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How to design in warp speed

How to design in warp speed

Engineer Chris Stergiou thought he had moved pretty fast when he designed and built prototype tooling for a cellular phone component in just eight months. Then, the parameters changed and he got the order to do the next-generation design for production tooling.

Allowable time: 12 weeks, from concept to finish.

"We skipped the usual planning huddle and jumped right in, doing design, fabrication, and assembly at the same time," says the presidentof Global Design and Procurement, Inc., North Andover, MA.

He could trade war stories with Senior Designer Richard Han-naby, of ORTECH Corp. Hannaby recently slashed design time for an automotive engine manifold--by 75%. His weapon: software. "We cut development time and prototype costs by using SDRC's I-DEAS CAD software," he says.

Stergiou and Hannaby are engineering consultants, and their livelihood depends in part on their fast turn-around ability. But, that's no less true of engineers everywhere these days.

In an exclusive Design News Career Survey, 79% of the engineers who responded said they have less time to design products than they had five years ago. Seventeen percent said design cycles are only half as long as they used to be.

Speed, it seems, has become the watchword of the 90s in product design, and virtually every manufacturer is racing to find tools and techniques for slashing design time.

What's the hurry? Increased competition, shorter product life, and the increased fragmentation of markets, which leads to demands for customization, says Preston Smith, president of New Products Dynamics, Inc. and author of the book, Developing Products in Half the Time.

Plus, the longer it takes to develop a product, analysts say, the more money companies spend on salaries, overhead, and prototypes. Time, apparently, really is money.

Whatever the specific incentive at any company, the race to market has spawned some remarkable successes as well as several new corporate strategies.

Among the successes:

- Using Cadra software from Adra Systems, Manitowac Engineering Company went from concept to first prototype for a high-tech crane in ten months vs the normal two years.

- At Outboard Marine, Inc., engineers shaved design time for the new Mirage engine 1/3 to 1/2 by integrating Pro/ENGINEER CAD software with Pro/MECHANICA finite element analysis software.

- Engineers at the Northrop Grumman Military Aircraft Division used Mantix's Cascade project management system to get its F-18 fighter project on time and on budget.

And among the strategies:

- By having manufacturing teams work as partners with product development teams, GE Fanuc has cut its own product design and manufacturing time significantly. By the time the design gets to the factory, engineers have already solved potential manufacturing problems. For some of the company's newer boards, that process has cut the cycle from the previous eight to 14 days down to three to five days. Additionally, the company's Flow Technology concept ties all pieces together on the assembly line so there are no bottlenecks.

- Newport Corp. will use the Internet to cut the time for solving customers' positioning problems. Customers state the parameters of the problem over the net, and Newport applications engineers will follow up quickly.

- To save customers meshing time in finite element analysis, Algor innaugurated "Speed Mesh." Customers send their CAD files to the Pittsburgh software company, whose engineers then create an eight-node brick model of the design suitable for analysis in any FEA program, and send it back.

Computers are the enabler in these and virtually all other examples of design-time pruning. "They are among the principal tools for cutting design time," says ORTECH's Hannaby. Design News readers agree. Respondents to the magazine's Career Study overwhelmingly say faster computers give them the head start they need in the race to get products to market. And, they say, the CAD software those machines allow them to run is their sharpest axe for cutting design time.

But computers can be a double-edged sword. "The faster the machines get, the faster customers expect us to do design," says Hannaby.

Luckily, there are other tools engineers can use. Survey respondents say that rapid prototyping, project management, and concurrent engineering are important too.

And, so are communication skills. With the movements toward cross-disciplinary development teams and alliances with suppliers and other companies, engineers more than ever are finding that their ability to communicate their needs and ideas is critical. In fact, respondents to the Design News survey ranked communications skills virtually even with design skills when it comes to getting products to market fast.

And, making use of both is one of the surest ways to avoid the fear readers express about the effect of speed on quality. Nearly half of the respondents to the Design News survey feel quality has suffered under the demands of ever-faster time to market. "Customers are demanding speed, but they don't want garbage," says Al Stephan, president of Stratos Product Development.

Here's how engineers in several industries are shortening design times while maintaining quality--and some tips on how you can too.

--Paul E. Teague, Chief Editor


Intranets speed data to the desktop

Think quick. What eight-letter word begins with "i-n-t," ends with "n-e-t," and describes the world's fastest growing computer network? The Internet, right? Sorry, try Intranet, the Internet's younger cousin. Little more than a year ago the word "Intranet" first appeared in print. Now the new kid is snatching headlines, grabbing business-investment dollars, and offering engineers powerful new ways to access information, and tighten collaboration. The result: big cuts in the time engineers spend searching for information.

That's great, you say, but what's an Intranet? In general, it's any distributed, on-line corporate information system--a LAN or WAN, for example--based on World Wide Web technologies. As with the Internet, Intranets run TCP/IP (transmission control protocol/Internet protocol) and use HTML (hypertext markup language), SMTP (simple mail transport protocol), and other open standards for moving information from clientsto servers.

Attempting to track the Intranet's meteoric ascent is Charles Foundyller, president and CEO of Daratech, a market analysis firm based in Cambridge, MA. He notes that the Internet is expanding at roughly 10% a month, and Intranet servers are outselling Internet servers two to one. "I can't think of another phenomenon that hit this quickly," says Rich Buchheim, executive vice president of Intergraph Corp. (Huntsville, AL), "CAD took ten years to become real."

Several things are driving this growth. Blessed with Internet genes, Intranets are fast, cheap, robust, easy to use, almost infinitely scaleable, and extremely tolerant of network problems. Deployable on most any combination of computer and operating system, Intranets deliver cross-platform support that lets Sun workstations share data with a PC running Windows 95 as easily as a Macintosh. By contrast, the proprietary nature of many current networks is "like a highway system built just for Fords," says Jim U'Ren, manager of the Engineering Data Management System at NASA's Jet Propulsion Laboratory (JPL).

In its simplest form, an Intranet can be established with little more than a Web browsing program--which is often free. "Technically it's trivial to set one up; that's why it's just exploding," says Rick Brennan, manager of web services for National Semiconductor (Santa Clara, CA), "all of the hardware and much of the software is just sitting there."

For engineers, Intranets can deliver to the desktop massive amounts of information, inexpensively, from both inside and outside the enterprise. By placing searchable databases of parts, specifications, standards, and engineering references on the Intranet, a company can tremendously reduce the man-hours spent researching engineering information. And by publishing, posting, and sharing HTML documents, designers can collaborate with coworkers down the hall or in another country, without concerning themselves with the type of computer being used.

Yet the most powerful advantage an Intranet holds over a conventional network is provided by the Web: the ability to hot-link interrelated pieces of information. Unfortunately, hyperlinking has been limited to text or raster graphic images, not CAD files. But that's about to change.


How to start an Intranet
Like the Internet itself, Intranets are almost infinitely scaleable. They can be limited to a single engineering workgroup or envelop a corporate WAN spanning several states or countries. The only real prerequisite is that the network run TCP/IP (transmission control protocol/Internet protocol).
To set up an Intranet, most engineers will probably have to involve the corporate IS department. But don't get overwhelmed by the process and all the available options. Says Intergraph's Rich Buchheim, "The benefits of simply making drawings available on an Intranet--and not doing anything else--are pretty high." Consider some of these possibilities:
- Author an engineering-workgroup homepage in HTML and save it at a location on the network that others can access. Embed links to other company-Web-based documents, drawings or databases, or to relevant URLs on the Internet itself.
- Convert CAD drawings ready for release to hyperlinked Active CGM or DWF format with tools from InterCAP or Autodesk. Define one of these formats as the standard for your online drawing "vault." Make a Web-based front end that provides access to the drawings from any authorized computer on the network capable of running a Web browser.
- Look for software tools to make existing ODBC or SQL databases of information available online. Web Pipeline (Gresham, OR) makes a program that allows Web browsers to directly access data inside a Sherpa PDM database.
- Provide every workstation, PC, or Mac with a Web browser. Install the necessary plug-in program to view interactive CAD file formats such as Active CGM or DWF.
- Get creative. Video, sound, and 3D graphics are all formats supported to some degree today on the Web--and the landscape is always improving. Incorporate as many capabilities as you have imagination to create and time to implement.

Two CAD/CAM giants, Intergraph and Autodesk (San Rafael, CA), have begun battling to establish an Internet-ready, hot-linkable vector file standard for engineering drawings. Autodesk calls their format DWF, and the company has made available a Web-browser plug-in program, named WHIP!, to view DWF files. By contrast, Intergraph leveraged its subsidiary, InterCAP Graphics Systems, to create the InterCAP Inline plug-in that supports ISO-standard computer graphics metafiles (CGM).

The strength of each file format is the ability to embed hyperlinks to other images or objects within the drawing. Using just a Web browser, engineers can zoom in on an assembly drawing in real time, click on a hotlink, and "drill down" to a detail-part drawing, specification, standard, or other supporting document. It would even be possible to attach video or audio files--all supported by existing WWW technology. "The ability to link drawings to documents, drawings to drawings, and components to documents--all the things that normally have people thumbing through paper--are extremely powerful tools for engineers," says Buchheim.

A compelling example dances the wires between Tektronix (Beaverton, OR) and National Semiconductor. Engineers at Tektronix regularly face the chore of tracking down technical specifications for any of the 30,000 parts supplied by National. Datasheets for many ICs might be 40 pages in length, and a Tektronix designer could easily spend days gathering necessary information from the rows of file cabinets that fill a 16,000 sq-ft area.

Meanwhile, National found itself sitting with databases of sophisticated part information, and no good way to get it to the customer. Enter both the Intranet and Internet.

In a collaborative effort, the companies worked with CADIS (Boulder, CO), developer of parametric parts-management software. Together they created a Web-based parts information system that delivers up-to-date specifications on any of National's components to any engineer connected to Tektronix's Intranet. Each semiconductor is listed in an HTML-based part selection program and associated with a unique URL. Clicking on the component's hotlink takes the engineer to a database at National's Web site, and pops up the information in Adobe Acrobat format. No more paper, no more microfilm.

"On one recent project, I didn't have a datasheet for a part," says Wilton Hart, a component engineer at Tektronix. "Normally it would take a week or more to get one from the factory, yet because I was online, I got a copy in just a few minutes."

Such speed isn't the net's only benefit. It also allows engineers to cross-reference every datasheet at National that contains a particular topic--something that would have been impossible manually. National itself gains from the Web's transparent cross-platform support. "We don't have to care about our customer's computer platforms, operating systems, or applications," says Brennan. "Information can be placed on our Web site once, and then used by about one-million engineers worldwide."

Still in the beta stage is a "whiteboard" software program that allows visual information to be passed in real time between engineers at the two companies over the Internet. Need an answer? Tektronix engineers can simply launch the whiteboard, triggering a six-inch-square white window to appear on the workstation monitor. At National, a similar window pops up for a waiting applications engineer.

The two then communicate by drawing on the whiteboard with their cursors, or they exchange information by dragging-and-dropping it into the window. Text messages can be sent as well by typing into a box at the bottom of the screen. "This is powerful," says Hart. "It gets the person who has the question in direct contact with the person who has the answer--no middlemen."

In house, Tektronix leverages its Intranet in other ways as well. Daily, the company publishes an HTML-based online resource manual, called NETbook(R). It looks on screen like a spiral notebook, and it contains hyperlinks to press announcements from both inside and outside the company about relevant engineering topics or products. "You can just click on an item like DRAMs, and it takes you to the latest information on the technology," says Hart.

Intranets make online communication so easy, that experts who have experience with them see just one real risk: unfiltered or obsolete data. "The Internet can also be a great way of distributing out-of-date information," cautions Glenn Williams, a network expert at Intergraph. If a drawing or document isn't suitable for publishing on paper, don't make it accessible over the network. And strive to develop a system of screening and purging dated information.

Yet the advantages to engineers of a corporate Intranet easily outweigh these caveats. "The bottom line is that it saves time," says JPL's U'Ren. "An Intranet delivers most of the information an engineer needs right to their desk."

--Mark A. Gottschalk, Western Technical Editor


'Skunk Works' cut through the 'red tape'

When Phillips Plastics' Francis Peterson re-designed a new medical device last September, the veteran engineer never bothered to draw up his concepts. Nor did he use a CAD system. Peterson merely strolled to his company's lab and began building the hardware for his new prototype. Two days later--still without drawings or documentation--Peterson completed his work. Except for a minor alteration, his design remains intact in the production version of the medical device.

For St. Paul-based Microvena Corp., a Phillips customer and maker of the new "heart patch" device, Peterson's design has been a stroke of good fortune. The firm's product is now "several hundred percent" less costly to manufacture. Its part count has been reduced from 16 to 10. And it is lighter than before.

How did Peterson work such miracles in just two days? The answer is simple: He operates in a "Skunk Works" (a registered service mark of Lockheed). There, he is encouraged to move ahead without paperwork, red tape, or formal planning. In the case of the heart patch device, he ultimately cut about six weeks from the design process. "If we did it in the conventional way, we would have drawn it, then prototyped it, then gone back later and changed everything that was wrong," Peterson explains. "But doing it our way, we avoid all that."

Unconventional process. For Peterson's employer, Phillips Plastics Corporation, the Skunk Works operation is no accident. Phillips' founder, Robert Cervenka, established a special Technical Center in 1987 after some of the firm's projects slipped behind schedule. Cervenka saw a need for a separate operation that could minimize bureaucracy and maximize productivity. So he built a stunning new facility on a secluded bluff overlooking the Mississippi River, and staffed it with talented engineers offering expertise in materials, manufacturing, finite element analysis, and electrical engineering, among other disciplines. Then he encouraged the engineers to unshackle themselves from conventional design processes.

"In the classic corporate setting, the engineer writes up a request and a proposal, and then finds three people to sign off on it," notes Cervenka. "We don't do that here. That's why we love to compete against big companies."

The heart patch device, or Angel Wings, as it is called, was a classic example of the Technical Center's methods. Peterson began working on it almost immediately after Microvena agreed to have Phillips re-design it for production. He never wrote a formal proposal or a request, and didn't ask for approval on any of his ideas.

From the outset, Peterson's goal was to simplify the original design. The device, designed to patch congenital holes in the hearts of infants and adults, is, by nature, a relatively complex mechanism. During operation, it deploys a pair of tiny, thermoplastic cloth umbrellas inside the heart. To accomplish that, it feeds the umbrellas through a catheter inserted in the patient's femoral artery. Once the umbrellas are correctly positioned within the heart, the feeding mechanism detaches them, leaving them behind to "plug" the abnormal opening. In time, human tissue grows over the tiny umbrellas, forming a living heart patch.

When Peterson initially saw the device, however, he knew that it needed considerable simplification. The focus of his efforts was a screw drive delivery mechanism that employed threads on its inner diameter. To build such a part out of plastic, Peterson knew, would be almost impossible. So he designed an entirely new mechanism with easily moldable, exterior threads. In the process, he eliminated at least six parts. "I went back to the shop and, without drawings, built the first one in two days," he recalls. "I wanted to prove the concept before we wasted a lot of time designing it."

After Peterson had proven the concept, Phillips engineers began a CAD design based on his hardware. The product then went from CAD to rapid prototyping, where stereolithography techniques were used to build models that could be tested. "It survived almost intact," Peterson says. "Only one part was changed along the way."

For Microvena, the new design was less costly and reached production more quickly. "Any time you eliminate parts, you speed production," Peterson says. "If you can make your product with six tools, instead of 12, you can cut your tooling time down."

Cultural change. For Phillips Plastics, as well as other companies that have tried it, establishment of a Skunk Works can bring great engineering advancements. But it can also elicit wrenching cultural changes.


How to start a Skunk Works
- Eliminate normal policies and procedures.
- Find staff members who work well in team settings.
- Create an air of openness, in terms of communication and physical structure.
- Provide unflinching management support.

The term Skunk Works, taken from the old "L'il Abner" comic strip by engineers at Lockheed Corp., refers to an organization detached from the larger corporation. But such detachment, while good for the development process, can provoke jealousy within the company. Such was the case at Lockheed and at virtually every other company that has tried it. "It's an independent group," notes Peterson. "So you always run the risk of it being looked at in an unfriendly fashion by the rest of the company."

For that reason, the Skunk Works must have unflinching corporate support to succeed. It must also focus on eliminating policy and procedure, as well as staffing itself with people who are open to others' ideas. "You have to have a mentality in which the ideas of the machinist are just as important as those of someone who has a doctorate in mechanical engineering," Cervenka says.

Like the founders of the Lockheed Skunk Works, Cervenka believes the atmosphere should have an air of openness. At the Phillips Technical Center, engineers work in a two-story-high lab that includes injection molding machines, pressure chambers, and environmental ovens. In an adjoining room, they have access to lathes, milling machines, and other machine tools. All of the engineers readily work together.

Cervenka says that the work areas in a Skunk Works should have as few walls as possible, thus encouraging a greater spirit of cooperation. When searching for engineers to work in the Phillips Technical Center, he has even bypassed candidates who expressed concerns over the lack of walled offices.

Lastly, Cervenka says, the Skunk Works team must have talent. He has sought out members with high level expertise, either academic or industrial. Peterson, for example, has a 30-year track record of success, with over 100 patents granted to him.

For corporations, the big advantage of the skunk works culture is a more efficient organization. Cervenka says that their Technical Center has helped Phillips Plastics save time and money. "We can crudely try out an idea without a big economic investment," he concludes. "It's an easy way to identify a problem and solve it more quickly."

--Charles J. Murray, Senior Regional Editor


Rapid prototyping weeds out bad designs early

A decade ago, "rapid prototyping" was little more than a laboratory curiosity. Today, it's an estimated $295 million business, used by virtually every major manufacturer of autos, airplanes, medical equipment, and computers. "On a list of, say, five things would-be innovation stars should do, working at creating a full-blown culture of rapid prototyping surely merits inclusion," according to management guru Tom Peters.

Rapid-prototyping (RP) systems make physical models directly from 3-D CAD data, eliminating the need for hand-crafted mockups or expensive tooling. The results? Companies say this shaves anywhere from 10 to 50% from their overall product-development time.

"We do design iterations a heck of a lot quicker," says Steve Deak, manager of rapid-prototyping services at Hasbro in Cincinnati. "We can weed out wrong ideas much earlier. Once you get a prototype, a lot of things become obvious, because you can hold it and feel it."

Hasbro recently used RP to develop a Nerf "Backwards Basketball" game, in which a child would strap a small molded backboard to his or her back while an opponent tried to slam dunk the ball. Under the company's previous system, a Hasbro artist would first sketch the product and then hand that over to engineering for a detailed drawing to be made. Then, a model shop machined half the part, so a mold could be produced. At this point, many of the screw bosses and webs weren't designed in, but worked in on the fly.

"Then you might find out, 'There's no room to put a screw in there,''' Deak says. "It's a tedious process that doesn't allow concurrent work."

Now, engineers develop products with 3-D CAD software, including details such as stiffening webs, from the outset. Those data are then sent to Hasbro's SLA 500 stereolithography machine purchased from 3D Systems, Valencia, CA, which builds a physical model layer by layer, using a laser to solidify a liquid resin.

"If there's going to be a problem, you'll catch it a lot sooner than waiting for production molds to be completed," says Randy Stewart, a mechanical engineer at Hasbro.

CAD models on a computer screen can help engineers check for interferences and other glitches, Deak says, but physical models are necessary to find other problems, such as checking to make sure a toy has no sharp edges. A toy company also needs physical models early in the design process to test for children's reactions.

It would have taken 12 weeks to get the first part with Hasbro's old product-development system; the new process cut that to between nine and 10. And in the hotly competitive toy market, sales can depend on getting to the stores in time to catch a hot fad or before a big holiday. "Two weeks means a heck of a lot," Deak says.

Overall, he estimates time savings between 10 and 25%, depending on a product's complexity. "There's so much to be saved if you design it right, and make the tools right the first time."

Boeing Defense & Space Group needed a cast-titanium fitting for one of its space programs, recalls Gil Starkey, rapid-prototyping specialist at Boeing's Kent, WA, facility. The conventional approach involved a 2-D engineering drawing, manufacturing plan, and NC machining. This all might have taken four months, including detail-design time and waiting for available NC programmers. Instead, engineers developed the part in 3-D using Pro/ENGINEER, then sent the drawing out to a stereolithography machine to create a model used to produce a titanium casting with some minimal EDM machining. Time saved: six weeks for the new process vs. four months for the old.

In another case, tools for a key program got lost. "In a matter of two weeks, I reproduced them, from the phone call to parts on my desk," Starkey says. "Conventionally, it would be a month just to go back and re-create the drawings."

RP alternatives. While 3D Systems' stereolithography was the first in this new generation of RP technology, and is still the most widely used, there are several other prototyping options. Selective Laser Sintering, from DTM Corp., Austin, TX, creates models by using a laser acting on powdered materials such as metals and nylons.

Israeli-based Cubital features a high-end, high-precision process called solid ground curing that builds objects in slices. A thin layer of photo-reactive polymer is solidified with ultra-violet light projected through a photo mask; untreated resin is vacuumed off and replaced with liquid wax. The wax is chilled, and the layer ground to correct thickness.

Fused Deposition Modeling, from Stratasys, Eden Prairie, MN, puts modeling material on a spool, where the filament is fed into an extrusion head. Laminated Object Manufacturing from Helisys, Torrance, CA, creates parts by layering sheets of material such as plastic or composites, with a laser cutting away excess material. Relative newcomer BPM Technology, Greenville, SC, uses a robotically controlled extruder nozzle to shoot drops of molten thermoplastic.

Most of these RP processes were initially aimed at providing fairly realistic models for validating engineering designs. More recently, several of these companies moved into "rapid tooling." DTM, for example, can make metal molds for $7,000 in 200 labor hours, versus $28,000 and 600 hours for conventional core and cavity sets, according to vice president Tom Lee.

"On most programs, we cut a minimum of 30% off our time," says Paul Chelaeyn, CEO of D&C, which makes tools and parts for automotive companies. Instead of generating CNC paths, the company goes from CAD data to a finished mold in a week, eliminating machining and cutting patterns.

So-called rapid tooling has "helped bring manufacturing and design to-gether," says consultant Terry Wohlers at Wohlers Associates, Fort Collins, CO. "Design engineers are a very integral part in producing prototypetooling. In the past, they handed that off tosomeone else. It's changed--quite dramatically in some cases--how design engineers work with manufacturing."

Prototyping in the office. Now, several RP companies are targeting the earliest stages in the design process. New "desktop" systems are aimed at making it as easy to generate a 3-D concept model as it is to do a 2-D plot. These systems offer less accuracy than conventional RP; but the trade off is faster, easier, and less-expensive modeling.


How to implementrapid prototyping
- Move to 3-D CAD
- Determine if you are interested in concept models, functional prototypes, and/or a process for speedy toolmaking
- Test various processes by prototyping at one or more service bureaus
- Don't underestimate the resources needed to run an in-house RP system, including infrastructure and technicians

Such systems are meant to sit in the engineering office as another computer peripheral, much like a printer or plotter. That means engineers have more control over when to make a model, because there's no need to use a specialized RP department or outside service bureau.

"This is brand new and exciting, to make parts in a design office," Wohlers says. "You can take some of your first ideas and give it a try." A small part might cost $30 and run overnight, compared to waiting a week and spending $500 for a conventional prototype.

The Actua 2100, from 3D Systems, uses a 96-jet "print head" in a linear array, speeding back and forth like a printer to build models layer-by-layer from a thermopolymer. "It's a tremendous technology. It's what we have been looking for," says Fred Brotherson, engineering supervisor at Caterpillar. "It gives us time back in our design cycle."

Genisys, from Stratasys, creates concept models from a polymer, using a cassette system feeding material through an extrusion head.

Ultimately, Wohlers says, rapid-prototyping systems of all types are communications tools, allowing engineers not only to understand their own designs better, but to more effectively show colleagues, executives, and customers the full potential of their ideas.

RP also allows engineers to better examine more ideas earlier in the design process, Deak says. "It sparks a lot of creativity. It's a different way of thinking."

--Sharon Machlis, Senior Editor


'Solid' grounding for CAD models

Among the time-saving design tools software companies are providing engineers is 3-D solid modeling. "There is a high interest in 3-D modeling among engineers," says Bruce Jenkins, vice president of Daratech, Cambridge, MA. "And there are a significant number of companies migrating to 3-D products from entirely 2-D systems."

PLC Medical Systems, Inc., Milford, MA, is one of those companies. It manufactures a CO2 Heartlaser used as a clinical alternative to bypass surgery in patients with end-stage coronary artery disease. Holes burned into the heart's left ventricle permit sufficient oxygen to be diffused into the heart muscle to compensate for clogged arteries.


How to begin using solid modeling
- Investigate benchmarks and ease-of-use claims made by software vendors.
- Invite vendors to demonstrate their software's ability to solve one of your common design problems.
- Analyze packages for ease of model creation, editing, assembly modeling, and available complimentary software packages.

Though the procedure is currently performed abroad, it is pending FDA approval in the U.S. Still, the growing international market and the promising potential market in this country prompt PLC Medical to continually upgrade their product.

"We constantly receive feedback data from the field, which we turn into design modifications," says Larry Brodsky, senior mechanical engineer at PLC Medical, noting that these modifications often turn into subsystem improvements.

To tackle concerns about sheet-metal fit, component interference, and manufacturability, PLC Medical engineers turned to Prelude software from Matra Datavision, Andover, MA, for its 3-D solid modeling capabilities. He estimates that solid modeling cuts the time required to complete a given project by as much as half.

In one project, engineers redesigned a fitting carrying CO2 gas under pressure so it could be oriented in any direction. The original design used threaded fittings, permitting only one orientation when fitted securely. The redesigned pipes use Swagelok(R) fittings and allow more freedom of motion. Prelude enabled Brodsky to recreate the gas-handling assembly with the required length and fittings, while resolving such issues as interference checking resulting from the new assembly's flexibility, he says.

Brodsky also discovered that computer-controlled solenoid valves in a bank of such devices were too large for the task of routing gas to different laser subsystems. To solve the problem, he developed an assembly of more efficient valves and redesigned the attending manifold block. He says he could easily see the relationship between the parts in an assembly in solids.

Such capabilities enhance a designer's ability to uncover interference conflicts, fitting problems, and other errors early on when they are easier to fix, Brodsky says.

--Deana Colucci, Associate Editor

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