Engineering News 7580

CAD industry embraces NT

More powerful Intel-based hardware and a Windows operating system designed for serious computing are prompting engineers to switch from UNIX. The appeal: 'one box that does it all.'

The technical computing industry appears poised on the brink of a major shift to Windows NT, according to many analysts and industry officials--and away from UNIX as the sole platform of choice for high-horsepower CAD.

For engineers, this offers the promise of a single desktop machine instead of using an engineering workstation along with a general-purpose PC. "Right now, everyone has a UNIX box for CAD and a PC for word processing, business applications, and mail," says Gary Gray, a designer and system manager for Hill-Rom, a hospital-bed manufacturer in Batesville, IN. "We are migrating all of our UNIX stuff to NT." This cuts the costs of buying and maintaining two systems per engineer--and reduces desktop clutter.

"How many engineers do you see these days who have big offices?" notes Ty Rabe, manager of CAD applications at Digital Equipment Corp.'s Software Partners Group.

Other potential NT benefits: easier "cutting and pasting" between engineering and non-engineering software, less expensive hardware platforms, and that familiar user interface most people already know. "NT dramatically simplifies taking design information and putting it into a user manual, spreadsheet, or word processor," Rabe says.

Opinions differ on how fast the overall industry will move in significant numbers to NT. Few experts expect UNIX to disappear anytime soon--if ever. Nevertheless, many of the top names in the industry are rushing to develop or enhance NT offerings for the engineering desktop.

- Compaq, the nation's top personal-computer maker, is debuting an NT technical workstation this quarter;

- Digital Equipment and Hewlett-Packard, long known for their proprietary workstation architectures, have moved into the NT market in a big way;

- The makers of Pro/ENGINEER, I-DEAS, Unigraphics, MSC, and CATIA software have all ported to NT, or are finishing up NT versions of their flagship engineering software; while SolidWorks designed its engineering software suite for NT from scratch.

Intergraph, which launched an aggressive NT strategy relatively early, says 86% of this year's unit sales have been for NT. "The entire environment is changing rapidly," says Gisela Wilson, director of mechanical CAD/CAM/CAE at International Data Corp., Framingham, Mass.

Fortuitous convergence. Each new generation of Intel processor--386, 486, and Pentium--has doubled performance every 18 months or so, and made the PC platform more attractive for technical work. The Pentium Pro is about 1.5 times more powerful than the Pentium, already considered a processor capable of mainstream engineering design work. "A $3,500 Intel platform does what a $35,000 RISC platform did a few years ago," says Tommy Steele, president of Intergraph Software Solutions.

At the same time, Microsoft NT matured as an operating system, offering enough features to make users and system administrators happy, as well as development tools to attract software companies. CAD houses don't need to develop their own database, spell checking, or user interfaces, Steele notes. "It's plug and play, we don't have to invent every piece of the applications." The company had 100 million lines of UNIX code when it started porting to Windows in 1992.

The Windows interface is a familiar one to most computer users as well as software developers, which can make training engineers on specific packages easier and faster. And with OLE for Design and Modeling, which Intergraph helped develop, engineers can easily plug design data into other applications.

The NT phenomenon is still in its early stages. International Data Corp. estimates that Windows NT had a slender 4% slice of the CAD/CAM revenue pie in 1995, while UNIX held 67%. But with a projected 83% grown in NT through the year 2000, IDC forecasts Windows NT will pull almost even, 38% to 41%.

Dataquest, though, is less bullish, forecasting a 20% share for NT by 2000. "In our studies, we have seen it is mainly the current DOS/Windows users that are looking to go to NT in the near term," according to Senior Analyst Sharon Tan. The big attraction for them: more power and functionality of NT-based CAD software.

At red-hot Parametric Technology Corp., spokesman Brian Shepherd characterizes "gentle growth, not a landslide" in NT sales, which account for about 20% of PTC licenses.

But at Autodesk, which made its name in the Microsoft-compatible marketplace, Ken Welch says: "We have seen a real trend going to 32-bit Windows (Windows95 as well as Windows NT)." Autodesk has ported its popular AutoCAD software for UNIX platforms, but Welch says now: "All the growth is in 32-bit Windows. There's no growth in UNIX whatsoever. NT machines have the performance curve today that they didn't have in the past."

NT is not the answer to all engineering tasks. RISC chips can offer substantially better floating-point performance than the Pentium Pro, and heavy-duty analysis work typically puts high floating-point demands on a system. (Digital claims to have solved this dilemma with its Alpha systems, also running NT but with a higher performing chip design.) Some analysis software is available only on UNIX. And a spokesman for one hardware vendor says that "extremely challenging network activity--large transfers of files, many accesses to a PDM system might not be appropriate for NT. That scaling up of NT in enterprise workloads hasn't been demonstrated."

Some companies, such as Hewlett-Packard, suggest an NT system for work like component design and a more powerful RISC workstation for larger models and complete-system design.

In addition, RISC systems focusing on low-end price/performance can still be an attractive option versus a fully loaded PC. Others, such as Silicon Graphics, focus on a particular niche like high-end graphics where Intel-based systems can't yet compete; and their low-end graphics can offer more bang for the buck on specific tasks such as texture mapping.

Still, an increasing number of industry experts are betting on the rising popularity of Windows NT with engineers. "UNIX is not going to go away," Wilson says, "but NT is where the action is."

What this means to you.

--Sharon Machlis, Senior Editor

RP slashes tooling from weeks to a day

Webster, NY--Xerox Corp. says it slashed 90% off conventional tooling costs and cut a weeks-long process to one day by using so-called "rapid tooling" to create an integral bearing for a new office machine.

Xerox engineers created a mock-up of the new product using parts generated by a stereolithography machine from 3D Systems. However, one resin part proved inadequate to test whether a bearing would function properly on a paper-feeding shaft, and engineers sought a prototype made from production-run material.

Jeffery R. Heath, supervisor of Xerox's Rapid Prototyping Shop, turned to Direct ACES Injection Molding. He first created a twin-cavity mold from a stereolithography pattern of the part using CIBATOOL SL 5180 epoxy resin. The tool's interior was hand finished, and the mold was placed directly into an injection-molding machine to test different plastics and see what performed best. Using this process, he ran 14 shots in ABS/polycarbonate as well as 18 shots in 10% glass-fill-ed polycarbonate.

Heath praises Direct ACES Injection Molding for "allowing you the flexibility to make alterations without worrying about cost." With one tool, he can make multiple cavities and test two or three designs. When prototyping a spring clip, for example, he produced parts with varying wall thickness using a single tool. "We've even used this process for pre-production runs," he says. "We've molded a hundred parts for a customer."

Polymer protects aircraft engine harness

Cincinnati, OH--When General Electric's Aircraft Engine division decided to replace sleevings on the electrical harnesses in its large aircraft engines, it switched to a PEEK (polyaryetheretherketone) monofilament woven braid. The reason: the polymer provides the cut-through resistance and chafe protection required in long-term exposures to engine environments.

The sleevings, made from braided Victrex(R) PEEK^TM supplied by Victrex USA Inc., West Chester, PA, protect cable assemblies in Boeing 747 and 767 engines. "We chose PEEK polymer because it gives us the kind of mechanical protection we need," says Steve Hanak, electrical specialist at GE. "We wanted a material that would prevent chafing on engine hardware, such as metal tubes, brackets, and other electrical harnesses. It is essential that these assemblies remain isolated from any kind of a rub or interference."

In addition, PEEK sleevings provide this protection at up to 500F (260C). This, says Hanak, "is more than adequate for our engine environment."

Prior to choosing the PEEK polymer, GE used a PTFE (polytetrafluoroethylene) spiral wrap for protection. "The spiral wrap was a problem in certain locations," Hanak explains. "Cuts and nicks, combined with engine temperatures, would cause it to loosen and eventually degrade the appearance of the harness. Because they are braided and not wrapped, PEEK sleevings actually improve the assemblies' appearance by providing a snug fit around the cables."

Another advantage of PEEK in comparison to PTFE: cut-through resistance. "PTFE will 'cold flow' in tight cable clamps," Hanak reports. "This problem has not been observed with the PEEK composites."

There's even a side benefit. "We experienced almost a pound of weight reduction per harness with PEEK," Hanak adds. "We have seven harnesses in each engine, and when you consider a three- or four-engine aircraft, that's a significant weight savings."

Chopped fiber shaves rear-seat weight

Shelby, NC--By replacing a 6.5-kg (14.3-lbs) steel rear-seat frame with a chopped-fiber composite, the Mercedes-Benz Class-C achieved a weight savings of 4 kg (8.8 lbs). The materials switch, say Mercedes-Benz engineers, did not compromise strength, stiffness, or crash performance in the design.

AZDEL, Inc. introduced the new chopped-glass-fiber technology. The firm's thermoplastic composites have already made their mark in the auto industry as a material solution for large, structural, lightweight parts. AZDEL is a joint venture of PPG Industries and GE Plastics.

"Chopped-fiber composites add more versatility to our material family," says Greg Gallager, AZ-DEL business director. "With this new technology, we can offer manufacturers the ability to form complex geometries previously difficult to mold using traditional products."

The new materials have demonstrated the ability to be molded into wall thicknesses as low as 1.8 mm. The chopped-fiber thermoplastics come in a variety of glass contents and weights. They also can be thermoformed using vacuum or other low-pressure processes.

"The chopped-glass-fiber mat product is ideal for parts where impact performance requirements are less stringent than unidirectional glass-fiber mats used for bumper beams and knee bolsters," Gallager explains. "We anticipate their use for door trim, head liners, and truck liners, or where complex, thin-wall part design presents a major design challenge."

RIT

students build for speed, not comfort

Rochester, NY--For mechanical engineering students, there is nothing quite like hands-on experience. A team of students from the Rochester Institute of Technology (RIT) has an opportunity to leave its mark on every part as it designs and builds a racer from scratch for entry into an event hosted in April, 1997 by the Big Three in Detroit.

The annual competition, sponsored by the Society of Automotive Engineers (SAE), attracts scores of collegiate teams from all over North America. Although the cars have motorcycle engines for power, they are more than grandiose go-carts. Their designers wrestle with the same steel/aluminum/composite materials questions faced by Supercar engineers.

"Although the base design comes out of our imaginations, we pay close attention to what industry--and the successful teams--are do-ing," says Scott Embree, chief designer for RIT's '96 team and now an engineer at Honda. "With only nine months, there is no time to build and test multiple design iterations. We have to be bold and get it right the first time."

An example of this spirit is RIT's approach to improving acceleration performance. The team developed a dual-runner air intake with short and long feeds for the cylinder heads. Embree says such a configuration provides low-end torque and high performance in the same package. "Plus, it's a hell of a lot cheaper than turbo," he adds.

The design helped propel RIT's car to first place in the last competition's acceleration category. Next outing, RIT may attempt a continuously variable intake system.

Another area of design innovation centered on the rear upright connecting the wheels to the suspension. Since the uprights are located outboard of the springs and dampers, any weight-savings in them improves responsiveness in the vehicle by allowing the suspension to react more quickly to dynamic track conditions. Embree says the team decided to invest in composite upright assemblies in order to reduce their weight.

Using Pro/ENGINEER from Parametric Technology Corp., Waltham, MA, Embree created solid models of the uprights and connecting components. The CAD system's assembly module was useful for determining the position and geometry of the connection points and, importantly, the aluminum inserts required by composite uprights for strength. Pro/E's Mechanica structural analysis module provided the means for performing mass-optimization studies.

Manufacturing the uprights was itself a study in innovation. The students converted the Pro/ENGINEER solid models to STL files and used these to produce stereolithography rapid prototypes. Silastic-J, a silicon compound from Dow , was packed around the cured resin parts and allowed to harden. When split, the team had mold negatives for manufacturing the composite parts. In the end, the composite uprights were 40 percent lighter than the previous all-aluminum design.

Simulation helps stunt show take off

Camarillo, CA--Like any true stunt show, Waterworld at MCA Universal Studios features lots of live action, including a seaplane that crashes through a wall toward the audience, skidding to a stop just yards from where spectators stand.

For Spectra F/X Inc., creating the illusion of a crashing plane was no easy task. Developers wanted to build a mechanism from which an actual plane is launched into the air, without the aid of cables or tracks. "The real challenge was to find a plane and launching method that could withstand crashing into a lagoon with a force ten times that of gravity, ten times a day, 365 days a year," says Spectra F/X Director of Advanced Technology Aiden Bradley.

Bradley designed the plane, a modified 0V10-A Bronco, in AutoCAD, then turned to Working Model software from San Mateo, CA-based Knowledge Revolution to design the launch pad. "Working Model simulates two-body collisions of solid objects, which was crucial to this analysis," notes Bradley. "Also, we couldn't afford to build a prototype of the launch pad and seaplane. We had to get it right the first time." Another consideration for the launch-pad design: the plane had to perform exactly the same each time.

Bradley imported an AutoCAD design of the plane into Working Model, and removed unnecessary geometries to create a silhouette of the plane. Using Working Model's drawing tools, he designed a hydraulic catapult assembly and launching shoe in which the plane would rest for launch. He then added strakes, long metal tubes that trailed along the plane fuselage and attached to the cam rollers located on the shoe.

"The goal of the simulation was to launch the plane in a manner that would keep the tail down and feather it into the water in a controlled crash," explains Bradley. "That way both the plane and the audience stay intact."

Once the initial concept was drawn, Bradley assigned parameters to the model, including the plane mass, initial rotation of the plane when it left the launch pad, and angle in relation to the launch shoe. "The orientation of the plane when it leaves the catapult is critical," says Bradley. "Working Model gave me a better understanding of what happens to the tail section of the plane in its relationship to the catapult in the milliseconds between when the catapult shoe decelerates and the plane continues on its trajectory."

During the simulation, on-screen graphs measured the position, orientation, and velocity of the aircraft as it left the catapult. Bradley ran many "what-if" scenarios, varying the angles each time until a simulation determined the plane's tail would clear the pad and not be damaged during repeated crashes.

Based on simulation results, Spectra F/X constructed just one plane for the Waterworld show. Bradley estimates that if he had to build a prototype, it would have added $600,000 to the budget and taken another three months to complete. "There's no way we could do all of this by hand," he says.

New tape sticks on difficult-to-bond surfaces

Bloomsburg, PA--Magee Carpet Co. recently needed to bond the irregular backing of its tufted carpet trim to a molded polypropylene storage-area lid in the rear of a sport utility vehicle. The carpet's rough textured backing consists of peaks and valleys that prohibit complete surface contact with a tape's adhesive layer.

Magee Carpet had been laminating FasTape^TM 1191, an unsupported adhesive transfer tape from Avery Dennison (Painesville, OH), to the back of its tufted carpet. The material was later die-cut and applied to the storage-area lid. But laminating the adhesive to the carpet's textured backing proved difficult.

Heat-assisted lamination and increased pressure and dwell time were used to soften the adhesive and force a more complete bond with the textured backing. However, these processing adjustments made it difficult to control the amount of adhesive that flowed deep into the carpet's texture, as well as the amount of adhesive that remained available for bonding the trim to the automotive surface. Peel tests across the applied carpet trim revealed inconsistent adhesion.

Bonding to the molded polypropylene lid was also difficult because low-surface-energy plastics don't allow a conventional adhesive to "wet out" properly on the surface. "Wetting out" depends on the surface energy of the adhesive and substrates being bonded, and on the adhesive's viscosity. The lower the surface energy, the weaker the molecular attraction between the bonded materials.

To meet Magee Carpet's needs, Tom Epple, senior research associate at Avery Dennison, developed a fastening system that incorporates the use of a non-woven carrier support into the tape's construction. Avery's UHA^TM (Ultra High Adhesion) adhesive formulation was coated on both sides of the nonwoven carrier. UHA technology allows a quick and aggressive bond to low-surface-energy substrates while withstanding a long-term operating temperature of 240F. The adhesive system was tested and approved against GM Spec 3608-M.

The final product, FasTape 8791, consists of a 1.0 mil nonwoven material coated on the laminating side with 2.9 mils of the UHA adhesive. The tape's liner side is coated with 5.2 mils of the same adhesive. The differential coat weights provide a strong bond to the irregular surface of the carpet backing, and to the low surface energy of the polypropylene mounting substrate.

Other benefits of the tape: The nonwoven carrier acts as a support to the adhesive mass and allows the wide-web product to be easily processed, such as die-cutting into intricate parts. At the same time, the softness and conformability of the tape allow it to bond around curved surfaces without lifting.

Easier riding

Huntsville, AL--When crew chief Keith Perry joined Team Suzuki's endurance racing team in 1988, there were 10 races a year and time off in the winter.

Now, the number of events has almost doubled. The WERA (Western Eastern Racing Association) endurance champion team competes in other races as well, and the number of bikes to maintain and redesign has mushroomed from one to four or five. That means the same time-to-market pressures facing conventional manufacturers have come to the world of motorbike racing.

"Then, we didn't use computers at all," Perry recalls. "We were hand-fabricating everything." And if something didn't work or fit right, they simply started over. "Today we use computers more and more."

The motorcycles they use start off as conventional models anyone can buy in a store. For some events, "modifications are almost unlimited," he says, including everything from changing the wheel size to relocating steering gear. When problems crop up on a track, there is often little time to make a change.

In one case, a foot peg--fine for normal riding--was too low for driving around sharp corners at high speeds with racing tires. While the team was on its way to Portland, Oregon, it contacted Anderson Race Engineering about designing a foot-peg relocation bracket. The part would allow the peg to be in two different positions, depending on rider preference.

"They found the problem while on their way to Portland and didn't have much time," says Don Anderson at Anderson Race Engineering. He proposed a part using Solid Edge software from Intergraph, modified it after discussions with the team, and then translated the CAD file to generate toolpaths.

He says the flexibility of using associative CAD software made it easier to change a few dimensions and get a part right quickly. "It took six hours to draw, I showed it to them, modified the part, and it was ready to ship in about a week," Anderson recalls. "That is almost unheard of in this business."

'Rapid tooling' cuts time, money from auto-part run

Torino, Italy--"Rapid tooling" helped Italian auto-part manufacturer Carrozzeria Bertone cut its tooling costs in half and shave weeks off development time by using an injection-molded plastic part instead of metal assembly.

Carrozzeria Bertone recently needed a short-run production of front-door window guides for the popular Fiat Punto Cabriolet convertible. For a run as small as 400, traditional production methods were too expensive and time consuming. In addition, engineers were unhappy that the part was so heavy--due to producing it by cutting, plying, and welding sheet metal.

Technimold, a plastics engineering service bureau, recommended spray-metal tooling and fused deposition modeling (FDM) to develop the new part. They revised the existing de-sign using Computervision CADDS 5 software, and built an ABS prototype on an FDM prototyping system from Stratasys Inc. The spray-metal mold was created directly from the FDM pattern.

Carrozzeria Bertone officials say only one mold test of 100 parts was necessary. And, in just six and a half weeks, the tool was ready--compared to at least three months using conventional steel tooling. In addition, the company estimates saving 55 to 65% on the process.

'Ride and Drive' showcases aluminum-intensive car

Braselton, GA--A technology that joins aluminum without welding or adhesive bonding has produced a chassis for what's billed as the first aluminum-intensive passenger car made in North America.

Alumax Transportation Products demonstrated the successful application of its retrogression heat treatment (RHT) process technology on the Panoz Roadster during a "Ride and Drive" event hosted by Panoz Automotive Development Corp.

"The RHT manufacturing technique will permit faster, simpler, and more cost-effective assembly, allowing us to build a high-quality, small-volume specialty car in the same time and with the same efficiencies it takes to produce a mass-production car," says Dan Panoz, Panoz president.

RHT achieves fabrication and joining without welding or adhesive bonding. The frame's simple design enabled Panoz to complete research, design, engineering, fabrication, and testing of the space frame in just 18 months.

With RHT, rapid, short-term, and localized heat treatment of aluminum takes place in tune with the fabrication process. It can be applied to bending, joining, coining, flanging, or collaring. For example, heat is applied to a localized section of an extrusion exclusively where a bend is planned. When the material cools, it regains strength and toughness, without softening or needing subsequent heat treatments.

"Bends found on the Panoz space frame were once thought impossible," according to Jay M. Linard, president of Alumax Extrusions Inc. "The process is so rapid (a few seconds for heating and a few hours for cooling) that there is no bottleneck in the fabrication process."

Moreover, RHT allows a manufacturer to join a transverse member to a longitudinal member by using the members as the joint. In other words, the aluminum is attached to itself without external adhesives, welds, or bolts. The ends of the extruded members are formed to such a precise degree that they lock into place using simple compression, Linard adds.

Panoz and Alumax conducted extensive tests to assure that the compression joining process wouldn't loosen or lose its stiffness. A 50,000-mile durability test revealed that chassis stiffness actually increased, the companies report. Other tests conducted by Global Vehicle Service at Ortech International and Calspan testing facilities included: torsional, dynamic durability, and impact.

"RHT may well spur the penetration of aluminum extrusions into the next generation of vehicle production," Linard predicts. "Automakers want durable, lightweight, corrosion-resistant materials that are easy to assemble. We believe that the RHT-design space frame meets their needs."

A marriage of convergence

Chatsworth, CA--Idea: Take a device that's always been a separate peripheral, a scanner, and join it to the place where a user's hands are--the keyboard.

Opportunity: The number-one seller of personal computers is excited at the proposal.

Challenge: To pull it off, Palo Alto-based Visioneer would pair up with keyboard experts NMB Technologies--and while the technical specialties were a natural mix, the two companies had different engineering tools, locations, and corporate cultures.

But through a combination of high-tech communications and basic "roll-up-your-sleeves" engineering, officials at both companies say they were able to meet their customer's schedule.

"We used e-mail, and a World Wide Web site so anyone around the world could download information," says Todd Basche, vice president of engineer-ing at Visioneer. "And a lot of time on the airplane."

After coming up with the idea for a scanner-keyboard, Visioneer took the concept to Compaq Computer, which was intrigued by the notion. Visioneer, a maker of scanners with no experience at keyboards, then approached NMB with the proposal. The companies decided to partner.

"We merged Visioneer's level of automation with NMB's processes and technical expertise--which have been in existence far longer than our company has been," says Mike Gifford at Visioneer.

EMI became a major issue facing engineers as they put the two devices together. Although each part independently met all federal EMI requirements, putting them in close proximity generated new problems to solve. Engineers also had to mesh computer tools.

"We did our mechanical engineering in CATIA, all in 3-D," Gifford says. "We provided the database to build the keyboard frame and structure."

"We took it from there," adds Don Johns, NMB's vice president of engineering. "We took their drawings and converted them for tooling." NMB converted the 3-D drawings to 2-D in order to make tooling fit its usual processes.

The two companies had to hash out procedures for sharing information and how to test prototypes. In addition, they needed to meet Compaq's re-quirements for indus-trial design.

Industrial design work began on the scanner-keyboard in February of 1995; full production kicked off before the end of the year. Compaq had exclusive rights to the device for sever-al months; recently, Visioneer was able to come to market with an altered retail version under its own Paperport/ ix name.

Their advice to others ready to launch a joint development venture? "Mock up your final configuration as quickly as you can," Basche says. "That's the biggest time-to-market advantage. Doing it in two pieces doesn't give you the same information as one part."

And, he adds, despite all the useful high-tech communications tools the teams took advantage of, "There's no substitute for sitting down face to face."

Valve eases grease application woes

Kent, MI--FKI Automotive has solved a problem with grease application by automating the process on its door-handle assembly line.

Previously, a line worker would dip a brush into a small container of grease and apply it to the spring on the back of the part. The amount of material brushed varied from part to part--and FKI received a customer complaint that too much grease was getting onto some of the handles.

Engineer Dave Amerson looked to remove the variation, and purchased a Model 780S valve from EFD Inc. (East Providence, RI). The valve uses two separate air inputs for controlled applications: one, at 70 psi, to open the valve; the second, 20 psi, to atomize the material and eliminate overspray. A controller monitors exactly how much grease is applied.

"It's worked out really well," he says. Grease is now applied uniformly. Along with improving quality, production time has been cut: What used to take a worker 5 seconds, now takes the machine less than half a second. "That's over the course of making 1,500 parts a day, two shifts a day, five days a week," he notes. "And, we are using less grease."