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Articles from 1998 In January

Coating Minimizes Thrombosis and Restenosis in Cardiovascular Stenting


Surface Treatment

Coating Minimizes Thrombosis and Restenosis in Cardiovascular Stenting

Prevents adsorption of potentially thrombogenic proteins

A SURFACE COATING developed by Advanced Surface Technology Inc. (Billerica, MA) has the potential to minimize the thrombosis and restenosis that commonly occur in cardiovascular stenting. It may also serve as a suitable coating for other implantation procedures that face similar biocompatibility challenges.

BioLAST is a nonthrombogenic biocompatible coating that, when it comes in contact with physiological fluids containing albumin, selectively and reversibly binds the endogenous albumin. Subsequently, the albumin prevents chaotic adsorption of denatured and potentially thrombogenic proteins. Additional benefits include reduced platelet adhesion and activation and inhibited microbial adhesion.

Advanced Surface Technology is an ISO 9001­certified company offering a variety of proprietary coating and surface modification technologies to the medical device industry. These include the LubriLAST hydrogel coating, which enhances the surface lubricity of such devices as catheters, drainage tubing, and guidewires; the HydroLAST surface treatment, which creates a highly wettable surface on polymeric porous materials and fabrics; and ParyLAST, a combination of the company's cold plasma surface modification technology and a parylene conformal polymeric coating. Coatings can be applied to devices on a contract manufacturing basis or licensed on a tech-transfer basis.

For more information, contact Advanced Surface Technology Inc. at 978/663-7652.

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Rapid Prototyping

Service Bureau Uses New 3-D Printing System to Create Prototypes

Parts can be created faster than with other technologies

SANTIN ENGINEERING INC. (Peabody, MA) has become the first service bureau to offer prototypes using a new 3-D printing system.

Developed by Z Corp. (Somerville, MA), the Z402 system is especially useful for the creation of appearance models. These models can be used by industrial designers and product-development specialists in the early stages of product development to test concept designs, verify CAD files, or serve as 3-D product renderings to elicit feedback from focus group research. They can also be used as patterns for investment casting applications.

According to Santin, the Z402 system creates parts up to 20 times faster and at a lower cost than currently available processes. For example, a part with dimensions of 8 x 4 x 1 in. takes only 32 minutes. The system receives data from a CAD file and produces a 3-D model layer by layer using starch-based powders bound together by an adhesive. The technology, called the 3DP process, has been patented by the Massachusetts Institute of Technology and licensed for commercialization by Z Corp., which has developed the proprietary software that runs the system.

To build a part, the machine spreads a single layer of nontoxic cellulose powder onto the movable bottom of the build box. A binder is deposited onto each layer of powder to form the shape of that cross section of the CAD file. The bottom of the build box is then lowered by one-layer thickness (ranging from 0.005 to 0.009 in.), and a new layer of powder is spread until the part is complete. The unbound powder is then removed from the final part, which can then be impregnated with hot wax or other materials to add strength and finishability.

For more information, contact Santin Engineering Inc. at 508/535-5511. Contact Z Corp. at 617/628-2781.

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New Software

Validation Software Developed for Medical Device Manufacturers

Standardizes documentation required by FDA

KMI SYSTEMS (Belmont, MA) has developed a software package to assist medical device manufacturers with the production of such complicated documents as validation protocols and engineering specifications. ValPro Intelligent Protocol Software is an easy-to-use database application that can improve documentation consistency and efficiency.

According to KMI Systems, ValPro can save as much as 40% of the validation costs of an individual project, and it allows users to standardize the documentation required by FDA for qualification. The software is also designed to allow users to take advantage of their own past work and legacy documents.

ValPro helps automate the production of validation protocols using a library of guidelines, test procedures, and data sheets. Users can rapidly create protocols by selecting and assembling test procedures from an extensive library of standardized tests or by creating (and saving for future use) their own new test procedures.

The software provides a change-history configurable option that creates a history file for each library object such as protocols and test procedures. With the change-history option enabled, the date, time, and user ID are automatically captured in the change history record, along with a user-supplied reason for the change.

KMI Systems is a division of Kemper-Masterson Inc., a company specializing in compliance and validation services. The division develops compliance and validation software for the pharmaceutical, biopharmaceutical, and medical device industries.

For more information, contact KMI Systems at 617/484-9920.

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Medical Device Professionals Convene in Minneapolis


Medical Device Professionals Convene in Minneapolis

A bright future for the medical device industry foreseen

This past November 4—6, nearly 3000 members of the medical device industry gathered in Minneapolis for the Medical Design & Manufacturing Conference and Exposition, an annual event sponsored by Canon Communications lcc (Santa Monica, CA).

In the keynote address, Medtronic chairman and CEO William George discussed some opportunities and challenges facing the medical device industry. "Medical technology is truly one of the great opportunities of our era," he said. "Despite many obstacles during the 1980s, including the Kessler-led FDA and well-publicized safety issues related to breast implants and heart valves, the device industry is entering an era where the benefits of medical technology are appreciated by the public," George explained.

"Public sentiment about health care is changing," George said, adding that consumers are taking a more active stance in learning about treatment options via the Internet as well as television programs and news magazines.

Conferences covered a range of industry topics, such as the effects of human factors on medical device design. According to Pamela Jamar, a human factors engineer for Medtronic, recent technological developments are forcing designers to ask new questions with respect to device usability.

As the health-care industry continues to evolve, designers must adopt an increasingly user-based approach to device development to ensure user acceptance and market success. Session chair Susan Dray, president of Dray & Associates (Minneapolis), asked device engineers to consider her motto: "If the users can't use it, it doesn't work."

In another session, a panel of experts explored the challenges of microelectromechanical systems (MEMS) in medical devices. MEMS can be produced as millions of components simultaneously, require little power, and are fast and lightweight. The market for MEMS devices is about $2 billion, but is expected to reach $9.74 billion by 2002.

However, the key dilemma facing developers in the MEMS field is whether to produce integrated systems that carry out all functions on a single MEMS, or hybrid systems that make use of components and a modular structure. Kurt Peterson, PhD, president of Cepheid (Santa Clara, CA), stated his belief that the trend is away from individual components and sensors and toward complete systems.

When they weren't attending conferences, attendees could visit an exposition hall housing nearly 400 suppliers, equipment manufacturers, and service providers. Minnesota-based AutoTran displayed several series of pressure transducers, such as the 561 that features differential or gauge pressures ranging from 0—1 to 0—500 psi. The unit is suitable for use with any harsh media (wet or dry) that is compatible with brass, silicon, glass, and gold. For further information, call AutoTran at 800/735-8998.

A sample processor designed for liquid-handling operations and multifaceted diluting/dispensing was demonstrated by Hook & Tucker Instruments (New Addington, Croydon, UK). The Beeline 3 features fully programmable PC-driven operation and a variety of options. For more information, call Hook & Tucker at +44 0689 843345.

St. Paul Technology (St. Paul, MN) representatives were present to discuss property and liability insurance benefits offered to businesses in the medical device industry. Coverage can be tailored to meet customer needs. For more information, call St. Paul Technology at 612/310-5032.

The regional conference and exposition attracted a large crowd of professionals wishing to stay current about topics relevant to the industry as well as locate the latest in products and services. Manufacturers interested in attending future MD&M events should contact Canon Communication LLC, Trade Show Div., at 310/392-5509.

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Study on Medical Plastics Market Published

Growth in engineering resins expected

According to a study by the Business Communications Company, Inc. (Norwalk, CT), the total market for medical plastics reached 100% of total volume and is expected to remain the same through 2001.

Several hundred different resins are employed in the manufacture of medical products. Virtually every plastic resin has at least one grade that is suitable for medical and/or pharmaceutical applications. These resins can be grouped into six major classifications: commodity thermoplastics, styrenics, engineering resins, thermoset resins, elastomers, and a miscellaneous category. The commodity thermoplastic category includes polyethylenes, polypropylenes, and PVC.

The study predicts some growth in the market for engineering resins. The outstanding thermal and mechanical properties of engineering resins are often preferred for certain medical devices. Nylons, polycarbonates, polyacetals, and polysulfones find wide applications in life-supporting and critical devices, such as kidney dialyzers, blood oxygenators, sutures, catheters, and labware. Engineering resins made up 11.9% of the total market volume in 1996 and are expected to grow to 12.4% in 2001. For more information, contact Business Communications Company, Inc. at 203/853-4266.

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Precision Wire Components Receives ISO 9002 Certification

Company president credits QA system initiated at inception

Precision Wire Components (Portland, OR), a manufacturer of precision-made wire components supplied exclusively to the medical industry, has been awarded ISO 9002 certification by British Standards Institution Inc.

Company president Charles Trover credits his company's achievement to quality assurance systems written and designed during the company's initial stages of development, as well as to the company's decision to manufacture exclusively for the medical industry. For more information, contact Precision Wire Components at 503/570-9032.

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Medical Design Excellence Awards Jury Appointed

Deadline for entries approaching

Organizers of the 1998 Medical Design Excellence Awards have named a jury to select the winners of the annual design and engineering competition. The awards will celebrate technological innovation in medical devices, components, and materials. The deadline for entries is January 26, 1998.

The awards program is sponsored by Canon Communications llc (Santa Monica, CA) and endorsed by the Industrial Designers Society of America (IDSA, Great Falls, VA), which will oversee the judging process. "Canon Communications has attracted an excellent jury for the 1998 Medical Design Excellence Awards," says Robert T. Schwartz, executive director and chief operating officer of IDSA. "With the jury's depth and diversity of expertise and perspective, it can objectively and thoroughly evaluate the entries."

Kent Ritzel

The jury is headed by Kent Ritzel, a director for Metaphase Design Group (St. Louis) and chair of IDSA's medical section. Other jurors include Leonard Friedman, ScD, head of product development, American Red Cross (Rockville, MD); James Young, president and chief operating officer, General Physiotherapy Inc. (St. Louis); Seth Banks, manager, global design and user interface, GE Medical Systems (Milwaukee); Bronwen Walters, president of Outcomes Analysis Corp. (Dania, FL); and Bill Wood, vice president of R&D, RELA Inc. (Boulder, CO).

Leonard Friedman

The jury will evaluate entries based on criteria such as benefits to users and patients, safety, cost-effectiveness, technological innovation, and advancement of the state of the art. "This award is an opportunity to recognize innovation that extends the quality of life," says Bill Wood. "As a juror, I'll be looking at some of the most innovative ideas and products."

Juror Bronwen Walters comments that "there are a lot of aspects of the industry that don't get recognized in broad-based design competitions." Specifically, she notes, materials such as medical films, plastics, and adhesives are not traditionally included in such competitions. "The Medical Design Excellence Awards will encourage the people involved in the design of behind-the-scenes products to come forward and show their skill and receive some glory." Finalists will be announced in the May 1998 issue of Medical Product Manufacturing News, and winners will be announced at a gala dinner held during Medical Design & Manufacturing East 98, June 2—4, in New York City.

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Shop-Floor Control System Helps Device Manufacturer Shed Its Paper Trail

Manufacturing facilities can generate mountains of paperwork each year. This is particularly true in the medical device industry, where tight controls are mandated.

Rather than getting buried by its paperwork, one device manufacturer decided to break free. The Scottsdale, AZ--based Pacesetter Inc. manufactures cardiac rhythm management products. At the center of the company's pacemakers and implantable cardioverter defibrillators (ICDs) is a hybrid component that serves as the brains of these sophisticated medical devices. Via the hybrid, a cardiac rhythm management device collects, analyzes, and stores information on cardiac activity and can detect when to generate electrical impulses to provide appropriate therapy.

The hybrid is the sole output of the company's new 60,000-sq-ft Scottsdale facility; once produced, units are shipped to Pacesetter plants in Sylmar, CA, and Veddesta, Sweden, for assembly into pacemakers and other cardiac devices. The facility includes a 22,000-sq-ft cleanroom, advanced electronics technology and manufacturing processes, sophisticated air-handling environments, and robotics for assembly and test operations.

Logically, an advanced shop-floor control system was necessary for this advanced facility. Such a system, however, was going to be a first for the company; Pacesetter had grown accustomed to paper control systems at its other manufacturing facilities. In a paper system, each part is accompanied throughout the production process by several pieces of paper. At each assembly step an operator is required to manually enter process information and initial the paper to verify that each step in the process has been completed.

Besides being time-consuming, Pacesetter's paper control procedure was cumbersome and difficult to manage. It was not the type of process the company intended to bring to its showpiece Scottsdale facility. Thus, the decision to acquire a modern, state-of-the-art shop-floor control system was a relatively easy one.

Reducing Production Costs

Selected members of the Pacesetter management team were designated to conduct a thorough review of competitive systems. Ultimately, the team agreed on the Promis manufacturing execution system (MES) from Promis Systems (Toronto).

The company's software is the cornerstone of a new technology known as informed manufacturing. A modular system that works well in open-system environments, Promis's versatility offers users flexibility in their selection of operating platforms, including Digital Open VMS, Digital UNIX, and Hewlett-Packard UX systems.

While the need to eliminate the paper travel system, as well as an ongoing desire to reduce process costs, were the primary catalysts in the company's search for a new system, the Promis MES has delivered a number of additional benefits, such as reduced production cycle times, faster data collection and improved data integrity, reduced scrap, and reduced labor costs.

Cycle times have been reduced by a full week, which translates to a corresponding reduction in work-in-progress (WIP) inventory costs of at least $500,000 annually. With easier and faster access to real-time data and WIP information, process problems can be immediately identified and corrected. And because the data are more accessible, process modification decisions can be made more quickly. Since the production process is more efficient, more raw material is eventually turned into finished product. This reduction of scrap will mean another $250,000 in annual savings. Finally, the reduced labor costs save $200,000 a year. All told, the system is expected to help Pacesetter realize a yearly savings of over $1 million.

"We were convinced that we would get a return on our investment with the Promis system," explains Kelly Summers, manager of computer integrated manufacturing and information technology. "We knew the system would pay for itself in terms of efficiency and reduced labor and overhead costs."

The system's ability to give Pacesetter a paperless operation also meant that it fit very well with the guidelines for a cleanroom facility. Because of the delicate nature of the microelectronic components produced at the plant, as well as their sensitivity to contaminants, this benefit was a perfect complement to the cleanroom environment that the company requires.

Summers also points to Promis's ease of use and, even more important, the program's ability to understand microelectronics manufacturing. "It was apparent that the system was very much in tune with the intricacies of semiconductor manufacturing," he says.

Quick Implementation

Pacesetter is using a high-speed hardware package to run the Promis system. Two Digital Equipment Corp. Alpha 5/300 servers (one primary, one secondary) each feature 512 MByte of RAM. These interface to an SW400 with 87 GByte of disk storage. Operators access data from DEC VT510 terminals at various locations throughout the facility. Currently, the Promis WIP Tracking model is fully deployed. Future plans call for the deployment of additional modules, such as equipment and task management, advanced statistical control, and planning and costing.

While complete implementation of the system at full production capacity was achieved in only four months, Summers cites the number of procedural steps leading up to the implementation. "FDA has very strict guidelines for software validation in the medical device industry, and so we had to develop an entire system validation plan. Plus, we had to devise a complete training plan." As part of the training process, Pacesetter first effected a "parallel" build, using both systems simultaneously to ensure a smooth transition to Promis.

"Although only minimal support was required," Summers continues, "Promis has been assisting us with the training as well as consulting with us on other issues. The implementation was probably faster than most, but there was still a great deal of legwork needed to get there."

The Scottsdale facility is being used as a beta site for the Promis system. Should it continue to perform as well as it has, the company will implement it at its other plants. While the Promis system has brought a number of tangible benefits to Pacesetter, it has also, perhaps indirectly, brought another less tangible benefit. "Implementing a factorywide solution in a high-tech manufacturing facility such as Pacesetter challenged everyone in the facility to come together as a team," Summers says. "In examining our requirements for a shop-floor control system, we were forced to effectively examine all our business practices.

"Clearly, the Promis system has provided us with all of the benefits that we envisioned."

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Spotlight on Rapid Prototyping

Spotlight on Rapid Prototyping

Stereolithography molds

Stereolithography molds can be built quickly and with less expense than molds made by traditional methods. The process is similar to building stereolithography parts, but the mold is reinforced to withstand injection molding conditions for 50 or more cycles. Although they may not be as attractive as parts from other prototyping methods, parts produced from stereolithography molds can be used to verify part design and functionality in many specified materials, including polycarbonate, ABS, polypropylene, and polystyrene. The primary benefit of stereolithography molds is rapid turnaround of parts in specified materials. Philips Plastics Corp., N4660 1165th St., Prescott, WI 54021.

Design and prototyping

A firm provides industrial design and rapid prototyping services to medical OEMs, including CAD, computer rendering, finite element analysis, stereolithography, and laminated object manufacturing. Also available is a model shop. Parts can be made in both rigid and flexible urethane, metals, and various other materials. A recent project involved the prototyping of an esophageal balloon dilator produced using CAD and stereolithography. Axiom, 4912 Wallace Neel Rd., Charlotte, NC 28208.

Multiple prototype copies

Multiple copies of limited-production-run prototype parts are available in as little as a week. A proprietary reaction injection molding (RIM) process permits the production of parts at a rate 8—10 times faster than that of urethane casting techniques. The material used, which exhibits properties similar to those of ABS plastic, is stronger and more temperature resistant than standard urethane. As many as 40 parts can be produced per day on a single-cavity mold, and multiple-cavity or multiple molds can produce as many as 650 parts per week. The full-service product design and prototyping firm also offers CAD, fabricating, machining, sculpting, and injection mold tooling. Sonos Product Development, 17862 Metzler Ln., Huntington Beach, CA 92647.

Plastic prototype parts

A company's complete stereolithography apparatus system includes an ultraviolet laser, a scanner, photopolymer, a vat, an elevator, and a controlling computer. The company uses an Aries Technology "concept station" to convert a customer's input into a computerized model. The solid model is input into the SLA, and the part is built by successively curing cross sections of photopolymer on top of one another to form a 3-D part. The company uses stereolithography to make model or prototype plastic parts, soft tooling for blow molding, and patterns for metal castings. The technology directly addresses the problems of time and expense in traditional model building. Laser Prototypes Inc., 3155 Rte. 10, Denville, NJ 07834.

Contract stereolithography

A firm manufactures prototype and conceptual models using stereolithography. Typically produced within one week, the prototypes can be used to evaluate design feasibility, verify manufacturability, perform functional tests, and reduce or eliminate engineering changes in the production phase. Prototypes produced can be as large as 20 x 20 x 24 in.; larger prototypes are available on a contract basis. Typical tolerances are ±0.005 in. for parts of less than 5 in. and ±0.0015 in./in. for parts greater than 5 in. Also available are cast polyurethane parts and silicone rubber molds for limited production quantities. Protogenic Inc., 1490 W. 121 Ave., Ste. 101, Westminster, CO 80234.

Design and development

A full-service product design and development company supports many levels of the medical device community. In-house capabilities include a full complement of industrial design, mechanical and electronic engineering, prototyping, regulatory support, tooling, and production. Development phases range from initial product specification and design conceptualization to engineering, stress analysis, prototype fabrication, bills of materials, and production tooling and manufacturing. I.N. Inc., 4392 Corporate Ctr., Los Alamitos, CA 90720.

Product development and prototyping

Twenty full-time employees, including machinists, designers, engineers, and model makers, give a company the ability to do virtually all development, design, and prototyping on its premises. The company is fully CAD integrated, its capabilities including solids modeling, photorealistic rendering, electronic schematic capture/layout, and CNC machining. It also specializes in custom product design and development. Services include industrial design, mechanical engineering, electronic design, software engineering, CAD/CAM/NC functional prototyping, and 3-D computer rendering. Omnica Corp., 15560-D Rockfield Blvd., Irvine, CA 92618.

Rapid product development

Providing a complete range of product development services, a company places special emphasis on significantly reducing time to market. CAD capabilities include mold-flow analysis, geometric analysis, and tolerance checking. Among the prototype production techniques used are selective laser sintering, stereolithography, fused deposition modeling, urethane molding, and CNC machining. Recently added to the firm's array of rapid prototyping equipment is the Cubital Solider 5600 system, which quickly transforms computerized design files into 3-D models using the solid-ground curing process. Compression Inc., 7752 Moller Rd., Indianapolis, IN 46268.

Rapid functional prototypes

Advanced methods for producing rapid functional prototypes (plastic and cast metal), rapid stereolithography (SLA) models, and rapid tooling have been developed. The company specializes in prototyping complex injection-molded designs using an automated molding technology called vacuum cast molding (VCM). Some advantages of VCM over conventional RTV molding include thin-walled complex geometries filled without air voids, resins more closely resembling engineered plastics, part repeatability and consistency, and higher production rates. SLA models are handcrafted to meet dimensional and aesthetic specifications. SICAM Corp., One Harvard Way, Ste. 1, Somerville, NJ 08876.


Stereolithography services are offered by a company that can produce prototypes in as little as 24 hours. Stereolithography can be used for small-run items and RTV molding. It can also be used for casting, sand casting, and die casting, and is a hands-on way for companies to further product development. The company's other services include short-run injection molding, mold inserts, and sheet-metal-forming prototypes. Vista Technologies LLC, 4457 White Bear Pky., Ste. D, White Bear Lake, MN 55110.

Rapid tooling manufacturer

A company uses the latest in CAD/CAM technology to make production-level tooling in two to six weeks. This allows clients to build a tool in a prototype time frame and then make a timely transition to production. Not only does the tooling's high quality and the dramatic reduction in lead time satisfy start-up requirements, but in many cases it may end up being the only set of plastic- injection-mold tooling built. The company uses Pro/Engineer and SDRC software to interface with customers. All tooling is built directly from solid-model data. Molds are usually constructed of P-20 steel and guaranteed for 100,000 pieces. There are no restrictions on tolerances or the type of geometries that can be built. Global Tool & Engineering Inc., 2009 McKenzie Dr., Ste. 116, Dallas, TX 75006.

Model-making services

Skilled in traditional handcrafting techniques as well as 3-D CAD/CAM and rapid prototyping processes, a company produces models for a wide variety of applications ranging from 3-D conceptual studies and medical diagnostics to sophisticated product design prototypes. Stereolithography is used to create precise physical parts directly from CAD files, shortening the modeling process from days to hours. Urethane casting using RTV molds is a rapid and inexpensive solution for short production runs of rigid or flexible parts; numerous durometers, colors, and textures can be cast to represent all surface details. Satellite Models, 950 Rengstorff Ave., Ste. C, Mountain View, CA 94043.

UV Curing Device Plays Integral Role in Bonding Guidewires


UV Curing Device Plays Integral Role in Bonding Guidewires

Chosen for its reliability, repeatability, and ease of setup

North American physicians perform an estimated 1 million angioplasty procedures each year. Essential to the success of these procedures are guidewires—the rails over which all other devices used in angioplasty must travel. These guidewires are made up of stainless-steel and gold-platinum components bonded together.

C.R. Bard Inc. (Billerica, MA)—a developer, manufacturer, and marketer of cardiovascular, urological, and surgical products—recognized that a comprehensive line of high-quality guidewires would enhance its position in the highly competitive industry.

Traditionally, guidewires have been bonded with welding, brazing, or soldering methods. However, when Bard began developing its Commander platform of guidewires, UV-cured adhesive was the bonding method chosen. Critical to successful adhesive bonding is the reliability and overall quality of the UV-light device employed. With this in mind, Bard chose the Novacure system by EFOS (Mississauga, Ontario, Canada) for bonding its new line of guidewires.

"We had used other lights previously," Bard engineer Paul Marad explains, "but we experienced time-consuming problems. With other lights, for instance, at the beginning of each workday a technician would have to turn on the light, get a reading from a radiometer, and enter the data in a setup logbook. When we're using numerous lights, there's a lot of setup time involved. The Novacure, on the other hand, has its own built-in radiometer for measuring light delivery. In addition, setup is done by the operator. We eliminated technician overhead and increased productivity time," he says.

According to Marad, the EFOS units were easily integrated into Bard's manufacturing fixtures. Using a microscope, the operators position the guidewire components according to built-in indexes, apply adhesive, and spot-cure the joints using the Novacure. Because it has integral self-diagnostic capability, the instrument will alert the operator if any of the preset curing parameters are not met.

Data logging and documentation were also of importance to Bard and its overall quality assurance. "The Novacure has an internal process validation system that provides records showing the bulb number, date, time, accumulated lamp hours—everything we need for continuous repeatability verification," Marad notes.

The Novacure also provides up to 20,000 mW/cm2 of energy, critical during the product development phase. The Novacure unit also features a front-panel control for adjustments. In addition, curing data acquired during development are easily transferred to the manufacturing floor.

Marad concludes that the Novacure system made a significant impact on Bard's overall process. "First, the ease of setup is key in the manufacturing environment. Then there's the continuous monitoring with built-in alarms that allows us to run the process with great confidence. Finally, it's good to know that we are dealing with an ISO-certified supplier that meets GMPs and provides rapid technical responses to developmental or process-oriented inquiries. For us, all of these features add up to value."

For more information on the Novacure system from EFOS, call 905/821-2600.

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Infection-resistant coating suitable for medical devices

Products Featured on the Cover of Medical Product Manufacturing News

Infection-resistant coating suitable for medical devices

An "actively sterile" infection-resistant coating for medical device components can be applied to the surfaces of metal, polymer, or ceramic devices. The deposition process, known as ion beam—assisted deposition, combines metal evaporation with state-of-the-art ion beam technologies. The result is a permanent, adherent thin film that is effective against a variety of nosocomial bacteria. In addition to being infection resistant, the SPI-Argent minimally-leaching coating provides a slick surface that prevents biodeposit and thrombosis attachment while reducing mucosal irritation. Spire Corp., One Patriots Park, Bedford, MA 01730. Ph: 617/275-6000.

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Endoscopes provide flexibility and small diameters

Medical endoscope products are available for use in a variety of microinvasive surgical and diagnostic procedures. The products offer high image resolution, small diameters, flexibility and steerability, and good optical performance. The company's proprietary micro-optics enable physicians to visualize patients' anatomy with the resolution and light efficiency of larger, more costly, more invasive devices. Galileo Corp., P.O. Box 550, Sturbridge, MA 01566. Ph: 800/648-1800.

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Bearings and assemblies meet strict requirements

A company provides miniature ball bearings and mechanical assemblies to medical device manufacturers. An in-house machine shop is equipped with high-precision CNC machine tools. Products can be assembled in Class 10,000 cleanrooms with Class 100 benches if required. Components are tested and inspected to ±0.0001-in. tolerances; detailed and traceable production records are maintained for all assemblies. Dynaroll Corp., 551A Fifth St., San Fernando, CA 91340. Ph: 800/235-1235.

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Editor's Page

Editor's Page

The Internet: Flash in the Pan or Medium of the Future?

I'm sure that by now, you have already formed an opinion about the Internet. Some of you have undoubtedly embraced it, while others remain skeptical about its future. One thing that's for certain, however, is that businesses and associations are taking notice. Some organizations are investing in their own Web sites and advertising with industry-related sites because they truly believe in the Internet's usefulness. They also believe that their investment will pay off in the end.

Surveys of the readers of Medical Product Manufacturing News have shown that many in the industry are using the Internet as a way to get information that can make their jobs easier. Whether it's to order supplies, to communicate with customers and colleagues, or to conduct research, our readers are using the Internet with increasing frequency.

There are several Web sites that can be particularly useful to medical product manufacturers. Medical Device Link offers original content designed specifically for you. Everything from sourcing information and regulatory updates to industry news and job listings can be found here. The site is updated daily, so it's worth returning to regularly.

FDA's Center for Devices and Radiological Health also has an informative Web site. The CDRH site includes a center overview, a staff search engine, recent CDRH federal register notices, blue book memoranda, and more.

Also be sure to visit the Federal Register on-line. For a variety of regulatory communications from FDA ranging from announcements of public meetings to publication of final regulations (such as the revised GMPs), this searchable version of the Federal Register provides the complete text for volumes published after 1994.

Other industry organizations with valuable Web sites include the Association for the Advancement of Medical Instrumentation; the Health Industry Manufacturers Association; and the Medical Device Manufacturers Association.

Popular opinion is that the potential of the Internet has yet to be realized. Some believe that we've only scratched the surface of what can be achieved. Certainly there has never been a faster way to communicate or disseminate information. As time goes on, we will find ourselves more and more dependent on the medium. Soon we'll wonder how we ever got along without it.

Ursula Jones

EQUIPMENT NEWS : Syringe and pipette printers


Syringe and pipette printers

Direct product printing equipment can be used to mark pipettes, syringes, catheters, and centrifuge tubes. Standard machines include medium-speed arc, high-speed mandrelized, and high-speed convolute printers. The arc printer can feed, treat, print, dry, and exit up to 300 syringes per minute, and accepts 2-, 3-, and 5-cm3 syringes. The mandrelized printer, designed for thin-walled syringes, handles up to 500 per minute. The convolute printer, designed primarily for large, rigid syringes, can operate at more than 550 parts per minute. Apex Machine Co., 3000 N.E. 12th Terr., Ft. Lauderdale, FL 33334.

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Laser marking systems

Three lines of laser marking systems can be used on virtually all medical products, including tubing, syringes and syringe caps, surgical or dental tools, IV bags, and implants. The systems permanently and cleanly mark date and batch codes, bar codes, 2-D symbologies, graphics, and logos. These markings, readable with machines or by eye, can be used for product traceability on plastics, metals, glass, rubber, and paper. Lumonics Corp., P.O. Box 9010, Oxnard, CA 93031.

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Turnkey labeling systems

Integrated labeling systems incorporating infeed conveyor, product orienters, label applicator, bar code verifier, label-on-package verifier, package rejecter, and outfeed conveyor are available as complete systems or individual components. Labels can be applied to a variety of products. Wipe-on application ensures accurate and consistent label application on packages. The systems are available in stainless steel or painted, and a variety of conveyor belt materials can be specified. Labelmation, div. of Technomation, 3408 South 1400 West, Salt Lake City, UT 84119.

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Four-color printer

A digital, four-color thermal-transfer label printer can print on both sides of labels simultaneously; it can also cut and stack them for easy access. The QuickLabel-4 requires no printing plates, inks, toners, or hot-stamp dies. Label data go directly from a PC to the printer, allowing variable data to be altered during printing. The unit operates without hesitation between labels at speeds up to 5 in./sec even when a different database field is selected for each successive label. Astro-Med Inc., Astro-Med Industrial Park, West Warwick, RI 02893.

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Microprocessor-controlled labeler

A microprocessor-controlled label applicator provides precise label placement and reduces downtime with automatic web-break, end-of-label-supply, and missing label detection. The microprocessor eliminates the need for costly add-ons. The 2330 wraparound labeler can apply pressure-sensitive labels to all types of cylindrical packaging, including glass, plastics, and metals. The machine, which can label up to 350 products per minute, allows easy integration of hot-stamp imprinters and ink-jet and thermal-transfer printers for printing batch, date, and lot code information. Willett Labeljet, 6318-C Airport Fwy., Ft. Worth, TX 76117.

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Printing plates

A wide range of photopolymer and rubber printing plates for unit dose, pharmaceutical, and medical packaging applications are available. Plates are tailored to the specific equipment and substrate used. Manufacturing is performed in a GMP environment and complies with industry standards. Quint Co., 3725-26 Castor Ave., Philadelphia, PA 19124.

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Portable label printers

Thermal printers for bar code labeling are designed with functionality and portability in mind. The Panther line consists of five models that operate in direct thermal mode and range in print width from 2 to 4 in. and in weight from 1.25 to 3.3 lb. All models meet the need for on-the-move printing and produce bar codes, text, and graphics in on-site labeling environments. The printers produce images of 203-dpi resolution. They support an RS-232 serial interface for one- or two-way communication to a terminal or other host. Other features include programmable inactivity shutoff, label odometer with on-demand terminal reporting, and removable nicad battery pack with a charge duration of 2000—3000 labels. Datamax, 4501 Parkway Commerce Blvd., Orlando, FL 32808.

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Refurbishment of Medical Devices: Patent Infringement or Permitted Repair?

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

An MD&DI  January 1998 Column


Understanding judicial precedents can help manufacturers protect their medical device patents.

As the use of remanufactured medical devices continues to increase, fueled by market demands for health-care cost containment, so too will the attention that medical device manufacturers must pay to the question of when refurbishing becomes patent infringement. Unlike the issues raised by the applicability of FDA's new quality system regulation to remanufacturers, the patent infringement issue is not new, but its importance to the device industry has been growing.1 In addition, even though the courts have long struggled with the issue of distinguishing permitted repair from infringing reconstruction, the line of where one ends and the other begins remains, at best, murky. This lack of certainty makes it difficult for manufacturers to decide how best to protect their device patents and market share in the face of competition from refurbishers. This article seeks to define the boundaries of this vexing problem by citing recent relevant case law, and, in this way, to limit the mystery and reduce the risk.


A patent gives the patent holder the exclusive right to make, use, import, and sell the patented device, or, in more rigorous terms, the right to exclude all others from doing so. The patent itself contains drawings and a detailed description of the invention, but its most important part in terms of refurbishment is the patent claims paragraphs appended to the end of the patent, which identify the components or elements that make up the protected device. Normally this list is open-ended, as indicated by a legalistic use of the term comprising. Any other device containing at least all of the listed components or elements infringes the claim; adding one or more extra elements does not avoid infringement.

Assume, for example, that a combination of a needle (element A), a syringe (element B), and a handle (element C) was a new design and hence patentable. The patent claim is not infringed unless elements A, B, and C or their equivalent can be found in the alleged infringing device. If one element is left out, then there is no direct infringement, but if A, B, and C are present along with additional elements, infringement exists.

In most cases, a problem arises when a refurbisher supplies a component or assembly of components that comprises less than all of the claimed elements of a patented invention, but that in the viewpoint of the patent holder essentially makes or completes the patented device. If the aftermarket supplier intentionally provides some of the claimed elements to another party, who then uses or combines them to complete the claimed combination, the aftermarket supplier can theoretically be held liable for contributory infringement or for inducing infringement. If taken literally, this rule would mean that sale of a replacement oil filter for an automobile could be contributory infringement if the combination of the filter and engine were the subject of a patent claim.

To counter this untoward result, the courts have developed the concept that "repair" of a claimed combination does not constitute infringement but "reconstruction" of the claimed combination does. (The historical legal path leading to this distinction is outlined in the sidebar on page 146.) Unfortunately, the line that divides repair and reconstruction is rarely very distinct. The issue becomes particularly convoluted when the repair concept is applied to medical devices where the replaced element of a claimed combination is a spent component or a disposable labeled for single use to protect patient safety.

The 1961 Supreme Court ruling that is currently being applied can be stated briefly as follows: No element of a claimed combination that in itself is not separately patented is entitled to patent monopoly, however essential that element may be to the device as a whole and no matter how costly or difficult its replacement may be. The purchase of a patented device includes a license for use that includes the right to preserve the claimed combination's fitness for use insofar as it may be affected by wear or breakage. Therefore, "maintenance of the 'use of the whole' of the patented combination through replacement of a spent, unpatented element does not constitute reconstruction" and is not an infringement.2 On the other hand, if a remarketer remakes the entire claimed invention, it is considered a reconstruction and is an infringement.


The rule delineated above would appear to provide medical device manufacturers with guidance on how to proceed into the area of remanufactured medical devices. However, some recent cases confuse the issue again.

The Mallinckrodt Case. In Mallinckrodt Inc. v. Medipart Inc., the Court of Appeals for the Federal Circuit, which is the national appellate court subservient only to the Supreme Court in patent matters, ruled on Mallinckrodt's appeal regarding infringement of a patented medical device sold to hospitals for single use only.3 Mallinckrodt supplied the device as a unitary kit consisting of a nebulizer that generated a mist of radioactive material, a manifold that directed the flow of oxygen or air containing the active substance, a filter, tubing, a mouthpiece, and a nose clip (Figure 1). The radioactive material or drug was placed in the nebulizer and atomized. The patient inhaled and exhaled through a closed system in which the patented device trapped and retained any radioactive or other toxic materials in the exhalate. The device components fit into a lead-shielded container, which was provided by Mallinckrodt to minimize exposure to radiation and to ensure safe disposal of the biohazardous materials after use.

Figure 1. Top and side elevational views (a and b, respectively) of Mallinckrodt's nebulizer device. Radioactive material is contained in chamber 82 and inhalation gas enters port 106 and is administered to the patient through port 92 after passing through filter and valve combination 90. Radioactive exhalant is absorbed by filter 90.

Mallinckrodt held five U.S. patents on various aspects of the device: one covered the overall combination, including the lead-shielded container, the nebulizer, and the manifold; another was directed to the structure of the manifold; and three were directed, respectively, to various aspects of the nebulizer.4 The device was sold inscribed with the words "SINGLE USE ONLY" and with a package insert stating "FOR SINGLE PATIENT USE ONLY." The user instructions called for disposal of the entire contaminated apparatus, and the hospitals that purchased the device were instructed to seal the used unit in the radiation-shielded container prior to proper disposal.

Some hospitals instead shipped the used manifold/nebulizer assemblies to defendant Medipart, which sterilized the devices using gamma radiation, checked the processed assemblies for damage or leakage, and then placed them in a plastic bag, together with a new filter, tubing, mouthpiece, and nose clip. The refurbished units were then resold to the hospitals. Mallinckrodt charged that Medipart was reconstructing the patented device through its reconditioning processes, while Medipart argued that sterilizing the nebulizer assemblies and replacing other minor components was merely repair. The trial court found that the single-use only restriction could not be enforced based on any patent law theory and agreed with Medipart that its activities were merely permissible repair.

After a lengthy analysis, the federal circuit court reversed the trial court as to the enforceability of the restriction on reuse and remanded the case for trial under laws governing sales, licenses, antitrust, and patent misuse. The court then turned to the issue of repair and reconstruction, finding that

Even an unconditioned sale of a patented device is subject to the prohibition against "reconstruction" of the thing patented. A purchaser's right to use a patented device does not extend to reconstructing it, . . . for reconstruction is deemed analogous to construction of a new device. However, repair is permissible. Although the rule is straightforward, its implementation is less so, for it is not always clear where the boundary line lies: how much "repair" is fair before the device is deemed reconstructed.5

In its examination of what was "fair," the appeals court found the single-use restriction to be the decisive issue between the parties. If the single-use restriction was enforceable, then, the court reasoned, even a repair constituted a license violation and an infringement of the patent since manufacture and sale of the original device was not licensed to Medipart. The court held the reconstruction-repair distinction to be decisive only when replacement is made in a structure whose original manufacture and sale had not been licensed by the patent holder. Therefore, the federal circuit court vacated the trial court's holding that reconditioning by Medipart was a permissible repair and remanded the case for trial.

The Sage Case. The unresolved Mallinckrodt case aside, most courts have generally been liberal in finding permissible repair in medical product cases. One example is the appeals case Sage Products Inc. v. Devon Industries Inc.6 Sage Products owned a patent to a sharps disposal system that consisted of an outer enclosure mounted on a wall and a cooperating, removable inner container that was an unpatented element of the claimed invention.7 The outer enclosure included an elongated slot, and the removable inner container, marked "BIOHAZARD—SINGLE USE ONLY," had an opening aligned with the slot in the outer enclosure to receive the sharps (Figure 2). When the inner container became full, it was to be removed from the outer enclosure, and Sage's literature instructed its customers to discard the filled inner container. Sage also actively campaigned against reusing the inner container, even to the point of refusing to sell to buyers who did so. Because the outer container could last indefinitely under normal use, Sage based its business upon selling replacements for the inner container, which it clearly intended to be removable and disposable.

Figure 2. Cross-sectional side view of Sage Products' sharps disposal box. Devon made an inner container to replace element 14 within the permanent container 12.

Devon, the defendant in the patent infringement case, also made and sold an inner container for use in Sage's outer enclosure. Devon did not itself manufacture an outer enclosure, which when combined with its inner container would infringe the claims of Sage's patent. Nevertheless, Sage brought suit alleging that hospitals directly infringed the claims of its patent by using Devon's replacement container with Sage's outer enclosure and that Devon was therefore liable for contributory infringement.

In Sage Products Inc. v. Devon Industries Inc., the Court of Appeals for the Federal Circuit cited the Supreme Court's opinion in the 1961 Aro Manufacturing case, which addressed the repair/refurbishment issue,2 as well as its own decisions, maintaining that the doctrine of permissible repair was not limited to temporary or minor repairs but encompassed any repair necessary for the maintenance or the use of the whole patented combination through replacement of a spent unpatented element. Sage disputed that the full inner containers were damaged, spent, used up, or in need of repair, arguing rather that since it was physically possible to reuse the inner containers, replacing them was impermissible reconstruction. Here the federal court found Sage's argument to ring hollow because of the company's notice "BIOHAZARD—SINGLE USE ONLY," which was viewed as an admission by Sage of its intention that its customers were not to reuse the inner container. Sage had also recommended that it would be prudent to replace the expendable inner container before it was completely filled. Thus, Sage was caught by its own warning message. Basically, the appellate court found that an element can be considered spent even when it is possible to reuse it. It agreed with the trial court that when it is neither practical nor feasible to continue using an element that is intended to be replaced, then that element is effectively spent. Therefore, the court found that when the inner container marketed by Sage was filled, it was effectively spent, and the user may replace it with an inner container from another supplier without infringing Sage's patent.

Sage had also argued that the patent claim did not require a "disposable" inner container but only a "removable" one; therefore, it would be possible in the future for the company to provide the patented combination with a reusable inner container and still be within the scope of the claim. The appeals court ruled that if this were in fact the case, it might have found impermissible reconstruction. However, Sage's single-use-only notice and the means by which the company marketed the inner container as disposable to ensure that customers did not reuse it persuaded the court that the facts were otherwise. The court noted that Sage also sold replacement inner containers and concluded that Sage's seeking to keep for itself the marketing of replacement parts was no more than an impermissible attempt to expand patent rights to an unpatented product. The court stated: "It is at least difficult to accept the notion that one who purchases a disposable [element of a product] under instructions to replace it [periodically] is guilty of an infringement when the buyer does precisely that."

The Kendall Case. In Kendall Co. v. Progressive Medical Technology Inc., Kendall asserted that Progressive was infringing a patent covering a medical device for applying a compressing pressure to a patient's limbs in order to increase blood flow and treat or prevent deep vein thrombosis.8 The patented combination comprised a controller/pneumatic pump for supplying pressurized fluid, a pair of pressure sleeves that wrap around a patient's limbs, and connecting tubes (Figure 3).9 Kendall intended that its customers replace the pressure sleeves after each use to avoid cross-contamination between patients and marked the replacement sleeve packaging "FOR SINGLE PATIENT USE ONLY. DO NOT REUSE." Both the plaintiff and the defendant agreed that the sleeves were intended to be replaceable since they could be contaminated by the patient's blood, body fluids, and other excretions resulting from contact with any cuts, sores, or other abrasions on the skin. The market for the replacement sleeves was substantial, representing $80 million of the $85 million in total annual sales relating to the patented device.

Figure 3. Perspective view of the Kendall system for which Progressive manufactured replacement sleeves.

After some health-care facilities had purchased replacement sleeves for the Kendall device from Progressive, Kendall sued for contributory infringement. Progressive defended based upon permissible repair. Kendall argued that the repair doctrine did not apply because the sleeves were not physically worn out when they were replaced after a single use and that they could be used repeatedly for three years or more before wearing out. The trial court found in Progressive's favor based on the concept of permissible repair, relying on the Supreme Court's decision in Aro and the federal appellate court's opinion in Sage Products to find that a hospital's replacement of pressure sleeves after a single use constituted permissible repair.

In its finding on Kendall's appeal of the trial court decision, the federal circuit court, after reviewing the decision in Sage Products, stated that:

[a]lthough, as Kendall urges, the replacement sleeves theoretically could have been used repeatedly for three years or more before they physically wore out, this practice would not have been feasible because of the risk of contamination between patients. Kendall's customers never agreed to sterilize and reuse the sleeves. Moreover, Kendall sold its [product] knowing that, to prevent contamination between successive patients, the sleeves would have to be used once and then discarded. It marked "FOR SINGLE PATIENT USE ONLY. DO NOT REUSE." on the packaging of its replacement sleeves. Kendall thus clearly intended to permit its customers to replace the sleeves after each use; its product labeling instructed them to do precisely that. Therefore, we conclude the District Court correctly held that, consistent with Sage Products, Kendall's customers' right of repair includes the right to replace the sleeves after each use.10

The court found it to be of no significance that Kendall's patent failed to describe the sleeves as disposable or for single use only, concluding that the right of repair exists regardless of what the patent holder says about the components being replaceable. The purchaser may repair or replace any unpatented component that wears out or otherwise becomes spent, whether or not the patent holder believes such replacement to be necessary. In addition, the court found such premature repair to be the business of the purchaser of the product and not the patent holder who sold it.

Unlike in the Mallinckrodt case, where a single-use restriction placed on an entire patented device was ignored by the customers, Kendall's customers followed the company's restrictive labeling and replaced the sleeves as directed, albeit not with sleeves from the patent holder. Kendall's suggestion in the product's instructions that the sleeves should be replaced only with its own sleeve-and-tubing assemblies was regarded by the appeals court as having no contractual significance; it was considered merely a recommendation for safety and efficiency, not a customer obligation.

In the final paragraph of the Kendall ruling, the court concluded that the company had made a "sky is falling" argument when it claimed that to allow Progressive to supply replacement sleeves would make it uneconomical for companies to invent and develop devices such as the one involved in this case, where much of the profit arises from the sale of replacement elements rather than from the sale of the original device. The court's response was that it was not in a position to guess whether this catastrophic result would arise from the pricing of the original device, from failure to obtain effective patent protection for the replaceable element, or from other factors. In any case, adverse economic outcome to the patent holder had never been found as a ground for overcoming established law on patent repair.


A quick review of patent law history is the easiest way to understand the repair/reconstruction dichotomy. One of the earliest American cases addressing the issue is Wilson v. Simpson, a mid-19th century Supreme Court case in which replacement of cutting knives, which had an expected lifetime of 60—90 days, was found to be permissible repair.1 In this case, the Supreme Court focused on the fact that the inventor did not intend the machine as a whole to be used without replacement of the knives at short intervals. The Court found that replacement of short-lived parts did not alter the identity of the claimed machine but preserved it even though not all components remained original.

The next important Supreme Court decision in this area was American Cotton Tie Co. v. Simmons, which dealt with a metallic tie for a cotton bale comprising the combination of a buckle and a band.2 In normal use the band was severed at the cotton mill. The defendant refurbished the band for reuse by riveting the cut ends together to form a usable tie. The Court found that this riveting constituted an impermissible reconstruction and, hence, was patent infringement. Here the inventor intended the device to be disposable and never contemplated the reuse of the tie.

Subsequent Supreme Court infringement cases fall on one side or other of the reconstruction/repair divide. For example, in Morgan Envelope Co. v. Albany Perforated Wrapping Paper Co., the Court found that manufacture and sale of toilet paper rolls for use in a claimed combination of the toilet paper roll and holder to be permissible repair.3 On the other hand, manufacture of phonograph records for use in a claimed combination of stylus and record was determined to be impermissible reconstruction in Leeds & Catlin Co. v. Victor Talking Mach. Co.4 However, sale of gelatin bands as replacement "stencils" in a machine used to print document copies was found to be permissible repair in Heyer v. Duplicator Mfg. Co.5

In their decisions, the lower appellate courts generally found replacement of soft or temporary parts, clearly intended to be replaceable by the original manufacturer, to be permissible repair. The right to repair also was extended to more durable parts, such as gears and shafts used in automobile axles, when, in the view of the court, the replacement parts did not constitute "the gist or essence of the invention."

Other appellate courts found replacement of old parts with new parts to constitute an infringement only if the new parts so "dominated the structural substance of the whole" as to justify the conclusion that the device had been made anew. On the other hand, where the original parts remaining after replacement constituted such a large part of the device as to dominate the new parts, the court would find permitted repair. To lend even more confusion to an already confused state, other lower courts also extended the right of repair to replacement parts that improved or altered the performance of the patented device. Still other cases found impermissible reconstruction when burned out light bulbs covered by Edison's patents were remanufactured by adding new carbon filaments.

Following the enactment of the current Patent Act in 1952, the Supreme Court rendered its decision in Aro Mfg. Co. v. Convertible Top Replacement, which continues to be cited as the controlling precedent on the issue of repair or refurbishment.6 The Aro case involved a patent on a convertible top mechanism for automobiles, which claimed the combination of a flexible top fabric, a supporting structure, and a sealing mechanism, all mounted on the automobile body. The convertible tops in question were replacements for cars made by General Motors, which held a license from the patent holder. Because the fabric tops typically lasted only three years, Aro Manufacturing Co. had a brisk business supplying replacements; however, Aro Manufacturing did not hold a license for the patent.

The trial court held the sale of the replacement tops to be contributory infringement. The First Circuit Court of Appeals, which reviewed the district court's judgment, affirmed it, finding that the life of the fabric is not so short, nor is the fabric so cheap, that an owner would rationally believe that replacing it was only making a minor repair. Here the appeals court applied a rule based on the preponderance of the replaced element versus the other elements of the claimed combination.

The six to three Supreme Court decision reversed both the trial court and the appellate court and found permissible repair. American Cotton Tie Co. v. Simmons and Wilson v. Simpson were cited by the Court as the continuing twin pillars of the American rule of law regarding repair versus reconstruction. The durability and expense required to replace a part or whether the part was essential were not considered relevant. Rather, the Court held that no element of a claimed combination that in itself is not separately patented is entitled to patent monopoly, however essential it may be to the combination and no matter how costly or difficult its replacement. The Court also held that purchase of a patented device includes a license for use that includes the right to preserve the claimed combination's fitness for use insofar as it may be affected by wear or breakage. The Court, therefore, held that "maintenance of the 'use of the whole' of the patented combination through replacement of a spent, unpatented element does not constitute reconstruction."


1. 50 U.S. (9 How.) 109, 13 L.Ed. 66 (1850).

2. 106 U.S. (16 Otto) 89, 27 L.Ed. 79, 1 S.Ct. 52 (1882).

3. 152 U.S. 425, 433, 38 L.Ed. 500, 14 S.Ct. 627 (1894).

4. 213 U.S. 325, 53 L.Ed. 816, 29 S.Ct. 503 (1909).

5. 263 U.S. 100, 68 L.Ed. 189, 44 S.Ct. 31 (1923).

6. 365 U.S. 336, 5 L.Ed.2d 592, 81 S.Ct. 599, 128 USPQ 354 (1961); rehearing denied, 365 U.S. 890 (1961).


Many original equipment manufacturers in the medical field are in the same position as Kendall. The most expensive part of their patented combination device is permanent and is sold for little if any profit, while the least expensive component is disposable and represents the majority of the manufacturer's profit. The lessons for these manufacturers from the recent cases are fairly clear. The older doctrines of "intent of the patentee" and "preponderance of original versus replaced parts" (see sidebar) have been swept away. If the disposable item is in itself unpatentable, its replacement when spent will most likely be found permissible repair. Such replacement could include not only single unpatented elements like the pressure sleeves for the Kendall device, but unpatentable multiple-component subassemblies such as the manifold/nebulizer assembly, filter, tubing, mouthpiece, and nose clip of the Mallinckrodt product. In addition, the decision of when to repair seems to be entirely up to the purchaser. Certainly, whenever the reuse of a component raises a risk of patient contamination, that component is deemed to be spent; various warnings by the manufacturer do not seem to influence this matter. The inclusion of single-use labeling does not prevent repair by the purchaser (although failing to warn of single-use requirements may well violate FDA rules or visit liability upon the manufacturer). The fact that a contaminated component could be sterilized and acceptable for reuse does not seem to make any difference either, since Kendall's sleeves could have been sterilized.

An obvious way around this situation seems to be use of the licensing claim cited in the Mallinckrodt case. Such a situation is rather like the marketing strategy of software vendors who never actually sell a program but merely license their software to end-users. Unfortunately, while software subject to copyright is a natural candidate for licensing, it is far from clear that an attempt to license a device for a single use will always avoid the repair problem. It also should be kept in mind that the Mallinckrodt case represented an instance where an entire patented unit was refurbished. Thus, a similar device requiring total refurbishment probably would be a good candidate for a single-use license, but it remains to be seen to what extent single-use patent licenses can be imposed unilaterally on purchasers by OEMs to avoid the refurbishment or repair defense. It will be very important for OEMs to mark such a unit appropriately and to obtain customer execution of a license agreement if possible. Failing this, a "shrink-wrap" license document should be included with the device.

Device OEMs should also consider several other ways to control disposables intended for use in patented products. One method would be to develop an agreement similar to the reagent rental technique that has been used for clinical chemistry devices. In those instances, the instrument requiring disposables is leased to the customer at a favorable rate in return for an agreement to purchase all disposables from the equipment manufacturer. This approach is probably tenable only when the cost of the device is fairly high and a large amount of disposables will be consumed.

Another step, seemingly obvious, is to obtain patent protection for the key disposable elements of a device. Frequently a manufacturer licenses a patented device from a researcher who had the original patent written to cover only the primary invention and not any potential disposables. A similar situation may arise with in-house R&D, when only the key invention is patented. It is imperative that product development personnel be involved early in the patenting process so that any novel aspects of the disposable components also can be considered for separate patent protection.

Viewing the patent infringement issue from another perspective, those manufacturers wishing to supply a disposable component for a patented device should check carefully to see if there is any patent protection covering the disposable. While "patent pending" marks may be used solely for deterrent value, they should be taken seriously before launching a major disposable supply business. Postmarket suppliers also should investigate the original devices to see if a viable single-use license exists. If it does, refurbishing an entire patented device could be considered infringement. If there is no single-use license and the disposable is clearly unpatentable, however, then current law strongly favors the replacement part manufacturer.


Medical equipment manufacturers seeking to protect their products from patent infringements involving the refurbishment or replacement of various components need to understand the principles behind recent court rulings. Although current law favors postmarket suppliers, there are steps that OEMs can take to strengthen their positions.


1. Basile EM, Quarngesser SS, "Remanufactured Devices: Ensuring Their Safety and Effectiveness," Med Dev Diag Indust, 19(1):153—166, 1997.

2. Aro Mfg. Co. v. Convertible Top Replacement, 365 U.S. 336, 5 L.Ed.2d 592, 81 S.Ct. 599, 128 USPQ 354 (1961); rehearing denied 365 U.S. 890 (1961).

3. 24 USPQ2d 1172 (CAFC 1992).

4. U.S. Pats. 4,782, 828; 4,529,003; 4,456,170; 4,251,033; and 4,116,387.

5. 24 USPQ2d at 1180.

6. 33 USPQ2d 1765 (CAFC 1995).

7. Reissue U.S. Pat. 33,413.

8. 38 USPQ2d 1917 (CAFC 1996).

9. U.S. Pat. 4,253,449.

10. 38 USPQ2d at 1921.

Daniel L. Dawes, JD, is of counsel, and Stefan Kirchanski, PhD, JD, is an associate in the firm of Graham & James LLP (Costa Mesa, CA).

Copyright ©1998 Medical Device & Diagnostic Industry

Thermal Management Techniques for Medical and Laboratory Equipment

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

An MD&DI  January 1998 Column


Choosing the right thermal control element helps ensure accurate functioning of complex electronic, imaging, and processing systems.

Equipment engineers seeking to develop faster and more accurate medical and laboratory products are beginning to recognize the importance of proper thermal management. The speed or accuracy of sensitive electronic devices such as microprocessors and lasers can be affected by thermal conditions, and cooling generally has a positive effect on equipment reliability. Chemical reaction rates are proportional to temperature, and the working time or shelf life of a biological sample or laboratory reagent can be increased by keeping the substance at an optimal temperature. Instruments such as DNA cyclers, tunable laser diodes, and thermal-stress analyzers all require a capacity for cycling an object or sample through a range of temperatures with speed and precision.

Heat sinks can be used with or without fans and offer considerable installation flexibility, but they cannot cool components below ambient temperature. Photo courtesy of Melcor Corp. (Trenton, NJ)

There are many different tools and methods for transferring heat. Which method is best depends on the temperatures and tolerances of the application. Simpler devices might function well enough with passive cooling elements such as heat sinks, while devices that operate in more demanding environments might require an active cooling method such as a compressor-based or thermoelectric system. A fan, for example, can be used to remove the heat generated inside an electronics cabinet. If the cabinet is sealed, a heat sink or heat pipe is needed. If the cabinet's temperature must be controlled, a heat pump or air conditioner is indicated. The best design will be determined by system needs and limitations. System needs would address the amount of heat to be added or removed to achieve the required temperature. Limitations might involve space, cost, allowable vibration, and available power. Once these factors are defined, the thermal engineering choices become apparent. The following is an overview of the thermal management technologies readily available to the engineer, listed from the simplest to the most sophisticated.


Fans operate by passing air over a hot component, absorbing the component's heat. Overall cooling effectiveness is determined by the air's flow rate and temperature together with the component's size and output. Typically, fans and fan trays are used in cabinets for bulk cooling of electronics. Fans and blowers are relatively inexpensive and provide a high measure of flexibility in installation. On the other hand, the constant exchange of air raises the potential for contamination from dust and moisture. Moreover, fans and blowers can prove ineffective for high-power devices and cannot cool an object at or below ambient temperature.


Generally, heat sinks are made from aluminum because of the metal's relatively high thermal conductivity and low cost. They are either extruded, stamped, bonded, cast, or machined to achieve a shape that will maximize surface area, facilitating the absorption of heat by the surrounding cooler air. Most have a fin or pin design. When used with fans (forced convection), heat sinks can dissipate large amounts of heat while keeping the targeted components at 10°—15°C above ambient temperature. Heat sinks without fans (free convection) result in a higher component temperature because of the decreased impingement of air. Like fans, heat sinks are inexpensive and offer installation flexibility but cannot cool components at or below ambient temperature. Also, heat sinks do not permit temperature control.

Thermoelectric coolers made from semiconductor pairs between ceramic plates (Melcor Corp., Trenton, NJ).


Liquid cold plates are typically made from copper, aluminum, or aluminum-clad copper tubing. Heat is absorbed by a liquid pumped through the plate, which is attached directly to the object being cooled. In an open-loop system, the liquid (usually tap water) runs through the plate and out through a drain. In a closed-loop system, a pump recirculates the liquid through a heat exchanger or radiator. Liquid cold plates are characterized by a small size (at point of attachment), and they offer effective heat dissipation. The devices are limited by the fact that they cannot cool below ambient (liquid) temperature and permit no temperature control. The potential for leakage is also a concern, and the availability of liquid sources can sometimes pose a problem.

  Cooling Method Advantages Disadvantages
Passive Fans/blowers Low cost
Installation flexibility
Potential for dust and moisture
Ineffective for high-power devices
Can't cool below ambient temperature
 Heat sinks Low cost
Installation flexibility
Can't cool below ambient temperature
No temperature control
  Liquid cold plates Small size
High heat dissipation
Can't cool below ambient temperature
No temperature control
Potential for leaks
Liquid source availability
  Heat pipes Reliability
Small size
Can't cool below ambient temperature
No temperature control
Active Compressors High cooling capacity
Can cool below ambient temperature
Allow temperature control
Maintenance/reliability concerns
Typically bulky size
Limited installation flexibility
  Thermoelectric coolers Installation flexibility
No moving parts
Can cool below ambient temperature
Allow temperature control
Offer heating capability
Compatible with heat sinks, cold plates, and heat pipes
Require dc power source

The best design will be determined by system needs, such as the amount of heat to be removed, and limitations, such as space, cost, power, and permissible vibration.


A heat pipe is a sealed vessel that transfers heat by the evaporation and condensation of an internal working fluid. Ammonia, water, acetone, or methanol are typically used, although special fluids are used for cryogenic and high-temperature applications. As heat is absorbed at the evaporator, the working fluid is vaporized, creating a pressure gradient within the heat pipe. The vapor is forced to flow to the cooler end of the pipe, where it condenses, giving up its latent heat to the ambient environment. The condensed working fluid returns to the evaporator via gravity or capillary action within the wick structure. Because heat pipes exploit the latent heat effects of the working fluid, they can be designed to keep a component near ambient conditions. Though they are most effective when the condensed fluid is working with gravity, heat pipes can work in any orientation. Using forced air at the condenser allows for larger amounts of heat dissipation. Heat pumps are typically small and highly reliable, but they can't cool objects below ambient temperature and do not permit temperature control.


Compressor-based cooling systems, found in commercial refrigerators and air conditioners, contain three fundamental parts: an evaporator, a compressor, and a condenser. In the evaporator, pressurized refrigerant is allowed to expand, boil, and evaporate, absorbing heat as it changes from a liquid to a gas. The compressor acts as the refrigerant pump and recompresses the gas to a liquid. The condenser expels the heat absorbed (along with the heat produced during compression) into the ambient environment. Compressor-based refrigeration is effective for large heat loads (300 W or more) and can cool components far below ambient temperature. The technique also allows users to control temperature. These refrigerators must be used in their designed orientation, which limits installation flexibility. Maintenance and reliability are also compromised by moving parts. Compressor-based systems also tend to be bulky and noisy.


Thermoelectric coolers (TECs) are solid-state heat pumps made from semiconductor materials. They have no moving parts but comprise a series of p-type and n-type semiconductor pairs or junctions sandwiched between ceramic plates. Heat is absorbed by electrons at the cold junction as they pass from a low energy level in a p-type element to a higher energy level in an n-type element. At the hot junction, energy is expelled to a heat sink as the electrons move from the high-energy n-type element to a low-energy p-type element. A dc power supply provides the energy to move the electrons through the system. A typical TEC will contain up to 127 junctions and can pump as much as 120 W of heat. The amount of heat pumped is proportional to the amount of current flowing through the TEC; therefore, tight temperature control (<0.01°C) is possible. By reversing the current, TECs can function as heaters, which can be useful in controlling an object in changing ambient environments or in cycling at different temperatures. Sizes range from 2 to 62 mm, and multiple TECs can be used for greater cooling. Because of the relatively large amount of heat being pumped over a small area, TECs require a heat sink to dissipate the heat into the ambient environment. The modular units can be used in any orientation and are compatible with heat sinks, cold plates, and heat pipes. On the down side, TECs require a dc power source and are more expensive than passive components.


When mounting a cooling device to a component or assembling a cooling system, designers must select a thermal bonding material that will allow heat to flow out of the device with minimal resistance. Designers should take into account mechanical stresses at the interfaces caused by differing material coefficients of thermal expansion. The idea is to eliminate any air pockets between the two surfaces.

The most common interface material is thermal grease, typically made from zinc oxide in a silicon or petroleum base. There are also pastes available with thermal conductors such as aluminum oxide and aluminum nitride. Pads and foils are less messy to apply and can be cut to match the component footprint. Some pads are available with adhesive surfaces to allow permanent attachment. Aluminum oxide and aluminum nitride are used in thermal pads, as are sheets made from graphite, indium, and aluminum.

Thermal epoxies create rigid, permanent bonds. They are typically supplied as two-part systems comprising a hardener and a resin filled with silver, aluminum, aluminum oxide, or aluminum nitride. Because they are permanent, epoxies should be used only in areas that will not require future disassembly. Rigid bonds can also be achieved using solder. Eutectic and noneutectic formulations are available for use in a wide temperature range. Soldered surfaces offer a good rigid thermal joint and can be disassembled by simply reflowing the solder. As with all rigid joints, the effects of differing thermal expansions should be considered.


High-performance electronics, sensitive imaging equipment, and sample-processing systems all require proper thermal control to ensure accuracy and functionality. Design engineers need to identify temperature-sensitive components in order to create an integrated system with parts that are both compatible and economical. They should do this early in the design process; the sooner thermal limitations are identified, the more flexibility the engineer has in choosing from the available options. In the final analysis, retrofitting thermal products is usually not as effective and economical as generating a solid thermal design from day one.

Robert Smythe is vice president of sales and marketing at Melcor Corp. (Trenton, NJ).

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