When Manufacturing Requires Surgical Precision

Implantable devices are among a host of innovations that medical manufacturers are bringing to market with the help of contract manufacturers skilled in tight-tolerance processes.

By Mark Shortt
Editorial Director, Design-2-Part Magazine

The medical industry, a tightly regulated and competitive market that demands quick lead times, is at the center of some of the most important and innovative research, engineering, and product development taking place in the world today. If you look closely, you'll find medical manufacturers that are skillfully combining the latest breakthroughs in materials, miniaturized electronics, production techniques, and software to develop powerful diagnostic, therapeutic, and monitoring tools that can help raise the quality of health care to levels never seen before.

Minimally invasive diagnostics and surgery continue to lead the trend toward increasingly smaller medical devices and component parts. Implantable monitoring devices are one application that is benefiting from advances in miniaturized electronics, including micro-electromechanical systems (MEMS). But amid the many promising developments, a need has emerged to help assure the reliability of electronic components used in medical applications.

A new project being launched by the International Electronics Manufacturing Initiative (iNEMI), headquartered in Herndon, Va., will address this need by developing testing and use condition guidelines. The Medical Components Reliability Specifications Project is charged with developing "test and extrapolation methodologies that can be used to predict the reliability of components in actual use conditions," according to iNEMI.

"There are very high expectations for reliability in medical devices, especially implantable devices, and a product's reliability is significantly affected by the components used in that product," commented Anthony Primavera, Boston Scientific CRM and chair of the iNEMI Medical TIG and the Medical Components Reliability Specifications Project. "Drivers such as high quality and reliability, shorter development cycles, a simplified supply chain, extended product lifecycles, and increased complexity of medical electronics have resulted in a need for guidelines and specifications for assessing the reliability of electronic components used in medical devices."

It is believed that the adoption of commonly accepted testing, extrapolation analysis, materials, and processes will help medical manufacturers achieve proven quality, reliability, and consistency while also helping suppliers to focus on a single set of criteria, instead of having to meet different requirements for each customer. The team involved with the Medical Components Reliability Specifications Project has defined four areas of concentration: discretes (surface mount multi-layer chip capacitors, surface mount tantalum capacitors, surface mount resistors, and surface mount inductors); array packages (CSP, BGA); substrates and interconnects; and hybrids.

"This project will develop specifications for testing medical electronics and will work with the appropriate standards-making body or bodies to implement those specifications," continued Primavera. "We see this project as a major advancement for the medical electronics field."

The importance of electronics in today's medical devices has heightened the demand for contract manufacturers that can provide reliable, high-quality components and electronics manufacturing services. But the sheer diversity of innovation in medical device manufacturing highlights the need for industry sources that can help solve critical engineering challenges through a variety of custom design, engineering, production, and product development services.

Supporting Technology Innovators

Start-up medical device companies that are looking to bring innovative emerging technologies to market quickly are finding a strong and experienced partner in ATEK Medical Manufacturing, a medical device contract manufacturer based in Grand Rapids, Michigan. One example is CardiacAssist, Inc., an emerging company dedicated to providing cardiologists and cardiac surgeons with innovative tools for treating weakened and damaged hearts. ATEK Medical recently worked in partnership with CardiacAssist to provide final assembly and support the company's launch of its new TandemHeart® Transseptal Cannula Set - Extended Flow (THTC-EF).

Based in Pittsburgh, Pa., CardiacAssist develops, manufactures, and markets products that are often used as bridges to support the circulation systems of patients as they recover from reversible heart failure brought on by disease, heart attacks, or complications of open-heart surgery. The company recently developed a unique ventricular-based assist device (VAD) platform technology - the TandemHeart® PTVA® System - for the treatment of acute heart failure. A key subsystem of the technology is the TandemHeart Transseptal Cannula Set, which connects another essential subsystem, the TandemHeart System Pump, to the patient's body through two percutaneous access points in the patient's groin. Rounding out the system is a third subsystem, the TandemHeart PTVA System Controller, which provides operating power and a controlled flow of lubricant to the pump. The controller also provides automatic system monitoring and alarms to indicate conditions that require immediate attention.

The TandemHeart Transseptal Cannula - EF, featuring a curved design at the distal end of its body, is advanced through the patient's femoral vein into the left atrium. Its curved design is intended to facilitate optimal placement of the tip in the left atrium. Location of the cannula at placement is recorded with the aid of centimeter markings at the proximal end of the cannula; these markings also serve as a visual aid for monitoring any change in location that could occur when the patient is moved. Holes located on the distal tip and sides are configured to permit adequate blood flow and drainage of the left atrium.

The TandemHeart Transseptal Cannula Set also includes an obturator with a short, tapered tip for easy insertion. At the proximal end of the obturator is a standard locking Luer connector that permits the attachment of a hemostasis valve for injecting dye, measuring pressure, or sampling blood. The blood is returned into the patient's systemic circulation through the femoral arterial system, using commercially available wire-reinforced arterial cannulae.

The Cardiac Assist project brought typical start-up challenges, including the coordination of multiple suppliers and components to create a final assembly package. It also required the development of a quality-system requirements process that would ensure product integrity throughout the supply chain. ATEK's history of process development and product launch expertise, with emphasis on quality systems requirements, was invaluable. The firm's product launch team experience is said to have provided the stable environment and robust manufacturing and process discipline that Cardiac Assist sought in a product launch and manufacturing partner. All of this resulted in improved quality, lower costs, and compressed time to market.

"We partnered with ATEK for their strong history of bringing new products to market and their commitment to quality," said Doug Smith, vice president, engineering, Cardiac Assist. "ATEK's experienced team communicates well and brought structure and process to our business, which significantly shortened time to market, assured a high-quality product, and helped contain costs. CardiacAssist will continue to expand its relationship with ATEK."

Fully Dense Metal Parts Fabricated Directly from CAD Models

Any methods that can save time or costs have particular value for product makers in the pressure-cooker environment that surrounds medical manufacturing. One is Laser Engineered Net Shaping (LENS®), an additive manufacturing technology developed by Sandia National Laboratories and now available from Optomec® Inc., of Albuquerque, New Mexico. According to Optomec, LENS is a natural for high-performance medical parts because it can fabricate "superior metal components in less time and at a lower cost than competing methods."

Laser Engineered Net Shaping is a material deposition process that employs energy from a high-power (500W to 4kW) laser to build up parts one layer at a time from powdered metals. Working directly from CAD models, the process can rapidly and cost-effectively produce custom surgical instruments and orthopedic implants for the hip, knee, and spine. According to Richard Grylls, LENS product manager for Optomec, the resulting components are fully dense, fully functional three-dimensional structures with mechanical properties equivalent or superior to those of conventional wrought materials.

"LENS Additive Manufacturing enables unique designs, unique mechanical properties, and unique tailored surfaces for metal implants and tools," says Grylls, who holds a doctorate in metallurgy. "You can construct a part from the inside out, which you couldn't normally do." The process can produce unique tailored surfaces, he says, because two separate powder feeders can be used to create combinations of materials on the fly. Users can design a part with different materials in different places, varying the mechanical properties within the part, and can vary the powder feed rate for greater control.

Optomec's LENS® systems are used to develop functional prototypes and manufacture wear-resistant metal components in materials such as titanium, Stainless Steel, nickel-based super alloys, and Inconel®. No specialized tooling is required for the process, which typically provides a surface finish of 12 - 15 microns, Grylls says. Parts are usually oversized by up to 1mm to allow stock for finish machining.

The system is housed in a hermetic chamber, purged with argon to ensure that oxygen and moisture levels remain below 10 parts per million. The environment helps keep the part clean and prevents contamination from oxygen or nitrogen. A proprietary powder-feed system, able to precisely regulate the flow of materials, delivers the metal powder to the deposition head. After depositing one layer, the deposition head moves on to the next, building up successive layers until the whole part is constructed. When the process is completed, the part is removed; it can then be heat treated, machined, or subject to hot isostatic pressing.

According to the company, the better mechanical properties obtainable through LENS are the result of an "improved microstructure with significantly reduced grain sizes." When 316 Stainless Steel, for example, is used with LENS, it reportedly shows a cellular spacing of only a few microns. As a result, yield strengths are said to be nearly double those of conventionally processed 316 Stainless Steel.

In the case of a special surgical tool needed for a particular operation, LENS and tumbling were the only processes used to manufacture the instrument. The tool required medical-grade material that would be strong enough to resist breaking under the surgeon's pressure. No specialized tooling and little engineering were required because the LENS process "takes the CAD model and slices and builds it automatically," Grylls said. "The major technical challenge was to finish the part so it was smooth enough; this was achieved by tumbling," he added.

This summer, Optomec was named one of the New Mexico Technology Flying 40 top companies for 2005, based on revenue growth. The company also won a NACFAM Defense Manufacturing Excellence Award in 2002, and was on Inc. 500's list of fastest growing private companies in 2000 and 2001.

Implantable Pressure Sensor Wirelessly Gathers Information inside the Body

CardioMEMS Inc., an Atlanta-based developer of wireless medical pressure sensors for the management of abdominal aortic aneurysm (AAA) and heart failure, won a Frost & Sullivan 2006 Product Innovation of the Year Award earlier this year for its development of the EndoSureTM Wireless AAA Pressure Measurement System. Manufactured with the help of recent breakthroughs in micro-electromechanical systems (MEMS), the EndoSureTM sensor is an implantable device that measures blood pressure in people who have been treated for abdominal aortic aneurysm. It is believed to be the first wireless, MEMS-based, permanently-implantable pressure sensor to be commercially available in the United States.

The EndoSure system comprises a sterile implantable sensor, approximately the size of a paperclip, and a separate electronics cart containing a 15-inch touch screen monitor and lightweight, ergonomically designed antenna. It also uses proprietary EndoSure software. The sensor is a hermetically sealed circuit, encapsulated in fused silica and silicone and surrounded by a PTFE-coated nickel-titanium wire.

During a procedure to repair the aneurysm, doctors insert a stent graft into the artery to relieve pressure on the walls of the aneurysm sac by opening a channel for blood flow. But patients must be monitored regularly because the stent graft can fail. Whereas expensive CT scans have traditionally been used to monitor the stent graft's success in relieving pressure within the sac, doctors can now insert the pressure sensor along with the stent graft during the procedure. Once inserted into a patient's aneurysm sac, the sensor measures the blood pressure and can wirelessly relay the information to the electronics on the cart.

By receiving FDA 510 (k) clearance for the EndoSure system, CardioMEMS has taken a significant step toward a medical future in which implanted chips can cost-effectively monitor critically ill patient populations without the imposition of bulky non-invasive devices or the risk of infection with invasive needles.

Precision, Functionality Prove Vital for Medical Components

Residual flash or particulates can have serious consequences for medical applications. One company known for resolving these types of problems is Da/Pro Rubber, Inc., an ISO 9001:2000-certified manufacturer with facilities in Valencia, Calif., Broken Arrow, Okla., Singapore, and Newburyport, Massachusetts.

Using a special molding process, Da/Pro manufactures a variety of custom seals, gaskets, and diaphragms from rubber, plastic, and thermoplastic elastomer (TPE) materials. For the medical industry, Da/Pro produces tight-tolerance parts used in respiration equipment, catheters, IV components, ultrasound equipment, and blood pumps, as well as in electrical connectors, surgical instruments, and dental instruments. Conductive touch buttons, drug delivery devices, and implantable grade components are among the additional medical applications.

"Da/Pro's engineering expertise and experienced mold-making capabilities enable us to mold highly intricate and precision parts to within +/- 0.002," according to Gretchen Brauninger, president of Da/Pro Rubber. In addition to drawing on the talents of its engineers for design and R&D assistance, the company can tap the expertise of staff chemists, who can formulate custom compounds for specific medical applications. Also available is a Class 10,000 clean room for medical parts that require special molding, handling, and packaging.

Da/Pro's process has roots in the development, by company founder Charles Daubenberger, Sr., of a unique low-pressure press for compression molding. Today, the company uses an automatically controlled rubber molding machine that adjusts for compound and part configuration variables. The computer-controlled molding process is monitored to maintain consistent molding conditions and ensure repeatability throughout the molding cycle. It also offers flexibility by allowing the molding of different rubber part configurations in the same production cycle. By using the process, Da/Pro can mold diaphragms that are stress-free throughout the convolute section, holding uniform thickness to a tolerance of +/- 0.0015-inch (0.038mm), Brauninger says. Electrical connector inserts, with hardness ranging from 40 to 90 Shore A durometer, are another specialty. They can be molded with complex internal hole configurations and minor diameters as small as 0.017-inch x 0.75-inch (0.43mm x 19mm) long.

One component that Da/Pro produced, a highly complex manifold for a respiration machine, was a tight-tolerance part that required multiple moving cores. Manufactured in a Class 10,000 clean room, the part required a material that could withstand multiple autoclave treatments with temperatures up to 134°C.

In another case, while working with engineers on a drug delivery device, Da/Pro reduced costs and assembly time by overmolding two functional areas at once. The customer had designed the plastic part so that the drug delivery area, in contact with the patient's skin, would have a soft feel and an O-ring seal. Da/Pro suggested using TPE, overmolded to plastic to create a padded area with the desired soft feel. It also suggested using the same TPE material to fashion a lip seal for the vacuum seal. One overmolding operation was used to create both the soft padded area and the seal.

Da/Pro offers insert molding, overmolding, and bonding of custom molded rubber to metal or plastic; it also offers stamping, sub-assembly, laboratory testing, and full quality assurance. The company is skilled in working with a wide range of materials, including general-purpose rubber, oil-resistant rubber, and various specialty rubbers; engineering and commodity plastics, thermoplastic elastomers (TPEs), and silicone. Because its projects may involve components that have direct contact with human blood or other bodily fluids, Da/Pro works with customers to develop materials that meet hemolysis and cytology test requirements, as well as FDA standards.

Smaller Parts, Tighter Tolerances

Some of the most difficult projects in medical manufacturing involve production of smaller, increasingly complex parts with tighter tolerances, better surface finishes, and verifiable cleanliness. For Johnson Matthey, Inc., a Canada-based company with West Coast operations in Temecula, Calif., and U.S. headquarters in West Chester, Pa., these challenges come with the territory of being an approved supplier to some of the top medical device makers in the world. The ISO 9001:2000-certified company produces components, tools, and fixtures used in the manufacture of pacemakers, defibrillators, electro-physiology catheters, coronary catheters, dental implants, and cochlear implants. Applications also include coronary guide wires and guide wire tips, minimally invasive surgical instruments, orthopedic reamers, and endoscopic fiber bundle guides.

A common denominator throughout much of Johnson Matthey's work for the medical industry is its ability to produce components from specialty materials, ranging from aluminum to 400 series Stainless Steels, Nitinol, cobalt-based superalloys, and titanium. The company's expertise also spans 300 series Stainless Steels and medical-grade and engineering polymers, such as Victrex PEEK and DuPont Delrin. "Our technical understanding of materials and how they respond to our processes makes us unique," says Joseph Kain, product manager.

Johnson Matthey's metallurgical expertise includes extensive knowledge of Nitinol (nickel-titanium) alloys, used in fabricating a variety of custom components from tubing, wire and ribbon, and sheet. By drawing upon trial-and-error experience to optimize changes in alloy composition, mechanical working, and heat treatment, the company is able to modify the unique properties of Nitinol for a particular application. These properties include high damping capability, as well as shape memory effect and superelasticity.

Nitinol tubing components can be machined, laser welded, or cut to length; they also include formed tubing shapes and beveled needle points. Wire and ribbon-based components include tapered tip guidewires, formed wire and ribbon shapes, trocar and rounded points, and laser-welded parts. Johnson Matthey can also fabricate parts from Nitinol sheet using photochemical etching, EDM, or laser cutting.

For customers interested in the unique shape memory and superelastic properties of Nitinol, Johnson Matthey offers assistance with materials selection and optimization, product design assistance, process development, and small scale prototyping. In addition to the medical device industry, Johnson Matthey provides tooling and fixtures for aerospace, dental, and general manufacturing floor applications.

Peridot Corporation, based in Pleasanton, California, manufactures components and assembles devices for use in cardiac care, cancer treatment, diabetes management, and spinal surgery. According to Patrick Pickerell, president, Peridot is unique in the substantial number of micro-fabrication processes that it performs in one facility. Its diverse component fabrication capabilities include electrical discharge machining (EDM), CNC wireforming; laser welding, cutting, and marking; CNC machining, metal stamping, and CNC Swiss turning.

"We specialize in complex forming and cutting operations on small diameter hypo-tubing," says Pickerell of the ISO 9001:2000-certified company, which also has a certification pending for ISO 13485:2003, the medical device standard. "We are very experienced with Nitinol and other super-elastic alloy fabrication; we machine all types of plastics. This diversity of processes allows for a one-stop-shop approach for medical device companies who are faced with the short product development cycles demanded by the market.

"The biggest challenge we face today is lead time pressure from our customers," Pickerell continues. "We deal with a lot of startup device companies where their ability to secure successive rounds of funding is often directly tied to how quickly clinical trials can be completed. The second biggest challenge is the ever-shrinking part size mandated by the minimally invasive device markets we serve."

Peridot's EDM machines are said to easily hold tolerances of ± 0.0001 inch with surface finishes as fine as 6 RMS. Its lasers can hold positional accuracy within ± 0.001 inch and can cut slots in parts as small as 0.001-inch wide. For the pointing of trocars and needles, the company employs multiple wire EDM machines that produce burr-free point geometries. Peridot is also adept at using "gang fixturing" to stack the optimum number of parts for cutting, Pickerell says.

Following its recent completion of a new class 10,000 clean room, Peridot offers component fabrication and device assembly, including sterilization and packaging. The company also services the computer and computer peripheral markets and makes parts for major sporting goods companies. Industrial lighting companies are also a large consumer of the firm's stamped metal contacts.

One of the firm's projects involved fabrication of hollow formed needles from 300 series Stainless Steel. The component, previously shape set from nickel titanium tubing, was to be stored in a straight position for up to two years and then deployed into its original curved shape. According to Pickerell, Peridot's greatest challenge was to form and stress-relieve the part so that it would approximate the performance of Nitinol without its cost.

"Our customer presented the design of the device to us and challenged us to develop a manufacturing process that would achieve their cost goals," he said. "We developed a multi-stage forming and stress relieving process to arrive at the desired curvature."

Along the way, Peridot developed bending and stress relief fixtures that reliably produced the required memory in the 300 series tubing, Pickerell said. In addition to forming and EDM pointing, the company used EDM to drill 0.005-inch-diameter holes through 0.016-inch OD tubing. It also applied pencil point rotary swaging of the needle tip, as well as metal stamping, soldering, solvent bonding, assembly, testing, and packaging.

ZA-12 Casting Process Meets Critical Tolerances

Permanent graphite molds and proprietary LTA^TM auto-pour technology are key elements of a casting process used by a Jaffrey, N.H. firm to produce custom medical components from ZA-12, a zinc-aluminum alloy with approximately the same density as cast iron. The ZA-12 casting process offered by Graphicast, Inc., uses permanent graphite molds to economically produce high-precision medical parts in quantities from 300 to 20,000 parts per year. It employs a proprietary LTA auto-pour technology that reportedly produces castings with dimensional stability, low porosity, and exceptional consistency. No heat treating is required, and typical turnaround time from finished CAD to first article samples is 4-6 weeks.

"Typically, graphite mold castings can be produced in volume with critical dimension tolerances of ± 0.003-inch per inch for the first inch and ± 0.001-inch per inch for additional inches, and surface finishes better than 125 micro-inches," according to a statement from Graphicast. "Parts from the mold have a lustrous, bright metal finish that in most cases requires no preparation or coating for corrosion protection. If desired, parts can be painted, powder coated, or finished with electro-coated acrylic or epoxy to simulate black anodized aluminum."

Castings can include contours, variation in surface elevations, holes, and other precise features, the company says. Graphicast offers comprehensive design assistance; its state-of-the-art software is said to facilitate "any modification to draft or radii required to accommodate the casting process." Parts are cast to near net shape and require no machining to meet tolerances. The company recently used the ZA-12 casting process and other capabilities to produce a swivel elbow for a medical equipment stand. In addition to making the mold and casting the parts, the firm provided custom steel shafts and assembled the shafts to the castings. Graphicast also designed reusable packaging to protect the finished parts in shipping and storage. Perpendicularity specifications were 0.002-inch to base and 0.008-inch to the opposite face.

The zinc-aluminum alloy ZA-12 has about the same density as cast iron but is harder, stronger, and provides better wear than aluminum or bronze. It machines as easily as brass or bronze and more easily than cast iron or aluminum, according to Graphicast.

Complex Electromechanical Devices

An engineering and contract manufacturing firm that specializes in complex electro-mechanical medical instruments, Aubrey Group, Inc., offers rapid product development, safety and regulatory compliance, and turnkey manufacturing to emerging start-ups and established companies. The Irvine, Calif., company has partnered with a number of medical technology firms to develop innovative devices, including the A-Syst^TM Right Heart Support System for A-Med Systems, Inc., West Sacramento, California; the TLC-II Portable VAD Driver for Thoratec Corporation, Pleasanton, California; and the DayLink® Monitor for Alere Medical, Reno, Nevada.

Used in minimally-invasive cardiac surgery, the A-Syst^TM Right Heart Support System is a centrifugal blood pump that is said to improve access to vessels while managing a patient's hemodynamics and cardiac output. The pump is designed to support the right heart to maintain circulatory stability during cardiac surgery manipulation. Another cardiac device, the DayLink® Monitor, is designed for home use by patients being treated for congestive heart failure. The system offers precise measurement of weight, physician-specified questions about a patient's symptoms via audible voice and visual display, and speech capability. It automatically sends, via the patient's regular phone line, accurate measurements and the patient's responses to the Alere® Data Exchange Network.

Founded in 1994 by Vytas Pazemenas, currently the president, Aubrey Group has been involved in the development of numerous other medical instruments and devices, including blood collection and separation devices, ultrasound cardiac ablation systems, bio-artificial liver systems, infusion pumps, RF generators, and implantable sensors. Additional projects include development of dental perioscopes and ophthalmic surgery controllers. The company provides services such as software development, mechanical engineering, medical system design, electronics and computer design, and RF system and circuit design. Aubrey Group is FDA-registered, as well as certified to ISO 9001 and ISO 13485.

Aubrey Group also offers rapid prototyping, testing, validation and verification, thorough documentation, and turnkey manufacturing. Recently, the company moved to a new, 30,000-sq-ft facility in Irvine, California, doubling its available floor space to support product development and contract manufacturing growth.

The company's move to a larger facility came about in response to strong demand from clients for increased services. Medical device investment has been on the rise in recent years, and because Aubrey Group works closely with start-ups, incubators, and entrepreneurs, the rising investment has translated into higher demand for its services.

Ergonomic Suturing Device is Designed for Safety, Ease of Use

According to the American College of Surgeons (ACS), 59% of all suture needle injuries occur during the closure of fascia, the underlying layer below the skin that must be closed at the conclusion of most major surgical procedures. A critical operation performed at the conclusion of 5 million surgical procedures in the United States each year, fascia closure has traditionally been performed manually with the use of large, unprotected sharp needles.

Last October, SuturTek Incorporated (North Chelmsford, Mass.) announced its commercial launch of a patented device specifically designed to protect surgeons, nurses, and operating room staff against potentially deadly suture needlestick injuries during fascia closure. The SuturTek 360° Fascia Closure Device^TM is said to provide this protection by ensuring that the sharp point of the suture needle-which is contained within a sterile, disposable suture cartridge at all times-is never exposed.

An ergonomic, reusable suturing device that uses patented disposable suture cartridges, the SuturTek 360 is reportedly faster, easier, and safer for surgeons than tedious and difficult hand suturing. Its suture cartridges use standard taper-point fascia closure needles and all types of standard absorbable or non-absorbable sutures. Most important, hands and fingers are not exposed to the sharp point of the needle before, during, or after the surgical procedure. The device has been used extensively in the United States and Europe for a wide variety of surgical procedures, including many types of major abdominal surgeries, caesarian deliveries, abdominal hysterectomies, hip and knee replacements, and spinal surgery.

Earlier this year, SuturTek received two major design awards - a 2006 Industrial Design Excellence Award and a 2006 Gold Medical Design Excellence Award-recognizing the excellence of the SuturTek 360° Fascia Closure Device^TM. In a statement from the company, SuturTek's president and CEO, Gerald Brecher, credited the firm's industrial design and manufacturing partners-Bleck Design Group and Lacey Manufacturing, Inc.-with being instrumental in the success of the product. "We are extremely appreciative of their contributions," Brecher said.

Bleck Design Group, based in North Chelmsford, Mass., has designed medical devices ranging from a surgical laser to a connector system that complies with FDA process regulations. With a staff that includes industrial designers, mechanical engineers, and electronics and software professionals, Bleck Design Group offers concept-to-production design programs. The company is said to create "innovative product designs that are clean, simple, and encourage intuitive interaction."

Lacey Manufacturing, of Bridgeport, Conn., is a vertically integrated, FDA-registered contract manufacturer that provides services ranging from engineering to metal stamping, injection molding, and assembly. The firm's staff of more than 35 engineers work in cross-functional teams to create innovative product and tooling designs, the company says. Certified to ISO 9001:2000, ISO 13485:2003, and ISO 14001:2004 standards, Lacey provides turnkey manufacturing services to the medical device and bearings industries, as well as various commercial markets.

Custom Rotational Molding

Precision molding tolerances and high cosmetic requirements are the norm for Bonar Plastics, a company that employs custom rotational molding to support the manufacturing of medical furniture, tanks, and reservoirs, as well as exterior covers, skins, housings, and armatures. Bonar offers mechanical engineering services and conversion of designs to rotational molding, and can also integrate rotational molding into its clients' designs.

"We specialize in custom short run, complex, one-piece designs; low entry-cost tooling compared to other plastic processes; and short time to market," says Mike Humes, Bonar's sales manager for the western region.

In rotational molding, products ranging in size from a ping pong ball up to fourteen feet in diameter are possible. Textures range from smooth to pebble grain to leather grain; finishes, from mirror polish to matte. Humes says that the company uses CNC machined molds, as opposed to cast molds, for the precision they provide. Its services include CNC secondary trimming operations, assembly, leak testing, and custom packaging.

Although Humes acknowledges that the selection of materials for rotational molding is somewhat more limited than for some other processes, he says that Bonar utilizes a variety of polyethylene (PE) materials. Examples include linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), crosslink PE, and EVA Co-Polymer. Other materials used are polypropylene (PP), polyvinyl chloride (PVC), Nylon 6, 11, and 12, and "specialty resins upon demand."

Furniture products made by the company span a variety of seat armatures, examination tables, chairs, stools, armrests, and headrests. Bonar has also molded coolant reservoirs, chemical tanks, low pressure tanks, hazardous/medical waste tanks, and structural frames and support armatures.

The company was acquired by Promens, a subsidiary of Atorka, in July 2005, and now operates nine manufacturing plants within North America.

Bonar Plastics won the 2005 Conversion Part of the Year Award from the Association of Rotational Molders (ARM), as well as the 2002 ARM Product of the Year Award, the 2003 ARM PVC Part of the Year Award, and the 2004 Society of Plastics Engineers (SPE) Presidents Award.

New Polymer Composite Targeted for Implantable, Load-Bearing Medical Devices

Endolign^TM composite is a new biocompatible, carbon fiber-reinforced thermoplastic material introduced by Invibio® for use in implantable, load-bearing medical device applications requiring contact with blood, bone, or tissue contact for more than 30 days. The Endolign composite and process are said to offer the first non-metallic biomaterial available for medical implants that provides "the high strength of metals combined with the extensive biocompatibility and imaging compatibility of polymers." It is currently being used in the development of load-bearing applications, including spinal fixation devices such as translaminar fixation pins and spinal fusion cages, and in trauma devices such as bone fracture plates, screws, and intermedullary nails.

Biocompatibility testing of Endolign composite reportedly confirms that it exceeds the requirements of ISO 10993 standards for long-term implantable medical devices. Endolign is manufactured to ISO 9001 quality standards by combining high levels of continuous carbon fibers with a PEEK-OPTIMA® polymer matrix in the form of a pre-impregnated tape. This tape can then be molded into rods or other forms. The continuous carbon fibers are said to significantly enhance the mechanical properties of the material, increasing its flexural strength when tested in molded unidirectional rod form. Flexural strength is reported to increase from approximately 150MPa for PEEK-OPTIMA polymer to more than 1000MPa.

A radiolucent material that offers superior imaging compatibility, Endolign enables clear visualization through imaging techniques such as X-ray and Computer Tomography (CT). As a non-metallic material, Endolign is compatible with magnetic resonance imaging (MRI), unlike traditional metallic implant materials, which can generate imaging artifacts and scatter. In cases where X-ray visibility is an advantage, Endolign can be tailored by adding a radiopaque component in different concentrations to vary the level of X-ray contrast, the company says.

"Endolign composite will enable medical device manufacturers to develop a new generation of implants with better imaging characteristics and improved strength," said Michael Callahan, president of Invibio. "Because of its outstanding properties, Endolign is ideally suited for the development of long-term implantable load bearing medical device applications."

Ohio Firm Brings Precision Manufacturing Processes under One Roof

Engineering prototypes and precision short-run machining services are two of the specialties of Triangle Precision Industries, Inc., a Kettering, Ohio company long known for its ability to make pre-production models. In business since 1982, Triangle Precision has also developed a range of capabilities in sheet metal forming and fabrication, in-house welding, special assemblies, and the manufacture of special tooling and fixtures for unique applications. The company, named Vendor of the Year in 2005 by one of its medical customers, serves industries ranging from medical to aerospace, high-speed printing, automotive, and R&D.

Through the years, Triangle Precision has brought previously outsourced processes in-house to gain more control of the manufacturing process, according to Harold Brown, sales and marketing manager. At the same time, the firm has emphasized continuing education for its staff to keep up with changing technologies. Today, the company offers 5-Axis CNC machining to increase productivity and reduce handling and setup times. Its machining services also include grinding, multi- spindle precision CNC turning, and wire and sinker EDM.

"Using wire EDM, we are able to machine and repeat down to 0.0005," Brown says. "We can also machine a surface to an 8RA finish."

Triangle Precision's personnel have CNC programming skills in multiple software programs and know the right speeds and feeds to utilize when machining various types of materials, according to Brown. These materials include medical-grade Stainless Steel, medical-grade plastics, and titanium. For medical product manufacturers, the company provides manufacturing support on projects involving orthopedic instruments, implants, and components for surgical instrument cases. Medical fixtures, burn care devices, and biological instrumentation are among the additional end-uses.