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Articles from 1999 In June

Cover Products

Cover Products

Angioplasty balloons

Advanced Polymers (Salem, NH) has expanded its lines of high-pressure angioplasty balloons to include varying diameters through the balloon; custom shapes; and tapered ends, angles, and diameters. The balloons offer good optical clarity and heat transfer characteristics.

Plastic shell connectors

Electronic connectors from Fischer Connectors (Atlanta) feature a SureGrip design for easy positive mating and unmating. The 405 series is available with up to 27 gold-plated contacts in an 18-mm-diam body.

Low-profile connectors

Brevet Inc. (Irvine, CA) manufactures large-bore disposable connectors from PVC and USP Class VI polycarbonate in a Class 100,000 cleanroom. The connectors feature a low-profile barb design with a seamless first barb and full-thread luer option.

Engineering thermoplastics

Carilon Polymers aliphatic polyketones from Shell Chemicals (Houston) exhibit natural lubricity, strength, flexibility, and resilience. The materials are available in extrusion grades and a variety of injection molding grades.

Injection-molded plastic parts

A range of injection molding services are offered by Brewster Plastics Inc. (Patterson, NJ) in its 40,000-sq-ft facility. The company provides services such as molding, engineering, assembly, and mold design, as well as secondary operations including ultrasonic welding, hot stamping, and printing.

Copyright ©1999 Medical Product Manufacturing News

Welding & Sealing Equipment

Welding & Sealing Equipment

Tube sealer

A sealer can handle PVC, EVA, and polyurethane tubing up to ½ in. OD. An RF generator ensures correct operation for all ac single-phase input voltages from 90 to 264 V ac. The generator powers the pneumatic handheld, midsized sealing head. RF power and dwell time can be controlled by computer or manually via the front panel. The sealer is suitable for closed plastic systems, including large-volume pharmaceutical processing and synthetic cell and tissue processing. SEBRA, 100 N. Tucson Blvd., Tucson, AZ 85716.

Power welder

A welder features a closed-loop ultrasonic power supply, built-in amplitude stepping, and a high-performance converter. The 2000-series is suitable for manual and automated production, with power outputs from 400 to 3300 W, frequencies of 15–40 kHz, and a 1-millisecond sampling rate. Also offered is the FS-180 ultrasonic sealer, which seals knitted, woven, and nonwoven thermoplastic materials without adhesives, chemical binders, or staples. The model features a variable-speed drive mechanism, a pneumatically activated sealing wheel arm, and a forward-angled head. Branson Ultrasonics Corp., 41 Eagle Rd., Danbury, CT 06813-1961.

Ultrasonic welders

Modular ultrasonic welders sense the reactions of the welder to the plastic parts during the process cycle, producing repeatable results regardless of minor part-dimensional variations. The Omega III MCX units have an electronic pressure regulator, an optical encoder, electronic amplitude regulation, and six-parameter monitoring along with traditional time, energy, power, height, and travel modes. Other features include an LCD screen and palm buttons. Forward Technology Industries Inc., 13500 County Rd. 6, Minneapolis, MN 55441.

Benchtop system

A compact, benchtop welding machine fuse welds balloons to catheter shafts that are composed of similar or identical materials. Features of the tubing welding machine include a PLC automated cycle, pneumatically activated heat shields, and independently controlled upper and lower welding jaws. Heat shields that fit the diameter of the shaft are provided to protect the balloon. Interface Associates, 27111 Aliso Creek Rd., Unit 180, Aliso Viejo, CA 92656.

Tip-forming machine

A tip-forming machine offers precision control and power for catheter-processing applications. A dual independent catheter-feeding system has a split pneumatic collet carriage, individual control of air pressure for each side of the tubing feeder, and adjustable pneumatic gripping of the catheter tubing. Front panel LEDs indicate overcurrent, overtemperature, and low water pressure fault status. A digital display provides load current readings, which can be utilized for process parameter verification. PlasticWeld Systems, 3690 Coomer Rd., Newfane, NY 14108.

Power supplies for welders

A company offers a variety of power supplies for plasma and TIG welding. The Plasmafix P+T power supply is fully transistorized, is programmable to 100 weld sequences, and has a welding range of 0.01–50 A for plasma welding and 0.8–50 A for TIG welding. The DT-100 weld programmer provides slopes, pulsing, added program storage, and three analog channels when integrated to the power supply. Process Welding Systems, 601 Swan Dr., Smyrna, TN 37167.

RF sealers

A company offers PLC-controlled RF sealers that automatically monitor and adjust the power settings for 360° tube seals and perimeter seals in real time. An operator interface features historically based, preprogrammed job settings; downloadable load production results; and on-screen diagnostic message capabilities. Kabar Manufacturing Corp., 140 Schmitt Blvd., Farmingdale, NY 11735.

Heat-staking press

A benchtop manually operated heat-staking press is suitable for low-volume production runs and prototyping applications. The 100-series press can perform multiple stakes and insertions on multiple planes in one cycle. Features include a 340-W tapped probe for replaceable tips and a 3 x 3-in. heated platen for custom tools. The press is equipped with six outputs and has two microprocessor-based, autotuning temperature controllers. Sonic & Thermal Technologies Inc., 84 Research Dr., Milford, CT 06460.

Ultrasonic welding system

A 15-kHz ultrasonic welding system is suitable for the joining of large parts, high-performance engineering thermoplastics, and some polyolefins. The Model 1595 can join materials at a greater distance than a 20-kHz welder because of its lower attenuation. It is available in 2500- and 4000-W configurations, and can integrate with a linear optical encoder for precise weld depth control. Sonics & Materials Inc., 53 Church Hill Rd., Newtown, CT 06470.

Assembly system

A 20-kHz assembly system is available as either a thruster system for automated assembly, or as a manual press system. The 220 features a cast aluminum frame; a nonslip, linear motion ball slide assembly; and smooth slide actuation. Other features include 500-, 1000-, 1500-, and 2000-W levels and an independent leveling plate. Dukane Corp., 2900 Dukane Dr., St. Charles, IL 60174.

RF welders

An RF heat-sealing machine manufacturer offers a range of products. Single- and multicycle RF welders can be used to produce products such as IV bags and blood bags. RF sealers and accessories come in a variety of sizes and styles designed to specifications, from 1 to 100 kW. Technicians are available to train operators and maintenance personnel. Hall Dielectric Machinery Company, Inc., 420 Bryant Blvd., Rock Hill, SC 29732.

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Copyright ©1999 Medical Product Manufacturing News

Stent-Cutting System Provides High Throughput


Stent-Cutting System Provides High Throughput

Features high-repetition-rate laser

FACTORS SUCH AS cutting speed, the degree of automation, and the time to convert a design into a cutting program all contribute to throughput in stent cutting. To address these factors, Lumonics (Kanata, ON, Canada) has added the following features to its StentCut 1000 stent-cutting system: automated tub indexing, software for quickly converting designs to cutting programs, control (System 94W/PC) that is network ready to speed transfer of stent-cutting programs to the laser cutting system, and Laser Process Manager software for documenting process conditions.

The StentCut 1000's laser is a high-repetition-rate pulsed Nd:YAG. It features electronic energy control for output stability, electronic pulse width control for accurately matching peak power and average power, and a diffuse ceramic cavity.

Lumonics provides training and service programs to support its laser cutting system. The training program covers programming, operation, and routine maintenance. Optional service-level maintenance courses are also offered.

For more information, contact Lumonics at 613/592-1460.

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Display Technology

Flat-Panel LCD Provides Space Savings and Other Benefits

The display meets worldwide regulatory requirements

ADVANCEMENTS IN LCD technology have allowed OEMs to build more-compact medical devices. The MediFlat 15 flat-panel display from Pixelink Corp. (Hudson, MA) is one such compact display. It is smaller and lighter than conventional displays. In addition, being specifically designed for the medical device industry, it meets all IEC standards, CE requirements, and FDA regulations and does not pose electromagnetic interference problems with other medical equipment.

The MediFlat 15 features a self-contained power supply, eliminating the need for a "brick" or wall-mounted power supply. Thus, OEMs need not be concerned about external components, which can get lost or disconnected from the display.

When OEMs develop their own video specifications or require the display to produce a 640 x 480-pixel image on a 1024 x 768 LCD, the resulting imaging is full of distortion and jagged edges. The MediFlat 15's custom ASIC allows for scaling of the image to eliminate such distortions. The scaling feature will not interfere with the OEM's software, and the ASIC works seamlessly with all operating systems.

OEMs use hundreds of different video resolutions and refresh rates. The MediFlat addresses these resolutions with an automatic picture setup. When the horizontal and vertical positioning is adjusted, the display automatically remembers the setting every time the monitor is turned on. Acceptable resolutions addressed are 640 x 480 up to 1024 x 768 at 75 Hz.

Other features include VESA standard mounting, autobrightness control, and optional touch screen technology.

For more information, contact Pixelink Corp., at 978/562-4803.

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Design Equipment

Stereoscopic Eyewear Allows Viewing of Complex 3-D Images

Enhances design review

MECHANICAL DESIGNERS working with complex 3-D images may be interested in CrystalEyes Wired, a stereoscopic eyewear system developed by StereoGraphics Corp. (San Rafael, CA). CrystalEyes Wired delivers high-definition Stereo3D viewing capability on Windows NT workstations in conjunction with compatible software and standard workstation displays. This accurate visualization of complex 3-D images helps reduce errors and facilitates design reviews.

A person sees with both eyes, each with a slightly different perspective, to perceive depth. Stereo3D uses computer technology to recreate this stereoscopic way of perceiving depth. The technology was developed to take advantage of the new generation of OpenGL graphics cards using the VESA three-pin mini-DIN connector. The user plugs the system's three-pin connector into a compatible graphics card, and the eyewear is automatically activated whenever a Stereo3D application is running. The technology delivers a very realistic visual representation of complex digital models, enabling engineers to throughly understand 3-D information.

For more information, contact StereoGraphics Corp. at 415/459-4500.

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Sterile Manufacturing Guide Released

The Society for Pharmaceutical and Medical Device Professionals (ISPE) has released its Sterile Manufacturing Facilities Baseline Guide, which addresses the design, construction, commissioning, and qualification of facilities designed for aseptic processing of formulated products. The guide, created to provide an interpretation of regulatory requirements, focuses on engineering issues and how to provide cost-effective facilities. For information on purchasing the guide, contact the society at 813/960-2105.

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Copyright ©1999 Medical Product Manufacturing News

Chip-Based Motion Control Improves Laser System that Corrects Farsightedness

Chip-Based Motion Control Improves Laser System that Corrects Farsightedness

When Sunrise Technologies International Inc. (Fremont, CA) developed its next-generation holmium-laser-based system to correct farsightedness, its engineers sought to automate the unit's motion control positioning. The system relies on a multiaxis positioning system to steer a laser beam to the precise cornea location and then emit laser light to alter the shape of the cornea without physically touching the eye.

Sunrise Technologies develops holmium-laser-based systems that correct ophthalmic conditions through a patented process that shrinks collagen. The company's Cornea-Sparing LTK system was designed to correct farsightedness, loss of focus due to natural aging, and overcorrection resulting from phototherapeutic keratectomy (PTK) and LASIK treatments for myopia. The system is in use in Europe and is in clinical trials in the United States.

Sunrise's previous laser correction system employed manual control of the positioning system. After exploring numerous options, the company decided to take a chip-based approach with its new LTK system and implemented the MC1401A servomotor chip set manufactured by Performance Motion Devices Inc. (PMD; Lexington, MA). By working with PMD, Sunrise was able to integrate the motion requirements onto a single card and realize a size reduction and cost savings.

By incorporating a servomotor chip set into its holmium-laser-based system to correct farsightedness, Sunrise Technologies decreased costs and simplified system maintenance.

To select the optimal motion control technology, Sunrise surveyed a variety of prospective motion solutions for the project. "We also looked at purchasing an off-the-shelf motion card," said Satish Herekar, engineering program manager at Sunrise Technologies. "However, cost was an issue, and by building our own, we were able to integrate the controller and the amplifier on a single card. In many medical applications, this high level of integration is important because it makes servicing the product simpler and reduces cabling cost." In addition, Herekar said, "by purchasing the motion ICs off the shelf, Sunrise was able to focus on the system software rather than low-level hardware development."

How the System Works

The LTK system's electronic motion system tracks eye location throughout the procedure. It incorporates 15 motors, some of which are used for driving x-y motors and others for beam shutter controls. During the procedure, the system automates the orientation of eight laser spots (which are 2.1-µm treatment beams) simultaneously.

System Requirements

Sunrise selected the MC1401A intelligent programmable chip set in part because of its ability to perform complete motion sequences, such as moving to a point using an S-curve profile or maintaining a position using position integral differentiation (PID) control. The chip set consists of a processor for profile and PID calculations and a logic device to handle motor-specific functions such as pulse width modulation (PWM). An important requirement of the LTK system was the ability to continuously track the motion platform using smooth profiles. The chip set's S-curve profiling mode met this requirement. S-curve profiling results in smoother motion by changing acceleration gradually rather than abruptly—as trapezoidal profiling does. These abrupt changes in acceleration inject oscillation-inducing energy into the components of a machine. The S-curve profile, on the other hand, reduces jerk (the rate of change in acceleration) by creating a transition between constant and zero motion. The S-curve profiles thus reduce vibration energy, resulting not only in smoother motion but also in a lower rate of component wear.

Chip Set Features

The chip set provides four axes of servo control with PWM or digital/analog (D/A)-compatible output. The motion processor consists of two ICs and is available in 1-, 2-, or 4-axis configurations. It provides trajectory generation and closed-loop digital servo control for a variety of servomotors, using incremental or absolute encoder-position feedback signals and a D/A- or PWM-compatible output drive. Axes can be programmed either independently or in synchrony to allow advanced multiaxis motion such as circular and continuous path profiles.

The MC1401A is controlled by a host processor that interfaces with the chip set via an 8-bit, bidirectional port. Communications to and from the motion processor chip set consist of packet-oriented messages.

Safety Features

The MC1401A is suitable for medical automation applications not only because it provides smooth and precise motion, but also for its safety features, such as its automatic position error rate. This feature can signal the user when certain predetermined conditions occur. Travel limit switches increase safety by automatically recognizing end-of-travel conditions on the fly. When the overtravel condition becomes active, such as during a system malfunction, the host can be automatically notified, thus limiting the potential for costly damage to the equipment.

"PMD's chip-based approach to motion control saved us a lot of space," Herekar concludes. "The MC1401A motion chip set came with example schematics and application notes that allowed us to develop a low-cost, yet powerful, motion controller relatively quickly."

Chuck Lewin, PMD's founder and president, sees great potential for the role motion processors can play in medical automation. "Until recently, many features required to reduce stability problems, such as oscillation, were available only in board-level products or top-of-the-line motion controllers. Now that's changed. Today's chip-based motion processors offer control technology and performance comparable to more expensive board-based controllers, but at a lower cost."

When designing its Cornea-Sparing LTK system, Sunrise Technologies integrated eight axes with amplifiers onto a single card.

MPMN is seeking success stories like this. If your company has one to share, please contact managing editor Karim Marouf at 11444 W. Olympic, Ste. 900, Los Angeles, CA 90064-1549; 310/445-4200 or e-mail

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Copyright ©1999 Medical Product Manufacturing News

With the help of new software, designers can simulate and retool molds before they reach production.

Simulation Solutions

With the help of new software, designers can simulate and retool molds before they reach production.

By David Bowen, MPMN Assistant Editor

C-Mold 3D Quickfill Simulates Hot- and Cold-Runner Systems

It is increasingly important for mold and part designers to be able to test the manufacturability of their designs before they reach the costly production stage. To this end, C-Mold (Louisville, KY) has created 3D Quickfill v99.7, a software application that lets them do just that, while also checking on cosmetic and structural concerns. 3D Quickfill is well suited for companies that make extensive use of CAD programs, since it works in conjunction with such solid modeling CAD systems as Cadkey, I-DEAS, Mechanical Desktop, Pro/Engineer, Solid Edge, and Unigraphics, among others. The modeling of the sprue, runners, gates, and mold cavity is done in CAD, while runner and gate design validation is done in 3D Quickfill, thus preserving the integrity of legacy data.

For mold designers, 3D Quickfill is equipped with the ability to simulate hot- and cold-runner systems, the impact of circular and noncircular gates, and a variety of mold cavity designs, including single-cavity, multicavity, and family molds. An option to assign multiplicity factors for mold cavities in order to receive multicavity simulation results from the modeling of only one cavity is also included. For part designers, 3D Quickfill is able to display sink marks on a solid model and clearly show the depth of each mark. Process engineers can use a pressure trace to inform the molder when to switch from filling the mold to packing it, how much pressure to use during packing, and when to turn the pressure off.

For more information, contact C-Mold at 502/423-4350.

Mold-Masters Debuts On-line Design Software

The conventional mold design process involves a great deal of exchange between designers and suppliers before a finished product is arrived. In an effort to speed up back-and-forth information transfer, Mold-Masters (Georgetown, ON, Canada) has introduced its Merlin on-line design wizard, which allows users to design their hot-runner systems in real time. Merlin starts with the application wizard, which lets users enter their key application parameters, such as choice of plastic material, shot weight per nozzle, system type, and gating method, by means of a database-driven interface. Users are then guided through a process of selecting the components for the system, with a list of all the components users choose always displayed on screen. Users have the option of downloading files containing detailed geometry of the components at any point in the process from their entire product catalog. Formats usable are IGES, DXF, and AutoCad 13 DWG. A catalog search engine allows searching by catalog page number, product number, product type, and system type. Technical help in laying out the various factors is available at each stage of the design process. Once the process is finished, specifications can be submitted to a Mold-Masters project engineer for verification.

For more information, contact Mold-Masters at 905/877-0185.

NC Technology a Feature of Cimatronit

The latest CAD/CAM offering from Cimatron (Givat Shmuel, Israel) provides flexible data translation, hybrid design-for-manufacturing capabilities, and the latest numerical control (NC) technology. "The software is comprehensive, which means you can do almost everything, but it's still very easy to learn how to use it," says Bernd Schrenk, design department manager of Otto Manner Co. (Bahlingen, Germany). Cimatronit is 3-D-solids based, employing a parametric and fully associative approach. Active part design features include mold expert, which produces parting lines and parting surfaces using surface and solid data, and also splits a part into core and cavity, thus creating geometric elements to design elaborate shapes.

The Mold Expert feature creates a hybrid modeling environment, which incorporates surface and solid models into a single design, while a tool set enables the creation of detailed parts. The Q Split feature takes model surfaces or solids and separates them into their core, cavity, slider, and insert components. Among the drafting capabilities are multiobject control over colors, levels, hatches, and attributes; 3-D sectional viewing, with an unlimited number of independent views; and use of TTF fonts.

Cimatron's NC machining tool operates directly on design model data, generating precise toolpaths for complex parts on the shop floor. Among its features are the templates used to define preset technology groups, intelligent roughing functionality, high-speed milling with nonuniform rational B-spline (NURBS) interpolation output and specific cutting strategies, an integrated simulator that supports up to five-axis continuous milling operations, and a verifier that performs QA checks on the entire machining process. Cimatron NC supports milling from 2.5- to 5-axis work, as well as drilling, turning, punching, and wire EDM operations.

For more information, contact Cimatron at 905/639-0802.

A Suite of Solutions Offered by PTC

The Pro/Engineer suite of solid modeling software from Parametric Technology Corp. (Waltham, MA) offers both simulation and production solutions for mold designers. For injection-molded plastic parts, the mold-filling simulation option requires the user to select the type of material and proposed gate-filling locations. What appears a few minutes later are an on-screen animation of the mold filling, a plot describing the moldability of the design, and the locations of the potential problem areas such as weld lines and air traps.

Paula Puglia, the principal plastics engineer for Digital Equipment Corp., remarks that "Amazingly, designers can take a solid model and analyze it directly—eliminating hours to days of modeling time." The simulation eliminates the need to create midplane geometry from complex solid models for accurate flow simulation, a process that is both difficult and time-consuming. If a part will not fill, the on-line adviser will recommend a fix to make it work. "The advisor portion of the software is even helpful to those designers who may not have a background in plastics," says Puglia.

For the design of mold assemblies, PTC offers a tool design option to be used in conjunction with Pro/Engineer that can create and modify complete mold and die assemblies. The user can create single or multiple mold cavities, inserts, and mold-base geometries based on design part definition, and then evaluate the parts needed using draft and thickness checks. Design part geometry can be directly referenced to create mold impression geometry. Parting surfaces and split molds can be broken down into their component geometries. Specific mold features such as sprues, runners, gates, and ejector pin holes can be created.

Other features include the simulation of the mold opening/ejection sequence with interference checking, compensation from isotropical and anisotropical shrinkage, and calculation of the fill volume and impression surface areas. The end result is a solid model of mold components that is associated with the design model and is ready for tool-path generation and detailing.

Another production option is Pro/Moldesign, which works directly with Pro/Engineer to provide impression geometry modeling capabilities to the user. This feature supports a large variety of tools for the mold designer, among them draft checking with three-color or multicolor shading and nonuniform and uniform shrinkage compensation based on both model dimensions and scaling of the model.

For more information, contact Parametric Technology Corp. at 781/398-5000.

Mold Adviser Offers Early Evaluation of Design Iterations

A suite of products using 3-D imaging allows designers to visualize and resolve potential problems early in the design phase. Mold Adviser is the latest addition to the Plastics Advisers suite of molding simulation tools by Moldflow (Lexington, MA). Designed to be used alongside the Part Adviser in the early stages of mold design, Mold Adviser is 3-D-solids based and integrated with numerous CAD programs, allowing mold designers and tool builders the opportunity to quickly evaluate every design iteration.

Part Adviser provides rapid feedback on how modifications to wall thickness, gate locations, and other design changes can affect the manufacture of a part. Mold Adviser extends the functionality of Part Adviser by allowing users to create sprues, runners, and gates for single-cavity, multicavity, and family mold layouts. The mold designer can then analyze the plastic's flow through the complete system.

For more information, contact Moldflow at 781/674-0085.

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Copyright ©1999 Medical Product Manufacturing News



Pediatric IV filters

A line of IV filters is specially designed for the needs of neonatal and pediatric patients. The AutoPrime filters feature both inlet and outlet connectors on a single plane to increase set-assembly efficiency and to ease patient stress during attachment. The filters are completely self-priming and are available in a variety of housing tint colors. The flat side of each filter can be printed with a customer logo or ID number. Whatman Arbor Tech, 401 W. Morgan Rd, Ann Arbor, MI 48108-9109.

Prefilter media

A type of prefilter media is custom manufactured using proprietary fiber conversion processes. Transorb prefilter media is available in acetate, nylon, and polyester fibers containing no resin or adhesive binders that could contaminate the filtrate. Typical applications include heat-moisture exchange, centrifugal platelet separation, and blood/mucus evacuation. The prefilter media is also used to provide membrane support and to improve membrane flow rate and life by removing coarse particulates that could cause plugging or surface binding of the membrane. Transorb can be manufactured in a wide range of cross-sectional sizes and shapes to provide consistent and cost-effective performance. Filtrona Richmond Inc., P.O. Box 34668, Richmond, VI 23234.

Air-eliminating filter

Featuring a streamlined design, a self-priming, air-eliminating filter offers high filtration performance for IV drug-delivery applications. The Gardian 3 rapidly eliminates air while providing protection from contaminants. It is available in a variety of pore sizes, including 0.2, 0.8, and 1.2 µm. The filter's Supor polyethersulfone membrane features low drug binding characteristics with more than 50 commonly infused drugs and provides bacterial and fungal retention with good throughput and flow rates. A dual-vent design allows the filter to provide position-insensitive air removal, rapid priming, and reliable fluid delivery. The filter is available in a variety of colors. Pall Medical, 600 S. Wagner Rd., Ann Arbor, MI 48103-9019.

Filter converting

A company converts membranes to filters for medical applications. Typical filter materials include Norton Zitex (porous Teflon) and Pall membrane. The company has a Class 1000 cleanroom and a temperature-controlled, low-humidity dry room for particularly sensitive medical applications. It also provides color printing, slitting, laminating, and sheeting services. G & L Precision Die Cutting Inc., 1766 Junction Ave., San Jose, CA 95112.

Filter for neonatal IV therapy

An in-line intravenous filter is designed for neonatal or ambulatory outpatient therapy. The small-diameter Microvex IV minimizes drug holdup while increasing patient comfort. The filter's sterilization-grade polyethersulfone membrane is 96-hour rated for high throughput. Its vent membrane is superhydrophobic for reliable air elimination. Millipore Corp., 80 Ashby Rd., Bedford, MA 01730-2271.

Transfer and filter devices

A complete line of transfer and filter devices for a variety of fluid-transfer applications is offered by a manufacturer of disposable medical devices. The line includes the Mini-Spike dispensing pin for preparing and dispensing diluent or additive from multidose rubber-stoppered vials. Also included is the Micro Chemo Pin with a 0.2-µm hydrophobic air-venting filter that prevents exposure to toxic fumes during drug reconstitution. Other products include filter needles, vented needles, double-ended transfer needles, air-venting filters, hydrophilic in-line cone filters, and filter hubs in a variety of configurations. Burron OEM Div., B. Braun Medical Inc., P.O. Box 4027, Bethlehem, PA 18018-0027.

IV filters

A company offers a complete line of IV filters for adult and pediatric applications. Related products include blood filters, check valves, lab and diagnostic filters, respiratory filters, vent caps, and transfer valves. The company can provide custom products if its standard products do not match the OEM's needs. The filters and devices are manufactured in Class 100,000 cleanrooms at ISO-certified manufacturing centers. Filtertek, P.O. Box 310, Hebron, IL 60034.

High-performance laminates

A company provides high-performance expanded PTFE (ePTFE) laminates for medical venting applications. The Gore-Tex laminates are readily available for incorporation into transducer protectors, IV filters and spike vents, respiratory filters, and suction canisters. The company also offers Drylife vent laminates. Suitable for urine and ostomy applications, they help retard vent blockage by discouraging the adhesion of aggressive waste material to the membrane surface. Samples of the laminates are available from the manufacturer. W.L. Gore, P.O. Box 1550, Elkton, MD 21922.

Filter screens

According to their manufacturer, filter screens etched from solid sheets of metal offer several advantages over traditional mesh screens: mechanical strength, integrity of pore size regardless of flow characteristics, high electrical conductivity, and a large choice of material types and thicknesses. Possible applications include particulate filtering, light filtering, and electronic signal (Faraday) filtering. They can also be used as implantable devices and for sensor applications. Screens are available in materials such as titanium, stainless steel, nickel, copper, aluminum, brass, and nitinol. Material thicknesses range from 0.0005 to 0.090 in. Vacco Industries, 10350 Vacco St., South El Monte, CA 91733.

Thermoplastic netting

A company manufactures thermoplastic netting for a wide range of applications. It partners with medical device manufacturers to enhance the performance, cost-effectiveness, and appearance of medical products. An area of special expertise is the extrusion of diamond-shaped netting used throughout the medical industry. Naltex, P.O. Box 17155, Austin, TX 78760.

Woven filtration materials

A supplier of precision-woven filtration materials offers a broad range of synthetic and wire cloth fabrics. Many standard weave styles and surface modification treatments are available. Materials offered include nylon, polyester, PEEK, polypropylene, polyethylene, fluorocarbons, stainless steel, and others. Mesh openings range in size from 1 to 12,500 µm. Off-the-shelf roll goods can be delivered quickly, and custom components can be cleanroom fabricated in ISO 9001–certified facilities. Medifab synthetic fabrics have been developed specifically for healthcare customers who need clean, pyrogen-controlled products. Full traceability is maintained for all woven products. Sefar America Inc., 111 Calumet St., Depew, NY 14043.

Hydrophilic filters

A company offers a complete line of filters for in-line filtration of IV solutions. The 0.22- or 1.2-µm polythersulfone membrane filters can be supplied with luer lock or luer slip connectors. These filters can be used in pediatric patient infusions, epidural procedures, and lipid filtration. All have high flow rates, low drug binding, and microbial retention. DirectMed Inc., 74 Valentine St., Glen Cove, NY 11542.

Bacterial viral filter

Made of polystyrene, a single-use bacterial viral filter is designed for use with lung-function testing equipment. The filter protects the patient and the equipment during testing. Cross-contamination risks for the patient are minimal, while the protection of the equipment shortens time spent disassembling and cleaning the test unit. The combination of the filter and the mouthpiece in one eliminates the need for separate mouthpieces and reduces the cost of the product. Qosina, 150-Q Executive Dr., Edgewood, NY 11717.

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Copyright ©1999 Medical Product Manufacturing News

The More Things Change...MD&DI Builds on a Mission Set 20 Years Ago

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

An MD&DI June 1999 Column

On MD&DI's 20th anniversary, a review of the magazine's first editorial reveals that although the cutting edge is always advancing, the overriding goal remains unchanged.

The passage that follows—which appeared on the "Publisher's Page" under the title "A New Avenue of Communication" in June 1979—represents the first editorial item published in the first issue of Medical Device & Diagnostic Industry. As one reads it again, two things stand out. The first is that the "complexity and sophistication" of devices and the "prodigious growth" of the industry celebrated in the essay have been multiplied many times over in the intervening 20 years, amid unimagined technological change. The second is that the essential mission of the magazine—the "timely dissemination of knowledge"—and the importance of input from our readers remain absolutely the same.—J.K.

"The medical device and diagnostic industry is, in the final analysis, an intricate network, a vast reticulum of individuals—biologists, chemists, engineers, researchers, and technicians—with widely divergent areas of specialization and expertise. The products for which these individuals share responsibility are equally disparate, ranging from surgical implants to cardiac pacemakers, from limb prostheses to chemical reagents, from catheters to CT scanners.

"Were an informal poll to be conducted among industry members, however, few would dispute that the key watchword in the area of devices and diagnostics—that is to say, the word that best encapsulates the character and nature of the industry—is progress.

"Within the past decade, for example, artificial implants and electronic diagnostic and therapeutic devices have assumed such prominence and reached such a high level of complexity and sophistication that they have created new subdisciplines and areas of specialization in the allied healthcare field.

"Paralleling this dramatic increase in the complexity of devices and diagnostics has, of course, been a concomitant rise in productivity and in demand. Growth in the industry, then, has meant fast-paced technological innovation, increased productivity, and further product diversification.

"As would be the case in any industry, this prodigious growth has created new areas of concern for virtually all professionals involved in device and diagnostic manufacturing. For rapid technological advances are inevitably accompanied by a growing need for new avenues of communication and new means by which industry members can share and exchange ideas pertinent to their field. Promulgation of the device GMPs has added a further dimension to these areas of concern, as manufacturers strive to determine the precise manner in which the new regulations will affect their products and processes.

"It is in this arena of growth, of expansion, that Medical Device & Diagnostic Industry—the first magazine devoted exclusively to the needs and interests of device and diagnostic manufacturing professionals—makes its debut. Recognizing that its readers require timely dissemination of knowledge in this era of rapid change, Medical Device & Diagnostic Industry will take a pragmatic approach to advances, developments, and techniques. How-to articles will focus on applied technologies; monthly features will keep readers informed of regulatory trends, upcoming scientific and technical meetings, symposia and seminars, new product information, and industry news. It will be a source of facts, ideas, insights, and alerts—information that can be adapted, adopted, and used. Toward that end, we invite your comments and suggestions regarding topics pertinent to your interests.

"In short, this is your magazine—and in order to best serve your needs, we need to know what you want to know."

Jon Katz

Copyright ©1999 Medical Device & Diagnostic Industry

Twenty Candles for the Past, Some Thoughts for the Future

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

An MD&DI June 1999 Column

This column is normally dedicated to profiling an author or otherwise expanding upon information presented in the current issue. In putting together the 20th anniversary issue of the magazine, we sought out contributors who had a long history with the publication. Two of our authors, in fact, were included in the inaugural June 1979 issue, while one, columnist James G. Dickinson, has contributed to every issue (see Washington Wrap-up for some of his reminiscences about the early days of MD&DI).

Given the unusual circumstances of this very special occasion, I thought we might depart from the standard format of Inside MD&DI and talk about a few things that don't appear elsewhere in the issue. For example, during the preparation of the 20th anniversary timeline that begins on page 108, we were acutely aware that space and layout constraints meant we would necessarily leave out important events. Deciding between synthetic human insulin and cyclosporine, between toxic-shock syndrome and Voyager I, or between interferon and the big-bang theory are by definition judgment calls, subject to disagreement. Our readers will undoubtedly suggest alternative events and hierarchies of importance.

Additional information that didn't make it into the 20th anniversary section but nevertheless influenced our thinking about the issue came in the form of survey responses from MD&DI's editorial advisory and reader boards. We posed two questions related to the magazine's milestone: "What do you consider to be the most important developments in the medical device industry over the past 20 years?" and "What do you think the most important developments in the medical device industry will be over the next 20 years?"

The answers to the first question tended to fall into the areas of advances in technology, regulatory initiatives, and general business trends. Technological developments cited include new forms of imaging, minimally invasive surgical procedures, noninvasive diagnostic techniques, biodegradable implant materials and other novel polymers, implantable defibrillators and transplant-assist devices, medical lasers, device miniaturization, and embedded microprocessors.

In the regulatory arena, one respondent named "the Kessler FDA"; others listed design controls, the movement toward ISO standards and internationally harmonized regulations, GMPs and the QSR revision, FDAMA, and "the change in climate from open to restrictive to open once again." The most frequently cited general business factor was the globalization of the industry and the development of a world market.

Turning to the future, MD&DI board members predict breakthroughs in tissue engineering and organ-replacement techniques, gene-modification therapies, artificial blood, drug delivery modalities, custom-designed implants, and "smart" microdevices, among others. The picture is not entirely rosy: one respondent anticipates a host of "new diseases—for example, viruses, prions, and mutant micro-organisms resistant to conventional sterilization methods such as irradiation."

Regarding regulatory and industry concerns, along with expected benefits from continued global harmonization there are worries about increased federal oversight, the disappearance of small companies in a merger-dominated climate, and "the subversion of medical decisions by financial decisions."

Will the device industry in 2019 be anything like we imagine? Prophecy is a notoriously tough business, and not all birthday wishes come true. Whatever happens, as MD&DI blows out the candles on its first 20 years, we want to thank all those—authors, reviewers, board members, readers—who brought so much hard work, insight, and liveliness to the ongoing party.

Copyright ©1999 Medical Device & Diagnostic Industry

Human Factors and the Future of Telemedicine

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

An MD&DI June 1999 Column

A human factors specialist describes how human factors engineering can play a positive role in the development of telemedicine.

Telemedicine will be an important component in the healthcare delivery system of the future because it addresses three significant and persistent problems in the delivery of medical care:

  • The uneven geographic distribution of medical resources, including facilities and professional personnel.
  • Inadequate access to medical resources and expertise by certain segments of the population.
  • Continuing increases in the cost of medical care despite new business models and dramatic cost-cutting programs.

Through the use of telecommunications technologies and computer networking, telemedicine extends the reach of medical personnel over geographic areas and improves access to medical care. One impact of telemedicine will be to democratize the future of medicine. In effect, telemedicine will facilitate the involvement of patients in their own health and medical care to an extent never before imagined. The advent of high-definition television, broad bandwidth, high-speed transmission rates, and reliable low-cost devices for collecting biodata in the home will allow medical professionals to conduct triage, diagnostic consultations, and remote follow-up treatment with patients, as well as provide guidance to home caregivers. Interactive communications will allow patients and care providers access to information, advice, and guidance to improve home-based care.

The danger, however, is that the potential benefits of telemedicine could be lost if the users—professional and, especially, nonprofessional—cannot easily and effectively use such systems to meet their needs. The discipline of human factors and ergonomics can play an important role in making telemedicine a successful part of the medical industry.


Human factors focuses on system usability and designing system interfaces to optimize the users' ability to accomplish their tasks error-free in a reasonable time and, therefore, to accept the system as a useful tool. The discipline is rooted in understanding how people use tools, products, and systems to accomplish desired tasks, and it seeks to eliminate or, at least, manage the human errors that sometimes do occur.

Human factors engineering is an applied science that takes research about human abilities, limitations, behaviors, and processes and uses this knowledge as a basis for the design of tools, products, and systems. Applying human factors principles leads to designs that are safer, more acceptable, more comfortable, and more effective for accomplishing their given tasks.

Human factors engineering is often considered synonymous with other terms such as ergonomics, human engineering, human factors, usability engineering, and user-centered design. It is a multidisciplinary field in which individuals trained in human factors come from such diverse backgrounds as engineering, psychology, computer science, anthropology, and informational sciences. Specialists apply findings and principles from a range of disciplines including cognitive psychology, organizational psychology, industrial engineering, anthropometrics, biomechanics, motor skills, perception, and specific engineering areas such as vibration and noise.

Medicine is clearly an industry in which life and death can hang in the balance, and the consequences of a misadventure can be fatal. Since the 1980s, user-centered design has become recognized as a valuable approach to medical device design. From the late 1980s through the 1990s, several events reflected the growing importance of human factors and usability to medicine. The first was the development in 1988 of the guidelines for designing medical devices titled "Human Factors Engineering and Guidelines and Preferred Practices for the Design of Medical Devices" (ANSI/AAMI HE48–1993). It was revised in 1993 and under revision again in 1998. In 1996, FDA's Center for Devices and Radiological Health published a primer titled Do It By Design: An Introduction to Human Factors in Medical Devices to provide industry designers and developers with an overview of human factors, its perspective and techniques, and how it applies to their efforts. This publication was timed to coincide with the changes in CFR 21 (Food and Drugs) section 820, Good Manufacturing Practice for Medical Devices, regarding the incorporation of "design controls for intended use." These design controls refer to the documented process for ensuring that medical devices can be used as intended by the defined audience. Implementing usability test and evaluation techniques is an important approach to fulfilling this requirement.


A critical hurdle must be overcome if telemedicine is to have an impact on the medical industry. The products and systems, processes, and procedures that make up telemedicine must be usable. The degree to which telemedicine's components are usable will either inhibit or facilitate its acceptance, use, and growth and its effectiveness as a model for medical care provision. Poor usability could at a minimum retard the growth of telemedicine and drastically reduce acceptance of telemedical technologies.

Poor usability has already had a negative effect on acceptance of these technologies by some medical professionals. Human factors is a key discipline for addressing interface design, human-system interaction, user performance, and usability. Moreover, human factors is the primary discipline for reducing and managing human error and its consequences, particularly for systems that require decision making and complex cognitive activities. The addition of nonprofessionals to the ranks of users will amplify the role of human factors in facilitating interaction in telemedical areas. This large audience will be less educated and less sophisticated than practitioners and will include a wide range of capabilities and limitations. As John W. Gosbee, director of the Center for Applied Medical Informatics at Michigan State University, has pointed out, human factors will contribute to the design and development of telemedicine systems in many ways.1

Video-Based Behavior and Communications. The use of video-mediated channels will require human factors specialists to address issues relating to communicating. Communication and interpretation over such media can differ greatly from face-to-face conversations. Understanding the effect on users and information exchange will be critical to telemedicine's acceptance.

Needs Analysis for a Broad Audience. When designing a telemedicine system, it is crucial to conduct a needs analysis to define the types of users, which will range from medical professionals to the patients. These audience definitions are critical to design and evaluation activities. Knowing who the users are and how they intend to use the system is invaluable for ensuring that the system acts and reacts the way each user expects it to. Another key aspect of the needs analysis is to understand specifically what users want the system to do. This particular task analysis will define the nature of the functions and their allocation within the system.

Designing Systems and Components. Human factors specialists apply a user-centered perspective to designing hardware, software, procedures, and interfaces. This perspective and process complements those of engineering and programming disciplines by ensuring that the user rather than the technology remains the focal point of the system. Design considerations range from the physical (biomechanics, anthropometrics) to the perceptual (audition, vision) to the cognitive (decision making, memory load, verbal comprehension). For telemedicine to be successful, usability must be addressed as early as possible in the design.

Choosing among Competing Systems and Components. Benchmarking the usability of a system is important for evaluating its effectiveness, but competitive usability testing is also a powerful approach to selecting the best systems and components. Head-to-head tests and evaluations ensure that usability is given equal weight as functionality at the design stage.

Identifying Good Candidate Applications for Telemedicine. The emergence of certain fields amenable to telemedicine —such as teleradiology, teledermatology, teleoncology, and telediagnostics—has represented selection based on the existence or development of technologies supporting that field. Selecting appropriate candidates for telemedicine applications for the more general user population will not be as straightforward. Human factors specialists must employ observational and requirements-gathering techniques to assist medical professionals in identifying and defining candidate activities. Techniques may range from surveys or interviews to ethnographic techniques of field observation. For example, should people be allowed to perform minor medical procedures such as drawing blood for analysis (even if the technology would allow home analysis)? Another question might be whether activities such as hospice-related counseling are viable through telemedicine channels.

Designing Interfaces for TV Use. It is important that the links and equipment for home-based systems demonstrate very good usability. Moreover, for most home users, the less computer based a system is, the better. For this reason, and with the technology on the foreseeable horizon, the more that telemedical functionality can be channeled through television, the more accessible and usable it will be. It will be critical to design TV interfaces to provide functionality through on-screen menus and set-top-box technology.

Designing Home Medical Devices and Protocols. Because capabilities and limitations vary widely for general users, home-use devices need to be designed to be simple, safe, and extremely usable. Devices must be designed to be nonthreatening and to inhibit, if not prohibit, incorrect or unsafe use. Over time, many such devices could enable biodata to be collected by home-care providers or medical professionals who visit periodically. Device hardware, software, documentation, and training should be designed for the lowest reasonably defined level of skill and ability.

Test and Evaluation of Applications and Components. Devices, systems, products, applications, documentation, and training all need careful scrutiny. Human factors specialists must test all components of a system to ensure that it meets the intended use provisions of the FDA regulations. Such systems will require test protocols for data collection and analysis to ensure the usability and safety of components. They will also require measures and measurement systems for assessing the usability and efficacy of telemedicine services and functions.


Although there are still issues to address, the need for an alternative operational and business model for medicine as well as the drive to democratize medicine will accelerate the development of telemedicine. More importantly, we must recognize that telemedicine systems must be designed and implemented to include the general population of care providers, patients, and other users. This means that telemedical systems, products, tools, functions, and interfaces must be usable as well as useful. Usability will play a critical role in the acceptance and efficacy of telemedicine applications. Human factors as a discipline can and will play an important role in ensuring that the user remains central to the design of a system and that usability is designed into the system and verified and validated through test and evaluation.


1.John W Gosbee, The White Paper on Human Factors Engineering and Telemedicine, for the Focus Group on Clinician Acceptance Issues in Telemedicine Systems (Kalamazoo, MI: Federal Office of Rural Health Policy, Center for Applied Medical Informatics, Michigan State University, 1995).

Barry H. Beith, PhD, is vice president of Monterey Technologies Inc. (Cary, NC). [Online Update, April 2000: Dr. Beith is now president of HumanCentric Technologies Inc.]

Copyright ©1999 Medical Device & Diagnostic Industry

EtO Compatibility—and More

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

An MD&DI June 1999 Column


James M. Gibson, Jr., a sterilization consultant with J. M. Gibson Associates (Odessa, FL), provides information on humidity as it relates to sterilization and discusses the compatibility of Oxyifume 2000 (AlliedSignal, Morristown, NJ).

Why is humidity an important factor in EtO sterilization, and what would happen if there was no humidity?

Historical studies of the death kinetics of EtO sterilization have demonstrated that a relative humidity of 35 to 90% is necessary for effective sterilization. The upper limit has been debated. Humidity is thought to contribute to the penetration of EtO, particularly through the cell walls of microorganisms. Lack of humidity or insufficient time to allow the adequate penetration of humidity can result in an inability to sterilize the products.

How can humidity inside the chamber be measured during the sterilization process? Who are some manufacturers of gas units that can be fixed inside the chambers?

For processes that do not employ parametric release, humidity measurements are typically judged by a rise in pressure after steam injection. Relative humidity can be calculated from steam tables using the chamber temperature and pressure.

A number of companies manufacture electronic sensors for measuring humidity in EtO chambers. They include Phys-Chem (New York City), General Eastern (Woburn, MA), and Vaisala (Woburn, MA), to name only a few. These sensors are hardwired, and some are not intrinsically safe for operation when EtO is present. Degradation of sensor accuracy requires constant verification of the calibration.

There are also self-contained data-logging units that will record temperature and humidity during the cycles. These units have no wires to the chamber's exterior and are small enough to fit into many primary packages. Two suppliers of this type of unit are Sensitech (Beverly, MA) and Datatrace (Lakewood, CO). Such units can also be used exterior to the product loads in the chamber.

Is Oxyifume 2000 compatible with the various types of materials and devices usually sterilized by 100% EtO or CFCs/EtO 88/12?

There have been a few anecdotal stories of plastic components cracking or crazing following exposure to the new HCFC/EtO gas mixtures, as well as the 88/12 CFC/EtO mixture. In many cases, these problems were traced to manufacturing stresses that were relieved by the CFC in the mixture. In general, the conversion to the new HCFC/EtO mixtures seems to have proceeded without problems. However, exposure of materials to a new chemical in sterilant gas mixtures should be thoroughly evaluated. It is typical to expose samples to maximum sterilization conditions—in other words, the highest gas concentration, highest temperature, and longest exposure time.

Susan Edel Satter of Satter & Associates Inc. (Boulder, CO) has coauthored several articles on EtO sterilization for MD&DI in the past year.

What's the compatibility of polyamide materials (nylon)—particularly Zytel 408HS and RTP 225Z—and EtO sterilization?

Nylons are polyamides because of the characteristic amide groups in the backbone chain. Zytel 408H and RTP 225Z are both referred to as nylon 6/6 because each unit of the polymer chain has two six-atom stretches of carbon atoms. Nylon 6 has only one carbon chain of six atoms.

DuPont Engineering Polymers (800/ 441-0575) was contacted for information on Zytel 408HS NC010, both conditioned and dry, but information was unavailable regarding its compatibility with various EtO processes. RTP Co. (800/433-4797) was contacted for information on RTP 225Z. The RTP representative said that this formulation should be EtO compatible but that testing would have to be done to prove it. While nylon is generally considered to be compatible with EtO processes, specific compatibility must be determined after exposing the finished product to the specific EtO cycle intended for routine use. A careful examination of EtO residuals must also be completed. Nylon absorbs low levels of EtO but is slow to desorb it; therefore, the length of desorption time must also be determined.

Is it true that products sterilized by gamma radiation should not be resterilized with EtO because of potential toxic byproducts?

Different product and packaging materials have been successfully validated for both radiation and EtO gas sterilization. However, exposing some materials to EtO after radiation can result in toxic byproducts. Manufacturers of finished devices must determine each product's biocompatibility based on its intended use after being subjected to a full sterilization process, which may include radiation processing followed by one or more EtO processes. In all cases, the product must be validated for materials compatibility, functional efficacy, and biocompatibility following the complete sterilization cycle intended for routine use.

"Help Desk" solicits questions about the design, manufacture, regulation, and sale of medical products and refers them to appropriate experts in the field. A list of topics previously covered can be found in our Help Desk Archives. Send questions to Help Desk, MD&DI, 11444 W. Olympic Blvd., Ste. 900, Los Angeles, CA 90064, fax 310/445-4299, e-mail You can also use our on-line query form.

Although every effort is made to ensure the accuracy of this column, neither the experts nor the editors can guarantee the accuracy of the solutions offered. They also cannot ensure that the proposed answers will work in every situation.

Readers are also encouraged to send comments on the published questions and answers.

Copyright ©1999 Medical Device & Diagnostic Industry