Tubing

Gabe Spera

Device manufacturers everywhere are trying to cut costs, and component suppliers are feeling the pressure. The market for medical tubing is a prime example. "We're seeing a continuing emphasis on cost, much more than historically," remarks Greg Bischak of Raychem (Swindon, UK). Suppliers of PVC tubing probably have it harder than providers of specialty fluoropolymer tubes, but everyone is searching for ways to contain supply prices without cutting into margins. Jim Walton of SF Medical (Watford, UK) suggests the most effective way to keep costs down is to provide the best tubing for the job, and to get it right the first time. "It puts a burden on us to make sure we communicate well. It's not enough just to give a quotation; we need to work with our customers to understand their needs."

Other suppliers seek to trim costs by streamlining their operations. "We try to improve efficiency through new manufacturing techniques and waste reduction," says Dermot Kelly of TFX Medical (Annacotty, Ireland). "A lot comes down to production efficiency." Bischak agrees, adding, "We've put a very aggressive cost-reduction program in place, and we've been able to make dramatic efficiency improvements." Volume increases naturally help, and device manufacturers who can take advantage of economies of scale will experience the greatest cost savings.

Regulatory concerns exert an influence on the market as well. Strictly speaking, most types of tubing don't have to comply with regulatory standards and directives because they are supplied as components. Nonetheless, device manufacturers are asking component suppliers for some assurance that their products will contribute to the ultimate compliance of the finished device. "Companies are looking for information regarding specifications, validation, surveys on materials," says Kelly. "Our technical support has increased, and our obligations have increased. In the past, TFX Medical has supplied a certain amount of that information, but now we're being asked for much more." Raychem has experienced the same phenomenon, says Bischak. "We started with USP, then Tripartite, and now ISO standards. At the moment, our customers seem satisfied. If we say our products are USP Class VI, that gives them a high degree of confidence."

Jim Dandeneau of Putnam Plastics (Dayville, CT, USA) considers ISO certification of primary importance in selecting a supplier. "Some people have told us they won't deal with anyone who isn't ISO certified," he explains. "When a manufacturer comes to look at us, he knows that we've got good quality systems in place." Working with ISO-certified suppliers saves device manufacturers time and effort when it comes to subcontractor audits, documentation, and similar concerns.

"Documentation has become one of the major issues," says Leonardo Maghetti of SIFRA EST and Biex (Trieste, Italy), suppliers of PVC tubing. Even small companies, says Maghetti, are emphasizing ISO compliance, QC/QA systems, and a CE-mark orientation. Computerized tracking is also increasingly common. Before all else, says Maghetti, "customers want to see documentation. Only then will they ask you for samples."

Maghetti sees a positive aspect to this trend. "This 'ISO-mania' may result in a sort of natural selection, eliminating [from the medical marketplace] some small companies with an old mentality while helping well-organized medium-sized companies to remain competitive." Maghetti estimates that between 50 and 70% of Italian companies recognize the value of ISO standards and are even willing to go beyond the minimum requirements. On the downside, Maghetti expresses concern that NHS organizations are reluctant to pay more for this intense certification. "You have to quote the same price you were charging one or two years ago, but with additional documentation. Obviously that increases costs, but no one is willing to pay the difference."

Most tubing suppliers agree that in such a competitive market, it's important to work closely with customers on a technical level and to try to understand all aspects of the application. As Walton puts it, "You need to know what they're trying to make and where it's going to be sold." Suppliers and manufacturers, he says, must maintain an open dialogue in order to concentrate on those attributes that are most important. Tube manufacturers typically supply products worldwide, and though many concerns are the same from country to country, some markets impose slightly different restrictions. A knowledgeable supplier can help manufacturers avoid compliance problems down the road. "For example, we can help if we know the products are going to the US," says Walton, "because we know what FDA wants in terms of testing."

Whether you're looking for a tubing supplier with expertise in a particular market, a specific material, or simply one who can fill your order at a reduced cost, you might begin by contacting some of the following providers. All of them have a core focus on medical manufacturing.

Putnam Plastics

"Certainly, the trend is toward smaller components--manufacturers want to make smaller catheters that go where they haven't gone before," observes Jim Dandeneau, president of Putnam Plastics (Dayville, CT, USA). Size 3 and 4 French catheters, he says, are becoming the norm, at least for the cardiovascular market. Naturally, tubes of such miniature dimensions are quite difficult to extrude. Consistent wall thickness, for example, is tricky to maintain when walls are in the range of just 1/1000 in. Moreover, Dandeneau explains, "It's very difficult to keep from having pinholes or breakaways when you've got walls that thin." Standard equipment can't handle the job, he says, and his engineers have had to develop systems to accommodate such extremely small diameters. "But that's kind of our emphasis," he adds. "We're really attuned to the shift toward smaller and smaller tubes." Better frictional performance is currently one of the top challenges. Anticipating market needs, Putnam has recently introduced a line of USP Class VI polyimide tubing. "It's a very strong material," Dandeneau says, that can be extruded with IDs ranging from 0.0075 to 0.080 in. with very good integrity. Walls ranging from 0.0007 to 0.005 in. thick can be produced with no pinholes. Putnam's polyimide tubing has a frictional coefficient of 0.05, a dielectric strength of 4000 V/mil, a thermal endurance rating of 400°C, and a tensile strength of 20,000 psi. Moreover, the inert transparent tubing exhibits good radiation resistance. "We're looking at combining it with thermoplastic resins," Dandeneau says, "to form multilayer constructions." Putnam's QA systems are certified to ISO 9002--a necessity for the market they target. "We consider ourselves to be at the higher end of the technology," Dandeneau says. "We're not high volume--cost is not the major issue with us, quality is."

Solvay Draka

Widely known as a supplier of plastic films and lay-flat tubing, Solvay Draka (Enkhuizen, The Netherlands) is also highly specialized in the development of small-bore tubing. One of the company's particular areas of expertise, according to Paul Palthe, is coextruded tubing. Manufacturers can select from combinations of polyvinyl chloride and polyethylene, EVA and PVC, PVC and PUR, or PA and PVC. Multilayer tubes consisting of various EVA layers can also be produced. "The most important reason for using coextruded tubing," Palthe explains, "is that it enables the manufacturer to make the most reliable and efficient connection between a port or connector and the inner surface of the tubing." Solvay Draka also produces specialty tubing for steam sterilization, which can be autoclaved at 121°C, in line with most pharmacopoeia. The company's Solmed line of custom-fabricated semifinished products is marketed around the globe for applications ranging from IV-solution bags to infusion sets. Standard items include pump tubing and laser-printed tubing as well as the crystal-clear Medituub S line.

SIFRA EST/Biex

The SIFRA EST group consists of two complementary companies. SIFRA EST specializes in polyvinyl chloride compounding, lay-flat tube extrusion, and bag welding, while Biex concentrates on tube extrusion. Both companies were recently consolidated in Trieste, Italy, partly to contain costs. Like most suppliers of commodity tubing, SIFRA EST has felt considerable pressure to keep prices low. Cost concerns have even eclipsed toxicity issues in the market for medical-grade polyvinyl chloride. "The NHS is really concerned by prices," says Leonardo Maghetti. "We can supply infusion bags and tubing in materials other than PVC, but in the end they will cost probably twice as much, and the hospitals are not willing to pay the difference." Users are not necessarily more comfortable with PVC, he suggests, they just don't want to give up the cost and performance advantages. Of course, Maghetti can offer assurances to anyone still troubled by PVC. Each batch of product is accompanied by a certificate of conformity from the company's chemical lab, which has been authorized to issue these documents by the Italian Ministry of Health. The chemical lab is also responsible for controlling incoming raw materials. Moreover, various quality documents such as Drug Master Files, Device Master Records, and biocompatibility testing results are available upon request. "We produce exclusively medical-grade PVC," Maghetti adds, "so our machines can't be contaminated by non-medical-grade materials." Formulations have been implant-tested and meet USP Class VI criteria. In addition to a vast range of standard PVC tubes, the company can extrude and coextrude materials such as polyethylene, PUR, and EVA. The production facilities at SIFRA EST are geared for cost-competitive high-volume output, housing 1 compound extrusion line, 4 lay-flat tube lines, 4 standard tubing lines, and 8 bag-welding lines.

SF Medical

Drawing upon more than 40 years of experience, SF Medical (Watford, UK) designs and manufactures platinum- and peroxide-based silicone tubing for diverse applications worldwide. "We offer a broad range of proprietary items," says Jim Walton, "manufactured to meet the most stringent quality requirements." The company is fully accredited to ISO 9001, and the manufacturing facility is FDA registered. Although the company places heavy emphasis on quality, product engineers are still sensitive to the need to keep supply costs as low as possible. That's why Walton stresses good communication with customers: "It's a competitive market--you need to know what clients are trying to make and where it's going to be sold." Product engineers have an easier time when they know what sort of documentation and traceability will be required, what sort of testing procedures will be employed, and the end use of the product, he adds. SF Medical's dedicated manufacturing facility is equipped for moulding, die-cutting, braiding, and extruding. Advanced laser-based measuring instruments and SPC protocols help to ensure uniformity and product integrity. All products and devices are manufactured to strict GMP requirements, meet USP Class VI specifications, and are CE marked.

TFX Medical

Dermot Kelly, product manager at TFX Medical (Annacotty, Ireland), sees several forces shaping the industry for high-end medical tubing. "One of the key concerns is the Medical Devices Directive and all the regulatory requirements that it brings," he says. TFX Medical operates three related divisions focusing on precision and braided tubing, vascular-access components, and OEM guidewires. Accreditation is important in these market segments, Kelly points out, noting that his facility is ISO 9001 certified. TFX Medical's standard products include braided tubing, which is primarily intended for use in high-torque and high-pressure applications in cardiology and radiology. Nylon, Pebax, and PUR tubes can be specified with round wire as small as 0.001 in. diam or flat wire measuring 0.001 in. thick by 0.003 in. wide. Various radiopaque fillers can be added. Standard ID and OD tolerances can be kept to ±0.001 in. Standard diameters range from 4 to 8 French with walls as thin as 0.007 in. As for precision tubing, TFX Medical can produce single- and multiple-lumen designs from polyethylene, nylon, Pebax, FEP, PTFE, and PUR. "Our production capabilities and expertise, combined with our in-house compounding, ensure that we can produce tubing to exacting requirements," Kelly says. Those production capabilities achieve tolerances on the order of ±0.0001 in. for IDs ranging from 0.015 to 0.300 in. and ODs from 0.025 to 0.350 in.; tolerances for wall thickness can be kept to ±0.0005 in. Clear and radiopaque tubes can be provided as well as striped encapsulated tubes.

Gessil

"Tubing is our specialty but we also offer finished products," says Alain Climaud, marketing manager at Gessil (St. Quentin-Fallavier, France). Gessil can meet most needs for standard tubing, but specialty products are where its expertise shines through. "We supply tubes with colourants, technical tubing, double lumens, triple lumens on a regular basis." Gessil, Climaud adds, has been a leading source for silicone rubber products for almost 20 years and is well attuned to the concerns of medical manufacturers. Customers can expect thorough documentation concerning material specifications and tolerances. Stringent selection and inspection of materials ensures conformity with various international standards. Climaud notes that the demand for smaller tubing is growing, and that Gessil is currently working with tube dimensions on the order of 0.3­0.6 mm. Gessil was granted ISO 9002 certification in 1993 and EN 46002 certification in 1995. As a result, the company now offers CE marking on its Silmedic products. Manufacturers of devices that incorporate Silmedic products, Climaud says, will have an easier time obtaining their own certification. The Silmedic line includes standard and close-tolerance tubing as well as drains, feeding tubes, vascular loops, CPB tubing, and connectors. Reusable corrugated respiratory tubing and various types of catheters are also available. Products can be platinum cured or fabricated in peroxide silicone.

Minitubes

In response to what he calls "the present explosion of stent usage in Europe," Philippe Poncin of Minitubes (Grenoble, France) offers some guidelines to help designers and manufacturers specify the appropriate metal tubing for the job. To begin with, the biocompatibility of the base material "should not be altered by the manufacturer's fabrication processes," says Poncin. Tubes must exhibit ductility and mechanical resistance "to permit expansion and to resist collapsing once in place," he adds. Fatigue resistance, he advises, is particularly important for coronary stents exposed to the stress of heartbeats. Tubes must also be free from "localized defects that might cause a rupture of the very fine metal structure during or after implantation." And finally, an optimal surface finish is required on both the outer and inner surfaces to minimize clotting. "To meet these requirements and to offer safe and reliable materials to stent designers and manufacturers, Minitubes has developed proprietary processes," says Poncin. He cites as examples focused quality assurance plans covering raw material selection, process control, product testing, and certification. Minitubes can supply stent tubing in various alloys, including vacuum-melted 316L stainless steel and tantalum, which offers "outstanding radiopacity, ductility, and biocompatibility." Stent tubes can also be produced in Phynox, which is a patented cobalt-based alloy, and nickel-titanium alloys, which offer unique shape-memory and superelasticity properties.

Optinova AB

One of the world's leading suppliers of tubing for intravenous catheters, according to marketing manager Nils Manelius, Optinova AB extrudes small-diameter transparent and radiopaque tubing in a variety of materials, but the company has particular expertise processing fluoropolymers. "Extrusion of fluoropolymers requires special know-how," says Manelius. "You can't do it by using the ordinary extrusion methods. The materials are quite aggressive and you need to use special alloys." Tubing is produced at very close tolerances in PTFE and such thermoplastic fluoropolymers as FEP, PFA, ETFE, and PVDF. In addition to intravenous catheters, typical applications include central venous catheters, angioplasty catheters, and angiography and analytical instruments. The company also supplies protection tubing with client-specified profiles, and multilumen, coextruded, striped, and braided tubing in a wide choice of materials. The company adheres to the principles of good manufacturing practices and was recently certified to ISO 9002. "We are putting even more resources into quality management," says Manelius, "because today it is a necessity. You will lose customers if you don't have the appropriate systems in place." A loss of market share, however, does not appear to be in the cards for Optinova. "We have hit the ceiling in production capacity," adds Manelius, "and we will expand our production facility and add more cleanroom space."

Raychem

"We're the world's largest supplier of heat-shrink tubing," declares Greg Bischak of Raychem (Swindon, UK). "We pioneered that technology." In 1993, Raychem introduced the Altera line of medical-grade heat-shrink tubing. Bischak recalls, "We had three products at the time, and we've been expanding that line ever since. Our focus has been device manufacturers, as opposed to end-users, and our market is a reflection of their end market." Bischak cites a recent trend, partly spurred by cost considerations, toward reusable instruments--not just in Europe, but in the United States as well. Responding to the market, "We've tried to define products that will suit those applications, introducing cost-competitive reusable materials that are robust enough for autoclaving." As an example of a market-driven product, Bischak points to the Altera MT 2000 line, which has almost the same capabilities as FEP and Teflon products but at a much lower cost. Moreover, Altera MT 2000 heat-shrink tubing can be gamma sterilized. "That's an example of listening to market pressure for cost and for functionality, and then developing something that meets those needs," he says. Recent technical innovations have led to a new Altera product--heat-shrink tubing with an adhesive lining. Both the tubing and the adhesive meet USP Class VI requirements. When heat is applied, the tubing's outer jacket shrinks and the inner adhesive flows, sealing and bonding to the substrate to create a barrier to fluids and bioburden. The tubing is suitable for strain relief and component joining and for sealing reusable instruments to prevent tissues and fluids from seeping between the tubing and the instrument.

Zeus

Zeus (Rhose-St.-Genese, Belgium) ranks global distribution capabilities and market penetration among the most important qualities of a tubing supplier. It's not surprising, then, that Zeus USP Class VI fluoropolymer tubing is recognized by device manufacturers around the world. The company's PTFE Sub-Lite-Wall microminiature tubing rates as the world's smallest fluoropolymer tubing, according to the company. Produced in IDs as small as 0.001 in. with walls as thin as 0.0015 in., Sub-Lite-Wall tubing is also available in a heat-shrink version with shrink ratios up to 4:1 or greater to meet unique design requirements. Etching is also available on most products and can be done on the inner bore, outer surface, or both. Zeus also extrudes a number of other high-performance resins such as polyethylene, FEP, PFA, PVDF, ETFE, and PEEK. All products are manufactured in accordance with SPC and Cpk standards in over 9000 sq ft of Class 10,000 cleanrooms.