President George Perry, largely due to the increasing number of light trucks and two-door cars, where a back seat is not a reasonable option for parents transporting small children.

NEC, Itasca, IL, has a similar system scheduled to debut in 1999- or 2000-model-year cars.

The Passenger Sensing System controls airbag deployment based on who or what is in the passenger seat. Flexible antennae in the vehicle seats act as transmitters and receivers of low-level electric fields. By monitoring changes in the electric fields, the system measures the difference in strength between the signal sent and received due to "interference" from what is occupying the passenger seat--be it a teenager or a bag of groceries.

The end result is a system NEC says provides the best reaction in any crash situation. For example, the airbag can be made to deploy if the system identifies an adult passenger or a child in a front-facing child seat. But the airbag will not deploy if the passenger seat is unoccupied or if the system detects a child in a rear-facing child safety seat, eliminating potential airbag injury to the child.

The Passenger Sensing System works with all child safety seats without modification, and isn't affected by light, reflectivity, temperature, air conditioning, dust, or noise.

Customizing airbags. TRW has spent more than three years prototyping a system that senses an occupant's size and position to activate "smart restraints" during a crash. Company officials say the weight sensing part of the system should be in 1998-model-year cars, and the full system should be available the next year.

TRW's occupant-sensing modules use seat scales and web payout to determine an occupant's size, dash-mounted ultrasound sensors and seat track and angle sensors to figure out the person's position, and a buckle switch to see if the person is using the seat belt.

Sophisticated sensors also monitor change in vehicle speed and belt payout so a microprocessor can calculate crash severity. Taking all this data into account, the processor executes a proprietary program to adjust the occupant restraint system's response.

Microprocessor-controlled functions include: managing the volume of gas in the airbag as it deploys, pretensioning the seat belt to position the occupant, and preventing airbag deployment if no one occupies the seat. The combined response, say TRW officials, absorbs occupant body energy, reduces the load on the occupant's head and neck, and optimizes airbag protection.

The idea behind these systems is to make crash protection work for all car occupants--whether they're in a child safety seat or leaning forward to adjust the radio. The currently proposed airbag warning labels may serve only to cause drivers to permanently shut off their airbags.

--Julie Anne Schofield, Senior Editor


Turn your body into an antenna

Scientists at IBM's Al-maden Research Center, San Jose, CA, are perfecting Personal Area Network (PAN) technology that uses the natural electrical conductivity of the human body to transmit electronic data. Using a microcontroller-powered prototype transmitter--roughly the size of a deck of cards--and a slightly larger receiving device, the researchers can transmit a programmed electronic business card between two people via a simple handshake. What's more, the prototype allows data to be transmitted from sender to receiver through up to four touching bodies.

Did you know...
55.9%of all engineerssurveyed specify 32-bit micro-controllers.
Source: Design NewsMarket Beat survey.

The body's natural salinity makes it an excellent conductor. PAN technology takes advantage of this conductivity by creating an external electric field that passes a billionth of an amp to carry data. Data speed is equivalent to that of a 2,400-baud modem.

Possible applications include: electronic business card exchange, exchanging data between communications devices and electronic smart cards, public phones with PAN sensors automatically reading a user's calling-card number and PIN, and health care workers identifying patients and their medical histories simply by touching them.


Reinforced nylon overcomes fuel-system ESD concerns

This month, Texas Instruments introduces what it claims is the world's most powerful digital signal processor (DSP). First in the new TMS320C6x family, the TMS320C6201 fixed-point 200-MHz processor delivers 1,600 MIPS (million instructions per second)--reportedly 10 times the performance of the highest-performing DSPs currently on the market, including those from TI. At $96, the chip offers a 50% lower DSP cost per channel in such applications as wireless base stations, remote-access servers, pooled modems, cable modems, voice-mail systems, and digital subscriber loop (xDSL) systems, according to company spokespeople.

Analysts say this DSP will radically shift the emphasis of designing systems from hardware to software. This should result in performance that will not only eliminate the Internet bottleneck, but could also be the springboard to "unplugged" applications, such as instantly sending voice or data to anyone from anywhere in the world. The technology could also make possible extreme personalization of electronics--keyless home access via voice and face recognition, for example.

In terms of traditional benchmarks, the 'C6201 can perform a 1,024-point complex FFT (fast Fourier transform) in 70 microseconds--10 times faster than competing DSPs. Development tools for both PCs and Sun workstations include an efficient C compiler, an assembly-language optimizer, and a Windows-based debugger interface. A hardware emulation board is also available.

Additional details...Texas Instruments, Semiconductor Group, SC-97001A, Literature Response Center, Box 172228, Denver, CO 80217. Phone (800) 477-8924, ext. 4500 or http://www.ti.com/sc/C6x.


Get custom microcontrollers in 7 days

Austin, TX--The world may have been created in six days, but if you wait an extra working day you can get an 8-bit Motorola 68HC08 built to your specifications. Previously, this work could take several months.

Motorola's CSIC (Customer Specified Integrated Circuits) division's 7-day program uses ready-made modules in the 68HC08 development library. Designs start with the 68HC08 core, and customers can add such modules as I/O structures, A/D converters, timers, display drivers, and various types of memory.

The design methodology also lets Motorola engineers simultaneously create design and technical documentation for the device, delivering a complete package to a customer within a week. Customers can even submit software code while the company fabricates the device, allowing for late ROM programming.

"This new streamlined design program will let companies significantly reduce product development cycles, helping them to respond quickly to market opportunities anywhere in the world," says Motorola's Charles Studor, project manager. The firm will release the design methodology to all Motorola worldwide design centers this year.

For more information about Motorola's 7-Day CSIC program: visit http://design-net.com/csic.


Application tips

Single connection handles power and communications

Capacitor-inspired design packs 1.2 Ah in a 2.1V, 2.9-oz cell

Julie Anne Schofield, Senior Editor

Wheat Ridge, CO--Batteries aren't very efficient. In fact, at high discharge rates, they typically utilize 5% or less of their active material.

This fact bothers many engineers, but Tristan Juergens decided to make a goal of improving a battery's active-material utilization under all loads. Achieving this goal would make possible smaller batteries that could do more useful work.

While working at an electronics company, he took apart an electrolytic capacitor and noted how it was made with a large surface area and extremely thin plates.

"Capacitors have very low energy density and therefore aren't useful as a power source," says Juergens. "But by combining the construction form of a capacitor with the technology of lead-acid electrochemistry, it is possible to provide high sustainable power."

After several years of product development, Juergens perfected his Thin Metal Film (TMF) technology in the form of the Bolder 9/5 subC cell. The 2.1V, 1.2-Ah cell measures 2.76 inches (70.1 mm) long and 0.90 inch (22.9 mm) in diameter. It weighs just 2.9 oz.

TMF technology employs two key structural innovations: very large plate surface through the use of extremely thin, closely spaced plates; and unique end connectors that provide a very-low-impedance connection between plates and the device to be powered.

To form the positive and negative plates, 2/1,000-inch-thick lead foil is coated on both sides with 3/1,000-inch-thick lead oxide. A strip along the edge of each plate is left uncoated. A glass-fiber layer separates the positive and negative plates, which are then wound together in what Juergens calls a "jellyroll" configuration.

The uncoated strips of each plate protrude slightly from opposite ends of the wound cell. Lead terminals cast onto each end of the cell provide an electrical connection for the entire exposed edge. Encapsulating the entire edge of each plate facilitates current flow, minimizing cell internal impedance, which maximizes power.

The thin foil plates and cast-on terminals enable the cell to surpass the performance of other batteries, including NiCd designs, say Bolder Technologies officials. Compared with various conventional technologies, the design increases the ratio of plate surface area to active material by 16 to 19 times, and decreases the length of the electron flow path by 20 to 80 times.

"We're still using conventional lead-acid chemistry--the normal lead-acid charge and discharge reactions occur--but the fundamental difference is that the plate thickness is between 10% and 1% of the thickness of conventional lead-acid cells," says Juergens. Decreasing the plate thickness increases the surface area for the same amount of active material.

Greater surface area is key, stresses Juergens, because it allows more of the active mass to participate in the charge/discharge reactions at higher and higher rates. Another result, the company claims, is that users can charge the battery in five minutes.

In addition to the traditional lead-acid battery benefits of reliability, low cost, and long life, the Bolder cell also provides:

- Very fast discharge and recharge.
- Flat voltage profile.
- No memory effect.
- Cool operation.

Applications for the Bolder cell include: cordless power tools, backup power supplies, engine starting, hybrid electric vehicles, battery-powered toys, cellular phones, portable computers, grass trimmers, and patient-monitoring equipment.

Chrysler Corp. has said it will use 600 Bolder cells in its Dodge Intrepid ESX concept car, a prototype diesel-electric vehicle. Another company, Boulder Laser Systems, says it is designing the batteries into portable cordless laser welders.

Additional details...Contact Arnie Allen, Bolder Technologies Corp., 5181 Ward Rd., Wheat Ridge, CO 80033, (303) 422-8200.


Application tips

Thin-metal-film battery maximizes power density

Tom Rosenberg, INTERBUS System Group Engineer, Phoenix Contact Inc., Harrisburg, PA

PowerComTM connection technology is power and communications in a single connection. It enables device communications using the power supply connection in just three easy steps. Non-polarized, watertight IDC connectors provide error-free termination, lowering sensor and actuator connection costs for an I/O network.

INTERBUS Loop and PowerCom, using QuickOnTM connectors, are based on the industry-proven INTERBUS-S networking technology. INTERBUS Loop provides a single protocol solution for both device- and sensor-level I/O networking. Generation 4 INTERBUS-S systems can incorporate the IN-TERBUS Loop products directly into your existing application. Sharing the same protocol enables seamless integration between a device bus and a sensor bus. This creates a distributed I/O network that works and reacts as a single network.

This tight integration of INTERBUS Loop with INTERBUS-S takes advantage of the best of both bus types: device and sensor.

The loop network forms a medium to transmit a full-duplex signal for optimum speed while carrying the 24V dc power to the I/O devices. Fast, simple, single connectivity for both power and communications using a proven bus protocol makes the PowerCom, INTERBUS Loop, and QuickOn connectors a powerful tool for manufacturing and process-control applications.

To speak with a Phoenix Contact INTERBUS systems group engineer, call (800) 586-5535.

World's Highest IQ Tire

World's Highest IQ Tire

Under test by Goodyear since 1992, this smart tire contains a chip system that can gather and store data that identifies the individual tire, and detects tire air pressure and temperature.

Today, such information must be collected manually. Time-consuming and dependent upon operator skill and attitude, manual data collection can prove inexact and expensive. It's important to monitor tire pressure, because proper inflation directly impacts tire wear. By making it possible to keep tires properly inflated, the new chip system can reduce fleet maintenance costs.

In one version now under investigation, Goodyear engineers use a hand-held reader that can interrogate a computer chip linked to a transponder antenna embedded in a UnisteelTM commercial tire. These experimental tires, and the commercial versions that will be developed from them, will be able to give the reader information that can help cut truck fleet costs.

CAD vendors wrap the web

CAD vendors wrap the web

Purveyors of CAD systems tout their products as Web-enabled. But what, exactly, does the Web enable engineers to do with CAD?

According to Daratech, Cambridge, MA, and other industry research firms, the Internet and its intranet cousins represent nothing less than a revolution in engineering technology. Born in the secrecy of DARPA, nurtured in the circles of CERN, the World Wide Web was destined for collaborative engineering.

Commercial dial-in access and browser products now give engineers benefits their colleagues in the scientific and research communities have enjoyed for more than a decade. As a result, Griff Roberts, director of foundation products at Bentley Systems, Exton, PA, envisions four types of potential customers for his company's Web-related products:

- Design engineers sharing design data with partners for collaborative engineering.

- Engineering managers using the Web in the design review process.

- Contractors posting data on the Internet for subcontractors.

- Marketing organizations who want to take CAD images to the Internet. The Web allows users to fire up applications remotely, perhaps not so foreign a concept to design engineers. In fact, Bruce Boes, vice president of marketing at Matra Datavision, Andover, MA, points out that this technology has been around for some time: X-Windows makes it possible to access his firm's Euclid CAD/CAM package residing on a workstation through a networked PC. The latest offering, Euclid Quantum, introduced late last year, has the Netscape "N" proudly running in the upper right corner of the screen. The message: The Web is just another network, and a vast one at that.

"The year 1996 saw users reading information off the Web; 1997 will be the year engineers write to it," Boes predicts. "The Web gives access to information. Why not get into it?" But how does an engineer get into the Web?

Publish or perish. Bentley's strategy emanates from its Engineering Back Office line of products. It includes tools for exporting CAD models as Virtual Reality Modeling Language (VRML) files. "The idea is to provide dynamic, live publishing capabilities for engineers that do not require any intervention on the part of the publisher," Roberts says.

First among these products, the Model Server Publisher, will make its appearance in the first quarter of 1997. The software includes Netscape Web Server and Enterprise Server for posting to the Internet and intranets respectively. "We put all the programs on the server side so the person looking for information can do everything with a browser," Roberts explains.

In the view of Sabine Gossart, manager of marketing communications at Solid Works Corp., Concord, MA, the most prominent Web-enabling technology currently in CAD systems is outputting vector geometry in VRML format. "It permits the posting of 3-D images to the Web and their viewing with standard browser programs," Gossart says. Browsers typically require some sort of VRML plug-in, which can be downloaded freely from many sources.

Paul Mikle, manager of technical marketing, Parametric Technology Corp., Waltham, MA, adds that the capacity for VRML export is the main Web-enabling feature in Pro/ENGINEER. And the company has under development a Netscape plug-in for Pro/Flythrough that will let users virtually explore 3-D models over the Web.

Baystate Technologies Inc., Marlborough, MA, added VRML output to version 7.5 of its CADKEY software. This enables users to perform "walk-around" examinations of 3-D models using browsers, enhancing communication between engineers. One CADKEY user, XYCORP Co., Malibu, CA, used the Web as a design forum for its SuperCar green-technology demonstrator, a project funded in part by NASA and the DOE.

Ralph Mayer, vice president of technical marketing at Adra Systems, Chelmsford, MA, sees tremendous value on the Internet for engineers. Adra is beta testing a new product that will enable users to access engineering data through the Matrix product data management (PDM) system over the Web.

Matrix customer Draper Labs, specializing in guidance and control systems for the military, uses a secure Internet site to provide the DOD a way to get in and look at CAD drawings. Files that are 2-D are in Adobe Acrobat PDF; 3-D files are displayed in VRML. The DOD has added a note pad encryption scheme for securing access.

Matrix can automatically process CAD drawings into Web format. It also has the ability to provide built-in data management. "The benefit is that it is not necessary to have 3-D CAD software at both ends of the pipe," Mayer maintains. "The Object Management Group is working on standards for querying PDM systems. We are working with CERN, a Matrix user and Web pioneer, to help us push an object-oriented approach." The Object Management Group, based in Framingham, MA, was founded to promote object-oriented technology in software development.

Speed brakes. VRML's 3-D format draws much attention. However, Kim Corbridge, senior manager of product marketing, Intergraph Corp., Huntsville, AL, feels a main shortcoming of the Internet is the limited bandwidth available to most users. Many users do not have access to dedicated network connections, and are restricted to the speeds of their phone lines and modems. Both drawbacks can choke the flow of 3-D data.

"A 2-D format such as Computer Graphics Metafile (CGM) offers useful information in a compact form," Corbridge says. Intergraph's Solid Edge CAD system can create a CGM file. For 3-D work, Solid Edge's ACIS-based modeler has an ACIS to VRML translator.

The Active CGM authoring tools developed by Intergraph subsidiary Intercap Graphics Systems Inc., Annapolis, MD, let users prepare 2-D vector or vector/raster hybrid files for Web distribution. The files can be accessed with Active CGM browsers, or with such commercial programs as Netscape Navigator and Microsoft Explorer.

A file created with Active CGM might have hot links that the user can navigate graphically: an assembly drawing with balloons, for example. Detailed drawings of subassemblies could be retrieved by clicking on the desired balloon. In addition, there could be a text index in HTML.

As for the number of engineers on the Web, Intergraph suggests it's a 50/50 mixed bag out there. "The more forward-looking engineering companies let people have access to their data through the Web," Corbridge says. "They see the advantages of linking up with customers to show engineering drawings over the Web."

What price, freedom? "The Web scares some people," says John Gebhardt, Intercap's chief scientist. "Engineers don't want to publish things people can use inappropriately."

This presents a dilemma for the Internet community. On the one hand, the Web permits open access to data. On the other hand, well, it permits open access to data.

"The question is how comfortable engineers are about publishing their designs," relates Solid Works' Gossart. "In general they don't like to share important data in such a free space." However, she adds, this freedom can be used by engineers to good effect. One Solid Works user, the Agile Manufacturing Network, Spokane, WA, provides an Internet forum that links designers with manufacturers.

One solution: offer different layers of Web access for different audiences. Intergraph has a private intranet for internal use only, a public Internet Web site, and an "in between" Web site that is password protected.

Advocates find the Web no less secure than mail or other media. Good security features are available, they say, for encrypting messages and drawings. "1997 will be the year the Net is used for secure transactions in a big way," Gebhardt predicts. "The technology and infrastructure are there. People just haven't gotten around to taking advantage of them yet."

The state of existing Web-publishing technology also limits how many engineering secrets can be disclosed. "CGM and VRML dumb-down the data a bit," Gebhardt notes, making it impossible to machine directly from the models or get at the underlying features, associations, and intelligence. "People will also rethink what is needed to be secure. Half the time nobody is interested in what you're doing anyway," Gebhardt believes.

The great power in the Web is that it provides windows into your engineering repository. "It really enables people to streamline the publishing process," Gebhardt adds. "This changes the whole dynamics of multi-national, distributed design. You don't really have to send anything to anybody anymore. Just publish it and they see it. Document management is much simpler."

The enthusiasm among CAD vendors for the Web seems unbounded: "Our vision is to make Pro/ENGINEER a seamless part of the Web," declares PTC's Mikle.

PTC is developing technologies to embed Pro/E in HTML-based documents. This will enable engineers to use the associativity and parametrics features of Pro/E through a Web browser, with the host doing all the work. "However, we just can't stick stuff out on the Web for free," Mikle says.

Freedom for a price. And there's the rub. How do you make engineering products for the Web and still make money? Autodesk Inc., Sausalito, CA, uses the "dumb-down" approach for the Internet version of its PartSpec catalogue of mechanical parts.

"The question at Autodesk was how should PartSpec be delivered in the future," says Chris Hock, marketing manager. "Our research shows that 60% of Autodesk users have access to the Internet. It is easier to post information to the Internet than it is to produce CD ROMs. Therefore, we went live with our initial release of PartSpec Online last November."

The Internet version contains the same information as the CD ROM version, except drawings are in a DWF format rather than DWG. The former provides a quick view of vector data within the rather narrow restrictions imposed by a Web site. These cannot be downloaded into vector CAD files.

Technical product information remains free, but if the user wants to download DWG formats, he or she has to purchase the CD ROMs. Autodesk is working on this issue, and plans eventually to provide downloadable DWG to customers on a subscription basis.

Another approach: use the Internet as a network connecting full-blown CAD sessions. This goes beyond publishing--or falls short, in some views--in that both the sender and recipient must have licensed CAD seats. Henri Evain, marketing manager at Dassault Systemes, Paris, France, says Web-compliance at his company means products that publish CAD data in VRML format and make them available on the Internet while taking advantage of intranets as a means of collaborating in a networked environment.

Dassault's offering, Catia Conferencing Groupware, provides bi-directional coupling between two Catia sessions over an intranet. Through a Netscape Navigator interface, users can video conference while interacting with a CAD or assembly model, in real-time. Such sessions demand a lot of bandwidth, however, therefore the system works best on dedicated lines.

Catia Conferencing Groupware ships with Netscape/InSoft network conferencing software, which possesses all the audio and video plug-ins required. A Catia Conferencing plug-in is also provided. Users can open Catia sessions while navigating HTML pages. This gives intranet users access to Catia data from an intranet front end, such as a browser. However, Catia must reside with the browser.

Evain feels collaborative engineering is best provided within the secure and bandwidth-generous structure of an intranet: "Engineers balk at the Internet," he states.

This is not to say Dassault developers do not have more grandiose networking schemes in mind. In particular, Evain alludes to a project aimed at VRML acquisition and reading that would enable Catia files to be reconstructed from VRML format. "How much intelligence can be restored to VRML files?" he wonders. A tough question that most CAD vendors say they have no plans to tackle.

Just build it. Matra Datavision's Boes is mindful of the fact VRML provides little more than pictures. "Why not use STEP over the Web?" he asks, referring to the developing standard for transferring solid CAD models. He points to an initiative sponsored in part by D.H. Brown that would extend the graphics-exchange standard more rapidly to cover Web-related features.

Intercap's Gebhardt points out that transferring CAD intelligence over the Web is not as simple as transferring images. "VRML was designed as a publishing standard, not as a CAD interchange standard," he says. "It is not meant to exchange things that can be built. STEP, which is designed for manufacturing-caliber data exchange, is too big and heavy for publishing."

Performance issues come down to phone line and modem capacity. "We need to get the Internet to the performance of a dedicated line for real-time use," Boes says. "We know how to do it. Somebody just has to build it." dn

One of the world's largest research communities is concerned with how the very smallest objects conduct themselves. The nuclei of CERN, Geneva, Switzerland, are its facilities on the Swiss/French border. However, thousands of scientists all over the world are involved in particle physics research there. This is one of the reasons CERN initiated the World Wide Web in the first place.

The latest instrument of big science at CERN will be the Large Hadron Collider (LHC). Designing and building the massive LHC accelerator is a two-decade endeavor, and as much a global project as the research it will support. Therefore, CERN managers have ensured engineering data management will be a Web affair.

Claude Hauviller, senior engineer at CERN, says the data describing LHC and its resulting experiments, when built, will be complex, multi-disciplined, widespread, and long-lived. "Our work is performed in collaboration with many different institutes, located all over the world, in formats ranging from paper documents to Web-based information systems," Hauviller says. "CERN created the Web to provide a forum for communication and research exchange. For this reason, we wanted the engineering effort for LHC to integrate seamlessly with the Web, too."

CERN has installed 300 seats of Adra Systems' Matrix product data management system to manage and process data associated with the LHC project. With them, engineers at Geneva will be able to evaluate CAD drawings over the Internet with subcontractors and institutes, wherever they may be.


Cyber-contacts

Visit the following Web sites to get the latest on-line information from the CAD vendors in this article

Adra Systems: www.adra.com

Autodesk: www.autodesk.com

Baystate Technologies: www.cadkey.com

Bentley Systems: www.bentley.com

Dassault Systemes: www.dsweb.com

Intercap Graphics Systems: www.intercap.com

Intergraph: www.intergraph. com

Matra Datavision: www.matra- datavision.com

Parametric Technology: www.ptc.com

Application Digest

Application Digest

Corrosion-resistant PM stainless steel

Louis Desrosiers, Presidetn, Prectitech, Inc., Quebec, PQ, Canada

The corrosion resistance of stainless steel, combined with the unique economy of the powder metal (PM) process, makes PM stainless steel an attractive material for many types of parts. Recent developments in high-temperature sintering make it possible to manufacture corrosion-resistant stainless PM parts, opening a much wider range of cost-effective solutions for design engineers.

The inherent porosity of PMparts tends to increase crevice corrosion. A number of ap-proaches are being explored to improve corrosion resistance, and altering the sintering pro-cess promises to be the most cost-effective.

Corrosion resistance (as evidenced by the length of time before visible corrosion occurs) increases as sintering temperature rises. Sintering stainless steel parts at 2,350F (1,288C) promotes the deoxidation/reduction of oxides that inhibit metal-to-metal bonding of powder particles. In addition, controlling the sintering atmosphere to optimize nitrogen absorption results in significant improvements in me-chanical properties and corrosion resistance.

Traditionally, sintering is performed at a temperature of 2,050F (1,121C) because the metal belts used to transport the product through the furnace have a significantly reduced life above this temperature. High- temperature sintering--processing over 2,100F (1,150C)--can be performed in a pusher, walking beam, or vacuum furnace, eliminating the limitations imposed by the belt.

To contact a Precitech applications engineer, call 418-658-5335, or fax 418-658-5336.


Self-calibrating liquid level sensors

Will Atkinson, Product Manager KDI, Commercial Products Division, Cincinnati, OH

When measuring oil or fuel levels, factors such as degradation, contamination, difference in type and brand and, to some degree, lot-to-lot variation, can often cause capacitive liquid-level sensors to give inaccurate readings. This occurs simply because the majority of these sensors use a fixed reference and cannot allow for such factors.

The Commercial Products Division of KDI Precision Products has developed and patented a new capacitive liquid-. level sensing technology that continuously self-calibrates, thereby eliminating the fixed-reference problem. By locating a series of transmitting plates along the length of the device's sensing region, the KDI sensor can obtain capacitive measurements for liquid, air, and the liquid/air interface point several times/second.

Using these constantly updated readings, the oil level can be very accurately calculated. Just how accurately depends on the size of the transmitting plates but, in a typical application, accuracy to within a millimeter is obtainable.

In addition, KDI's microprocessor-based sensors are low power (less than 50 mW), rugged enough to withstand harsh operating environments, able to filter level variations caused by liquid sloshing, and can be factory-programmed with tank geometry to provide actual volume measurements.

To speak with a KDI representative, call 800-377-3334, extension 2047.

Engineering News

Engineering News

Engineers battle for right
to design next-generation fighter jet

The battle: Win the contract to build the Joint Strike Fighter (JSF). The players: Lockheed Martin and Boeing. The mission: Design and manufacture a supersonic, radar-evading, single-engine, combat aircraft so flexible it can be used by three branches of the armed service and that costs approximately $30 million. The stakes: With an estimated total-program life of 50 years, the project could guarantee their military-aircraft business' survival into the next century.

According to the Department of Defense, the JSF must fulfill certain requirements. For the U.S. Navy, JSF should be a first-day-of-war fighter aircraft to survive an enemy's initial strike. For the Air Force, JSF would be a multi-role aircraft; and for both the Marine Corps and U.K. Royal Navy, JSF is to provide short takeoff and vertical landing (STOVL) aircraft. Combining these requirements is where the engineering challenges lie.

Using in-house expertise. Boeing has experience with military aircraft, including the F-22. The company is responsible for 1/3 of the F-22 project, while Lockheed Martin, the prime contractor, is responsible for 2/3. But according to Aviation Week & Space Technology, Boeing has not built a successful military fighter in more than 50 years. Its recent acquisition of McDonnell Douglas, however, could provide the resources and talent lacking in the military-fighter arena. But McDonnell Douglas has had a 30-year lapse in winning a design competition for a major fighter or attack aircraft; the Pentagon rejected its bid to be included in the JSF competition and went with Lockheed and Boeing instead.

If a key to JSF is affordability, then Lockheed Martin seems well positioned. At its Fort Worth, TX, site the company has been producing F-16s for almost 20 years. According to Lockheed's Communications Manager for Tactical Aircraft Systems Joe Stout, Lockheed has managed to cut the cost of producing its F-16 by 38%--even though its factory volume dropped by 75% over four years.

To be all it can be for each service branch and still cost $30 million per plane, all models of the Lockheed Martin JSF would have common outer mold lines across the fuselage and wingbox. Other common parts include the canopy, radar, ejection system, subsystems, most of the avionics, and structural geometries. "With JSF, we're shooting for an optimum amount of commonality. We will manufacture the aircraft on a single production line with simple holding fixtures that can accommodate cousin parts and assemblies for each respective service variant," explains Mike Packer, director of manufacturing affordability on JSF.

The planes would also employ unitized structures: portions produced as single parts instead of being assembled by hand from a multitude of pieces and hundreds of fasteners. The canopy frame, for example, is fabricated from a single aluminum casting with no fasteners. By comparison, the F-16 canopy frame has 48 parts, 70 shims, and 500 fasteners.

Boeing incorporated affordability into its design by using a modular approach. Because this generated such a large number of common parts, all models can be assembled on a single production line resulting in lower unit cost.

The simplicity of the Boeing JSF design is underscored by having only four basic structural components: a single-piece wing, integrated forebody, center fuselage, and aft fuselage/tail. Instead of fastening two wings to the sides of a fuselage like most planes, this concept calls for the fuselage to be attached underneath a single composite wing.

"The biggest expense is drilling holes and filling holes, and we want to have as few of those as possible," notes Fred May, deputy program manager, JSF program at Boeing.

The Lockheed Martin team is cutting potential manufacturing costs by applying lessons learned from its experience with cocuring in the Japanese FS-X program. In cocuring, composite parts are bonded together without conventional metal fasteners. Tooling techniques also derived from the FS-X program, together with a proprietary new modular tooling approach, would allow Lockheed Martin Tactical Aircraft Systems to significantly reduce the cost of manufacturing composite materials for use in bulkheads of the JSF.

Boeing plans on producing its JSF prototypes with jigless manufacturing techniques, including determinant assembly, a process that uses part features to quickly align various components with very little assembly effort.

Tools for streamlining. Boeing will also use CATIA, a CAD program from Dassault Systemes, to further streamline manufacturing. "We will transfer digital component definitions from CATIA directly to computer-controlled machines for part fabrication," says May.

Lockheed is also using CATIA as its CAD program, but not an off-the-shelf version. "We and Dassault are working together to build one unique next-generation devlopment system," explains Woody Sconyers, director of modeling and simulation at Lockheed Martin.

Boeing is taking the CAD lead from its commercial arm. "Commercial went to CATIA quite a while ago, and they work regularly with Dassault Systemes. We have an agreement that allows us to take advantage of all of that work," May says.

The planned marriage of Boeing and McDonnell Douglas may cause some initial CAD problems. McDonnell Douglas uses EDS Unigraphics as its CAD system; in order for the two systems to communicate a STEP translator must be involved, perhaps causing initial confusion. According to a report in the Wall Street Journal, it could be early next summer before the deal between Boeing and McDonnell Douglas is approved by the government, so CAD changes don't appear imminent.

Lockheed has been very busy developing other integrated computer-based tools and capabilities to cut costs, including simulation software and virtual reality (VR).

"One of the concerns our engineers have about digital mock-ups is losing the sense of scale," explains Sconyers. "VR lets you regain that sense of scale and the engineers can then immerse themselves in the design. They can test for certain factors, such as, 'Can I really remove this part and replace it? Can I reach certain elements to assemble them in the factory?'" Simulation software, not yet chosen, will be physics-based and allow animation as well as actual sequences.

In other attempts to trim costs, both companies are instituting product data management (PDM) software systems, as well as using intranets and web-based technology. According to May, everything at Boeing is networked together. "Not only will we use PDM, but we have a network based on web technology that provides cost schedules."

Lockheed is still in the selection process for a PDM system, and is also integrating all of the development team efforts through Internet-based communications. "The Internet offers us some very powerful tools for collaboration and that's key," Sconyers says. "We have design talent at multiple sites and we want to take advantage of that talent by tying it together through a collaborative engineering environment. We call it virtual co-location."

In order to pool that talent, both Lockheed and Boeing are instituting the use of Integrated Product Teams (IPT). "We are a strong believer in IPTs, and used them on F-22 and 777," explains May at Boeing. "We set up a team that has total responsibility for its piece of the airplane; and it has to design, manufacture, and support everything that is involved in that product. It is almost as if we have a number of independent small companies all part of the JSF program."

Lockheed Martin, according to Dave Wheaton, vice president and JSF program manager, "takes advantage of the low-cost rapid-prototyping at the Skunk Works; the integrated product team structure, technology, and lessons learned from the F-22 program office in Marietta; and the total systems integration and lean production capability in Fort Worth."

But even with a highly trained team, revolutionary designs and manufacturing, and the best of computer technology, both competitors have a lot of challenges ahead. And even if working prototypes are delivered as scheduled in FY 1999, it remains to be seen if lawmakers will actually approve final production of the Joint Strike Fighter.

Some lawmakers view the development of JSF as a good determinant as to whether the defense industry can achieve the goals that the JSF puts forth. Actually dishing out the money could be another ballgame, since some in Congress may be more inclined to support upgrades of already operational aircraft or purchases of previously designed ones.

It is clear that in order to survive, JSF must prove it is a legitimate and affordable multi-service airplane. Engineers and engineering practices will be key to that effort.

--Marne Turk, New Products Editor

What this means to you

- New strategies for cutting number of components.

- New engineering opportunities.

- Potential new techniques in large-scale project management.


Turn-signal switch 'Escorts' in new era

Troy, MI--When DuPont Automotive Technical Specialist Paul Kane goes to work, he might be headed to Troy-based DuPont Automotive...or to Dearborn-based United Technologies Automotive (UT Automotive). As a resident engineer, Kane and his UT Automotive teammates recently realized the fruit of their labor with the launch of new turn-signal switches for the 1997 Ford Escort/Mercury Tracer in record time.

"Teamwork and communications during the three-year program allowed us to identify potential challenges early by working together," Kane explains. "This enabled us to develop plastics to meet stringent functional requirements for the switch."

"Having a resident engineer on site each week definitely improved communication and shortened the lead time on this complicated switch," adds Tom Allard, principal engineer, UT Automotive. "We evaluated existing switches and produced ours to surpass previous benchmarks."

The switch and housing feature materials never before used in automotive applications: two new grades of Zytel(R) 74G43WBK196, a 43% glass-reinforced nylon for the turn levers; and Zytel 74G33WKBK156, a 33% glass-reinforced nylon for the stem and hazard button.

For the switch body housing, UT Automotive looked to DuPont for an acetal resin with improved molding characteristics. Design of experimental molding trials were conducted at DuPont Automotive molding facilities in Troy to establish final molding parameters. Through process testing, DuPont Automotive found that Delrin(R) 8511 met the need for improved processing, better impact, and higher stiffness at elevated temperatures.


Computer simulation takes elevators to new heights

Brazil--When Atlas Ele-vators determined that computer-aided engineering (CAE) technology was the best solution for some of its engineering challenges, the company began using ANSYS finite-element analysis (FEA) software from ANSYS Inc., Houston, PA. Since that time, FEA capabilities have helped Atlas reduce time-to-market by allowing engineers to test designs on-screen without expensive testing and physical prototypes.

These benefits have increased Atlas' competitive edge, officials say, which is particularly important to a company that markets its products in more than 30 countries worldwide. "We completely reached our goals of reducing our design cycle by more than 50%. This advantage makes us a much more efficient and custom-er-driven company," says Hiroshi Jojima, project lead-er at Atlas.

Today, final testing and physical prototypes are only needed for safety evaluations. "Through the use of parametrized models, we can simulate and test many design alternatives and choose the optimal one that meets minimum weight requirements. Using this methodology, we reduced more than 50% of the material costs of our products," adds Jojima.

With ANSYS, Atlas engineers build just one prototype to validate models. The software's capabilities allow users from cross-functional teams to review and evaluate designs for performance--a strategy that was not possible using the traditional "build and break and redesign" approach to new product development.


Plastic fenders KO aluminum, fiberglass

Wakarus, IN--Front fenders for the redesigned Utilimaster Corp. walk-in van have thrown a knock-out punch to their aluminum and fiberglass predecessors. Although the polyurethane RIM components tipped the scales 20 lbs lighter, they gave away no points in the ring to their counterparts when it came to impact resistance and stiffness.

The new right and left fenders, weighing 12 lbs each, posed a filling challenge for molder R-I-M Inc., Elkhart, IN, due to their 20 x 24 x 30-inch dimensions. Enter Bayer Corp.'s Polymers Div., Pittsburgh. The winning formula: Bayer's Bayflex(R) XGT-140 elastomeric polyurethane RIM system. The new system, used for the first time on the fenders, combined an extended gel time for easy mold filling, yet exhibited the physical performance Utilimaster demanded. It also offered a flexural modulus of 140,000 psi at room temperatures.

"The Bayflex system gave us more flexibility with the design and assembly of the fenders by allowing more curved surfaces," says John Knudtson, Utilimaster's director of advanced engineering. "The fenders also will take tremendous impact and just bounce back, unlike aluminum and fiberglass fenders."

R-I-M's parent company, Elkhart Pattern Works (EPW), built the fenders' prototype tool, which featured an epoxy shell mounted in an aluminum casting. For production, the epoxy shell was replaced with an electroformed nickel shell. EPW also added more cooling lines to the mold to optimize heat transfer.

With the material, R-I-M experiences shot times of eight seconds, a cycle time of around four minutes, and a mold temperature of 150F. "The extended gel time helped us fill the mold and get excellent physical properties," notes Jerry Scrivo, R-I-M/EPW's engineering manager.


Digital Physics brings CFD to the desktop

Lexington, MA--Exa Corp. has introduced its PowerFLOW computational fluid dynamics analysis package based on what the company calls Digital Physics technology. This technique solves fluid-flow problems using integer processing, rather than floating-point processing. Company officials say that PowerFLOW is therefore well-positioned to leverage Sun's UltraSPARC-based machines; and Sun has partnered with Exa to port the software to its Ultra Workstations and Ultra Enterprise servers.

Exa aims to provide engineers with the ability to analyze designs on the same computers the designs are created on. To this end, PowerFLOW eschews the differential equations typical of CFD programs in favor of a particle-tracking approach. Solutions concentrate on the interaction between the surface of a solid object, such as a wing or car body, and the surrounding fluid. Engineers are able to construct and solve CFD on the desktop in a few hours.

PowerFLOW reads files from Pro/ENGINEER and other MCAD systems. The engineer specifies parameters describing the characteristics of the fluid. The software then automatically parallelizes the problem and builds a lattice of discrete elements, called voxels. The results of a simulation can be displayed in a variety of formats, including streamlines and ribbons, vectors, isosurfaces, and isolines.

Because of its reliance on Sun's Visual Instruction Set (VIS) graphics processing, PowerFLOW problems must run on UltraSPARC VIS-capable machines. Pre- and post-processing can be performed on other Sun platforms, as well as workstations from Silicon Graphics and Hewlett-Packard. Annual workstation licenses for PowerFLOW begin at $15,000 a seat.


Cavalier coupe aims for the high end

Watertown, MA--Since Chevrolet introduced the revamped Cavalier in 1995, the model has gotten a new lease on life. I recently drove the 1997 Cavalier Z24--a "high-end" Cavalier--and walked away impressed that a Cavalier could pack so much equipment and give a great ride, but slightly dismayed once I saw the price tag.

Already known for its safety features, the Cavalier Z24 comes with standard 4-wheel antilock brakes, automatic daytime running lamps, driver and front-passenger airbags, belt guide loops for seat belts, and an enhanced traction-control system. The car also meets federal dynamic side-impact requirements. The new PassLock theft-deterrent system eliminates the need for a special resistor-equipped ignition key. A sensor causes the ignition module and instrument cluster to become a matched set from the first time the vehicle is started at the assembly plant. If someone tries to start the car without using the proper key, the car will start but immediately shut down and remain disabled for 10 minutes.

A "progressive ride" system and coil-over-shock rear suspension let GM engineers tune the chassis to communicate responsive road control to the driver and minimize bumpiness. A torque axis mounting system that reduces engine vibration also makes for a smooth ride.

Features you might not expect to find on a Cavalier included: AM/FM stereo with CD player, electric sunroof, rear decklid spoiler, twin remote electric mirrors, electronic speed control, 4-speed electronically controlled automatic transmission, power windows and door locks, 16-inch cast-aluminum wheels, electric rear-window defogger, and remote keyless entry for both the doors and the trunk. (Some of these features are options, but they all came with the car I drove.) The Z24 comes standard with a quite responsive 4-cylinder, 16-valve 2.4l twin-cam engine (a 2.2l engine is standard with the other models) that delivers spirited acceleration.

One feature I missed was having the gear guides by the floor-based shift light up at night. I had parked the car at a shopping mall during the light of day and returned with my booty well after sunset. As I prepared to back out of my space, it occurred to me that I wasn't sure I was in reverse because I couldn't see the "R" on the floor. I actually opened the door to make sure I was in the right gear since the gear indicator on the dash didn't stand out enough for me to notice it right away.

Overall, though, I definitely enjoyed the Z24 and thought its looks and feature package rivaled those of more expensive sports cars. But the Cavalier line is known for two things: safety features and modest prices. And at $17,730 for the Z24 I drove, I wouldn't exactly describe it as inexpensive.

--Julie Anne Schofield, Senior Editor


Virtual prototyping key facet of design initiative

Sunnyvale, CA--Lockheed Martin Missiles & Space is using virtual prototyping software from Division Inc. to help integrate weapon systems into the next generation of warships for the U.S. Navy. The Simulation-Based Design (SBD) project, funded by DARPA's Tactical Technology Office, is initially intended to explore how the operation of ships' guns and missile launchers interact with the rest of the vessel in real time.

"Our final goal is a 50% reduction in development time," according to Paul Shattuck, director of simulation-based design at Lockheed Martin Missile & Space Advanced Technology Center, who is working on the SBD project. SBD engineers are looking at a variety of computer tools to compress the design cycle.

Using virtual prototyping in the design of complex military and commercial systems has the potential to substantially reduce design cost, risk, and development time, according to Jeff Hultquist, Division software development manager.

Division's dVISE virtual prototyping software is a suite of tools for creating, rendering, and animating 2-D and 3-D objects in realistic environments. The software can accept CAD models from a number of commercial programs, such as CADDS 5, Pro/ENGINEER, and Unigraphics. Division is assisting Lockheed Martin in integrating dVISE into the DOD High Level Architecture protocol for collaborative design.

Phase One of the SBD project concentrated on evaluating warship design. Lockheed Martin was selected as the lead system integrator for Phase Two, which will explore ways for the technology to be used in other DOD applications and by industry.

In addition to Lockheed Martin, other SBD participants include: Newport News Shipbuilding, Electric Boat Corp., and the Naval Research Labs.


Toaster has a 'crumb clean' design

St. Joseph, MI--Ever fight that never-ending battle of trying to keep crumbs and grease off the family toaster? Well, KitchenAid's(R) latest premium line of toasters should make that job much easier.

The new toasters, part of the KitchenAid Countertop CollectionTM, combine easy cleaning and long-lasting color. Helping to make this possible: Rynite(R) RE9100P PET thermoplastic polyester resin supplied by DuPont Engineering Polymers, Wilmington, DE.

"Rynite outperformed other plastics we evaluated in color stability, high-temperature resistance, and stain resistance," reports Kathy Hayes, product manager for the KitchenAid Small Appliance Business Group at Whirlpool Corp. Not only do the PET resins provide enhanced color stability, high-temperature stability, and chemical resistance, but they have a UL94 V-O flammability rating.

The housing's smooth-flowing lines and one-piece construction were designed to be both pleasing to the eye and easy to keep clean, Hayes adds. There are no seams to attract grease and grime.

The housing has large planar surfaces and measures 16.1 x 4.6 x 6 inches. The base design incorporates a variety of integral assembly features, including numerous vents and supports on its underside for power-cord storage.

A keypad component molded from DuPont Zytel(R) 101L nylon contributes to the convenience and reliability of toasters equipped for digital programming. Its four integrally molded touch pads maintain their spring-back features, thanks to the nylon's flex-fatigue resistance.

The new KitchenAid toaster line consists of four models with a variety of feature choices. All use microprocessor technology and a self-centering bread rack aimed at delivering consistently even toasting.


FEA optimizes seal design

Salt Lake City, UT--Finite element analysis (FEA) is sometimes portrayed as a tool suitable for only the most exotic problems--computing stress on the components for the Space Station, for instance. Don't tell that to Eric Anderson, FEA design engineer for Parker Hannifin's Packing Division. He specializes in leveraging the advanced nonlinear analysis capabilities of MARC Analysis Research Corporation's (Palo Alto, CA) FEA software for design optimization and problem solving on elastomeric components used in fluid-power equipment.

One such problem involved a leaky hydraulic cylinder on an exercise machine. The leak rate ranged from three to five percent, and proved quite irritating to consumers. And though Parker Hannifin didn't design the original seal, Anderson took up the challenge to improve it.

He began by modeling a cross section of the original design. It surrounds the shaft of the hydraulic piston, and is held in place by a coil spring that sandwiches it against a stop. Four lips on the working face of the seal were designed to wipe oil from the shaft, but obviously weren't doing the job.

Anderson's model showed that in the installed position, the last lip didn't even contact the rod and that the third lip touched just slightly. In addition, the contour of the outer edge of the seal was such that fluid pressure actually pulled it away from the inner wall of the cylinder. This leak path around the outside of the seal was exacerbated by the positioning of a mold code number on the bottom of the seal.

Still using MARC's FEA, he then modeled several possible solutions, finally settling on a three-lip design in which, unlike the original, the first lip exerts the least pressure and the third lip the most. He changed the material from a nitrile to a polyurethane for increased wear resistance and added two ridges to the bottom of the seal to prevent oil from escaping around the outer diameter.

The result: "Engineers at our customer tested the seal so hard that they burned it due to heating of the fluid," says Anderson, "but there were no leaks."

Applying similar analysis, Anderson has used MARC software to redesign bumper stops for a pneumatic nail gun and a U-cup seal for the piston of a snowmobile brake caliper.

--Mark A. Gottschalk, Western Technical Editor


A fuel-cell for the gas pump

Detroit--It was a rather lightweight forum for a call to arms. However, Chrysler Corp. announced at the 1997 International North American Auto Show that it was confident enough in its automotive fuel-cell technology to ask others to drop what they were doing in this area and join it.

"The components of Chrysler's fuel-cell stack are proven technologies," says Christopher Borroni-Bird, the auto-maker's advanced technology specialist. Nevertheless, he estimates it could be 15 years before fuel cells hit the streets, if ever. Concentrating research and development efforts on one approach could spur advances more quickly. "The main issues remaining to be solved are size and cost, neither of which are trivial," Borroni-Bird says.

Fuel-cells, which produce electricity at ambient temperatures from a reaction of hydrogen with oxygen aided by a platinum catalyst, are seen by some as possible successors to the internal combustion engine. Chrysler's configuration liberates the required elements from gasoline, or any readily available fuel. Surplus power is stored in batteries to aid in acceleration.

Chrysler is going with a gasoline-fuel approach--in the face of criticism from, among others, the Union of Concerned Scientists--primarily because of the multi-billion-dollar infrastructure already in place to support it. "What's better?" asks Peter Rosenfeld, Chrysler's director of advanced technology planning. "A vehicle that cuts emissions by 80% that's out on the road, or a zero-emissions vehicle that's gathering dust?"

--Michael Puttre, Associate Editor


Polymer gears up for gears

Houston, TX--If gear design presents a problem, try adding these letters to your alphabet soup of plastic materials--PK, which stands for polyketone. The versatile thermoplastic polymer offers a balance of material properties ideal for producing long-lasting, trouble-free gears when compared to polyamide (PA) and acetal (POM), the two polymers most widely used for this application.

Among PK's key balanced-property values: chemical resistance over a broad range of applications, and significantly less moisture absorption than most PAs, according to John Kelly, staff research engineer at Shell Chemical Co, which makes PKs under the tradename CARILON(R). As a result, the PKs have a negligible effect on gear performance and dimensions. Moreover, PKs are said to withstand impact and creep-rupture better than POMs, while exhibiting better creep-resistance than PAs. This, in turn, might offer some performance advantages for plastic gears that abruptly run into stalled conditions, specifically some actuator applications.

PKs have an added benefit in their favor for gear design--lubricity. When run against themselves in sliding or rolling contact, PKs have demonstrated they can stand up better against wear than PAs or POMs. And when run on steel under pure sliding conditions, PKs have shown they can operate longer than PAs and are the equivalent to or better than POMs.

For more information on CARILON thermoplastic polymers, call Shell's John Kelley at 888-CARILON .


Dispensing system improves pen assembly

Lincoln, RI--At the heart of Cross ball-point pens is a mechanical propel-repel mechanism that exposes the tip for writing and retracts it for storage. Though the mechanisms work well, the machines used in assembly required significant, costly maintenance. By changing the adhesive dispensing system, the A.T. Cross Co. improved throughput and reduced both maintenance and adhesive use.

Previously, automatic assembly machines incorporated dispensers to apply a dot of adhesive to one part and a dot of activator to a second mating part in the three-piece mechanical assembly. Joining the three pieces initiated curing, completing the subassembly.

Trying to reduce maintenance without sacrificing quality, Cross redesigned the assembly process. Now, two of the parts rotate as a fine bead of adhesive is applied over exactly 340 degrees of the circumference. The 20-degree gap is the key to preventing over application and avoiding adhesive buildup on the dispensing needle that could affect subsequent assemblies. Activator is similarly applied to the third surface to ensure a quality bond.

Another challenge was finding a reliable dispensing system that could make the adhesive bead on rotating cylinders only 0.203 inch in diameter, without requiring high maintenance. Cross turned to EFD Inc., East Providence, RI, which proposed a dispense valve/-control system with pressurized reservoirs for the adhesive and activator.

The model 752V-UH valve incorporates a flexible diaphragm with a life of more than 100 million cycles. It provides extremely fine output control and low maintenance. The matching model 7000 valve controller provides microprocessing circuitry to ensure repeat timed output within 0.00005 seconds. And the controller features input/output signals to allow the dispensing system to communicate with the assembly machine's computer.

Most importantly, mounting the controller near the valve enables time setup, adjustment, and purge functions to be performed at the point of valve output, simplifying dispensing-cycle setup. And using the controller's independent processor eliminates the need to reprogram the host computer when valve output is established or changed.

"The reduction in maintenance allows us much better utilization of our resources," says Gary Vario, tool engineering supervisor at Cross. "We used to have a skilled toolmaker spending 8 to 10 hours a week adjusting equipment. Now, that time has been reduced to almost zero." Another benefit: a 50% reduction in adhesive use.


Sports, smokes, and mirror images

Chrysler's introduction of the Dodge Durango sport utility at the 1997 Detroit Auto Show featured half a dozen puns on the names of competing vehicles. This served not only to stun the crowd into submission, but also pointed out how crowded the market is becoming.

The presentation typified the tempo of the show, where manufacturers seemed to be loudly bringing out vehicles to match something else already on the road. Lincoln had its own huge Navigator sport utility. Mercedes announced one too, the M-Class all-activity vehicle. Meanwhile, Land Rover, perhaps the originator of utilities--sport or otherwise--blanched, diluting its once-wicked Defender with automatic transmission and the designation "station wagon."

There was a lot of smoking on the show floor, only partially explainable by the pack of foreign journalists in attendance. The Auto Show struggles to resist 1990s sensibilities. BMW alone kept historical torches lit with dancing girls in short skirts ("Good for them," snorted a politically incorrect Canadian journalist.) And Volvo pointed out you can get a gun rack on the Outdoors package for the V70 wagon. Volvo also presented its sexy C70 convertible coupe: quite a departure for the safety-first Swedes. It's safe, too, they assured.

In fact, Europe was the soul of indiscretion. The sticker on the Lotus 3.5l turbocharged Esprit V8 proudly hailed its $1,500 Gas Guzzler Tax, kicking the price up to almost $85,000. Lamborghini's latest spacecraft, the 5.7l V12 Diablo Roadster VT, seemed to sneer "If you have to ask..." to passers by. Ferrari celebrated its fiftieth anniversary with an appearance at the show (after six years' absence) bringing the F50 Formula 1-capable road car, which sports a 4.7l V12 engine.

"North America is Ferrari's most important market," declared Gianluigi L. Buitoni, president and CEO of Ferrari N.A. Then he added, somewhat disingenuously, that the 1997 456 GT was available with automatic transmission for the "pleasure" of American drivers. This brought snickers from the Europeans. More candidly, Buitoni admitted that meeting U.S. government emissions and particularly safety standards was trying emotionally: "You have to crash six cars," he implored.

Washingotn Beat

Washingotn Beat

Global competition altering lives of American engineers

Like it or not, U.S. engineers are deeply involved in a worldwide scramble for technological advantages. That was the prevailing opinion at a symposium on "The Global Agenda for American Engineering" held by the National Academy of Engineering. Although international competition continues to heat up, participants reported, technological information is flowing more freely than ever across borders. "You have teams of engineers working on computers all around the world interacting every few moments without ever coming in direct contact," noted Norman R. Augustine, chairman and CEO of Lockheed Martin. Barriers previously established to keep defense information from moving outside U.S. borders are "no longer leakproof," he added. Cutbacks in defense spending have forced many engineering enterprises into the unfamiliar task of designing products for global commercial markets. Symposium members warned of the danger of dismantling military design and prototyping teams at a time when U.S. policy is shifting toward a new multifaceted defense system that calls for a new set of technologies.


Three major trends influence 1997 product design

Three converging trends are dominating decisions in product design this year. They are consumerism, technological innovation, and the continual drive for cost containment. So contend several U.S. designers who participated in a forum on trends in product design and development. Industrial Designers Society of America (IDSA), headquartered in Great Falls, VA., sponsored the forum. The trends, forum members say, equally affect product design engineers and industrial designers. Consumerism today is seen as a demand for simpler, safer, and more aesthetic goods. Technology innovations result in shorter life cycles for products. Price concerns are strongest in international and mass markets. Balancing the trends will be "the real test of a designer's genius," claims Craig Vogel, incoming president of IDSA.


'Smart' tools for surgeons will include voice controls

Doctors and engineers are dreaming up an array of sophisticated surgical tools for early in the twenty-first century. A report from the National Science Foundation (NSF) describes future surgical simulations, image-guided therapies, robotics, and "teleinterventions." The report summarizes findings of the Second International Workshop on Robotics and Computer Assisted Medical Interventions, held in England. The workshop convened 52 engineering, computer science, and medical researchers from seven nations. Participants envisioned voice-controlled surgical instruments, computerized systems that guide surgical tools, and three-dimensional images with cross hairs projected onto patients in the operating room. Physicians thousands of miles apart will participate in live surgeries. Support for the workshop came from NSF, the Defense Advanced Research Projects Agency, and commercial partners. NSF plans a follow-up workshop for 1999. "We're encouraging close collaboration between engineers and surgeons," says Gilbert Devey, program director in biomedical engineering at NSF.


Future general aviation engines to be developed by two firms

Two companies will develop revolutionary engines that could make future light aircraft safer, smoother, quieter, and more affordable. The National Aeronautics and Space Administration sponsors the project. Williams International Co. of Walled Lake, MI, and Teledyne Continental Motors (TCM) of Mobile, AL, will develop technologies for a turbine and intermittent combustion engine, respectively. Williams International plans to continue R&D on its FJX-2 Turbofan engine. It is intended for aircraft having six or fewer seats and cruising airspeeds above 200 knots. TCM plans to develop a two-cycle, direct-injected, compression-ignition piston engine that uses Jet A fuel. It will be used on four-seat planes with cruising speeds under 200 knots.


Facility simulates auto exhaust to help refine flow meters

Auto engineers soon will have more accurate meters for analyzing tailpipe exhausts. The National Institute of Standards and Technology (NIST) has opened a facility that simulates car exhaust. Automakers will use the facility to calibrate a new type of flow meter that can directly measure exhaust from a tailpipe. The laboratory, located in Gaithersburg, MD, simulates exhaust by mixing nitrogen, carbon dioxide, argon, and water vapor. NIST engineers can also include low levels of gases such as carbon monoxide and hydrocarbons. Called the Exhaust Meter Calibration Facility, the lab can measure the combined flow with less than 1% uncertainty. It also can duplicate flows of 1 to 100l/sec, the range of interest to vehicle manufacturers. Technicians can vary the ratio of gases and the temperature from 290 to 700K.

Help by wire

Help by wire

One of the great things about the booming Internet technology is the opportunity it offers to exchange ideas with peers in the same or different industries thousands of miles away.

Got an immediate problem? You can send out a general query asking for advice from others who have had the same or a similar problem, and benefit from their experience.

Or, you can join a "chat" group and get in on discussions about hot topics of professional interest.

www.designnews.com offers two ways to take advantage of the Net's capability for linking engineers together. By clicking on "Newsgroups," you can pose questions and get answers on technical basics in electronics, mechanics, and other fields. Among recent queries from users were suggestions for solution strategies for analysis of thin elastic shells, and tips on how to control large motors without getting power transistors too hot.

By clicking on the icon for "Forums," you can have a dialogue with other engineers on virtually any topic you choose.

Recently, one user took advantage of "Forums" to ask others about their experiences with design reviews. Defer arguments on conflicting solutions to one-on-one meetings, advised one reader. And welcome design reviews with non-peers, such as operations personnel, the same reader said, because their questions force you to think about their needs when it comes to im-plementing your design.

But, said another "Forum" participant, be sure to brief all those who will be in the review meeting on what you hope to accomplish, and establish firm ground rules. Otherwise, the review can take on a negative spin.

Other topics users are discussing in "Forums" include steps to take if you can't get support for a design idea, and how to keep your engineering job in tough economic times. There's no end to the kind of questions you can pose on the net through such a chat group.

Chat groups are one more way for members of the design community to connect with each other for their mutual benefit. Could a chat group help you solve that complex material or component problem you're wrestling with now? You never know, but it is one more resource for you to draw upon. And as all engineers know, the more information you can get the better off you are.

Technology Bulletin

Technology Bulletin

Space technology spins off knee brace

Engineers at NASA's Marshall Space Flight Center in Huntsville, AL, have leveraged space technology to invent an innovative knee brace for those recovering from strokes and knee injuries. Called the Selectively Lockable Knee Brace, the prototype device could mean quicker, less painful rehabilitation by allowing movement of the knee. Currently available knee braces lock the knee in a rigid, straight-leg position. In the new design, the upper part of the brace attaches around the thigh, with the lower part secured by a stirrup around the shoe. "It works by allowing the knee to bend when weight is not on the heel," explains co-inventor Neill Myers. "Once weight is placed on the heel, the brace locks into position." The device is a spin-off of mechanisms and materials technology used in developing propulsion systems at Marshall. The inventors are working with a private company to test the prototype and verify the design. For details, e-mail Dave Drachlis at dave.drachlis@msfc.nasa.gov.


Carbon nanotubes contain chemical reaction

A team of researchers from three institutions has carried out a chemical reaction in what may be the world's smallest set of test tubes: carbon nanotubes with inside diameters of less than 10 nanometers and lengths of just one micron. The work could ultimately have important applications in microelectronics and other fields where extremely small conductors and other structures would allow production of new types of nanoscale devices. Scientists from the Georgia Institute of Technology, the Laboratorio Nacional de Luz Sincotron in Brazil, and the Ecole Polytechnique Federale de Lausanne in Switzerland formed the carbon nanotubes, then opened the ends and allowed capillary action to fill them with molten silver nitrate. In the final step, they decomposed the silver nitrate into metallic silver by heating the tubes with a beam from an electron microscope. The process resulted in chains of tiny silver beads within many of the nanotubes, each bead separated by a pocket of gas under pressure as high as 1,300 atmospheres. Next, the team wants to use the process to produce a continuous metallic wire with a graphite sheath around it. The technique could also be used in flat-panel displays and to produce encapsulated compounds. For more information, visit http://www.gtri.gatech.edu/rco.asp.


Diaphragm pacemaker could enable independent breathing

Surgeons at Penn State's Milton S. Hershey Medical Center recently implanted a medical device that may eventually allow the patient--a former high-school athlete--to breathe without a ventilator for the first time since a summer sports injury rendered him a quadriplegic. If the surgery proves successful, the patient's nerves will regenerate enough to use the implanted device--a tiny electrode and radio receiver with an implanted antenna. Doctors performed two nerve grafts during the six-hour surgery. After a few months, the implanted pacemaker's application of repetitive stimulus patterns to the phrenic nerves should result in smooth, rhythmic contractions of the diaphragm, thus allowing air into the lungs. Diaphragm pacing is far less expensive than using a mechanical ventilator. The technology also lets patients live outside of hospitals and nursing homes, eliminating the cost of inpatient care. Added benefits include: more normal breathing and speech, ease of eating and drinking, increased patient mobility, unobtrusiveness of the equipment, and silent operation. E-mail msb3@psu.edu.


Satellite-based remote sensing to map Earth resources

Within two years, scientists hope to launch satellites that will let them produce the most complete maps of the composition and temperature of the Earth's surface. The data are essential in exploring for natural resources such as minerals and natural-gas deposits, monitoring global warming, or giving early warning of volcanic eruptions. The satellites, making up an Earth Observing System, will use remote sensing to gather data for studying the planet's surface and atmosphere. One of the goals is to make, for the first time, a worldwide map of the thermal radiation emitted from the planet's surface. John Salisbury, a research scientist at the Johns Hopkins Department of Earth and Planetary Sciences, pioneered the technique using an infrared spectrometer to learn what something is made of by analyzing the thermal radiation it emits. He is compiling a library of the spectral signatures of infrared radiation emitted by specific materials. These data will help scientists interpret the satellite data. FAX Johns Hopkins at (410) 516-5251.


Process yields durable, lightweight metal parts

A metals-forming process developed about 25 years ago by MIT scientists is now giving automobile components manufacturers a new way to produce highly durable, lightweight precision parts. The process, known as rheocasting, is taking off mainly because of new automotive industry requirements for long-life, reliable, and lightweight parts that cannot be met by the traditional forming process of die casting. MIT has licensed the process to Alumax Inc., St. Louis, which has used it primarily to make longer-lasting aluminum automotive components for suspensions and air conditioners. Rheocasting was discovered in 1971 by David Spencer, then a doctoral student in the lab of Professor Merton Flemings of MIT's department of materials science and engineering. Spencer found that agitation of a molten metal during solidification made it smooth and creamy when it was partly solid, like ice cream. It was immediately clear to researchers that this flowable semisolid material could be the basis of a wholly new metal-forming process. The original work was supported by the Office of Naval Research and the Army Research Office, subsequent work by the Advanced Research Projects Agency, and current work by the DOE and industry. E-mail Elizabeth Thomson at thomson@mit.edu.


Modems go cordless

Operating on the same principle as cordless telephones, new cordless modem technology jointly developed by IBM and Panasonic allows users to go on-line without physically connecting to a phone jack. Instead, the data are transmitted directly between the PC and a small device connected to the jack. Because the technology requires no software, driver, or operating-system changes to PCs, it literally offers users "plug-and-play" convenience. Based on patent-pending technology originally developed at IBM Research, the cordless modem technology delivers V.34 connections at speeds up to 28.8 kbps using a modified radio architecture similar to that used in current 900-MHz cordless phones. By basing the technology on existing protocols, the two companies each anticipate developing products this year that support high-speed analog modem data rates at an affordable cost. E-mail dyaun@watson.ibm.com or camerlengom@panasonic.com.


Plans afoot to convert natural gas to diesel fuel

Exxon Corp. may build the oil industry's first plant to cost-effectively convert natural gas into liquid fuels such as diesel. The firm is in talks with Qatar's state-owned oil company to build such a plant--using Exxon's technology--supplied by oil fields too remote for natural-gas pipelines. Such liquid fuels are more easily transportable and are cleaner, too: Natural gas-produced diesel is of a higher quality than that produced from crude oil, and has no sulfur. When burned, it produces less carbon monoxide and hydrocarbon emissions. Tulsa, OK-based Syntroleum Corp. is working on a similar project. Visit http://www.calstart.org.


Prosthetic foot promises better balance

ATufts University bioengineer has developed a prosthetic foot that he says better mimics how a biological foot works. Besides helping amputees maintain their balance and stand, walk, or run more naturally, the new design decreases the pressure that can cause painful and dangerous wounds to the area where the prosthesis attaches to the leg. Current prosthetic feet are fairly good at shock absorption and propulsion, or "push off," says inventor Mark R. Pitkin, research assistant professor of bioengineering at Tufts School of Medicine. But a natural foot also provides balance and gait control using 33 complex joints, 26 bones, and more than 100 ligaments, muscles, and tendons. Pitkin analyzed the electrical impulses in biological feet and lower leg muscles during a stance--the part of a stride when all or part of the foot is on the ground. Using that data, he pinpointed and measured the moments of resistance in the ankle joint produced by muscle and tendon contractions. Pitkin noticed that the pattern of resistance was nonlinear and concave, with resistance almost nonexistent in the first part of the stance as the body leans forward and weight shifts from the heel to the ball of the foot. He then mapped the resistance patterns of the most popular prosthetic feet and discovered that they didn't match the physical reality of the gait. Pitkin's device, called a rolling-joint foot, allows for a progressive buildup of resistance in each stance. "The idea is the foot rolls along, producing resistance in a certain pattern," he says. For more information, e-mail cwolff@infonet.tufts.edu.


Light-duty, long-range natural gas vehicle debuts

The nation's first long-range natural gas vehicle has hit the road. The "LongRanger" van, a working prototype developed by Long Beach, CA-based NGV/USA Inc., is a modified Chrysler Dodge Ram 350 van that achieves extended range by using a Multi-Fuel Storage Chassis. This chassis design incorporates cavities into the structure of the frame that allow natural gas cylinders to reside there, rather than attaching the cylinders as an afterthought. Two 62 x 14.8-inch cylinders are attached with steel hoop rings and brackets lengthwise within storage cavities located in the modified frame rails. The two existing smaller tanks remain perpendicular to them in the rear of the frame between the rear axle and bumper. The overall dimensions, suspension, and drive train of the Chrysler remain unaltered. Together, the cylinders hold 27 gasoline-gallons equivalent of compressed natural gas--enough for the vehicle to travel up to 340 miles before refueling. Previously, natural gas vehicles had been limited to a 150-mile range. Preliminary research indicates that when mass-produced, this adaptation can be cost effective and modified to accommodate other alternative fuels, such as propane, hydrogen, and even electricity. Interest in natural gas vehicles has increased over the last seven years due to governmental mandates and heightened concern for the environment--natural gas is about 30% cheaper and burns twice as clean as gasoline. FAX NCV/USA at (310) 595-0446