Permanent Antibacterial Coating Suited for Device Use

Permanent Antibacterial Coating Suited for Device Use

A polymer coating that adheres permanently to a variety of surfaces uses a powerful electrochemical action to kill some common bacteria that cause serious infections. Developed at Massachusetts Institute of Technology (Cambridge, MA; www.mit.edu), the hexyl-PVP compound has an intrinsic positive charge that destroys the cell walls and membranes of Staphylococcus, Pseudomonas, and E. coli. This kill mechanism makes it unlikely that bacteria could develop a tolerance, a problem for some antibiotic coatings. But the main benefit of hexyl-PVP is permanency. "Antibacterial agents that use a positive charge are not new," says Tony Dallmeyer, director of microbiology for Surmodics Inc. (Eden Prairie, MN; www.surmodics.com), an antibacterial coating company. "What makes this advance unique is that the scientists have been able to instill these qualities permanently in a solid surface coating." Hexyl-PVP attaches chemically so it can't be washed away. The compound is suited for incorporation into the manufacturing processes of many devices, including surgical instruments. According to the research team, the only required maintenance is periodic washing to remove dead bacteria.

Initial testing has demonstrated this coating to be very effective. Published in the May 22, 2001, Proceedings of the National Academy of Sciences, these results show that hexyl-PVP kills 94–99% of Staphylococcus and a consistent 99% of Pseudomonas and E. coli. The material was tested by spraying coated slides with a concentrated solution of these bacteria to simulate the effects of coughing or sneezing. The material was also successfully tested for human toxicity using mouse cells. Though the MIT researchers hold a patent on the coating and are performing further testing, they are not currently involved in any effort to bring this technology to market.

Zachary Turke

Internet Update

Internet Update

Materials Media Guide Available On-Line

www.pall.com

A supplier of porous material design, development, and production services has made its specialty materials catalog available on its Web site. Located at www.pall.com, Pall Corp.'s catalog is organized by industry and then broken down into four sections based on product application. For the medical device industry, the site offers information on a range of hydrophilic and hydrophobic materials that can be used in venting, wound healing, and drug delivery applications. A standard line of materials detailed in the guide is designed to help users implement cost-effective production solutions. Customized materials are also offered. Other features on the company's site include a free on-line newsletter, customer support information, a list of services provided, and technical resources.

Sealing Solution Web Site Launched

www.expresseal.com

A supplier of sealing solutions has introduced a Web site providing information on its computerized manufacturing technology. The technology enables Expresseal to produce seals including U-cups, wipers, piston rings, bushings, bearings, packings, O-rings, prototypes, and custom seals and shapes. The site, www.expresseal.com, gives details on a variety of seal materials such as polyurethane, Teflon, Viton, Buna N, and ethylene propylene. Users can learn about the availability of seals in a variety of standard profiles that meet customer specifications from 0.25 in. ID up to 10 in. OD. Color illustrations of available profiles are provided, including rod, piston, guide, backup, shaft wiper, and O-ring seals; all are accessible from a drop-down menu on the home page. The company's design engineering, manufacturing, and prototyping capabilities are also covered.

3-D Models of Jig and Fixture Components Viewable On-Line

www.jergensinc.com

A company Web site offers 3-D models of its standard jig and fixture components. The models are available free of charge at Jergens Inc.'s Web site, www.jergensinc.com. Presented in Step and Solid Works formats, the models can be used with many CAD packages including Catia, Pro/Engineer, Unigraphics Solutions, and Cadkey. Files are continuously updated with engineering changes and improvements. Also available is FixturePro fixture component software, which is also free and can be obtained on a CD or by downloading from the site. The FixturePro software part library includes 2-D drawing and 3-D wire frame versions in dwg, dxf, and iges formats. Jergens's fixture components include thousands of items used for work holding, positioning, and fixture construction, including hoist rings, drill brushings, handwheels, knobs and handles, clamps, and threaded inserts.

Katherine Sweeny

In Brief

In Brief

Two Ann Arbor, MI–based companies, Think & Do Software (www.thinkndo.com) and Steeplechase Software (www.steeplechase.com), have merged to form the PC-based automation and control division of Entivity Inc. (Ann Arbor, MI; www.entivity.com). The company was created to assist OEMs design, deploy, and utilize manufacturing and distribution systems....Precise Technology Inc. (North Versailles, PA; www.precisetech.com) was recently designated as a STAR safety facility by OSHA. The company provides product design, product engineering, injection molding, mold building, and contract manufacturing services....Boston Scientific Corp. (Natick, MA; www.bsci.com) has named Memry Corp. (Brookfield, CT; www.memry.com) as its strategic metal supplier for the next five years. Memry Corp. will supply nitinol tubing and wire and general wire applications to the company, as well as take on a primary vendor role for its coiling and value-added projects....GE Medical Systems (Milwaukee, WI; www.gemedicalsystems.com) has selected International Flex Technologies, div. of Sheldahl (Endicott, NY; www.internationalflex.com) as its 2000 Supplier of the Year for Quality for outstanding customer service. It has also chosen Dynarad Corp. (Deer Park, NY; www.dynaradcorp.com) as the winner of its 2000 Delivery Achievement Award for outstanding delivery performance....Outsourcing Group Inc. (Allendale, NJ) and Dermal Sciences Inc. (Fairfield, CT; www.dermalsciences.com) have entered a joint venture under which Outsourcing Group will provide the resources to rapidly scale up Dermal Sciences' capabilities for the coating and packaging of nonwoven products....Tekra Corp. (New Berlin, WI; www.tekra.com) has been named the exclusive North American supplier of polyester films for the medical diagnostic market by DuPont Teijin Films' (Wilmington, DE; www.dupont.com). Tekra Corp. is an international distributor and manufacturer of engineered plastic films, adhesive products, and advanced hardcoated films....Panasonic Industrial/Medical Group (Secaucus, NJ; www.panasonic.com/vsg) has changed its name to Panasonic Vision Systems Group/OEM to more clearly define its end-user and OEM applications. The company produces CCD cameras, digital and analog video recorders, and monitors....American Ultraviolet Co. (Lebanon, IN; www.americanultraviolet.com) and UV Source (Torrance, CA; www.uvsource.com) have merged and will continue to provide UV applications to healthcare and pharmaceutical industries.

Katherine Sweeny

Copyright ©2001 Medical Product Manufacturing News

Machining Equipment Suppliers Focus on Production Efficiency

Originally Published MPMN July/August 2001

EQUIPMENT NEWS: Machining Equipment

Machining Equipment Suppliers Focus on Production Efficiency

Machines offer quick changeover and precise cutting of a variety of materials

Used in a range of operations from prototyping to metal finishing, machining equipment is an integral part of the manufacturing process. To provide cost-effective solutions to manufacturers, equipment suppliers have developed machines that increase productivity and speed while maintaining quality levels. Following is a sampling of machining equipment suitable for medical device manufacturing.

YCI Supermax's FV105A has a powerful spindle for high-production applications.

A midsize vertical machining center that attains speeds of 20,000 rpm and has a 30-hp spindle can perform rough cutting and finished cutting from the same spindle. Supplied by YCI Supermax, the FV105A's rapid cutting and feeding rates, combined with its powerful spindle, allow cutting of a range of materials from aluminum to titanium. In addition, the center's speed and versatility result in very short cycle times. The x- and y-axes incorporate THK NR linear guide ways, while the z-axis features hardened and ground box ways. Standard features include oil and air-mist spindle bearing lubrication, an alphanumeric keyboard, a spindle and cutting air blast system, full chips and coolant guards, and a swivel control panel for easy operation. The center has a 40 x 20 x 24-in work envelope and a wide saddle and machine base. The center is made from Meehanite casting and has a rigid body construction. Preloaded ball screws are coupled to the servomotors for increased reliability.

Like the FV105A, the FV102A is a vertical machining center made from Meehanite casting and also includes ball screws attached to servomotors. Both systems have a 24-tool swing arm ATC system that optimizes production flow and efficiency, features a bidirectional random access tool magazine, and provides ±0.00016-in. accuracy with ±0.00008-in. repeatability. The FV102A's unique feature is an automatic pallet changer (APC). The APC utilizes a high-speed servo-driven mechanism that completes a cycle in 12 seconds, reducing machine idle time and increasing productivity. The operator is able to load, unload, inspect parts, and set up jobs while an alternate pallet is in the machine.

Surface grinder is suitable for fragile, thermosensitive materials

A precision surface grinder can machine hard materials such as tungsten carbide, cobalt-chrome, titanium, and stainless steel, and provides cool, burr-free grinding on many conductive materials. The Model EG618 from Everite Machine Products produces low cutting forces, which allow deep cuts to be achieved on thin, fragile materials without a heat-affected zone, a recast layer, or metallurgical damage to the workpiece. Accessories include a fully enclosed splash guard, a nickel-plated cast-iron table, vertical and cross-feed handwheels, and an automatic one-shot way-lube system. A digital readout and a table drive system are some of the available options. The electrolytic grinding spindle has integral brush rigging, a 300–1000-A capacity, and wheel guards and wheel adapters measuring up to 10 in. diam and 7 in. wide. The electrolyte supply system includes a pump, tank, filtration system, and mist collector, as well as a variety of nozzles for optimum electrolyte flow. Tubing and cannulae, arthroscopic and laproscopic instruments, and implant devices are among the components that can be machined using this system.

Short-wavelength lasers provide high-resolution features

A 0.675-mm-thick silicon wafer was machined by the PowerGator 532-15, supplied by Lambda Physik.

An industrial-grade diode-pumped solid-state laser delivers more than 13.5 W average power and up to 50 GW/sq cm peak-power intensity. Available from Lambda Physik, the PowerGator 532-15 microfabricates high-aspect-ratio features in hard materials that are more than 1 mm thick. Short 15-nanosecond pulses and green 532-nm wavelengths improve plasma penetration and reduce heat-induced effects, microcracking, and redeposition of material. These features yield higher quality surfaces than longer-pulse green, UV, and IR systems, according to the firm, and the unit's beam quality allows processing of feature sizes smaller than 20 µm. The PowerGator 532-15 has an MTBF rating of between 10,000 and 20,000 hours, and it is suited for processing ceramics, silicon, and metal alloys.

Photomachining Inc.'s roll-to-roll laser tool is also suitable for thermal-free cutting and scoring of plastics, metals, ceramics, and other materials. A frequency tripled Nd:YAG laser is used to pattern gold film and to completely cut though several plastic substrates. The laser emits photons at a 355-nm wavelength, in the ultraviolet portion of the spectrum. Short pulse lengths allow clean material removal and produce high-resolution features. The laser can be pulsed at a 100-kHz repetition rate and the beam can be delivered through a galvanometer-based system. The roll- to-roll system enables beam rastering at high speeds over a 12-in. scanfield with a <40-µm spot on target. Indium tin oxide, metal films, and other films can be removed to create simple or complex patterns that are easily generated on AutoCAD and directly downloaded to the laser tool in DXF or DXG formats. The system's reliability and low operating costs makes it suited for the production of disposable medical parts.

Self-contained systems offer hands-off machining

Designed to machine small parts at high speeds, a precision machining center has a 1 x 1.5-m footprint. Mikron Bostomatic's Model 12 can be equipped with a compact robotic part and tool loader for unmanned machining. The robot can feed as many as 48 cutters and 90 workpieces and can be configured to support EROWA, System 3R, and Mecatool tooling. A 30,000-rpm spindle increases roughing capability. The model has a 13 x 10 x 10-in. working cube and can precisely machine graphite, copper, and steel. Capable of 600 in./min 3-D contouring feed rates and 1-G accelerations, the Model 12 provides ±0.000075-in. accuracy and comes with 0.5-µm glass scales. Options include a sealed dust-removal system for graphite machining, mist lubrication for metal cutting and automatic tool measurement probing, a compact fourth axis, and a laser tool-setting system. Typical applications include production of graphite or copper electrodes, engraving, hard-die milling, and small medical component machining. The company's motion control technology ensures path accuracy for tight tolerances at high feed rates. New CNC features include fast microprocessors and software, large hard drives, a new flat-panel display, 3-D cutter compensation, advanced tool measurement, and a remote alert system.

A self-contained system, the SL-3020 from Online Inc. is suited for R&D labs or production use.

A self-contained laser system has the capability to mark and cut hundreds of different materials. The SL-3020 from Online Inc. has a 30 x 20 x 12-in. work area. An autofocus feature sets the laser beam focus to the substrate by the click of a button. The workpiece remains stationary while the laser beam moves overhead on a high-speed gantry system. The controls operate in a Windows 98 environment with familiar point-and-click operation. The noncontact method allows thin, delicate parts to be cut at speeds up to 80 in./sec without drag or tearing. System features include the ability to import more than 40 file formats and to control external inputs and outputs for streamlined, high-volume production applications. Serializing and bar coding are offered for product identification. CAD/CAM operation is possible through DXF file converting. A brushless ac servomotor provides high-resolution closed-loop feedback. The hardened rail and ball-bearing slide design does not require recirculating bearings that can transmit noise and vibration. The SL-3020's strong box construction allows integration of conveyors for pass-through applications. The center is suited for R&D labs as well as manufacturing production floors.

Laser system performs rapid prototyping of microfluidic devices

Potomac Photonics' laser system cuts and drills polyamides and similar materials.

A vertical laser micromachining center is suitable for manufacturing microfluidic channels in polyamides, polycarbonates, Mylar, acrylics, and similar materials. Based on Potomac Photonics' LMT-4500 laser, this machine features beam-shaping methods to prevent material buildup, turbulence generation caused by uneven channel floors, profile deviations, and channel widening at microchannel intersections. Another benefit of the machine is its ability to add microvias at desired locations within the channel structure. A programmable aperture increases production flexibility and eliminates the need to generate a mask. Product designs can be downloaded from a CAD file to the micromachining center, making the unit appropriate for rapid prototyping applications. The Waveguide excimer laser features a 248-nm wavelength, up to 0.45-mJ pulse energy, a 1.5-kHz repetition rate, and 0.45-W average power. The center has a 34 x 34-in. footprint.

EDM accessories allow automatic changeovers

Charmilles Technologies' Robofil 2030SI-TW integrates an automated dual-wire system.

A stand-alone robot provides speed, flexibility, and productivity for users of EDMs. Provided by Charmilles Technologies, the Roboform 35 QCRi allows users to realize up to 6000 hours of uninterrupted machining per year. Designed to handle magazine loading during machining, the robot reduces changeover times and allows machines to run on nights and weekends to make EDMs more productive. A magazine rack that stores electrodes and workpieces can be configured in three different ways and can hold up to 90 electrodes and up to 8 pallets. The robot can manipulate electrodes weighing up to 44 lb and pallets weighing up to 88 lb. An autorestart feature allows the robot to resume machining operations in the event of a tool changeover during a power failure. A dual gripper system integrated into the robot arm reduces changeover time from pallets to electrodes; the robot's transfer arm moves simultaneously in all four axes to minimize cycle times. Dielectric levels are adjusted automatically by the standard drop tank design, allowing various workpiece heights to be machined without manual intervention.

Also from Charmilles Technologies, the Robobil 2030SI-TW twin-wire EDM includes a fully automated dual-wire system for quick changeovers without operator intervention. The system includes a large-diameter wire designed for cutting large areas and a small-diameter wire used for fine cuts and surface finishing. The first wire has a 30° maximum taper, 30-second threading time, and 3.5–44-lb permissible stool weight. The second wire has a 1° maximum taper, 30-second threading time, and 3.5–17-lb permissible stool weight. Depending on the application, the system can reduce machining times by 30 to 50% because the large-diameter wire can be used for pocketing in the rough cut while the small wire is applied for small-radius finishing. The machine does not require special technologies or programming. Automatic setup eliminates complications in the installation and use of the two wires. During machining, the Robobil 2030SI-TW automatically switches to another wire as needed and the changeover takes less than 45 seconds.

Swiss-type turning machine provides machining flexibility

Single-spindle, Swiss-type turning equipment is designed to machine various types of medical components such as implants and bone screws. Provided by Tornos Technologies U.S. Corp., the Deco model is stepped in size and accommodates 7–13-mm part diameters, or 16-mm diameters with bar end preparation. Three of the back-working tools used for cross drilling, milling, and turning are mounted on an independent slide, permitting simultaneous turning and drilling. All of the drilling, milling, and turning tools can be driven or stationary. For greater setup flexibility, three tools on either the front or rear platen can be driven. ID and OD thread-whirling attachments provide one-setup machining of threaded parts. Key specifications include a 180-mm part length per chucking, main and subspindle speeds up to 12,000 rpm, and maximum spindle power of 3.7 kW with two optional C-axes. The machine accommodates up to 14 tools for main spindle machining, and up to 6 back-work operations.

Feed and cutoff system precisely machines thin metals

An advanced feed and cutoff system is suitable for 0.008–0.03-in. malleable material such as gold, solder, and silver. Offered by TAK Enterprises, the unit comprises a precision wire straightener and close-tolerance feed and cutoff head. An electronic stepper–controlled small spool payoff design provides controlled wire-line positional integrity and tension control. The combination of these elements allows the system to produce close-tolerance precision blanks for postoperation fabrication. It is capable of manufacturing 380 blanks per minute on 0.2-in.-diam x 0.1-in.-long material with ± 0.0005-in. length tolerance. The benchtop system includes safety interlocks, pinch covers, wire-out sensors, wire-buckle sensors, and an electronic controller for fully automatic operation.

Katherine Sweeny

Copyright ©2001 Medical Product Manufacturing News

Spotlight on Precision Motion Control

Originally Published MPMN July/August 2001

SPOTLIGHT

Spotlight on Precision Motion Control

Brushless dc motor controller

A three-phase bridge-type brushless dc motor driver uses pulse-width modulation to control speed. The BLDC-350 has a brake input to enable dynamic and static motor braking. The controller includes Hall-effect sensors for commutation, and an integral heat sink to allow the motor to run at full rated average current. Automation for Industry Inc., 2147-D Porter Lake Dr., Sarasota, FL 34240.


Microstepping drive

A precision microstepping drive weighs only 3.5 oz with a 2.5 x 2.5 x 0.85-in. footprint. The G201 drive provides speeds to 200,000 microsteps per second with 10-microstep circuitry. It has adjustable midband stabilization and opto-isolated step and directional inputs. Additional features include 1–7-A motor-phase currents, 24–80-V dc power supply voltage, 12-AWG MTW termination, 18-W heating, and 15-mA standby current. AutomationSolutions, 3925 Cypress Dr., Petaluma, CA 94954.


Digital-output position transducers

A line of position transducers offers measurement ranges up to 85 in. The transducers provide linear-position measurement with digital output and a variety of resolutions. They measure 3.2 x 3.2 x 3 in. or smaller, and weigh less than 10 oz. A range of custom configurations is available, including NEMA 4 environmental protection, absolute encoder input, and increased resolution. SpaceAge Control Inc., 38850 20th St. E., Palmdale, CA 93550.


Brushless dc motors

A line of high-speed brushless dc motors includes 0.5-, 0.9-, and 1.1-in.-diam frame sizes. The autoclavable models are designed for use in surgical hand tools. Hall-effect commutation sensors are standard, and options include a selection of precision planetary gear heads and optical encoders. PMI, 350 Kennedy Dr., Hauppage, NY 11788.


Timing belt–driven slides

A series of five timing belt–driven slides provide speeds up to 5 m/sec. The Blue Line 1, Blue Line 2, and ZF 1–3 series slides use HTD timing belts, have position switches with accuracy to ≤1.0 mm, and feature >0.2-mm repeatability of travel. Maximum speeds range from 1.5 to 5 m/sec. Techno-Isel, 2101 Jericho Tpke., Box 5416, New Hyde Park, NY 11042.


Self-lubricating bearings

Lead-free self-lubricating bearings are steel backed and have a sintered bronze lining infused with a PTFE compound and carbon fibers. They are designed for nonlubricated applications in harsh environments where the lead found in conventional bearings of this type can be subject to chemical attack. The standard-diameter bushings range from 5 to 165 mm, and from 5 to 65 mm in a flanged format. Peer Inc., 2200 Norma Dr. S., Waukegan, IL 60085.


Brushless dc motors

Custom-fabricated brushless dc motors are suitable for pump, medical, and industrial applications. The company uses high-energy materials including neodymium, iron-boron, samarium cobalt, and Hyperco 50. Plastic or metal chips can be used, depending on temperature requirements. Brushless rotor and stator kits are also available. Arc Industries Inc., 2090 Joshuas Path, Hauppage, NY 11788.


Microstepping drive

A microstepping drive uses a digital signal processor and a user-configurable I/O to active high or active low operation. The Impulse drive can detect a motor stall without an encoder or resolver, and provides low-resolution step input. Its programmable input resolution range is 200–100,000 steps per revolution. A 160-V dc bus voltage produces increased torque at higher speeds. Industrial Devices Corp., 3925 Cypress Dr., Petaluma, CA 94954.


Compact brushless dc motor

A line of 1.7-in. brushless motors features no-load speeds up to 15,000 rpm and stall torque up to 8 oz·in. The eight-pole, 12-slot and four-pole, 6-slot three-phase motors can be ordered for 12-, 24-, and 36-V inputs. Standard designs use Hall-effect devices and rare-earth magnets for electronically controlled commutation and minimal torque ripple. Ametek Rotron, 627 Lake St., Kent, OH 44240.


Brush-type motors

A line of brush-type motors provides 0.5–18 oz·in. of running torque and 2–110 oz·in. of stall torque. The voltage produced ranges from 1.5 to 140 V dc and sizes available are 16–52 mm diam and 19–96 mm long. Shaft lengths can be specified and are available with or without flats and keyways. Source Engineering Inc., 3440 De La Cruz Blvd., Santa Clara, CA 95054.


Rotary encoder

A rotary encoder has an Interbus interface that allows rapid and simultaneous transmission of input and output data in one transmission cycle at low transmission speed. The AG626 IBS absolute rotary encoder includes a CW/CCW switch, 25-bit multiturn resolution, and remote installation. It allows 100 G of shock for 6 milliseconds and 20 G of vibration at 20–2000 Hz. Operating temperature is 100°C. Stegmann Inc., 7496 Webster St., P.O. Box 13596, Dayton, OH 45413.


High-resolution optical encoder

An optical encoder that measures 0.75 in. diam and 0.9 in. long can be used as a conventional shaft encoder or as a blind hollow-shaft encoder with a flexible tether mount. The R119 generates quadrature square waves at up to 10,240 cycles per revolution. A 1Ž4-cycle-gated, once-per-revolution index signal is standard. Gurley Precision Instruments, 514 Fulton St., Troy, NY 12180.


Wash-down brushless servomotor

Design features on a wash-down brushless servomotor include a stainless-steel shaft extension and hardware, moisture-resistant wire, a double-sealed bearing, seals, and O-rings. Stock versions are available from 1/3 through 3 hp, and custom models are available. Baldor Electric Co., 5711 R.S. Boreham Jr. St., Fort Smith, AR 72908.

Copyright ©2001 Medical Product Manufacturing News

Spotlight on EMI/RFI Control

Originally Published MPMN July/August 2001

Spotlight on EMI/RFI Control

RFI cable filter ferrites

RFI cable filter ferrites are available in 74 different styles, including a full range of cable or bundle sizes up to 1 in. diam. Attenuation is up to 1 GHz. Mounting options include clamp on, adhesive, post mount, and tie wrap. Eclipse Shielding, 21121 Ponderosa, Mission Viejo, CA 92692.


RFI suppressors

Cable-snap bisected ferrite suppressors are available in 48 sizes and styles for round wires or bundles up to 1 in. diam. An internal spring-pressure system assures constant electromagnetic properties even in extreme cable positions. The suppressor attenuates RFI up to 1 GHz while allowing data signals to pass unimpeded. A variety of mounting options are available as standard from stock. FerriShield Inc., 350 Fifth Ave., Ste. 7310, New York, NY 10118-7591.


Shields, foil laminates, gaskets

A full line of EMI/RFI shields, foil laminates, thermal materials, and fabric-over-foam gaskets are designed and fabricated from a variety of materials to meet customer specifications. Working with the latest technology in die-cutters, water-jet cutters, stamping presses, laminating equipment, roll slitters, adhesive and assembly workstations, and forming machines, the company can develop a prototype in the lab and quickly take the project through to final production. Orion Industries Inc., 1 Orion Park Dr., Ayer, MA 01432.


RFI filters

Powerline filters are designed to meet requirements for conducted noise emissions. The manufacturer has recently added to its line of RFI filters with a 10-A power-entry filter for both medical and standard applications. Also available are a line of dc filters up to 700 A and three-phase filters rated from 8 to 600 A, 600 V. Curtis Industries, 2400 S. 43rd St., Milwaukee, WI 53219.


Precision-woven screening

A supplier of precision-woven screening offers a broad range of products suitable for EMI/RFI shielding applications. Materials include copper, stainless steel, carbonized nylon, and others. Various mesh sizes are available to meet required attenuation levels. Custom products are also available. Sefar America Inc., 111 Calumet St., Buffalo, NY 14043.


EMI/RFI/ESD coating services

A company provides coating services for EMI/RFI/ESD shielding. Physical vapor deposition (vacuum metallization) can be used to apply either a functional or decorative thin-film coating of 99.8% pure aluminum to most plastic injection-molded, extruded, or thermoformed enclosures. The company can also provide spray coating of conductive nickel-, copper-, or silver-filled water-based paints. Summit Coating Technologies LLC, 25 N. 43rd Ave., Phoenix, AZ 85009-4607.


RFI shielding

Used where a concentration of contact force is needed, the spherically radiused contact areas of low-contact resistance RFI shielding assure a strong electrical bond to the mating surface. The units are especially suited for vibrating or mechanical-shock environments. A variety of sizes for various gaps and mounting surfaces are available in a surface-mount adhesive tape version or a clip-on configuration. Omega Shielding Products, 9 Emery Ave., Randolph, NJ 07869.


Shielding systems

Two shielding systems, a screen room and a solid-cell enclosure, are designed to contain disruptive radiating signals from high-emission devices. The systems also guard against high-voltage sources and electromagnetic pulses. Applications include EMC product-compliance testing, instrumentation repair, and production-line testing. Lindgren RF Enclosures Inc., 400 High Grove Blvd., Glendale Heights, IL 60139.


EMI gaskets

Gaskets can be placed along the ground trace on a PCB to provide EMI shielding. As an RF grounding pad or interconnect, the Gore-Shield SMT EMI gaskets conduct currents of a primary RF signal much the same way a connector conducts RF currents from a PCB to a coaxial cable. Applications best suited for this use are found in situations where a RF signal needs to be sent from one PCB to another and the two boards are sandwiched together. W. L. Gore & Associates Inc., 750 Otts Chapel Rd., Newark, DE 19714.


Optical-quality fine-wire mesh

Sheets and custom sizes of fine-wire mesh with a conductive plating are available for EMI/RFI shielding of electronic displays and enclosures. EMIgard optical-quality meshes are produced in 304 stainless steel, copper, and custom alloys. Meshes come with 50 to 250 openings per inch in standard sheet sizes of 22 x 28 in. or precut to customer-specified sizes. In the company's manufacturing process, the mesh wires are encapsulated in a conductive silver-and-black alloy plating to maximize transmittance, shielding, and environmental durability. Dontech Inc., 700 Airport Blvd., Doylestown, PA 18901.

Copyright ©2001 Medical Product Manufacturing News

X-Ray Tube and High-Voltage Source Subsystem Simplifies Densitometer Design

Originally Published MPMN July/August 2001

PROFILE

X-Ray Tube and High-Voltage Source Subsystem Simplifies Densitometer Design
DynaRad's Monoblock incorporates an x-ray tube and a high-voltage source.

The MetriScan densitometer from Alara Inc. (Hayward, CA) allows doctors to test a patient's bone density in seconds. The simplicity and effectiveness of the device is reflected in its efficient design, which incorporates two technologies--an x-ray tube and high-voltage source--into a single, compact subsystem.

Alara produces medical imaging products based on storage-phosphor technology. The company was founded just 7 years ago, and its first product, the DenOptix radiography system, is a dental digital imaging system that is being used by thousands of dentists around the world. Alara's second imaging device, the MetriScan performs digital radiographic absorptiometry to estimate relative phalangeal bone density. The scan itself takes approximately 1 second and requires less than 15 seconds of patient and operator time.

After an extensive search, Alara chose DynaRad Corp. (Deer Park, NY), a specialist in the field of imaging technology, to provide the power supply and x-ray tube for the MetriScan. DynaRad's Monoblock integrates an x-ray tube and high-voltage source into a single critical subsystem. This design feature eliminates the need for costly cable connectors, which can cause frequent breakdowns. The cable-free design enabled Alara to create a highly reliable and relatively inexpensive bone densitometry machine.

The MetriScan densitometer takes less than 15 seconds to measure a patient's bone density.

"For Alara MetriScan, we needed a reliable, compact, and cost-effective [single-unit] solution," says Chris Mitchell, Alara's vice president of research and development. "Much of MetriScan's high precision and accuracy can be attributed to the reproducible output of DynaRad's Monoblock."

Ray Manez, general manager of DynaRad, adds, "The Monoblock's simple design allows it to deliver consistent performance with minimum maintenance, year after year. It allows the Alara MetriScan to provide quality imaging and a cost-effective, energy-efficient, and office-friendly instrument package."

DynaRad has been servicing the medical, analytical, and industrial x-ray communities since 1970. In addition to Monoblock, DynaRad offers a line of portable and mobile medical imaging systems, portable dental x-ray units, and advanced neonatal imaging systems.

Copyright ©2001 Medical Product Manufacturing News

Cross Sealer Makes Pouches from Monolayer Materials

Originally published MPMN July/August 2001

Hotline

Cross Sealer Makes Pouches from Monolayer Materials

Process results in strong seals and reduced costs

A servo-driven cross sealer makes pouch-type seals on lightweight monolayer blown films, an operation formerly only possible with multilayer plastics. The MS-CH-2 sealer from Amplas Inc. (Green Bay, WI) produces clear pouches with three sealed sides from these inexpensive materials at the rate of 60-100 cycles per second. This unique sealing process is made possible through the use of specially coated Teflon bands and a quick-release mechanism that eliminates sticking problems. Once formed, the pouches can be transferred to filling lines for product insertion and closure.

Manufactured by Amplas Inc., this sealer makes pouch-type seals using inexpensive monolayer films.

Pouch sealers have several benefits over the side sealers they were designed to replace. Pouch machines, unlike side sealers, do not have to cut materials during the sealing process.

This one-task operation makes them less likely to suffer from minor fluctuations in sealing temperature, machine speed, or pick-off timing. "Wide seals running around the product," explains marketing and communications team member Leon Delveaux, "make pouch seals sturdier and more airtight than side seals." The seals are so strong, according to Delveaux, that pouch-sealed bags could replace the resource-intensive plastic trays currently used to store and transport medical devices. The MS-CH-2 sealer is a component system that can be retrofitted to existing sealing machines.

Zachary Turke

Amplas Inc., 200 Packerland Dr., Green Bay, WI 54307-3397; phone: 920/496-0525; fax: 920/496-0560; URL: www.amplas.com


Closed-Loop Wind Tunnel Simulates Convection Airflows

Device is suitable for testing electronics in adverse environments

"All electronics, and specifically medical equipment, require thermal testing for proper functionality and reliable operation," says Advanced Thermal Solutions (Norwood, MA) CEO Kaveh Azar. "The CLWT-100 provides a controlled and reliable environment to allow for such testing." An integral part of thermal design for many electronic assemblies, wind tunnel testing permits experimental thermal analysis. The CLWT-100 closed-loop wind tunnel is capable of delivering airflows from 0 to 5 m/sec, simulating operating temperatures from -10° to 85°C, and operating at natural convection to 1000 ft/min of airflow.

Airflow temperature control is achieved using conventional heaters and refrigeration units. A Delrin frame thermally insulates the test section. Front and side windows made of heat-resistant, multilayer glass panes enable flow visualization. The test section is fitted with 24 ports that can accommodate a variety of cabling and measurement sensors. Adjustable fixturing is provided for specimen mounting. The unit can be adapted to perform tests that are not part of the standard package.

Katherine Sweeny

The CLWT-100 closed-loop wind tunnel from ATS can test the reliability of medical electronics.

Advanced Thermal Solutions Inc., 89 Access Rd. #27, Norwood, MA 02062; phone: 781/769-2800; fax: 781/769-9979; URL: www.qats.com


Benchtop Plasma System Allows Remote Process Monitoring

Organic, metallic, and composite substrates can be treated

Designed for laboratory and production use, a benchtop plasma system is suited for surface modification and cleaning of organic, metallic, and composite substrates. Developed by MetroLine Inc. (Corona, CA), the M4L RF system's applications include precision cleaning, adhesion enhancement, and surface modification of polymers.

The unit's networking capability allows users to program, monitor, and modify processing parameters from remote locations via Ethernet or the Internet. Features include a Windows-based, 10.4-in. color touch screen interface offering fully automatic control, multistep recipes, real-time graphic display, and real-time SPC monitoring. Process data can be examined on a variety of spreadsheet or statistics programs.

The aluminum chamber features a high-conductance KF 40 port, isolation valve, and shielded view port. The system's large 9 x 13 x 20-in. capacity allows simple loading of parts on trays. Complex shapes and small geometries can be repeatably plasma treated.

A benchtop plasma system can be programmed and monitored via Ethernet or the Internet.

Power and safety features include an integrated, air-cooled 13.56-MHz RF generator with an output range of 0–600 W; AutoMatch impedance optimization between generator and electrode; safety interlocks to protect the operator from RF power contact; and built-in system diagnostics.

Karim Marouf

MetroLine Industries Inc., 251 Corporate Terr., Corona, CA 92879-6000; phone: 909/371-2500; fax: 909/371-9792; URL: www.metrolineindustries.com


Medical Product Manufacturing News is always on the lookout for innovative products and services. If you are aware of any that have recently been or are about to be introduced, please call the Managing Editor, Susan Wallace at 310/445-4265.


Copyright ©2001 Medical Product Manufacturing News

Femtosecond Lasers: A Solution Looking for a Problem

Originally Published MPMN July/August 2001

EDITOR'S PAGE

Femtosecond Lasers: A Solution Looking for a Problem

High-power ultrashort-pulse laser systems have been migrating from research laboratories to industrial environments for the past couple of years. Although commercial applications have been limited to niche areas, the technology has much broader potential, according to researchers. Adding his voice to the chorus, John Girkin, a physicist at the Institute of Photonics, University of Strathclyde, in Glasgow, Scotland, explained the machining capabilities of femtosecond lasers at a conference on medical polymers in Brussels. Describing the technology as a "solution looking for a problem," he invited attendees at the meeting, organized by Rapra Technology Ltd., to seek industrial applications for the tool. It occurred to me that MPMN readers might be interested in taking part in the challenge as well.

Femtosecond lasers deliver pulse durations that can be as short as a few femtoseconds (10–15 second). Girkin put this in perspective by pointing out that light travels fast enough to circle the world seven times per second and crosses a human hair in 100 femtoseconds. These pulses are too short to transfer heat or shock to the material being processed. Consequently, there is little to no "collateral damage" to the surrounding material, said Girkin. This represents a clear advantage over thermal cutting and plasma ablation, the dominant laser-based machining techniques currently used by industry.

Ultrashort-pulse lasers break the material's intermolecular bonds in a manner similar to excimer lasers, noted Girkin, but they do so at near-infrared wavelengths. The UV light generated by excimer lasers can cause plasma to form in front of the workpiece, and these clouds absorb subsequent light pulses and distort the incoming beam. Femtosecond lasers deposit their energy so quickly that the beam does not interact with the plume of vaporized material. In principle, this enables "ultrashort laser systems to run at much higher repetition frequencies" than UV systems, according to Girkin.

Device designers and manufacturers should also be impressed by the precision of these systems, said Girkin. Holes measuring less than 100 µm have been ablated, and the lasers are able to machine inside materials without causing surface damage. Single pulses can be adjusted to remove material measuring only a few nanometers in thickness. To illustrate the laser's precision and the minimal energy or mechanical shock that is transferred to the material, Girkin cited an experiment conducted at Lawrence Livermore Laboratories in California, where researchers have used the system to machine an unstable and highly explosive material without causing it to detonate.

Thus far, the femtosecond laser has been used to machine materials ranging from collagen to metal with equally remarkable results. In all instances, the workpieces exhibited a similar cutting profile, and little or no damage was observed on the surrounding surface.

When evaluating femtosecond lasers for an industrial application, "there are some considerations to keep in mind," acknowledged Girkin. "They are not fast [in terms of throughput], they are not suited for drilling holes in the millimeter range, and the systems are currently priced at about $200,000." On the other hand, if you are looking for a tool to perform high-precision cutting with little or no collateral damage, then a femtosecond laser may indeed be worth a look. As for the price tag? Everything's relative, noted Girkin: if the femtosecond laser provides you with an enabling technology for an application that otherwise might not be feasible, then you might call it a bargain.

To find out more about research on femtosecond lasers conducted by Girkin and his colleagues, you can contact him via e-mail at j.m.girkin@strath.ac.uk.

Norbert Sparrow

Dear Reader:

A production error caused the Editor's Page from the May issue to be reprinted last month. In the editorial, I invited readers to turn to page 36 to discover the winners of the Medical Design Excellence Awards. It was the right page number, but the wrong issue, as several readers pointed out. The article can also be viewed at www.devicelink.com/mpmn/archive/01/05/mdea.html. Please accept our apologies for this error.

Copyright ©2001 Medical Product Manufacturing News

Fiber reinforces thermoplastics.

A new line of continuous-fiber thermoplastics (CFTs) combines the strength of fiber-reinforced materials with good design flexibility. All of the fibers are continually connected throughout the material, resulting in processing and product advantages over other fiber-reinforced composites. Features of the CFTs include impact tolerance, toughness, the ability to be postformed, secondary attachment capacity, joining capability, the ability to be recycled, light weight, corrosion resistance, and good insulating qualities. Suitable for medical tubing, the CFTs offer chemical resistance without conductivity and high strength and flared ends, if desired. The CFT line is from Polygon Co. (Walkerton, IN; 800/918-9261).