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Articles from 2004 In March

Stronger auto steels promise weight loss, safety gains

Stronger auto steels promise weight loss, safety gains

As automakers work to improve both fuel efficiency and safety, they increasingly need to add some lean muscle to their vehicles. Strong, lightweight structural components made from Advanced High Strength Steels (AHSS) may be just what the doctor ordered.

This diverse group of multiphase steels with high strain hardening rates generally offers yield and tensile strengths as least twice as high as conventional stamping steels. Their tensile strenghts, for instance, start at roughly 500 MPa. So AHSS can certainly help automakers cut weight of body structures without sacrificing strength. Yet the advanced steels do have some cost and manufacturing barriers to overcome before they can more widely displace their lower-strength predecessors. The Great Designs in Steel seminar, held last month in Livonia, MI, served as good progress report on these advanced steels.

The American Iron and Steel Institute's Automotive Applications Committee (AAC) sponsored the seminar, which consisted of 27 presentations and drew more than 1,200 automotive engineers. The presentations covered the full variety of steel applications, including fuel tank and wheel designs. "For the first time, the seminar also included engine components," notes Ron Krupitzer, the institute's senior director of automotive applications. But AHSS grabbed the lion's share of the attention, reflecting an increase in high strength steel development activities over the past few of years.

GLOBAL ADOPTION. And much of that activity has come from European automakers. "Offshore companies are pushing to higher and higher strength levels faster than domestic companies," Krupitzer says. A couple of key presentations illustrated this point.

Porsche engineer Michael Mehrkens gave a talk outlining the use of AHSS in the company's 2002 Cayenne sports utility vehicle. About 65percent of its body structure uses advanced steels, including DP 600, TRIP 700, and CPW 800. Compare that to the 33percent in the 1996 Porsche Boxster. What's significant about this vehicle, according to Krupizter, is that actually embodies many of the concepts developed for the institute's Ultralight Steel Auto Body (ULSAB) concept car. This 2001 concept used AHSS for about 98percent of the body structures, mostly in the form of tailor-welded blanks with a smattering of hydroformed sections. The Cayenne likewise made liberal use of advanced steels in tailor-welded blanks for a variety of components, including its bodyside inner subassembly and substantial parts of its front- and rear rails. "Porsche played a strong role in that project, and you can now see come of those concepts have come to fruition," says Krupitzer
Another key presentation came from Volvo engineer Jonas Bernquist, who described the body structure for the company's XC-90 sports utility vehicle. It features a new front structure to handle the higher forces of an SUV crash and to minimize the impact of collisions with smaller vehicles. It incorporates a "safety cage," a collection of reinforced side, roof, and seat structures designed to protect occupants from rollovers and side impacts. According to Krupitzer, this body design serves as an object lesson in how to "match a wide range of steels to specific tasks." The requirements for some cage components-the A-pillar upper, for example-were satisfied by high strength rephosphorized steels whose 380 MPa tensile strength falls a bit short of the AHSS range. But the company applied dual phase steels with tensile strengths in the neighborhood of 600 MPa, for selected reinforcements. And for components with the most extreme load cases, such as rear seat frame, the company used boron steel with a minimum tensile strength of roughly 800 MPa.

THE COMING REVOLUTION. North American automakers have not adopted true AHSS to the same degree as the Europeans, Krupitzer points out. "They use proportionately more steel intermediate range," he says. He cites bake hardenable (BH) and solid solution strengthened (SSS) steels with tensile strenghts up to about 300 MPa as two examples. Still, even stronger steels have sparked "a great deal of interest and some aggressive plans" among the domestic manufacturers, Krupitzer says. Ford gave two presentations on the use of AHSS-one covering the Ford Mustang and the other most recent Ford F-150. Another presentation at the seminar outlined the extensive use of AHSS in the new Chrysler LX sedan. "It has a larger assortment of high strength steel parts," he says. These include relatively large amounts of high-strength-low-alloy (HSLA) materials, whose tensile strenghts can reach about 500 MPa, but also a smattering of dual phase components with tensile strenghts above 600 MPa.

As for those "aggressive plans," look no further than a presentation given by General Motors development engineer Curt Horvath. He described an evolutionary path in which higher strength materials continue to gradually displaced the low-carbon steel that made up as much as 70percent of a typical body in the early 1990's. Already, GM has already incorporated significant amounts of HSLA-as much as 34percent in current midsized luxury models. Dual phase steels, meanwhile, have made an appearance too. The Chevy Malibu body structure, for example, has a 12 percent dual phase and a 5 percent HSLA content.

In the near future, Horvath predicts, a typical body structure will continue to shift up to AHSS-as much as 35 percent dual phase steels and another 8percent martensite. This near term scenario is based primarily on the strengthening existing components such as rails, pillars, and rocker inners to improve crash performance. As newer body designs appear, ones designed for AHSS from the get go, Horvath sees dual phase usage climbing to as much as 45percent and martensite to 12percent.

CHALLENGES REMAIN. For all their promise, AHSS do still have some barriers to overcome. At current production volumes, these materials do cost more than conventional steels and face a growing threat from aluminum. All the manufacturers want five-star crash ratings," Krupitzer says. "But a low-cost solution is always preferred."
AHSS steels may also be somewhat more difficult to fabricate-at least given the current state of knowledge about them. Krupitzer says they do exhibit more springback than conventional stamping steels. And their strain hardening tendencies, so beneficial from a mechanical properties standpoint, tends to cause a lot of die wear. Finally, the industry has less experience welding these materials. "You have to be careful how you stamp them and weld them." Krupitzer admits. But the seminar included presentations that addressed all these difficulties. "We've already gained a tremendous amount of knowledge in how to work with these steels," he says.

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This body-in-white for the Chrysler LX sedan, on display at the recent Great Designs in Steel seminar, illustrates the pending shift to higher strength steels for automotive body structures.

Bridging the CAD-PDM divide

Bridging the CAD-PDM divide

Translating geometry from one CAD system to another is not always the easiest process. You may lose some data during the importing process, and have to fill in the blanks later, recreating the missing links.

There are so many suppliers and customers with dissimilar mechanical design systems that translation products are becoming a necessity.

One company that has been in this space for nearly 20 years is Elysium Inc. (, which offers translation products that specialize in 3D CAD systems. The company offers about 50 different translators that cover just about all of the major and minor CAD systems out there.

Now the company is moving into the PLM space: It is developing products that integrate SMARTEAM ( Product Lifecycle Management solutions within the Unigraphics and I-DEAS CAD environments. This, the company says, should be another time-saver for OEMs.

The new integrations will let manufacturers use SMARTEAM from within the I-DEAS and Unigraphics NX environments to manage all product design and attribute data, including 3D geometry and product data intelligence, explains Peter Heath, director of product management for Elysium.

The products, which Heath says are expected to be available by the end of the second quarter, are a natural progression for the company, which continues to expand its expertise in the area of data exchange.

Elysium's PDM translation products, known as CAD.pdm, enable 3D product data, together with the "design intelligence" captured in the related 3D attributes and metadata, to be used, shared and manipulated throughout the product lifecycle.

"What we're starting to see is that some customers want to use PDM-enabled translation," Heath says. "As they buy PDM systems, they are trying to bring everything together. What we're enabling is for that translation to happen automatically. PDM is just starting to explode for a lot of people."

Elysium CAD.pdm links CAD systems and PDM systems for the engineer.

Telehealth companies poised for market growth

Telehealth companies poised for market growth

As health care costs become a growing concern, technology providers feel that patients and doctors alike can get better results by using telehealth products that can bring the benefits of personal visits without travel. Telemedicine has been around for years, but its use as a sophisticated health management tool is currently underutilized, promoters contend.

The demographics of an aging population and the focus on cutting health care costs have attracted a number of startups and major corporations, though usage is still quite limited. "When you're talking about videoconferencing and sophisticated multi-function devices, it's probably in the range of 15 to 20,000 homes now," says Jonathon Linkous, executive director of the American Telemedicine Association in Washington, D.C. ( He adds that the Veteran's Administration is installing equipment in 20-25,000 homes as part of a pilot cost-cutting program.

Most observers say the technology is ready, but the infrastructure is lacking. "One key issue is a lack of reimbursement. Another is that doctors and nurses need resources to help them understand the data and then create sustained operating procedures that include quality control," says Pramod Gaur, CEO of Viterion TeleHealthcare LLC, a Tarrytown, NY ( startup funded by Bayer and Panasonic.

Establishing standards so data from different systems can be used easily is another issue that must be resolved before the market will see solid growth, he adds.

Companies like Viterion and AMD Telemedicine Inc. of Lowell, MA, make systems that send data from patient to doctor ( The companies address two-way communications in different ways, addressing different cost levels. Viterion's hardware includes e-mail functions, so users have one machine to deal with, as well as eliminating the cost of a computer and Internet service provider. Viterion has also unveiled a service that lets clinicians access patient data from any computer, giving them more flexibility to access data. For patients that require more one-one-one personal care, AMD Telemedicine provides a videoconferencing system that can replace or augment its touch-screen workstation.

Viterion's Telehealth Monitor lets patients send blood pressure, temperature, sugar levels, and other data from their home. Data is then stored so doctors and nurses can analyze it when they have time.

Motion Control Connectivity Options Expand

Motion Control Connectivity Options Expand

These trends are driving motion and I/O vendors to increase the breadth and depth of their product offerings-and suppliers have recently introduced new support for open standard networking technologies including CANOpen and Ethernet.

CANOpen Master Interface
"Our customers told us very clearly they wanted to reduce cost and complexity with a single controller to handle all motion control and input/output functions," says Phil Strong, CEO of Motion Engineering Inc. (MEI). "We are offering our OEM customers more choices in their motion architecture, and expanding our product line to include machine I/O as a key part of that strategy."

MEI ( ) recently announced new networked I/O products for its XMP motion controllers equipped with the CANOpen master interface. The SLICE I/O products include over 60 different digital and analog I/O configurations, and provide machine builders with a single controller solution for I/O and motion control requirements. MEI says that, with the move to digital networks for motion control, customers are looking to pull cost out of a machine while increasing performance and throughput. Ross McMillan of MEI claims that, by consolidating the system I/O onto the SynqNet motion network, users can eliminate the need for additional interface hardware and the application programming interface (API) that goes along with it. He notes this can provide low latency I/O on a shared network with motion control. Networked I/O opens up performance solutions such as latching multiple I/O bits anywhere on the network, and then using time-based techniques to modify motion based on those latched values.

MEI's SLICE I/O products work with any XMP motion platform equipped with CANOpen master interface DS401 version 2.0 node support or better. Each CANOpen node can handle up to 64 digital inputs and 64 digital outputs, as well as 8 analog inputs and 8 outputs. All programming is under a single API.

The recently introduced CANopen master interface from Motion Engineering increases I/O connectivity options for highly centralized PC-based controls.

New I/O controller from Opto22 provides a solution for remote locations where an Ethernet network is not available or practical.

Expanded Support for Ethernet
Opto22 ( has also expanded its support of Ethernet I/O with a compact, standalone package that can network with multiple I/O units over standard Ethernet networks.

The SNAP-LCE unit provides a built-in 10/100-Mbps Fast Ethernet port for attaching the controller to Ethernet networks, to computers on the network running industrial automation software, and to Ethernet-based I/O systems without requiring additional network interface cards.

Communication with the controller can also be established through a modem connection using Point-to-Point (PPP) protocol over one of the two included serial ports-ideal for remote locations where an Ethernet network is not available or practical.



Power amplifier

High performance

The Si4300 is a monolithic CMOS power amplifier (PA) for GSM cellular applications. It is reportedly the smallest, high-performance, high-power PA available for GSM handsets. It is designed to reduce both board space and component count by more than 70 percent when compared to other solutions. Using only a single die on a small substrate, it is also reportedly the first functionality-complete monolithic GSM PA solution. Silicon Laboratories

Motion Controllers

Cost effective, easy setup

Designed to provide attractive price and performance for 1-axis and 2-axis systems, the RMC70 series motion controllers target hydraulic, pneumatic, and electric servo motion control applications with position, velocity, and position/pressure control capabilities. The initial version (RMC75S-MA1) is oriented toward linear motion control and includes RS232/485 Serial communications and interfaces to MDT and SSI absolute position transducers. The product's included software is powerful for easy setup, tuning, programming, and diagnostics, according to the company. Delta Computer Systems

Digital phosphor oscilloscopes

Customizable user interface

The TDS5000B series digital phosphor oscilloscopes (DPOs) reportedly feature the industry's first customizable user interface and new context-sensitive, Microsoft Windows(R) right mouse click and scroll wheel menus. It is designed to simplify and make more efficient design validation measurements and tests, allowing engineers to get work done more quickly and easily. Using a simple drag-and-drop procedure, users are able to pull all the oscilloscope features used into a single half screen control window, allowing them to tailor the oscilloscope to their particular style or measurement task. Relearning how to use the product after breaks from lab work is eliminated through the ability to save and reuse the customized control windows, according to the company. Tektronix

DIO and AO boards

Affordability, ease of use

The company's five new digital input/output and analog output boards are designed to offer an affordable and reliable I/O solution, as well as set a new price point for data acquisition and control. The new boards reportedly deliver NI-DAQmx software technology and superior ease-of-use and performance for industrial automation and control, test, and measurement and OEM applications. The five new boards are NI PCI-6509, NI PCI-6514, NI PCI-6515, NI PCI-6722, and NI PCI-6723. National Instruments


Digitally programmable

The AD8555 is reported to be the first digitally programmable, signal-conditioning auto-zero amplifier for strain-bridge and other sensors widely used in automotive, medical, industrial, and communication applications. Within the new chip, the product has integrated a full range of amplifier, comparator, resistor, trimpot, and buffer functionality into a small SOIC or 4 x 4-mm chipscale package. This is designed to allow users to automatically (under software control) eliminate variations between sensors. Analog Devices

Laser measurement sensor

Measures variety of shapes

Combining a wide-beam laser and a 2D CCD to conduct accurate 2D measurements in a single procedure, the Z500 laser measurement sensor uses a Class II or IIIb visible red laser (depending on model) and measures distances from 5.2 to 100 mm with resolutions from 2.5 to 1.0 microns. The product is designed to eliminate the time needed by traditional laser sensors for multiple single-point measurements, increasing accuracy by eliminating sensor and object movement during measurement. The system includes a sensor, controller, programming console, and a liquid crystal monitor that can display measurement data in four different formats. Omron Electronics Inc.


Low internal circuit losses

The GRF342 is a family of magnetic-latching, broadband, TO-5 electromechanical relays. They reportedly feature extremely low internal circuit losses for exceptional time and frequency domain response characteristics through and beyond the UHF spectrum and into the S-band. They are engineered for use in RF attenuators, RF switch matrices, and ATE and other applications requiring dependable high-frequency signal fidelity and performance. Teledyne Relays

LED Lamps

Ideal for industrial applications

The T3-1/4 BF321 series miniature bayonet-based LED lamps are engineered to incorporate advanced optical-grade epoxy, producing sunlight-visible illuminations that are bright and evenly dispersed. They are plug-compatible with illuminated switches and indicators from most major manufacturers. Ideal applications include industrial control push-button switches, industrial control communicators, indicators for process controls, aircraft instrumentation, elevator panels, automobile lighting, and medical and scientific equipment. Eight LED colors are available: red, orange, yellow, lime green, aqua green, blue, white, and 3,200K warm white. LEDtronics Inc.

Test cards

Reduces measurement time

The company has introduced two new multi-channel source-measure test cards with expanded operating ranges for its Model 4500-MTS Multi-Channel I-V Test System. Each Model 4510- and Model 4511-QIVC provides four source-measure channels in each of nine slots of the Model 4500-MTS PCI mainframe. Up to 36 I-V measurement channels are allowed. The Model 4500-MTS is designed for use with automated testing in multi-head production test environments. Keithley Instruments

I/O Interface

For PCI-bus computers

The PCI-DIO48H-RT, 48-bit digital I/O interface joins the company's PCI-DIO24H (24-bit) and PCI-DIO96H (96-bit) family of high-output, logic-level digital I/O boards. All boards in the family are based on STTL emulations of the 82C55 mode 0, and will reportedly sink 64 mA or source 15 mA at standard logic levels. All include InstaCAl, the company's installation and test application package, and all are fully compatible with the company's Universal Library (a language interface). Measurement Computing

Filtered power entry modules

With various terminations

The EEJ series filtered power entry modules have reported current ratings from 1 to 20A. The compact design is engineered to offer enhanced performance with a 20A filter attenuating 48 db at 30 MHz in common mode for non-medical versions. Available with several installation types, they are ideal for a variety of applications, including computer workstations, networking equipment, medical devices, test and measurement devices, telecom-datacom equipment, and fitness equipment. Tyco Electronics

Modular switch

For Ethernet applications

Designed specifically for the unique demands of rugged industrial use, the company's modular managed switch allows users to choose twisted pair, glass fiber, polymer, or HCS cables for a flexible connection. It reportedly requires no complex IT programming; the needed modules can be plugged in, and the expandable switch is ready once the browser-based interface has been configured. Simplified point-and-click diagnostics combined with intuitive LED indicators enable plant floor staff to easily install or perform ongoing device and network checks. Phoenix Contact

Tactile Sensors

Simple, thin, affordable

Engineered as an affordable solution to discerning the slightest of impressions or pressures on angular and curved surfaces, the C500 tactile sensor is a customizable, 3-wire device that uses capacitive-based conformable pressure sensors. According to the company, it can accurately and reliably quantifies applied forces, no matter how small. It is designed for lab use or for integration into OEM systems. The product uses the company's proprietary ConTacts technology to create less than 1 mm thin discrete tactile sensing elements that integrate the applied tactile pressure over the sensor, providing a measurement of total normal force. Pressure Profile Systems

Gap pad

With natural inherent tack

Designed for mid- to high-thermal performance applications, the Gap Pad 2500 features a 2.7 W/mK thermal conductivity for low thermal resistance. Its inherent natural tack is designed to eliminate the need for additional adhesive coating that inhibits thermal performance by increasing interfacial resistance. The soft and compliant resin formulation reportedly yields a material that does not crumble, flake, tear, or come apart. A variety of die-cut parts are available in 20 to 135 mil thickness. It is also available in sheet form. Bergquist Company

Laser sensor

Uses triangulation measurement

The 8200 mini digital laser sensor with background suppression uses triangular measurement. According to the company, it has the ability to be unaffected by background influences. The diffuse transmitted laser light will be reflected from the object, and the distance between object and sensor will be measured with an internal PSD-diode. It offers a working range of 20 to 120 mm, and the visible beam arrangement offers no adjustment and a recorded reaction time of 630 musec. It is housed in a glass re-enforced plastic. Component Engineering

If Sparks Fly, Chips Die

If Sparks Fly, Chips Die

Silicon Valley loves to see sparks of genius, but not during the production of sensitive integrated circuits. The microprocessor chips go through hundreds of processing steps on a wafer-fabrication line-a fab. Many of those steps involve subjecting the wafers to high-energy plasmas that deposit minute quantities of materials to form components. During the processing of expensive wafers, the last thing process technicians want are sparks, or arcs, caused by the plasma in the vapor-deposition equipment. Even a small arc can seriously damage a wafer that has a value of $10K to $30K. An undetected arc near the beginning of a fab line may mean damaged wafers go through the remaining steps-a waste of time, energy, and materials.

The semiconductor industry can't predict when arcs will occur, but it can now detect when they occur so technicians can weed out damaged wafers. That substitution improves processing yields-and profits. The detection process owes a lot to Paul Buda and the design team at Schneider Automation (Raleigh, NC).

When someone at Schneider says, "We could do that if only..." Buda and his small group get the call-as when a semiconductor company needed help to detect arcs in vapor-phase sputtering systems used to deposit materials on wafers.

During on-site investigations, Buda says, "We found the client's equipment had arc detectors, but they only detected arcs that could drive a hole in the side of the processing chamber and not the small arcs that can still cause considerable damage." Buda devised a solution on the trip home.

The arc-detection system centers on power-supply monitoring units, a sophisticated data-acquisition system, and tight integration with existing process-monitoring tools, as well as eliminating interference from other equipment. The final system had to fit within existing process equipment, and it had to use industry-standard protocols to communicate with other devices, including a PLC.

"We look for a 'voltage collapse' at the switching power supplies that power the plasma. When the system sees one, it tells an operator, 'Look at this batch.' Then the operator can decide what to do," says Buda. In some cases, little or no damage appears, so wafers can continue on. But at other times, seriously damaged wafers need to come off the line. Schneider Automation's arc-detection systems now operate in about 50 vapor-phase sputtering systems.

Producing the plasma takes a lot of energy, mostly contained in the radio frequency (RF) spectrum at around 13 MHz. "Protection from radio-frequency interference took a lot of careful investigation and design work," says Buda. "In one case, we had to mount the arc-detection equipment in an enclosure that also contained a 2 kW RF generator. Shielding, grounding, and installation presented a huge challenge." Buda notes that the data-acquisition system needed to monitor events that produced signals in the same frequency range as the plasma-generating gear. "There are lots of interesting things going on in processing," says Buda. "But we're not at a point where we can predict when an arc will occur so we can prevent it. That will come."

"There's a lesson in the project," says Buda, "Engineers need to get out and look at the problems they must solve. You can't do that sitting at a desk and running simulations. You need to see what's happening and what you have to work with."

Fast Update: The arc-detection circuit compares the output of a power-supply monitor with a preset threshold value. The comparator output gets sames every 33 nsec, ensuring every arc gets detected and measured.

Paul Buda, Principal Technical Specialist for Schneider Automation, received an MSEE from Syracuse University, and holds 13 patents with several pending. He has applied his knowledge of electronics, controls, and digital signal processing to a range of problems, from radar and appliance control to welding and semiconductor processing.

Simplified Packaging Streamlines GPS System

Simplified Packaging Streamlines GPS System

When Thales Navigation, a manufacturer of GPS systems, called Wagic Design ( in Los Gatos, CA, it had a problem-some of its portable GPS units required many individual modules and cables to set up a "package." And the portable equipment wasn't easy to configure and carry into the field. How could Wagic help with a new design?

Wagic actually offered several alternate designs. "The original design called for modules and cables, but Thales wanted to reduce complexity and cost. So, we eliminated the cables and created a modular design that users can quickly expand," says Neal Whitsett, Vice President of Engineering at Wagic.

Even though Thales supplied the GPS electronics and technology, Wagic's design team determined sizes and shapes of the printed-circuit boards, what connectors to use and where to place them, and the types of seals needed to provide weather protection. That last task involved keeping a GPS system dry even after submerging it in 1m of water for 30 minutes. "Thales furnished a 'marketing specification' that included plenty of restrictions and criteria we had to meet," says Whitsett.

One of the biggest challenges came in getting the best package-a case made out of cast magnesium-for the modules. Wagic had a vendor in the U.S. that could produce die-cast magnesium cases, but its capabilities couldn't meet the designers' exacting specifications for the new product. Through connections at Thales, Wagic found a supplier that uses relatively a new process-thixo molding-which offers better control over wall thicknesses. Joe Gallegos, Design Program Director, took responsibility for the case design.

The molding company hadn't done anything this complex so it learned much during the development of the case. "The complexity came when we needed to do the volumetric calculations: How much magnesium gets shot into the part and how do we increase the flow properly? Answering those questions took tremendous effort," says Whitsett. "At first, the injection time was about 10X off what the process finally required."

Sealing the case and the modules also presented challenges. In some areas Wagic used double tongue-and-groove construction with intermediate gaskets. Engineers also applied conventional sealing methods, but often had to adjust seals to meet unexpected changes. If parts didn't come out of a mold exactly as specified, designers had to figure out how to change the seals but still use existing tooling. In some cases, they went from a gasket seal to a UV-cure adhesive seal.

From Many, one: Designed for Thales Navigation by Wagic Design, the modular Z-MAX GPS system lets user select the modular functions they need. Special packaging makes the unit light weight and weather resistant.

Unlike some design firms that concentrate on packaging, Wagic's team also handled some of the electronic designs, including the battery circuits and the battery charger. Idriss Ruiz, the director of Mechanical Engineering, tackled the design of the modular antenna, which fits on a handheld unit or on a backpack system. The design team also took responsibility for all the module connectors and interconnections.

Neal Whitsett, VP of Engineering for Wagic Design was a member of the start-up team of Delfin Systems and Edge Diagnostic Systems. Prior to Wagic, Neal spent 20 years working in product design.

Electrifying Materials

Electrifying Materials

As electronic products get smaller, faster, stronger, and cheaper, can engineering thermoplastics keep up? The engineers at GE Advanced Materials have been hard at work to make sure their materials can keep pace. The company last month introduced a host of new plastics aimed at demanding electrical and electronic applications. Here's a closer look at them:

PEI flexes its muscles in circuitry

As a lower cost alternative to polyimide in flex circuitry applications, GE has developed a trio of polyetherimide (PEI) films that combine thermal and electrical performance with chemical resistance, adhesion to metals, heat-seal capabilities, and good tear strength. ULTEM EXSP0023 has the best heat performance of the three with a glass-transition (Tg) temperature of 245C. It also has a dielectric strength of 4,700 V/mil and a dielectric constant of 2.9 at 10 GHz. Next in line is ULTEM 500B film, which has a Tg of 225C and a dielectric strength of 5,300 V/mil, and a dielectric constant of 3.3. ULTEM 1000B has a Tg of 217 C and electrical properties slightly above those of the 500B. Aside from flex circuitry, applications for the new films include bar code labels, flexible heaters, stiffeners, insulative tapes, motor insulations, speaker cones, and wire wrapping. These films can also be >>thermoformed into a variety of products. All three products are available in thicknesses from 2 to 28 mils and in widths up to 48 inches.

Tough in the cold

For electronics enclosures needing good low-temperature impact performance, GE added two new grades to its LEXAN EXL polycarbonate-siloxane copolymer. The siloxane improves the cold temperature impact, allowing the material to remain ductile down to -80C. One of the new grades, LEXAN EXL 9112, has the best flow properties of any flame-resistant (UL 94-5VA) polycarbonate-based material in GE's portfolio, making it a good fit for thin-wall electronics enclosures. The other new grade, ELX 1434, has been formulated to endure long-term UV exposure. It targets stationary outdoor electronics and portable devices that see lots of sunlight.

Get the lead out

Two new THERMOCOMP glass-reinforced composites from LNP Engineering Plastics, a GE Advanced Materials Company, have been formulated to stand up to thermal demands of lead-free soldering methods, such as infrared reflow soldering. One new grade, HT Solder UF-1006, is based on polyphthalamide (PPA). The other, HT Solder ZF-1006, employs a matrix of modified polyphenylene ether (PPE). Both grades have a 30-percent glass filling, offer heat distortion temperatures in excess of 260C, and feature a halogen-free eco-compliant flame retardant package. They also have mold shrinkage values similar to those of the polyester materials, possibly allowing them to serve as a drop-in replacement for incumbent materials.

Wired plastic

Usually dc cords and plugs use vinyl, thermoplastic urethanes (TPU), or flame-retardant polyethylene (PE) as their wire-coating material. GE has come up with an alternative to these materials in the form of modified polyphenylene ether (PPE) resins. Unlike vinyl, these new modified PPE grades contain no halogens. And they offer a lower specific gravity than TPUs or flame-retardant PE, potentially reducing the weight reductions. Two new grades are available that have passed OEM bending-strength tests. NORYL WCD910 has been developed for use in dc cords, and NORYL WCP has been formulated for use in plugs.

Film viewing

For LCD diffusers, GE has developed a film that uses an optical quality polycarbonate with built-in diffusion properties to take the place of polyester films that get their optical properties from coatings. These ILLUMINEX films get their optical properties from two proprietary technologies. The first uses additives to incorporate diffusion properties into the resin itself. The second involves a surface modification to the films as part of the melt-calendaring process. This texturing process creates a "random surface profile" that helps distribute light evenly, one of the primary functions of diffuser films.

Circuit Substrate: Polyetherimide films could serve as an alternative to costlier polymide films in flexible circuitry applications.

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Thrown for a Loop

Thrown for a Loop

Some engineers have been known to drive their spouses batty pulling up to a traffic light sensor (a coil of wire set into a rectangle of pavement cuts) and rocking the car. They try to change the magnetic field generated and sensed by the coil in order to get a green light sooner. Occasionally this manuever makes a difference, but in northern climes sometimes the temperature extremes and thermal expansion differences in the ground cause the coils to break or the pavement to move, cutting the wires.

Now thanks to Banner Engineering (, a patented sensor based on magnetoresistive technology eliminates having to use a wire loop in the road surface and the required pavement cuts to install it. The M-GAGE(R) S18M detects 3D changes in the Earth's magnetic field when a large metal object is present, causing the sensor's outputs to switch.

The sensor is housed in an 18-mm diameter ABS/polycarbonate-blend molded housing. It can be installed in a conduit positioned below the pavement during construction or in an above-grade location. No external controller is needed and the sensor, which is push-button programmed, automatically "learns" its installation environment, determining background conditions and storing them in onboard, non-volatile memory.

The latest version of the detector comes in a "flat-pack" housing. Aimed at the retrofit and repair market, it can be used in existing traffic control systems to upgrade them or replace broken coils. The thin package permits the sensor to be installed in a pavement saw cut.

Scott Spinger, Banner product manager, says M-GAGE applications also include detection of vehicles at car wash entrances and exits, and drive-up kiosks. Industrial uses are at tractor-trailer loading docks and for vehicles such as forklifts passing through automatic overhead doors.

Point Sensor: Without needing a wire loop, the ferromagnetic vehicle sensor has less to go wrong.

System Makes Heart Surgery More Tolerable

Engineers from Santa Clara, CA-based CardioVention ( say they have departed from conventions developed during 50 years of heart-lung machine history, and in doing so are able to dramatically reduce the blood volume and surface area used by such machines. At the same time, they say, they've minimized the potential for dangerous air entrainment into the blood during heart surgeries. "Surgeons can still get the access they need to the heart without causing a huge (physiological) response to the invasiveness of the procedure," notes Ben Brian, VP of R&D for CardioVention.

The technology could be significant for patients undergoing extensive procedures that require surgeons to stop a beating heart and place the body on an "extracorporeal circuit" that circulates blood. Such systems typically draw large volumes of blood from the patient and place it in a venous reservoir, where they add chemicals and run the blood over a large surface area that removes air. But those conventional systems can be very stressful for some patients, making survival more difficult for the sickest of them.

CardioVention's solution is to integrate cardiopulmonary bypass system functions—such as pumping, oxygenation, filtration, and air removal—into a compact unit, which, by virtue of its smaller size, reduces trauma. The first step toward that downsizing is the use of an active air removal system, known as the AirVac. Developed by engineers at CardioVention, the disposable AirVac employs an air sensor and a solenoid valve. When air is sensed, the AirVac momentarily opens the solenoid valve, thus allowing air to be removed through a vacuum line.

With AirVac, the new system is able to eliminate the venous reservoir, the largest and most bio-incompatible part of a conventional cardiopulmonary system. "Instead of having an open reservoir with air and antifoam (chemicals), we've a closed flow path," Brian says. "So we remove air through a much smaller volume, and that allows us to scale back the size of the other devices."

Indeed, the other key component of CardioVention's CORx system is an Integrated Membrane Oxygenator (IOS), which incorporates an air filter, membrane oxygenator (artificial lung), and centrifugal pump in a single, small enclosure. The integrated centrifugal pump in the base of the IOS propels blood through the artificial lung via a vane-type impeller. Using a single-piece ferromagnetic insert molded into thermoplastic polyurethane, the impeller spins on dual ABEC-7 bearings sealed on a stainless steel shaft. As it rotates, the centrifugal pump also helps eliminate entrained air by "pulling Gs," and therefore enabling the air to move upward, toward the AirVac port. Furthermore, the IOS employs a filter designed to recirculate any entrained air up to the air removal chamber.

As a result of the more compact design, the new system exposes the patient's blood to less than 1.2m2 of surface area, whereas conventional systems typically range between 12 and 15m2. The new system also dramatically reduces the volume of blood that is recirculated from the patient.

Lessened exposure: CardioVention's cardiopulmonary bypass system (top left) is far smaller than conventional systems at right top and poses a patients blood to ony about 1/10th as much trama-inducing surface area. A centriugal pump at the bottom removes air from the blood by pushing it up to an air removal chamber.

CardioVention engineers say that the new design now makes it possible for even the sickest patients to tolerate recirculating blood through a machine while the heart is removed for surgery. "When you take blood outside the body and expose it to more than 10m2 of foreign surface area, that's very traumatic," Brian concludes. "Because this system is so much smaller, it makes complete bypass surgery more accessible to even the sickest patients."

Ben Brian holds a Ph.D. in chemical engineering. Previously, he developed oxygenators and biomaterials for Cobe Laboratories Inc. and served as a strategic marketing director for the Ethicon Division of Johnson & Johnson.